Nursing Theory Lecture 3: Dorothea Orem

Dorothea Orem 

(1970, 1985) 

Self-Care Deficit Theory 

Self-Care Deficit Theory 
•Defined Nursing: “The act of assisting others in the provision and management of self-care to maintain/improve human functioning at home level of effectiveness.”
•Focuses on activities that adult individuals perform on their own behalf to maintain life, health and well-being.
•Has a strong health promotion and maintenance focus.
•Identified 3 related concepts:
1.Self-care - activities an Individual performs independently throughout life to promote and maintain personal well-being.
2.Health - results when self-care agency (Individual’s ability) is not adequate to meet the known self-care needs.
3.Nursing System - nursing interventions needed when Individual is unable to perform the necessary self-care activities:
          Wholly compensatory - nurse provides entire self-care for the client. (Example: care of a new born, care of client recovering from surgery in a post-anesthesia care unit)
          Partial compensatory - nurse and client perform care; client can perform selected self-care activities, but also accepts care done by the nurse for needs the client cannot meet independently. (Example: Nurse can assist post operative client to ambulate, Nurse can bring a meal tray for client who can feed himself)
          Supportive-educative - nurse’s actions are to help the client develop/learn their own self-care abilities through knowledge, support and encouragement. (Example: Nurse guides a mother how to breastfeed her baby, Counseling a psychiatric client on more adaptive coping strategies.)

Nursing Theory Lecture 2: Betty Neuman

Betty Neuman 

(1972, 1982, 1989, 1992) 

Health Care System Model 

The Neuman System Model or Health Care System Model 
• Stress reduction is a goal of system model of nursing practice. Nursing actions are in primary, secondary or tertiary level of prevention.
• To address the effects of stress and reactions to it on the development and maintenance of health. The concern of nursing is to prevent stress invasion, to protect the client’s basic structure and to obtain or maintain a maximum level of wellness. The nurse helps the client, through primary, secondary, and tertiary prevention modes, to adjust to environmental stressors and maintain client stability.
Metaparadigm

Person 
• A client system that is composed of physiologic, psychological, sociocultural, and environmental variables.

Environment 
• Internal and external forces surrounding humans at any time.

Health
• Health or wellness exists if all parts and subparts are in harmony with the whole person.

Nursing 
• Nursing is a unique profession in that it is concerned with all the variables affecting an individual’s response to stressors.

Nursing Theory Lecture 1: Introduction

Nursing 

As defined by the INTERNATIONAL COUNCIL OF NURSES as written by Virginia Henderson.
• The unique function of the nurse is to assist the individual, sick or well, in the performance of those activities contributing to health, it’s recovery, or to a peaceful death the client would perform unaided if he had the necessary strength, will or knowledge.
• Help the client gain independence as rapidly as possible.

Nursing Theory 

Over the years, nursing has incorporated theories from non-nursing sources, including theories of systems, human needs, change, problem solving, and decision making. Barnum defines theory as “a construct that accounts for or organizes some phenomenon. A nursing theory, then, describes or explains nursing.”

With the formulation of different theories, concepts, and ideas in nursing it:
• It guides nurses in their practice knowing what is nursing and what is not nursing.
• It helps in the formulations of standards, policies and laws.
• It will help the people to understand the competencies and professional accountability of nurses.
• It will help define the role of the nurse in the multidisciplinary health care team.

Four Major Concepts 

Nurses have developed various theories that provide different explanations of the nursing discipline. All theories, however, share four central concepts: Person refers to all human beings. People are the recipients of nursing care; they include individuals, families, communities, and groups. Environment includes factors that affect individuals internally and externally. It means not only in the everyday surroundings but all setting where nursing care is provided. Health generally addresses the person’s state of well-being. The concept of Nursing is central to all nursing theories. Definitions of nursing describe what nursing is, what nurses do, and how nurses interact with clients. Most nursing theories address each of the four central concepts implicitly or explicitly.

Fundamentals of Nursing Drill #3

Test your knowledge on concepts in Fundamentals of Nursing. Get a piece of paper and a pen. Answer the following questions and check your answers. Be sure to read the rationale behind the correct answer. If you find something difficult check out of Fundamentals of Nursing Lecture Notes for quick review or browse your books.

1. The nurse is preparing to move an adult who has right-sided paralysis from the bed to the wheelchair. Which statement describes the best action for the nurse to take?
a. position the wheelchair on the left side of the bed
b. keep the head of the bed elevated at 10o
c. protect the client’s left arm with a sling during the transfer
d. bend at the waist while helping the client into a standing position


2. Which statement by the nurse best indicates a correct understanding of “log rolling” when moving a client?
a. one nurse may perform this task alone
b. pillows are needed for positioning in order to provide support
c. the legs should be moved before the head is moved
d. keeping the neck in a straight position is the primary concern


3. The nurse is caring for a client who has temperature of 105oF (40.50C). The physician orders the application of a cooling blanket. The nurse should know that which of the following statements is true about the use of a cooling blanket?
a. cold application will increase the metabolic rate
b. vital signs should be monitored every 8 hours
c. the client should remain in one position to conserve energy
d. skin hygiene and protection of body surface areas is essential


4. The nurse is preparing to administer a sponge bath to an infant with a high fever. Administration of the bath should include:
a. large amounts of alcohol to increase evaporation of heat
b. adjustment of the water temperature to 60-70 0F
c. wet clothes applied to all areas where blood circulates close to skin surfaces
d. small areas of the body sponged at a time to avoid rapid heat loss


5. The nurse is instructing the family of a homebound bedridden client in the general prevention of pressure sores. Measures to include in the teaching include:
a. promoting lifting rather than dragging when turning the client
b. massaging directly over pressure sites
c. changing the client’s position every 4 hours
d. cleaning soiled areas with hot water


6. Which of the following findings would the nurse note when assessing a client with Stage I pressure ulcer? The ulcer displays:
a. superficial skin breakdown c. subcutaneous damage or necrosis
b. deep pink, red, or mottled skin d. damage to muscle or bone


7. An adult has developed a Stage II pressure ulcer. He is scheduled to receive wet to dry dressings every shift. The nurse realizes that the purpose of receiving this type of dressing is to:
a. draw in wound exudate and decrease bacteria
b. debride slough and eschar
c. promote healing by gas exchange
d. promote a moist environment and soften exudate


8. The nurse is performing a wound irrigation and dressing change. Which action, when taken by the nurse, would be a break in the technique?
a. consistently facing the sterile field
b. washing hands before opening the sterile set
c. opening the bottle of irrigating solution and pouring directly into a container on the sterile field
d. opening the sterile set so that the initial flap is opened away from the nurse


9. Total Parenteral Nutrition (TPN) is ordered for an adult client. The nurse expects the solution will contain all of the following nutrients except:
a. dextrose 10% c. electrolytes
b. trace minerals d. amino acids


10. The nurse caring for an adult client who is receiving TPN will need to monitor him for which of the following metabolic complications:
a. hypocalcemia and hypercalcemia c. hyperglycemia and hyperkalemia
b. hyperglycemia and hypokalemia d. hyperkalemia and hypercalcemia


11. The nurse is caring for a client who is receiving IV fluids. Which observation the nurse makes best indicates the IV has infiltrated?
a. pain at the site
b. a change in flow rate
c. coldness around the insertion site


12. Within 20 minutes of the start of transfusion, the client develops a sudden fever. The most appropriate initial response by the nurse is to:
a. force fluids c. increase the flow rate of IV fluids
b. continue to monitor the vital signs d. stop the transfusion


13. The nurse is caring for a client who has had a chest tube inserted and connected to water seal drainage. The nurse determines the drainage system is functioning correctly when which of the following is observed?
a. continuous bubbling in the water seal chamber
b. fluctuation in the water seal chamber
c. suction tubing attached to a wall unit
d. vesicular breath sounds throughout the lung fields


14. The nurse is caring for a client who has just had a chest tube attached to a water seal drainage system. To ensure that the system is functioning effectively the nurse should:
a. observe for intermittent bubbling in the water seal chamber
b. flush the chest tubes with 30-60 ml of NSS every 4-6 hours
c. maintain the client in an extreme lateral position
d. strip the chest tubes in the direction of the client


15. The nurse enters the room of a client who has a chest tube attached to a water seal drainage system and notices the chest tube is dislodged from the chest. The most appropriate nursing intervention is to:
a. notify the physician
b. insert a new chest tube
c. cover the insertion site with petroleum gauze
d. instruct the client to breathe deeply until help arrives


16. A patient is ordered oxygen via nasal prongs. The nurse administering oxygen via this low-flow system recognizes that this method of delivery:
a. mixes room air with oxygen
b. delivers a precise concentration of oxygen
c. requires humidity during delivery
d. is less traumatic to the respiratory tract


17. An adult is receiving oxygen by nasal prongs. Which statement by the client indicates that the client teaching regarding oxygen therapy has been effective?
a. “I was feeling fine so I removed my nasal prongs.”
b. “I’ve increased my fluids to six glasses of water daily.”
c. “Don’t forget to come back quickly when you get me out of bed; I don’t like to be without my oxygen for too long.”
d. “My family was angry when I told them they could not smoke in my room.”


18. An adult client has a nasogastric tube in place to maintain gastric decompression. Which nursing action will relieve discomfort in the nostril with the NG tube?
a. remove any tape and loosely pin the tube to his gown
b. lubricate the NG tube with viscous xylocaine
c. loop the NG tube to avoid pressure on the nares
d. replace the NG tube with a smaller diameter tube


19. An adult client has just returned to his room following a bowel resection and end-to-end anastomosis. The nurse can expect the drainage from the NG tube in the early post-op period to be:
a. Clear        c. Scant
b. Mucoid    d. Discolored


20. The physician inserts a central venous catheter; the nurse should assist the client to assume which of the following positions?
a. supine                     c. reverse trendelenburg’s
b. trendelenburg’s        d. high fowler’s

Fundamentals Drill #2

Test your knowledge on concepts in Fundamentals of Nursing. Get a piece of paper and a pen. Answer the following questions and check your answers. Be sure to read the rationale behind the correct answer. If you find something difficult check out of Fundamentals of Nursing Lecture Notes for quick review or browse your books.

1. A nurse is reviewing the diagnostic tests prescribed for a client. The nurse notes that a lupus cell preparation (LE cell prep) has been ordered. The nurse determines that this test is used to screen primarily for which of following disorders?
a. Histoplasmosis
b. Systemic lupus erythematosus (SLE)
c. Human immunodeficiency virus (HIV)
d. Progressive systemic sclerosis

2. The nurse is caring for a hospitalized client with acquired immunodeficiency syndrome (AIDS) who is receiving didanosine (Videx). The nurse contacts the physician if which laboratory result is noted that may be an indication of potential pancreatitis?
a. Increased potassium
b. Increased serum triglycerides
c. Increased blood urea nitrogen
d. Increased creatinine

3. A client seeks treatment for a fractured radius. There is an open wound on the arm through which jagged bone edges protrude. The nurse determines that the client has a
a. Greenstick fracture
b. Comminuted fracture
c. Open fracture
d. Simple fracture

4. The client has been admitted to the hospital with a fractured pelvis sustained in a motor vehicle accident. The nurse monitors for complications and assesses the client most closely for which of the following complications in the early post-trauma period?
a. Bradycardia
b. Pain
c. Hematuria
d. Fever

5. The nurse is monitoring a client with a head injury for signs of increased intracranial pressure. Which finding indicates an early sign of increased intracranial pressure?
a. Increase in systolic blood pressure
b. Decreasing level of consciousness
c. Shallow, slow respirations
d. Decrease in pulse rate

6. The nurse is performing an assessment on a client with a diagnosis of Bell’s palsy. The nurse would expect to observe which of the following symptoms in the client?
a. Twitching on the affected side of the face
b. Ptosis of the eyelid and closure of the eye
c. Facial drooping
d. Periorbital edema

7. A client with a diagnosis of multiple myeloma is admitted to the hospital. On assessment, the nurse asks the client which question that specifically relates to a clinical manifestation of this disorder?
a. "Are you having any bone pain?"
b. "Do you have diarrhea?"
c. "Have you noticed an increase in appetite?"
d. "Do you have feelings of anxiety and nervousness, together with difficulty sleeping?"

8. The nurse is preparing to care for a client with a diagnosis of metastatic cancer and notes documentation in the client’s chart that the client is experiencing cachexia. Which of the following would the nurse expect to note on assessment of the client?
a. Sunken eyes and a hollow cheek appearance
b. Periorbital edema and swelling around the ears
c. Generalized edema and the presence of weight gain
d. Increased blood pressure and ascites

9. A nurse is caring for a client receiving hemodialysis who has an internal arteriovenous fistula. The nurse expects to note which finding if the fistula is patent?
a. White fibrin specks noted in the fistula
b. Palpation of a thrill over the site of the fistula
c. Lack of a bruit at the site of the fistula
d. Warmth and redness at the site of the fistula

10. A physician's office nurse is assessing a client who recently had a renal transplant. The nurse monitors for which signs of acute graft rejection?
a. Hypotension, graft tenderness, and anemia
b. Hypertension, oliguria, thirst, and hypothermia
c. Fever, vomiting, hypotension, and copious amounts of dilute urine
d. Fever, hypertension, graft tenderness, and malaise

11. A nurse is caring for a client with a tracheostomy tube who is receiving mechanical ventilation. The nurse is monitoring for complications related to the tracheostomy and suspects tracheoesophageal fistula when
a. Suctioning is required frequently
b. Excessive secretions are suctioned from a tracheostomy
c. The client’s skin and mucous membranes are light pink
d. Aspiration of gastric contents occurs during suctioning

12. A nurse is performing a cardiovascular assessment on a client with heart failure. Which of the following items would the nurse assess to gain the best information about the client’s left-sided heart function?
a. Breath sounds
b. Peripheral edema
c. Jugular vein distention
d. Hepatojugular reflux

13. A nurse suctioning a client through an endotracheal tube monitors the client for complications associated with the procedure. Which of the following indicates a complication?
a. A blood pressure of 138/88 mm Hg
b. An irregular heart rate
c. A reddish coloration in the client's face
d. A pulse oximetry level of 95%

14. An emergency department nurse is assessing a client who sustained a blunt chest injury and suspects the presence of flail chest. Which specific characteristic finding would the nurse note in this condition?
a. Slow deep respirations
b. Asymmetric chest movement
c. Loss of consciousness
d. Anxiety

15. A nurse is caring for a client with a tracheostomy tube and is monitoring the client for subcutaneous emphysema. The nurse identifies this complication by noting which of the following?
a. Crackling sounds heard in the upper lobes bilaterally
b. A puffy and crackling sensation on palpation of the tissues surrounding the tracheostomy site
c. Signs of respiratory distress
d. Dyspnea

16. A nurse is monitoring a client with a tracheostomy tube for complications related to the tube. The nurse suspects tracheoesophageal fistula if which of the following is noted?
a. Abdominal distention
b. Excess mucus production
c. Abnormal skin and mucous membrane color
d. Use of accessory muscles to assist with breathing
.
17. A nurse is assessing a client who was treated for an asthma attack. The nurse determines that the client's respiratory status has worsened if which of the following is noted?
a. Loud wheezing
b. Wheezing during inspiration and expiration
c. Wheezing on expiration only
d. Diminished breath sounds

18. A nurse is reviewing the assessment findings and laboratory results of a child diagnosed with new-onset glomerulonephritis. Which of the following findings would the nurse most likely expect to note?
a. Increased creatinine levels
b. Hypotension
c. Low serum potassium
d. Tea-colored urine

19. A nurse is reviewing the record of an infant admitted to the newborn nursery. The nurse notes that the physician has documented bladder exstrophy. On assessment of the infant, the nurse expects to note which of the following?
a. Undescended or hidden testes
b. The opening of the urethral meatus below the normal placement on the glans penis
c. The opening of the urethral meatus on the ventral side of the glans penis
d. The urinary bladder on the outside of the body


20. A newborn infant with a diagnosis of subdural hematoma is admitted to the newborn nursery. The nurse does which of the following to assess for the major symptom associated with subdural hematoma?
a. Checks for contractures of the extremities
b. Tests for equality of extremities when stimulating reflexes
c. Monitors the urinary output pattern
d. Monitors the urine for blood

Fundamentals of Nursing Drill #1

Test your knowledge on concepts in Fundamentals of Nursing. Get a piece of paper and a pen. Answer the following questions and check your answers. Be sure to read the rationale behind the correct answer. If you find something difficult check out of Fundamentals of Nursing Lecture Notes for quick review or browse your books.

1. A nurse is assessing the extent of pitting edema in a client with congestive heart failure. The nurse gently presses a finger on the client's ankle and notes a barely perceptible pit. The nurse interprets this finding as which measurement of pitting edema?
a. 1+
b. 2+
c. 3+
d. 4+


2. The nurse notes documentation that a client's peripheral pulses are +3. The nurse determines that the pulses are
a. Full and brisk
b. Absent
c. Normal or average
d. Palpable, but diminished


3. A nurse is reviewing a client’s record and notes that the results of the client’s vision test using a Snellen chart is 20/50. The nurse interprets this to mean that the client
a. Has normal vision
b. Has minimal visual
c. Can read at a distance of 20 feet what a client with normal vision can read at 50 feet
d. Can read at a distance of 50 feet what a client with normal vision can read at 20 feet

4. A prenatal client tells the nurse that she is really worried about knowing how to care for her first-born child. The nurse formulates which nursing diagnosis for this client?
a. Ineffective Coping
b. Dysfunctional Grieving
c. Situational Low Self-esteem
d. Deficient Knowledge

5. The nurse notes documentation that a client has the presence of cherry angiomas located on the abdomen. On assessment of the client, the nurse would expect to note which characteristic of this skin lesion?
a. Ruby red papules
b. Thickened skin areas
c. Pinpoint-sized red or purple spots
d. Areas of redness warm to touch

6. A nurse is assessing the risk factors for acquiring pneumonia during hospitalization for a group of clients. The nurse determines that which of the following clients is at lowest risk?
a. An older client with diabetes mellitus
b. A client with human immunodeficiency virus (HIV)
c. A client with a spinal cord injury who is immobile
d. A postoperative client who is ambulating

7. A nurse working in a prenatal clinic is reviewing the records of clients scheduled for prenatal visits. The nurse interprets that the client at greatest risk for abruptio placenta is the one who
a. Is 26 years old and is a primipara
b. Rides an exercise bike for 30 minutes 3 times weekly
c. Has maternal hypertension
d. Takes folic acid supplements daily

8. The nurse teaches a client with gastroesophageal reflux disease (GERD) about the measures to prevent reflux while sleeping. The nurse determines that the client needs additional instructions if the client states
a. "I shouldn't eat anything at bedtime."
b. "I should take an antacid at bedtime."
c. "I should sleep flat on my right side."
d. "Losing weight will decrease some of the stomach pressure."

9. A nurse provides instructions to a client about the measures to treat gout. The nurse determines that the client needs additional instructions if the client states that
a. The intake of red meats needs to be limited.
b. Weight loss can help prevent an attack.
c. Medication can help keep the uric acid level down.
d. Fluid intake needs to be limited.

10. A nurse provides instructions to a client who is being discharged 24 hours after undergoing a percutaneous renal biopsy. Which statement by the client indicates a need to reinforce the instructions?
a. "I need to avoid any strenuous lifting for about two weeks."
b. "I shouldn't work out at the gym for about two weeks."
c. "I will call the physician if my urine becomes bloody."
d. "A fever is normal after this procedure."

11. A clinic nurse has provided instructions to the mother of a child with a urinary tract infection. Which statement by the mother indicates a need for further instructions?
a. "I should wipe my child from front to back after urination or a bowel movement."
b. "I should increase my child's fluid intake."
c. "I should encourage my child to hold the urine and to urinate at least four times a day."
d. "I should avoid the use of bubble baths with my child."

12. A nurse provides dietary instructions to a client with hypertension. The nurse determines that the client understands the instructions if the client states that it is acceptable to eat which of the following food items?
a. Hot dogs
b. Turkey
c. Salad with blue cheese dressing
d. Corned beef hash

13. The nurse is providing dietary instructions to a client with ascites who will be discharged to home from the hospital. The nurse determines that the client understands the instructions if the client states that it is acceptable to eat which food item?
a. Canned green beans
b. Fresh plums
c. Cooked ham
d. Bologna


14. A nurse has provided instructions to a client with chronic obstructive pulmonary disease about the procedure for performing pursed lip breathing. The nurse observes the client perform the procedure and determines that he or she is performing it correctly if the client
a. Takes a deep breath and exhales quickly
b. Monitors inspiration time and ensures that expiration time is less than inspiration time
c. Lies on the side in a supine position to perform the procedure
d. Sits in an upright position, takes a deep breath, and exhales slowly


15. A nurse has completed discharge teaching with the family of a client who requires dressing changes at home. Which method of evaluation would the nurse use to best determine the family’s competence in performing the dressing changes?
a. Asking a family member to perform the dressing change and observing the procedure
b. Asking a family member to identify the supplies needed to perform the dressing change
c. Asking a family member to list the steps of the procedure for performing the dressing change
d. Asking a family member to verbalize the procedure for performing the dressing change


16. A nurse is teaching a client diagnosed with iron deficiency anemia about the foods that are high in iron. The nurse tells the client to consume which high-iron food?
a. Refined white bread
b. Egg whites
c. Mushrooms
d. Spinach

17. A clinic nurse provides instructions to a woman in the second trimester of pregnancy regarding measures to relieve backache. Which statement by the client indicates an understanding of these measures?
a. "I will sleep on a soft mattress."
b. "I will avoid doing those pelvic tilt exercises."
c. "I will avoid getting tired, and I should work at maintaining a good posture."
d. "I will wear shoes with a heel of at least 2 inches."


18. A prenatal client reports heartburn, and the nurse provides instructions to the client regarding measures to alleviate the discomfort. Which statement by the client indicates a need for further instructions?
a. "I need to eat small, frequent meals."
b. "I need to avoid fatty or spicy foods."
c. "I need to lie down after eating."
d. "I need to drink approximately 2000 mL fluid per day."


19. During the administration of a blood transfusion to a client, the nurse notes the presence of crackles in the client’s lung bases. On further assessment, the nurse notes that the client has distended neck veins and an increase in central venous pressure. The nurse suspects that the client is experiencing what complication of the blood transfusion?
a. Transfusion reaction
b. Allergic reaction
c. Sepsis
d. Circulatory overload


20. A client with type 1 diabetes mellitus has a blood glucose level of 554 mg/dL. The nurse calls the physician to report the level and monitors the client closely for which acid-base imbalance?
a. Respiratory acidosis
b. Respiratory alkalosis
c. Metabolic acidosis
d. Metabolic alkalosis

Health Assessment Lecture: Respiratory System A

Good assessment skill is paramount in providing quality nursing care. There is the reason why Assessment is the first step in the nursing process and is incorporated in every phase. In assessment nurses can gather pertinent information from the patient's health status so as to have a good overview of the patient's condition to be able to formulate a nursing diagnosis and even help doctors to come up with their medical diagnosis- much more it help the whole health care team.

The health history focuses on the physical and functional problems of the patient and the effect of these problems on his or her life. The reason the patient is seeking health care often is related to one of the following: dyspnea (shortness of breath), pain, accumulation of mucus, wheezing, hemoptysis (blood spit up from the respiratory tract), edema of the ankles and feet, cough, and general fatigue and weakness.

In addition to identifying the chief reason why the patient is seeking health care, the nurse tries to determine when the health problem or symptom started, how long it lasted, if it was relieved at any time, and how relief was obtained. The nurse collects information about precipitating factors, duration, severity, and associated

factors or symptoms and also assesses for risk factors and genetic factors that may contribute to the patient’s lung condition.

The nurse assesses the impact of signs and symptoms on the patient’s ability to perform activities of daily living and to participate in usual work and family activities. In addition, psychosocial factors that may affect the patient are explored. These factors include anxiety, role changes, family relationships, financial problems, employment status, and the strategies the patient uses to cope with them.

Many respiratory diseases are chronic and progressively debilitating. Therefore, ongoing assessment of the patient’s physical abilities, psychosocial supports, and quality of life is needed to plan appropriate interventions. It is important for the patient with a respiratory disorder to understand the condition and to be

familiar with necessary self-care interventions. The nurse evaluates these factors over time and provides education as needed.

Signs and Symptoms

The major signs and symptoms of respiratory disease are dyspnea, cough, sputum production, chest pain, wheezing, clubbing of the fingers, hemoptysis, and cyanosis. These clinical manifestations are related to the duration and severity of the disease.

DYSPNEA

Dyspnea (difficult or labored breathing, shortness of breath) is a symptom common to many pulmonary and cardiac disorders, particularly when there is decreased lung compliance or increased airway resistance. The right ventricle of the heart will be affected ultimately by lung disease because it must pump blood through

the lungs against greater resistance. It may also be associated with neurologic or neuromuscular disorders such as myasthenia gravis, Guillain-Barré syndrome, or muscular dystrophy.

Clinical Significance. In general, acute diseases of the lungs produce a more severe grade of dyspnea than do chronic diseases. Sudden dyspnea in a healthy person may indicate pneumothorax (air in the pleural cavity), acute respiratory obstruction, or ARDS. In immobilized patients, sudden dyspnea may denote pulmonary embolism. Orthopnea (inability to breathe easily except in an upright position) may be found in patients with heart disease and occasionally in patients with chronic obstructive pulmonary disease (COPD); dyspnea with an expiratory wheeze occurs with COPD. Noisy breathing may result from a narrowing of the airway or localized obstruction of a major bronchus by a tumor or foreign body. The presence of both inspiratory and expiratory wheezing usually signifies asthma if the patient does not have heart failure.

The circumstance that produces the dyspnea must be determined. Therefore, it is important to ask the patient the following questions:

• How much exertion triggers shortness of breath?

• Is there an associated cough?

• Is dyspnea related to other symptoms?

• Was the onset of shortness of breath sudden or gradual?

• At what time of day or night does the dyspnea occur?

• Is the shortness of breath worse when the patient is flat in bed?

• Does the shortness of breath occur at rest? With exercise? Running? Climbing stairs?

• Is the shortness of breath worse while walking? If so, when walking how far? How fast?

Relief Measures. The management of dyspnea is aimed at identifying and correcting its cause. Relief of the symptom sometimes is achieved by placing the patient at rest with the head elevated (high Fowler’s position) and, in severe cases, by administering oxygen.

COUGH

Cough results from irritation of the mucous membranes anywhere in the respiratory tract. The stimulus producing a cough may arise from an infectious process or from an airborne irritant, such as smoke, smog, dust, or a gas. The cough is the patient’s chief protection against the accumulation of secretions in the bronchi and bronchioles.

Clinical Significance. Cough may indicate serious pulmonary disease. The nurse needs to evaluate the character of the cough is it dry, hacking, brassy, wheezing, loose, or severe? A dry, irritative cough is characteristic of an upper respiratory tract infection of viral origin or may be a side effect of angiotensin-converting enzyme (ACE) inhibitor therapy. Laryngotracheitis causes an irritative, high-pitched cough. Tracheal lesions produce a brassy cough. A severe or changing cough may indicate bronchogenic carcinoma. Pleuritic chest pain accompanying coughing may indicate pleural or chest wall (musculoskeletal) involvement

The time of coughing is also noted. Coughing at night may herald the onset of left-sided heart failure or bronchial asthma. A cough in the morning with sputum production may indicate bronchitis. A cough that worsens when the patient is supine suggests postnasal drip (sinusitis). Coughing after food intake may

indicate aspiration of material into the tracheobronchial tree. A cough of recent onset is usually from an acute infection.

SPUTUM PRODUCTION

A patient who coughs long enough almost invariably produces sputum. Violent coughing causes bronchial spasm, obstruction, and further irritation of the bronchi and may result in syncope (fainting). A severe, repeated, or uncontrolled cough that is nonproductive is exhausting and potentially harmful. Sputum production is the reaction of the lungs to any constantly recurring irritant. It also may be associated with a nasal discharge.

Clinical Significance. A profuse amount of purulent sputum (thick and yellow, green, or rust-colored) or a change in color of the sputum probably indicates a bacterial infection. Thin, mucoid sputum frequently results from viral bronchitis. A gradual increase of sputum over time may indicate the presence of chronic bronchitis or bronchiectasis. Pink-tinged mucoid sputum suggests a lung tumor. Profuse, frothy, pink material, often welling up into the throat, may indicate pulmonary edema. Foul-smelling sputum and bad breath point to the presence of a lung abscess, bronchiectasis, or an infection caused by fusospirochetal or other anaerobic organisms.

Relief Measures. If the sputum is too thick for the patient to expectorate, it is necessary to decrease its viscosity by increasing its water content through adequate hydration (drinking water) and inhalation of aerosolized solutions, which may be delivered by any type of nebulizer. Strategies to assist the patient to cough productively are discussed later in this chapter.

Smoking is contraindicated with excessive sputum production because it interferes with ciliary action, increases bronchial secretions, causes inflammation and hyperplasia of the mucous membranes, and reduces production of surfactant. Thus, smoking impairs bronchial drainage. When the person stops smoking,

sputum volume decreases and resistance to bronchial infections increases.

The patient’s appetite may decrease because of the odor of the sputum or the taste it leaves in the mouth. The nurse encourages adequate oral hygiene and wise selection of food, measures that will stimulate appetite. In addition, the nurse encourages the patient and family to remove sputum cups, emesis basins, and soiled

tissues before mealtime. Encouraging the patient to drink citrus juices at the beginning of the meal may increase the palatability of the rest of the meal because these juices cleanse the palate of the sputum taste.

CHEST PAIN

Chest pain or discomfort may be associated with pulmonary or cardiac disease. Chest pain associated with pulmonary conditions may be sharp, stabbing, and intermittent, or it may be dull, aching, and persistent. The pain usually is felt on the side where the pathologic process is located, but it may be referred elsewhere—for example, to the neck, back, or abdomen.

Clinical Significance. Chest pain may occur with pneumonia, pulmonary embolism with lung infarction, and pleurisy. It also may be a late symptom of bronchogenic carcinoma. In carcinoma the pain may be dull and persistent because the cancer has invaded the chest wall, mediastinum, or spine.

Lung disease does not always produce thoracic pain because the lungs and the visceral pleura lack sensory nerves and are insensitive to pain stimuli. However, the parietal pleura has a rich supply of sensory nerves that are stimulated by inflammation and stretching of the membrane. Pleuritic pain from irritation of the parietal pleura is sharp and seems to “catch” on inspiration; patients often describe it as “like the stabbing of a knife.” Patients are more comfortable when they lie on the affected side as this splints the chest wall, limits expansion and contraction of the lung, and reduces the friction between the injured or diseased pleurae on that side. Pain associated with cough may be reduced manually by splinting the rib cage.

The nurse assesses the quality, intensity, and radiation of pain and identifies and explores precipitating factors, along with their relationship to the patient’s position. Also, it is important to assess the relationship of pain to the inspiratory and expiratory phases of respiration.

Relief Measures. Analgesic medications may be effective in relieving chest pain, but care must be taken not to depress the respiratory center or a productive cough, if present. Nonsteroidal anti-inflammatory drugs (NSAIDs) achieve this goal and thus are used for pleuritic pain. A regional anesthetic block may be performed to relieve extreme pain.

WHEEZING

Wheezing is often the major finding in a patient with bronchoconstriction or airway narrowing. It is heard with or without a stethoscope, depending on its location. Wheezing is a highpitched, musical sound heard mainly on expiration. 

Relief Measures. Oral or inhalant bronchodilator medications reverse wheezing in most instances.

CLUBBING OF THE FINGERS

Clubbing of the fingers is a sign of lung disease found in patients with chronic hypoxic conditions, chronic lung infections, and malignancies of the lung. This finding may be manifested initially as sponginess of the nailbed and loss of the nailbed angle.

HEMOPTYSIS

Hemoptysis (expectoration of blood from the respiratory tract) is a symptom of both pulmonary and cardiac disorders. The onset of hemoptysis is usually sudden, and it may be intermittent or continuous. Signs, which vary from blood-stained sputum to a large, sudden hemorrhage, always merit investigation. The most common causes are:

• Pulmonary infection

• Carcinoma of the lung

• Abnormalities of the heart or blood vessels

• Pulmonary artery or vein abnormalities

• Pulmonary emboli and infarction

Diagnostic evaluation to determine the cause includes several studies: chest x-ray, chest angiography, and bronchoscopy. A careful history and physical examination are necessary to diagnose the underlying disease, irrespective of whether the bleeding involved a very small amount of blood in the sputum or a massive hemorrhage.

The amount of blood produced is not always proportional to the seriousness of the cause.

First, it is important to determine the source of the bleeding— the gums, nasopharynx, lungs, or stomach. The nurse may be the only witness to the episode. When documenting the bleeding episode, the nurse considers the following points:

• Bloody sputum from the nose or the nasopharynx is usually preceded by considerable sniffing, with blood possibly appearing in the nose.

• Blood from the lung is usually bright red, frothy, and mixed with sputum. Initial symptoms include a tickling sensation in the throat, a salty taste, a burning or bubbling sensation in the chest, and perhaps chest pain, in which case the patient tends to splint the bleeding side. The term “hemoptysis” is reserved for the coughing up of blood arising from a pulmonary hemorrhage. This blood has an alkaline pH (greater than 7.0).

• If the hemorrhage is in the stomach, the blood is vomited (hematemesis) rather than coughed up. Blood that has been in contact with gastric juice is sometimes so dark that it is referred to as “coffee grounds.” This blood has an acid pH (less than 7.0).

CYANOSIS

Cyanosis, a bluish coloring of the skin, is a very late indicator of hypoxia. The presence or absence of cyanosis is determined by the amount of unoxygenated hemoglobin in the blood. Cyanosis appears when there is 5 g/dL of unoxygenated hemoglobin. A patient with a hemoglobin level of 15 g/dL will not demonstrate cyanosis until 5 g/dL of that hemoglobin becomes unoxygenated, reducing the effective circulating hemoglobin to two thirds of the normal level. An anemic patient rarely manifests cyanosis, and a

polycythemic patient may appear cyanotic even if adequately oxygenated. Therefore, cyanosis is not a reliable sign of hypoxia. Assessment of cyanosis is affected by room lighting, the patient’s skin color, and the distance of the blood vessels from the surface of the skin. In the presence of a pulmonary condition, central cyanosis is assessed by observing the color of the tongue and lips. This indicates a decrease in oxygen tension in the blood. Peripheral cyanosis results from decreased blood flow to a certain area of the body, as in vasoconstriction of the nailbeds or earlobes from exposure to cold, and does not necessarily indicate a central systemic problem.

A&P Lecture 4.3: Ventilation Perfusion Ratio

The following picture shows the Ventilation Perfusion Ratio. Please click the picture to be enlarged

Normal Ratio (A)

In the healthy lung, a given amount of blood passes an alveolus and is matched with an equal amount of gas (A). The ratio is 1:1 (ventilation matches perfusion).

Low Ventilation–Perfusion Ratio: Shunts (B)

Low ventilation–perfusion states may be called shuntproducing disorders. When perfusion exceeds ventilation, a shunt exists (B). Blood bypasses the alveoli without gas exchange occurring. This is seen with obstruction of the distal airways, such as with pneumonia, atelectasis, tumor, or a mucus plug.

High Ventilation–Perfusion Ratio: Dead Space (C)

When ventilation exceeds perfusion, dead space results (C). The alveoli do not have an adequate blood supply for gas exchange to occur. This is characteristic of a variety of disorders, including pulmonary emboli, pulmonary infarction, and cardiogenic shock.

Silent Unit (D)

In the absence of both ventilation and perfusion or with limited ventilation and perfusion, a condition known as a silent unit occurs (D). This is seen with pneumothorax and severe acute respiratory distress syndrome.

A&P Lecture 4.2: Gas Exchange

ANATOMY AND PHYSIOLOGY LECTURE 4.2

GAS EXCHANGE

The air we breathe is a gaseous mixture consisting mainly of nitrogen (78.62%) and oxygen (20.84%), with traces of carbon dioxide (0.04%), water vapor (0.05%), helium, and argon. The atmospheric pressure at sea level is about 760 mm Hg. Partial pressure is the pressure exerted by each type of gas in a mixture of gases. The partial pressure of a gas is proportional to the concentration of that gas in the mixture. The total pressure exerted by the gaseous mixture is equal to the sum of the partial pressures.

PARTIAL PRESSURE OF GASES

Based on these facts, the partial pressures of nitrogen and oxygen can be calculated. The partial pressure of nitrogen is 79% of 760 (0.79 × 760), or 600 mm Hg; that of oxygen is 21% of 760 (0.21 × 760), or 160 mm Hg. Chart 21-3 spells out terms and abbreviations related to partial pressure of gases.

Once the air enters the trachea, it becomes fully saturated with water vapor, which displaces some of the gases so that the air pressure within the lung remains equal to the air pressure outside (760 mm Hg). Water vapor exerts a pressure of 47 mm Hg when it fully saturates a mixture of gases at the body temperature of

37°C (98.6°F). Nitrogen and oxygen are responsible for the remaining 713 mm Hg (760 − 47) pressure. Once this mixture enters the alveoli, it is further diluted by carbon dioxide. In the alveoli, the water vapor continues to exert a pressure of 47 mm Hg. The remaining 713 mm Hg pressure is now exerted as follows:

nitrogen, 569 mm Hg (74.9%); oxygen, 104 mm Hg (13.6%); and carbon dioxide, 40 mm Hg (5.3%).

PARTIAL PRESSURE IN GAS EXCHANGE

When a gas is exposed to a liquid, the gas dissolves in the liquid until an equilibrium is reached. The dissolved gas also exerts a partial pressure. At equilibrium, the partial pressure of the gas in the liquid is the same as the partial pressure of the gas in the gaseous mixture. Oxygenation of venous blood in the lung illustrates this point. In the lung, venous blood and alveolar oxygen are separated by a very thin alveolar membrane. Oxygen diffuses across this membrane to dissolve in the blood until the partial pressure of oxygen in the blood is the same as that in the alveoli (104 mm Hg). However, because carbon dioxide is a byproduct

of oxidation in the cells, venous blood contains carbon dioxide at a higher partial pressure than that in the alveolar gas. In the lung, carbon dioxide diffuses out of venous blood into the alveolar gas. At equilibrium, the partial pressure of carbon dioxide in the blood and in alveolar gas is the same.

EFFECTS OF PRESSURE ON OXYGEN TRANSPORT

Oxygen and carbon dioxide are transported simultaneously dissolved in blood or combined with some of the elements of blood. Oxygen is carried in the blood in two forms: first as physically dis-olved oxygen in the plasma, and second in combination with the hemoglobin of the red blood cells. Each 100 mL of normal arterial blood carries 0.3 mL of oxygen physically dissolved in the plasma and 20 mL of oxygen in combination with hemoglobin. Large amounts of oxygen can be transported in the blood because it combines easily with hemoglobin to form oxyhemoglobin: O2 + Hgb ↔ HgbO2

The volume of oxygen physically dissolved in the plasma varies directly with the partial pressure of oxygen in the arteries (PaO2). The higher the PaO2, the greater the amount of oxygen dissolved. For example, at a PaO2 of 10 mm Hg, 0.03 mL of oxygen is dissolved in 100 mL of plasma. At 20 mm Hg, twice this amount is dissolved in plasma, and at 100 mm Hg, 10 times this amount is dissolved. Therefore, the amount of dissolved oxygen is directly proportional to the partial pressure, regardless of how high the oxygen pressure rises.

The amount of oxygen that combines with hemoglobin also depends on PaO2, but only up to a PaO2 of about 150 mm Hg. When the PaO2 is 150 mm Hg, hemoglobin is 100% saturated and will not combine with any additional oxygen. When hemoglobin is 100% saturated, 1 g of hemoglobin will combine with 1.34 mL

of oxygen. Therefore, in a person with 14 g/dL of hemoglobin, each 100 mL of blood will contain about 19 mL of oxygen associated with hemoglobin. If the PaO2 is less than 150 mm Hg, the percentage of hemoglobin saturated with oxygen is lower. For example, at a PaO2 of 100 mm Hg (normal value), saturation is 97%; at a PaO2 of 40 mm Hg, saturation is 70%. 

OXYHEMOGLOBIN DISSOCIATION CURVE

The oxyhemoglobin dissociation curve  shows the relationship between the partial pressure of oxygen (PaO2) and the percentage of saturation of oxygen (SaO2). The percentage of saturation can be affected by the following factors: carbon dioxide, hydrogen ion concentration, temperature, and 2,3-diphosphoglycerate.

A rise in these factors shifts the curve to the right so that more oxygen is then released to the tissues at the same PaO2. A reduction in these factors causes the curve to shift to the left, making the bond between oxygen and hemoglobin stronger, so that less oxygen is given up to the tissues at the same PaO2. The unusual shape of the oxyhemoglobin dissociation curve is a distinct advantage to the patient for two reasons:

1. If the arterial PO2 decreases from 100 to 80 mm Hg as a result of lung disease or heart disease, the hemoglobin of the arterial blood remains almost maximally saturated (94%) and the tissues will not suffer from hypoxia.

2. When the arterial blood passes into tissue capillaries and is exposed to the tissue tension of oxygen (about 40 mm Hg), hemoglobin gives up large quantities of oxygen for use by the tissues.

Clinical Significance. 

The normal value of PaO2 is 80 to 100 mm Hg (95% to 98% saturation). With this level of oxygenation,

there is a 15% margin of excess oxygen available to the tissues. With a normal hemoglobin level of 15 mg/dL and a PaO2 level of 40 mm Hg (oxygen saturation 75%), there is adequate oxygen available for the tissues but no reserve for physiologic stresses that increase tissue oxygen demand. When a serious incident occurs

(eg, bronchospasm, aspiration, hypotension, or cardiac dysrhythmias) that reduces the intake of oxygen from the lungs, tissue hypoxia will result.

An important consideration in the transport of oxygen is cardiac output, which determines the amount of oxygen delivered to the body and which affects lung and tissue perfusion. If the cardiac output is normal (5 L/min), the amount of oxygen delivered to the body per minute is normal. If cardiac output falls, the amount ofoxygen delivered to the tissues also falls. Under normal conditions, most of the oxygen delivered to the body is not used. In fact, only 250 mL of oxygen is used per minute. Under normal conditions, this is approximately 25% of available oxygen. The rest of the oxygen returns to the right side of the heart, and the PaO2 of venous blood drops from 80 to 100 mm Hg to about 40 mm Hg.

Carbon Dioxide Transport
At the same time that oxygen diffuses from the blood into the tissues, carbon dioxide diffuses from tissue cells to blood and is transported to the lungs for excretion. The amount of carbon dioxide in transit is one of the major determinants of the acid–base balance of the body. Normally, only 6% of the venous carbon dioxide is removed in the lungs, and  nough remains in the arterial blood to exert a pressure of 40 mm Hg. Most of the carbon dioxide (90%) is carried by red blood cells; the small portion (5%) that remains dissolved in the plasma (partial pressure of carbon dioxide [PCO2]) is the critical factor that determines carbon dioxide movement in or out of the blood. Although the many processes involved in respiratory gas transport seem to occur in intermittent stages, the changes are rapid, simultaneous, and continuous.

 Neurologic Control of Ventilation
Resting respiration is the result of cyclic excitation of the respiratory muscles by the phrenic nerve. The rhythm of breathing is controlled by respiratory centers in the brain. The inspiratory and expiratory centers in the medulla oblongata and pons control the rate and depth of ventilation to meet the body’s metabolic demands.

The apneustic center in the lower pons stimulates the inspiratory medullary center to promote deep, prolonged inspirations. The pneumotaxic center in the upper pons is thought to control the pattern of respirations.

Several groups of receptor sites assist in the brain’s control of respiratory function. The central chemoreceptors, located in the medulla, respond to chemical changes in the cerebrospinal fluid, which result from chemical changes in the blood. These receptors respond to an increase or decrease in the pH and convey a message to the lungs to change the depth and then the rate of ventilation to correct the imbalance. The peripheral chemoreceptors are located in the aortic arch and the carotid arteries and respond first to changes in PaO2, then to partial pressure of carbon dioxide (PaCO2) and pH. The Hering-Breuer reflex is activated by stretch receptors in the alveoli. When the lungs are distended, inspiration is inhibited; as a result, the lungs do not become over distended. In addition, proprioceptors in the muscles and joints respond to body movements, such as exercise, causing an increase in ventilation. Thus, range-of motion exercises in an immobile patient stimulate breathing. Baroreceptors, also located in the aortic and carotid bodies, respond to an increase or decrease in arterial blood pressure and cause reflex hypoventilation or hyperventilation.

A&P Lecture 4.1: Function of the Respiratory System

The cells of the body derive the energy they need from the oxidation of carbohydrates, fats, and proteins. As with any type of combustion, this process requires oxygen. Certain vital tissues, such as those of the brain and the heart, cannot survive for long without a continuous supply of oxygen. However, as a result of oxidation in the body tissues, carbon dioxide is produced and must be removed from the cells to prevent the buildup of acid waste products. The respiratory system performs this function by facilitating life-sustaining processes such as oxygen transport, respiration and ventilation, and gas exchange.

Oxygen Transport

Oxygen is supplied to, and carbon dioxide is removed from, cells by way of the circulating blood. Cells are in close contact with capillaries, the thin walls of which permit easy passage or exchange of oxygen and carbon dioxide. Oxygen diffuses from the capillary through the capillary wall to the interstitial fluid. At this point, it diffuses through the membrane of tissue cells, where it is used by mitochondria for cellular respiration. The movement of carbon dioxide occurs by diffusion in the opposite direction—from cell to blood.

Respiration

After these tissue capillary exchanges, blood enters the systemic veins (where it is called venous blood) and travels to the pulmonary circulation. The oxygen concentration in blood within the capillaries of the lungs is lower than in the lungs’ air sacs (alveoli). Because of this concentration gradient, oxygen diffuses from the alveoli to the blood. Carbon dioxide, which has a higher concentration in the blood than in the alveoli, diffuses from the blood into the alveoli. Movement of air in and out of the airways (ventilation) continually replenishes the oxygen and removes the carbon dioxide from the airways and lungs. This whole process of

gas exchange between the atmospheric air and the blood and between the blood and cells of the body is called respiration.

Ventilation

During inspiration, air flows from the environment into the trachea, bronchi, bronchioles, and alveoli. During expiration, alveolar gas travels the same route in reverse. Physical factors that govern air flow in and out of the lungs are collectively referred to as the mechanics of ventilation and include air pressure variances, resistance to air flow, and lung compliance.

Air Pressure Variances

Air flows from a region of higher pressure to a region of lower pressure. During inspiration, movement of the diaphragm and other muscles of respiration enlarges the thoracic cavity and thereby lowers the pressure inside the thorax to a level below that of atmospheric pressure. As a result, air is drawn through the trachea and bronchi into the alveoli. During expiration, the diaphragm relaxes and the lungs recoil, resulting in a decrease in the size of the thoracic cavity. The alveolar pressure then exceeds atmospheric pressure, and air

flows from the lungs into the atmosphere.

Airway Resistance

Resistance is determined chiefly by the radius or size of the airway through which the air is flowing. Any process that changes the bronchial diameter or width affects airway resistance and alters the rate of air flow for a given pressure gradient during respiration. With increased resistance, greater-than-normal respiratory effort is required to achieve normal levels of ventilation.

Compliance

Compliance, or distensibility, is the elasticity and expandability of the lungs and thoracic structures. Compliance allows the lung volume to increase when the difference in pressure between the atmosphere and thoracic cavity (pressure gradient) causes air to flow in. Factors that determine lung compliance are the surface tension of the alveoli (normally low with the presence of surfactant) and the connective tissue (ie, collagen and elastin) of the lungs. Compliance is determined by examining the volume pressure relationship in the lungs and the thorax. Compliance is normal (1.0 L/cm H2O) if the lungs and thorax easily stretch and distend when pressure is applied. High or increased compliance occurs if the lungs have lost their

elasticity and the thorax is overdistended (eg, in emphysema).

Low or decreased compliance occurs if the lungs and thorax are “stiff.” Conditions associated with decreased compliance include morbid obesity, pneumothorax, hemothorax, pleural effusion, pulmonary edema, atelectasis, pulmonary fibrosis, and acute respiratory distress syndrome (ARDS), which are discussed in later chapters in this unit. Measurement of compliance is one method used to assess the progression and improvement in patients with ARDS. Lungs with decreased compliance require greater-thannormal energy expenditure by the patient to achieve normal levels of ventilation. Compliance is usually measured under static conditions.

Lung Volumes and Capacities

Lung function, which reflects the mechanics of ventilation, is viewed in terms of lung volumes and lung capacities. Lung volumes are categorized as tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. Lung capacity is evaluated in terms of vital capacity, inspiratory capacity, functional residual capacity, and total lung capacity.

A&P Lecture 4: Sturcture Respiratory System

NOTE: The following organ lecture on Anatomy and Physiology will be structured closely to concepts by which nurses must know to be able to have a good foundation in the normal Anatomy and Physiology to know the normal from abnormal findings for Health Assessment and to have a good grasp regarding deviations in the normal functions and structures of the the body in contrast to that during an illness state for advance subjects such as Medical-Surgical Nursing, Maternal and Child Nursing and Psychiatric Nursing.

ANATOMY AND PHYSIOLOGY LECTURE 4

RESPIRATORY SYSTEM

Nurses often encounter disorders of the respiratory system from the community to the intensive care unit. The diversity of respiratory ailments from simple colds to an evolving pulmonary edema necessitates an the development of expert assessment  skills to provide accurate problem identification and prompt treatment to be able to return patients in their optimal level of functioning. In order to differentiate between normal and abnormal assessment findings, an understanding of respiratory function and the significance of abnormal diagnostic test results is essential.

Overview

The respiratory system is composed of the upper and lower respiratory tracts. Together, the two tracts are responsible for ventilation. The upper respiratory tract warms and filters inspired air so that the lower respiratory tract can accomplish gas exchange. Gas exchange involves delivering oxygen to the tissues through the bloodstream and expelling waste gases, such as carbon dioxide, during expiration. The respiratory system works with the cardiovascular system; the respiratory system is responsible for ventilation and diffusion, and the cardiovascular system is responsible for oxygen delivery. 

Upper Respiratory Tract

Nose

Our nose serves as a passageway for air to pass to and from the lungs. It filters impurities and humidifies and warms the air as it is inhaled. The nose is composed of an external and an internal portion. The external portion protrudes from the face and is supported by the nasal bones and cartilage. The anterior nares (nostrils) are the external openings of the nasal cavities.

The internal portion of the nose is a hollow cavity separated into the right and left nasal cavities by a narrow vertical divider, the septum. Each nasal cavity is divided into three passageways by the projection of the turbinates from the lateral walls. The turbinate bones are also called conchae for the name suggested by their shell-like appearance. Because of their curves, these bones increase the mucous membrane surface

of the nasal passages and slightly obstruct the air flowing

through them.

Air entering the nostrils is deflected upward to the roof of the nose, and it follows a circuitous route before it

reaches the nasopharynx. It comes into contact with a large surface of moist, warm, highly vascular, ciliated mucous membrane (called nasal mucosa) that traps practically all the dust and organisms in the inhaled air. The air is moistened, warmed to body temperature, and brought into contact with sensitive nerves. Some of these nerves detect odors; others provoke sneezing to expel irritating dust. Mucus, secreted continuously by goblet cells, covers the surface of the nasal mucosa and is moved back to the nasopharynx by the action of the cilia which are fine hairs.

Paranasal Sinuses

The paranasal sinuses include four pairs of bony cavities that are lined with nasal mucosa and ciliated pseudostratified columnar epithelium. These air spaces are connected by a series of ducts that drain into the nasal cavity. The sinuses are named by their location: frontal, ethmoidal, sphenoidal, and maxillary . A prominent function of the sinuses is to serve as a resonating chamber in speech. The sinuses are a common site of infection.

Pharynx, Tonsils, and Adenoids

The pharynx, or throat, is a tubelike structure that connects the nasal and oral cavities to the larynx. It is divided into three regions: nasal, oral, and laryngeal. The nasopharynx is located posterior to the nose and above the soft palate. The oropharynx houses the faucial, or palatine, tonsils. The laryngopharynx extends from the hyoid bone to the cricoid cartilage. The epiglottis forms the entrance to the larynx. The adenoids, or pharyngeal tonsils, are located in the roof of the nasopharynx. The tonsils, the adenoids, and other lymphoid tissue encircle the throat. These structures are important links in the chain of lymph nodes guarding the body from invasion by organisms entering the nose and the throat. The pharynx functions as a passageway for the respiratory and digestive tracts.

Larynx

The larynx, or voice organ, is a cartilaginous epitheliumlined structure that connects the pharynx and the trachea. The major function of the larynx is vocalization. It also protects the lower airway from foreign substances and facilitates coughing. It is frequently referred to as the voice box and consists of the following:

• Epiglottis: a valve flap of cartilage that covers the opening to the larynx during swallowing

• Glottis: the opening between the vocal cords in the larynx

• Thyroid cartilage: the largest of the cartilage structures; part of it forms the Adam’s apple

• Cricoid cartilage: the only complete cartilaginous ring in the larynx (located below the thyroid cartilage)

• Arytenoid cartilages: used in vocal cord movement with the thyroid cartilage

• Vocal cords: ligaments controlled by muscular movements that produce sounds; located in the lumen of

the larynx. 

Trachea

The trachea, or windpipe, is composed of smooth muscle with C-shaped rings of cartilage at regular intervals. The cartilaginous rings are incomplete on the posterior surface and give firmness to the wall of the trachea, preventing it from collapsing. The trachea serves as the passage between the larynx and the bronchi

Lower Respiratory Tract

The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange.

Lungs

The lungs are paired elastic structures enclosed in the thoracic cage, which is an airtight chamber with distensible walls. Ventilation requires movement of the walls of the thoracic cage and of its floor, the diaphragm. The effect of these movements is alternately to increase and decrease the capacity of the chest. When the capacity of the chest is increased, air enters through the trachea (inspiration) because of the lowered pressure within and inflates the lungs. When the chest wall and diaphragm return to their previous positions (expiration), the lungs recoil and force the air out through the bronchi and trachea. Inspiration occurs during the first third of the respiratory cycle, expiration during the later two thirds. The inspiratory phase of respiration normally requires energy; the expiratory phase is normally passive, requiring very little energy. In respiratory diseases, such as chronic obstructive pulmonary disease (COPD), expiration requires energy.

Pleura

The lungs and wall of the thorax are lined with a serous membrane called the pleura. The visceral pleura covers the lungs; the parietal pleura lines the thorax. The visceral and parietal pleura and the small amount of pleural fluid between these two membranes serve to lubricate the thorax and lungs and permit smooth motion of the lungs within the thoracic cavity with each breath.

Mediastinum

The mediastinum is in the middle of the thorax, between the pleural sacs that contain the two lungs. It extends from the sternum to the vertebral column and contains all the thoracic tissue outside the lungs (heart, thymus,

certain large blood vessels [ie, aorta, vena cava], and esophagus).

Lobes

Each lung is divided into lobes. The right lung has upper, middle, and lower lobes, whereas the left lung consists of upper and lower lobes. Each lobe is further subdivided into two to five segments separated by fissures, which are extensions of the pleura.

Bronchi and Bronchioles

There are several divisions of the bronchi within each lobe of the lung. First are the lobar bronchi (three in the right lung and two in the left lung). Lobar bronchi divide into segmental bronchi (10 on the right and 8 on the left), which are the structures identified when choosing the most effective postural drainage position for a given patient. Segmental bronchi then divide into subsegmental bronchi. These bronchi are surrounded by connective tissue that contains arteries, lymphatics, and nerves.

The subsegmental bronchi then branch into bronchioles, which have no cartilage in their walls. Their patency depends entirely on the elastic recoil of the surrounding smooth muscle and on the alveolar pressure. The bronchioles contain submucosal glands, which produce mucus that covers the inside lining of the airways. The bronchi and bronchioles are also lined with cells that have surfaces covered with cilia. These cilia create a constant whipping motion that propels mucus and foreign substances away from the lungs toward the larynx.

The bronchioles then branch into terminal bronchioles, which do not have mucus glands or cilia. Terminal bronchioles then become respiratory bronchioles, which are considered to be the transitional passageways between the conducting airways and the gas exchange airways. Up to this point, the conducting airways contain about 150 mL of air in the tracheobronchial tree that does not participate in gas exchange; this is known as physiologic dead space. The respiratory bronchioles then lead into alveolar ducts and alveolar sacs and then alveoli. Oxygen and carbon dioxide exchange takes place in the alveoli.

Alveoli

The lung is made up of about 300 million alveoli, which are arranged in clusters of 15 to 20. These alveoli are

so numerous that if their surfaces were united to form one sheet, it would cover 70 square meters—the size of a tennis court.

There are three types of alveolar cells. Type I alveolar cells are epithelial cells that form the alveolar walls. Type II alveolar cells are metabolically active. These cells secrete surfactant, a phospholipid that lines the inner surface and prevents alveolar collapse. Type III alveolar cell macrophages are large phagocytic cells that ingest foreign matter (eg, mucus, bacteria) and act as an important defense mechanism.

A&P Lecture 2: Cell Cycle and Cell Division

ANATOMY AND PHYSIOLOGY LECTURE 2

CELL CYCLE AND CELL DIVISION

The life of a cell is called the cell cycle. It is usually divided into five phases or gaps: G0, G1, S, G2, and M. Some cells may not have a G1 phase, and others may not have a G2 stage. However, all cells must grow, replicate their genetic material if they are to divide, and undergo the process of mitosis if they are to replicate. G0 is the stage during which the cell may leave the cell cycle and either remain in a state of inactivity or reenter the cell cycle at another time. G1 is the stage during which the cell is starting to prepare for mitosis through DNA and protein synthesis and an increase in organelle and cytoskeletal elements. The S phase is the synthesis phase, during which DNA replication occurs and the centrioles are beginning to replicate. G2 is the premitotic phase and is similar to G1 as for RNA and protein synthesis. The M phase is the phase during which cell mitosis occurs. Nondividing cells, such as mature nerve cells and cells not preparing for mitosis, are said to be in the G0 phase of the cell cycle .

Cell Division

Cell division, or mitosis, which was first described in 1875, is the process during which a parent cell divides and each daughter cell receives a chromosomal karyotype identical to the parent cell. Cell division gives the body a means of replacing cells that have a limited life span, such as skin and blood cells; increasing tissue mass during periods of growth; and providing for tissue repair and wound healing. Despite the early cytologic description of the four stages of mitosis, it was not until the early 1950s that the importance of the cell cycle was realized. 

Mitosis, which is a dynamic and continuous process, usually lasts from 1 to 11⁄2 hours. It is divided into four stages: prophase, metaphase, anaphase, and telophase (Fig. 4-13). The phase during which the cell is not undergoing division is called interphase. During prophase, the chromosomes become visible because of increased coiling of the DNA, the two centrioles replicate, and a pair moves to each side of the cell. Simultaneously, the microtubules of the mitotic spindle appear between the two pairs of centrioles. Later in prophase, the nuclear envelope and nucleolus disappear. Metaphase involves the organization of the chromosome pairs in the midline of the cell and the formation of a mitotic spindle composed of the microtubules. Anaphase is the period during which separation of the chromosome pairs occurs, with the microtubules pulling one member of each pair of 46 chromosomes toward the opposite cell pole. Cell division, or cytokinesis, is completed after telophase, the stage during which the mitotic spindle vanishes and a new nuclear membrane develops and encloses each complete set of chromosomes.

Cell division is controlled by changes in the intracellular concentrations and activity of three major groups of

intracellular proteins: (1) cyclins, (2) cyclin-dependent kinases, and (3) the anaphase-promoting complex. The central components of the cell cycle control system are the cyclin-dependent kinases, whose activity depends on association with the regulatory units called cyclins. Oscillations in the activity of the various cyclin-dependent kinases lead to initiation of the different phases of the cell cycle. For example, activation of the S-phase cyclin-dependent kinases initiates the S phase of the cell cycle, whereas activation of the M-phase cyclin-dependent kinases triggers mitosis. The anaphase-promoting complex is responsible for the breakdown of the M cyclins and other regulators of mitosis.

Cell division is also controlled by several external factors, including the presence of cytokines, various growth

factors, or even adhesion factors when the cell is associated with other cells in a tissue. In addition, the cell cycle is regulated by several checkpoints that determine whether DNA replication has occurred with a high degree of fidelity. Two of the better understood are the DNA damage and the spindle formation checkpoints. If these biochemical checkpoints are not faithfully met, the cell may default to programmed

cell death or apoptosis.

Anatomy and Physiology Compiled Lecture Notes: The Cell

THE CELL

• Introduction

• The Cell Membrane

• The Nucleus

• The Cytoplasm

• The Ribosomes

• The Endoplasmic Reticulum

• The Golgi Complex

• The Secretory Vesicles

• The Lysosomes

• The Peroxisomes

• The Proteasomes

• The Mitochondria

• The Accessory Parts

• Cillia
• Flagella
• Microvilli
• Centrioles
• Spindle Fibers

A&P Lecture 1.11: Centrioles and Spindle Fibers

This is an in depth  explanation of Centriloes and Spindle fiber as a part of the cell. This lecture note is linked to A&P Lecture 1: The Cell

ANATOMY AND PHYSIOLOGY LECTURE 1.11

CENTRIOLES AND SPINDLE FIBERS

Centrioles and Spindle Fibers

The centrosome, a specialized zone of cytoplasm close to the nucleus, is the center of microtubule formation. It contains two centrioles . Each centriole is a small, cylindrical organelle about 0.3–0.5 μm in length and 0.15 μm in diameter, and the two centrioles are normally oriented perpendicular to each other within the centrosome. The wall of the centriole is composed of nine evenly spaced, longitudinally oriented, parallel units, or triplets. Each unit consists of three parallel microtubules joined together.

Microtubules appear to influence the distribution of actin and intermediate filaments. Through its control of microtubule formation, the centrosome is closely involved in determining cell shape and movement. The microtubules extending from the centrosomes are very dynamic—constantly growing and shrinking. Before cell division, the two centrioles double in number, the centrosome divides into two, and one centrosome, containing two centrioles, moves to each end of the cell.

Microtubules called
spindle fibers extend out in all directions from the centrosome. These microtubules grow and shrink even more rapidly than those of nondividing cells. If the extended end of a spindle fiber comes in contact with a kinetochore, a specialized region in the centromere of each chromosome, the spindle fiber attaches to the kinetochore and stops growing or shrinking. Eventually, spindle fibers from each centrosome bind to the kinetochores of all the chromosomes. During cell division, the microtubules facilitate the movement of chromosomes toward the two centrosomes

A&P Lecture 1.12: Cilia Flagella and Microvilli

This is an in depth  explanation of Lysosomes as a part of the cell. This lecture note is linked to A&P Lecture 1: The Cell

ANATOMY AND PHYSIOLOGY LECTURE 1.12

CILLIA, FLAGELLA AND MICROVILLI

Cilia and Flagella

Cilia  are structures that project from the surface of cells and are capable of movement. They vary in number from one to thousands per cell. Cilia are cylindrical in shape, about 10 μm in length and 0.2 μm in diameter, and the shaft of each cilium is enclosed by the plasma membrane. Two centrally located microtubules and nine peripheral pairs of fused microtubules, the so-called 9 2 arrangement, extend from the base to the tip of each cilium. Movement of the microtubules past each other, a process that requires energy from ATP, is responsible for movement of the cilia. Dynein arms, proteins connecting adjacent pairs of microtubules, push the microtubules past each other. A basal body (a modified centriole) is located in the cytoplasm at the base of the cilium. Cilia are numerous on surface cells that line the respiratory tract and the female reproductive tract. In these regions, cilia move in a coordinated fashion, with a power stroke in one direction and a recovery stroke in the opposite direction. Their motion moves materials over the surface of the cells. For example, cilia in the trachea move mucus embedded with dust particles upward and away from the lungs. This action helps keep the lungs clear of debris.

Flagella  have a structure similar to cilia but are longer (45 μm). Sperm cells are the only human cells to possess flagella and usually only one flagellum exists per cell. Furthermore, whereas cilia move small particles across the cell surface, flagella move the entire cell. For example, each sperm cell is propelled by a single flagellum. In contrast to cilia, which have a power stroke and a recovery stroke, flagella move in a

wavelike fashion.

Microvilli

Microvilli ) are cylindrically shaped

extensions of the plasma membrane about 0.5–1.0 μm in length and 90 nm in diameter. Normally, many microvilli are on each cell, and they function to increase the cell surface area. A student looking at photographs may confuse microvilli with cilia. Microvilli, however, are only one-tenth to one-twentieth the size of cilia. Individual microvilli can usually be seen only with an electron microscope, whereas cilia can be seen with a light microscope. Microvilli do not move, and they are supported with actin filaments, not microtubules. Microvilli are found in the intestine, kidney, and other areas in which absorption is an important

function. In certain locations of the body, microvilli are highly modified to function as sensory receptors. For example, elongated microvilli in hair cells of the inner ear respond to sound.