Anatomy and Physiology Notes: The Heart

Heart and heart wall layers
1. The heart is located in the left side of the mediastinum.
2. The heart consists of three layers.
a. The epicardium is the outermost layer of the heart.
b. The myocardium is the middle layer and is the
actual contracting muscle of the heart.
c. The endocardium is the innermost layer and lines
the inner chambers and heart valves.


Pericardial sac
1. Encases and protects the heart from trauma and infection
2. Has two layers
a. The parietal pericardium is the tough, fibrous outer membrane that attaches anteriorly to the lower half
of the sternum, posteriorly to the thoracic vertebrae, and inferiorly to the diaphragm.
b. The visceral pericardium is the thin, inner layer that closely adheres to the heart.
3. The pericardial space is between the parietal and visceral layers; it holds 5 to 20 mL of pericardial fluid, lubricates the pericardial surfaces, and cushions the heart.


There are four heart chambers
1. The right atrium receives deoxygenated blood from the body via the superior and inferior vena cava.
2. The right ventricle receives blood from the right atrium and pumps it to the lungs via the pulmonary artery.
3. The left atrium receives oxygenated blood from the lungs via four pulmonary veins.
4. The left ventricle is the largest and most muscular chamber; it receives oxygenated blood from the lungs via the left atrium and pumps blood into the systemic circulation via the aorta.

There are four valves in the heart.
1. There are two atrioventricular valves, the tricuspid and the mitral, which lie between the atria and ventricles.
a. The tricuspid valve is located on the right side of the heart.
b. The bicuspid (mitral) valve is located on the left side of the heart.
c. The atrioventricular valves close at the beginning of ventricular contraction and prevent blood from flowing
back into the atria from the ventricles; these valves open when the ventricle relaxes.

2. There are two semilunar valves, the pulmonic and the aortic.
a. The pulmonic semilunar valve lies between the right ventricle and the pulmonary artery.
b. The aortic semilunar valve lies between the left ventricle and the aorta.
c. The semilunar valves prevent blood from flowing back into the ventricles during relaxation; they open during
ventricular contraction and close when the ventricles begin to relax.

Sinoatrial (SA) node

1. The main pacemaker that initiates each heartbeat
2. It is located at the junction of the superior vena cava and the right atrium.
3. The sinoatrial node generates electrical impulses at 60 to 100 times per minute and is controlled by the sympathetic and parasympathetic nervous systems.

Atrioventricular (AV) node
1. Located in the lower aspect of the atrial septum
2. Receives electrical impulses from the sinoatrial node
3. If the sinoatrial node fails, the atrioventricular node can initiate
and sustain a heart rate of 40 to 60 beats/min.

The bundle of His
1. A continuation of the AV node; located at the interventricular septum
2. It branches into the right bundle branch, which extends down the right side of the interventricular septum, and the left bundle branch, which extends into the left ventricle.
3. The right and left bundle branches terminate into Purkinje fibers.

Purkinje fibers
1. Purkinje fibers are a diffuse network of conducting strands located beneath the ventricular endocardium.
2. These fibers spread the wave of depolarization through the ventricles.
3. Purkinje fibers can act as the pacemaker with a rate between 20 and 40 beats/min when higher pacemakers fail


Coronary arteries 
1. The coronary arteries supply the capillaries of the myocardium with blood.
2. The right coronary artery supplies the right atrium and ventricle, the inferior portion of the left ventricle, the posterior septal wall, and the sinoatrial and atrioventricular nodes.
3. The left main coronary artery consists of two major branches, the left anterior descending and the circumflex arteries.
4. The left anterior descending artery supplies blood to the anterior wall of the left ventricle, the anterior ventricular septum, and the apex of the left ventricle.
5. The circumflex artery supplies blood to the left atrium and the
lateral and posterior surfaces of the left ventricle.

Notes on Fluid and Electrolytes 3: FLUID VOLUME EXCESS

FLUID VOLUME EXCESS

A. Description
1. Fluid intake or fluid retention exceeds the fluid needs of the body.
2. Fluid volume excess also is called overhydration or fluid overload.
3. The goal of treatment is to restore fluid balance, correct electrolyte imbalances if present, and eliminate or control the underlying cause of the overload.

B. Types
1. Isotonic overhydration
a. Known as hypervolemia, isotonic overhydration results from excessive fluid in the extracellular fluid compartment.
b. Only the extracellular fluid compartment is expanded, and fluid does not shift between the extracellular and
intracellular compartments.
c. Isotonic overhydration causes circulatory overload and interstitial edema; when severe or when it occurs in a client with poor cardiac function, congestive heart
failure and pulmonary edema can result.

2. Hypertonic overhydration
a. Occurrence of hypertonic overhydration is rare and is caused by an excessive sodium intake.
b. Fluid is drawn from the intracellular fluid compartment; the extracellular fluid volume expands, and the intracellular fluid volume contracts.

3. Hypotonic overhydration
a. Hypotonic overhydration is known as water intoxication.
b. The excessive fluid moves into the intracellular space, and all body fluid compartments expand.
c. Electrolyte imbalances occur as a result of dilution.

C. Causes
1. Isotonic overhydration
a. Inadequately controlled IV therapy
b. Renal failure
c. Long-term corticosteroid therapy

2. Hypertonic overhydration
a. Excessive sodium ingestion
b. Rapid infusion of hypertonic saline
c. Excessive sodium bicarbonate therapy

3. Hypotonic overhydration
a. Early renal failure
b. Congestive heart failure
c. Syndrome of inappropriate antidiuretic hormone secretion
d. Inadequately controlled IV therapy
e. Replacement of isotonic fluid loss with hypotonic fluids
f. Irrigation of wounds and body cavities with hypotonic fluids

D. Assessment
1. Cardiovascular
a. Bounding, increased pulse rate
b. Elevated blood pressure
c. Distended neck and hand veins
d. Elevated central venous pressure

2. Respiratory
a. Increased respiratory rate (shallow respirations)
b. Dyspnea
c. Moist crackles on auscultation

3. Neuromuscular
a. Altered level of consciousness
b. Headache
c. Visual disturbances
d. Skeletal muscle weakness
e. Paresthesias

4. Integumentary
a. Pitting edema in dependent areas
b. Skin pale and cool to touch

5. Increased motility in the gastrointestinal tract

6. Isotonic overhydration results in liver enlargement and ascites.

7. Hypotonic overhydration results in the following:
a. Polyuria
b. Diarrhea
c. Nonpitting edema
d. Dysrhythmias
e. Projectile vomiting
8. Laboratory findings
a. Decreased serum osmolality
b. Decreased hematocrit
c. Decreased BUN level
d. Decreased serum sodium level
e. Decreased urine specific gravity

E. Interventions
1. Monitor cardiovascular, respiratory, neuromuscular, renal, integumentary, and gastrointestinal status.
2. Prevent further fluid overload, and restore normal fluid balance.
3. Administer diuretics; osmotic diuretics typically are prescribed first to prevent severe electrolyte imbalances.
4. Restrict fluid and sodium intake.
5. Monitor intake and output and weight.
6. Monitor electrolyte values, and prepare to administer medication to treat an imbalance if present.

Anatomy and Physiology Quiz

I. Fluid and Electrolyte and Acid – Base Balance

1. Approximately 60% of the weight of a typical adult consists of fluid. Body fluid is located in two fluid compartments namely what?
a. Intracellular and intravascular
b. Extracellular and intracellular
c. Intracellular and interstitial
d. Extravascular and intracellular

2. When two different solutions are separated by a membrane that is impermeable to the dissolved substances, fluid shifts through the membrane from the region of low solute concentration to the region of high solute concentration until the solutions are of equal concentration. This diffusion of water caused by a fluid concentration gradient is known as what?
a. Diffusion
b. Filtration
c. Osmosis
d. Active Transportation

3. Hydrostatic pressure in the capillaries tends to filter fluid out of the intravascular compartment into the interstitial fluid. Movement of water and solutes occurs from an area of high hydrostatic pressure to an area of low hydrostatic pressure is known as what?
a. Diffusion
b. Filtration
c. Osmosis
d. Active Transport

4. A patient presented the following signs and symptoms: confusion, muscle cramps and weakness,  dry skin, ↑pulse,  ↓ BP. The patient’s lab result shows ↓ serum and urine sodium and  ↓ urine specific gravity. The doctor told you that the patient is exhibiting hyponatremia. Hyponatremia is having a serum sodium below what? (Smeltzer 2012)
a. 145 mEq/L
b. 108 mEq/L
c. 96.5 mEq/L
d. 135 mEq/L

5. A patient with congestive heart failure is given oral potassium supplements to avoid digoxin toxicity. As a nurse you are aware that the normal serum level for potassium is what? (Smeltzer 2012)
a. 135-145 mEq/L
b. 3.5-5.0 mEq/L
c. 8.5-10.5 mg/dL
d. 1.8-2.7 mg/dL

Evaluate the following arterial blood gas values

6. pH: 7.5   PaCO2: 31   HCO3 : 26

7. pH: 7.38  PaCO2: 32  HCO3: 19

8. pH: 7.24  PaCO2: 60  HCO3: 32

9. pH: 7.41  PaCO2: 30  HCO3 18

10. pH: 7.5  PaCO2: 42  HCO3: 33

II. Respiratory System

11. 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 center is located in the?
a. Medulla Oblongata
b. Hypothalamus
c. Pons
d. Cerebellum

12. The _____ center in the lower pons stimulates the inspiratory medullary center to promote deep, prolonged inspirations.
a. Pneumotaxic
b. Apneustic
c. Chemotaxic
d. Physiotaxic

13. A term that correspond the amount of air inhaled and exhaled with each breath.
a. Residual Volume
b. Inspiratory Reserve Volume
c. Expiratory Reserve Volume
d. Tidal Volume
14. It is the volume of air in the lungs after maximum inhalation
a. Vital Capacity
b. Inspiratory Capacity
c. Functional Residual Capacity
d. Total Lung Capacity

15. The volume of air remaining in the lungs after a normal expiration .
a. Vital Capacity
b. Inspiratory Capacity
c. Functional Residual Capacity
d. Total Lung Capacity

III.  Cardiovascular System

16. It is the ability of the heart to initiate electrical impulse.
a. Excitability
b. Automaticity
c. Conductivity
d. Permeability

17. It is called as the primary pace maker of the heart which fires 60 to 100 impulse per minute
a. SA Node
b. AV Node
c. Bundle of His
d. Purkinje Fibers

18. The ___  coordinates the incoming electrical impulses from the atria and after a slight delay, allowing the atria time to contract and complete ventricular filling then relays the impulse to the ventricles.
a. SA Node
b. AV Node
c. Bundle of His
d. Purkinje Fibers

19. This heart sound is created by the closure of the tricuspid and bicuspid valve
a. S1
b. S2
c. S3
d. S4

20. This heart sound is created b the closure of the pulmonic and aortic valves
a. S1
b. S2
c. S3
d. S4

Anatomy and Physiology Notes: Respiratory System

Primary functions of the respiratory system
1. Provides oxygen for metabolism in the tissues
2. Removes carbon dioxide, the waste product of metabolism

Secondary functions of the respiratory system
1. Facilitates sense of smell
2. Produces speech
3. Maintains acid-base balance
4. Maintains body water levels
5. Maintains heat balance

Upper respiratory tract
1. Nose: Humidifies, warms, and filters inspired air

2. Sinuses: Air-filled cavities within the hollow bones that surround the nasal passages and provide resonance during speech

3. Pharynx
a. Passageway for the respiratory and digestive tracts located behind
the oral and nasal cavities
b. Divided into the nasopharynx, oropharynx, and laryngopharynx

4. Larynx
a. Located above the trachea, just below the pharynx at the root of
the tongue; commonly called the voice box
b. Contains two pairs of vocal cords, the false and true cords
c. The opening between the true vocal cords is the glottis.
d. The glottis plays an important role in coughing, which is the most
fundamental defense mechanism of the lungs.

5. Epiglottis
a. Leaf-shaped elastic structure attached along one end to the top of
the larynx
b. Prevents food from entering the tracheobronchial tree by closing
over the glottis during swallowing

Lower respiratory tract
1. Trachea: Located in front of the esophagus; branches into the right
and left main stem bronchi at the carina

2. Main stem bronchi
a. Begin at the carina
b. The right bronchus is slightly wider, shorter, and more vertical than the left bronchus.
c. The mainstem bronchi divide into secondary or lobar bronchi that enter each of the five lobes of the lung.
d. The bronchi are lined with cilia, which propel mucus up and away from the lower airway to the trachea, where it can be expectorated or swallowed.

3. Bronchioles
a. Branch from the secondary bronchi and subdivide into the small terminal and respiratory bronchioles

b. The bronchioles contain no cartilage and depend on the elastic recoil of the lung for patency.
c. The terminal bronchioles contain no cilia and do not participate in gas exchange.

4. Alveolar ducts and alveoli
a. Acinus (plural acini) is a term used to indicate all structures distal to the terminal bronchiole.
b. Alveolar ducts branch from the respiratory bronchioles.
c. Alveolar sacs, which arise from the ducts, contain clusters of alveoli, which are the basic units of gas exchange.
d. Type II alveolar cells in the walls of the alveoli secrete surfactant, a phospholipid protein that reduces the surface tension in the alveoli; without surfactant, the alveoli would collapse.

5. Lungs
a. Located in the pleural cavity in the thorax
b. Extend from just above the clavicles to the diaphragm, the major muscle of inspiration
c. The right lung, which is larger than the left, is divided into three lobes, the upper, middle, and lower lobes.
d. The left lung, which is narrower than the right lung to accommodate the heart, is divided into two lobes.
e. The respiratory structures are innervated by the phrenic nerve, the vagus nerve, and the thoracic nerves.
f. The parietal pleura lines the inside of the thoracic cavity, including the upper surface of the diaphragm.

g. The visceral pleura covers the pulmonary surfaces.
h. A thin fluid layer, which is produced by the cells lining the pleura, lubricates the visceral pleura and the parietal pleura, allowing them to glide smoothly and painlessly during respiration.
i. Blood flows through the lungs via the pulmonary system and
the bronchial system.

6. Accessory muscles of respiration include the scalene muscles, which elevate the first two ribs, the sternocleidomastoid muscles, which raise the sternum, and the trapezius and pectoralis muscles, which fix
the shoulders.


Respiratpry Process
a. The diaphragm descends into the abdominal cavity during inspiration, causing negative pressure in the lungs.
b. The negative pressure draws air from the area of greater pressure, the atmosphere, into the area of lesser pressure, the lungs.
c. In the lungs, air passes through the terminal bronchioles into the alveoli to oxygenate the body tissues.
d. At the end of inspiration, the diaphragm and intercostal muscles relax and the lungs recoil.
e. As the lungs recoil, pressure within the lungs becomes higher than atmospheric pressure, causing the air, which now contains the cellular waste products carbon dioxide and water, to move from the alveoli in the lungs to the atmosphere.
f. Effective gas exchange depends on distribution of gas (ventilation) and blood (perfusion) in all portions of the lungs

Human Immunodeficiency Virus / Acquired immunodeficiency syndrome Lecture Notes

This is a Medical Surgical Nursing lecture note on AIDS/HIV in outlined format. Information and concepts are compressed to provide a quick review of the topic. Some information are so compressed that some concepts are not expounded in detail. If it is your first time to meet such information please refer to your textbook for further explanation of the concept. This review material requires a student to have a prior knowledge and good foundation of the subject matter for this only emphasizes important/ key information deemed important in understanding concepts in Pathophysiology and Medical Surgical Nursing.

Acquired immunodeficiency syndrome (AIDS)

•  AIDS is a viral disease caused by human immunodeficiency virus (HIV), which destroys T cells, thereby increasing susceptibility to infection and malignancy
•  The syndrome is manifested clinically by opportunistic infection and unusual neoplasms.
• AIDS is considered a chronic illness.
• The disease has a long incubation period, sometimes 10 years or longer.
• Manifestations may not appear until late in the infection.

High-risk groups
Heterosexual or homosexual contact with high-risk individuals
Intravenous drug abusers
Persons receiving blood products
Health care workers
Babies born to infected mothers

Assessment
Malaise, fever, anorexia, weight loss, influenza-like symptoms
Lymphadenopathy for at least 3 months
Leukopenia
Diarrhea
Fatigue
Night sweats
Presence of opportunistic infections
Protozoal infections (Pneumocystis jiroveci pneumonia, major source of mortality)
Neoplasms (Kaposi's sarcoma, purplish-red lesions of internal organs and skin, B-cell non-Hodgkin's lymphoma, cervical cancer)
Fungal infections (candidiasis, histoplasmosis)
Viral infections (cytomegalovirus, herpes simplex)
Bacterial infections

Interventions
1. Provide respiratory support.
2. Administer oxygen and respiratory treatments as prescribed.
3. Provide psychosocial support as needed.
4. Maintain fluid and electrolyte balance.
5. Monitor for signs of infection.
6. Prevent the spread of infection.
7. Initiate standard precautions.
8. Provide comfort as necessary.
9. Provide meticulous skin care.
10. Provide adequate nutritional support as prescribed.

"Success is not final, failure is not fatal: it is the courage to continue that counts"