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73 Cards in this Set

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What are the layers of the heart?
1. Epicardium
2. Myocardium
3. Endocardium
What is the epicardium?
The outer protective layer of the heart that consist of connective tissue covered by epithelium; contains blood, lymph capillaries as well as nerve fibers.
What is the myocardium?
The relatively thick middle layer that consists primarily of cardiac muscle tissue, which is responsible for the pumping action of the heart.
What is the endocardium?
The inner layer that lines all of the heart chambers and covers heart valves; contains many elastic and collagenous fibers; is continuous with the intima of the blood vessels.
What is the pericardial sac?
A fibrous sac of double walls that contains a lubricating fluid between the layers.
What are the four chambers of the heart?
1. Right atrium: site where blood enters heart through the vena cava.
2. Right ventricle: pumps blood into the lungs via te pulmonary artery for gas exchange with the pulmonary vasculature before the pulmonary veins carry the blood into the left atrium.
3. Left atrium: pumps blood through the mitral valve into the left ventricle.
4. Left ventricle: forcefuly pumps blood into the systemic circulation through the aortic valve and into the aorta.
** Although the same events occur on the right and left side of the heart, pressures are lower on the right.
** The ventricles are the more muscular chambers of the heart, which contract with a twisting motion, squeezing blood into arteries.
What are the valves of the heart?
1. Tricuspid valve: separates the right atrium from the right ventricle.
2. Mitral valve: separates the left atrium and left ventricle.
3. Pulmonic valve: separates the right ventricle and pulmonary artery.
4. Aortic valve: separates the left ventricle and the aorta.
** The sympathetic and parasympathetic nervous systems are in constant opposition with one another in order to regulate the heart rate.
What is the cardiac cycle?
The series of electromechanical events consisting of two phases (systole and diastole) that occur during an individual heartbeat; each cardiac cycle lasts approximately 0.8 seconds and covers the period from the end of one cardiac contraction to the end of the subsequent cardiac contraction.
** Although the atria and ventricles act simultaneously, they function as separate units because they enter systole and diastole at different times; when the atria are in systole, the ventricles are in diastole.
**Blood tends to flow from an area of high pressure to one of lower pressure.
What is systole?
The period of ventricular contraction.
What is diastole?
The period of ventricular relaxation; usually lasts longer than systole.
** Seventy-five percent of ventricular filling occurs during diastole.
** Contraction and relaxation of the heart muscle produces sequential pressure changes within the chambers of the heart and the blood vessels, which results in the orderly passage of blood.
What is the sinoatrial (SA)node?
A group of specialized conduction cells located in the superior aspect of the right atrium that trigger a heart beat about once every 0.8 seconds; commonly known as the pacemaker of the heart for its ability to spontaneously generate an action potential; depolarization of the SA node marks the beginning of the cardiac cycle; the SA node regulates the heart rate at 60 to 100 beats/min.
What is the atrioventricular (AV)node?
A group of specialized conduction cells in the inferior aspect of the right atrium that serves as a bridge between the atria and ventricles; in the AV node, a delay (0.1 second)in the transmission of the electrical impulse from the atria to the ventricles occurs so that blood has time to empty out of the atria before the ventricles contract.
What are the bundle branches?
Nerve fibers that carry electrical impulses from the AV node; divided into left and right bundle branches.
What are the bundle of His?
Conduction fibers that transmit the electrical impulse at a rapid rate throughout the ventricular myocardium.
What are Purkinje fibers?
Very large, specialized conduction fibers that transmit the electrical impulse from the AV node throughout the walls of both ventricles simultaneously; conduct action potential at six times the velocity of normal cardiac muscle.
What are the coronary arteries?
The arteries that supply the cardiac muscle with oxygen-rich blood; any coronary artery disorder that reduces blood flow to the heart can result in myocardial infarction and possibly, death.
What are the two main coronary arteries?
The right coronary artery (RCA)and the left coronary artery (LCA).
What are the brances of the two main coronary arteries?
The RCA branches into the right posterior descending artery and a marginal branch, which provide blood to the ventricles, right atrium, and SA node; the LCA branches into the left anterior descending artery (LAD) and the circumflex branch, which supply blood to the front of the heart and the back of the heart, respectively; smaller divisions of the coronary arteries include the acute marginal, posterior descending, obtuse marginal and diagonals.
** The LAD is commonly referred to as the "widow maker" because it supplies blood to 75% of the left ventricle, and a sudden occlusion within this artery is usually fatal.
What is stroke volume?
The volume of blood ejected from each ventricle in a single beat at systole.
What is cardiac output (CO)?
Stroke volume (SV) x heart rate (HR); CO is an important indicator of cardiac function; normal CO is 4 to 6L/minute.
What is cardiac index (CI)?
CO divided by body surface area; a normal CI is 2.5 to 4.0 L/minute/m^2.
Why is CI a better indicator of left ventricular function than CO?
CO varies according to body size, whereas CI does not.
What is preload?
Ventricular volume at the end of diastole, or the amount of stretch on the ventricular myocardium prior to its contraction; an increase in preload produces and increase in stroke volume; it's primarily dependent on venous blood return from the body.
What is afterload?
The resistance to ventricular ejection, which is caused by the systemic vascular resistance (resistance to flow in the systemic circulation); stroke volume decreases as afterload increases.
What is contractility?
The myocardium's ability to contract and empty the ventricle in the absence of a change in preload or afterload; the sympathetic nervous system is the most critical influence on contractility.
What is the ejection fraction?
An index of the contractile status of the heart; a normal EF is greater than 50% and can be measured by an echocardiogram or cardiac catheterization.
What produces the characteristics "lub dup" heart sounds?
Vibrations caused by closure of the heart valve in various parts of the cardiac cycle; the "lub" sound occurs at the beginning of systole and is due to the closure of the mitral and tricupsid valves; the "dup" sound marks the beginning of diastole and is due to the closure of the aortic and pulmonary valves.
** In a healthy heart, the only detectable heart sounds are those of closure of the valves.
What is an S1?
The first heart sound, which is produced by closure of the mitral and tricuspid valves.
** The closure of the mitral and tricupsid valves occurs so closely together that they're commonly perceived as a single sound.
What is an S2?
The second heart sound, which is produced by closure of the aortic and pulmonic valves; the interval between the closure of the two valves widens with inhalation.
What is a pulse?
The rhythmic arterial expansion that's produced by the ejection of blood from the left ventricle.
What is blood pressure?
The force exerted on the walls of arteries as blood is pumped through the body; a product of the cardiac output and total peripheral resistance; blood pressure is measured with a sphygmomanometer and is described as systolic pressure over diastolic pressure.
What is systolic BP?
The point at which arterial blood pressure is at its highest level.
What is diastolic BP?
The point at which arterial blood pressure is at its lowest level.
**An increase in cardiac output usually produces an increase in systolic pressure. An increase in peripheral resistance (vasoconstriction) usually produces an increase in diastolic pressure.
** Because of the relationship between HR and CO (heart rate x stroke volume = cardiac output), any factor that increases the heart rate will also increase the blood pressure, and any factor that increases the blood pressure will also increase the heart rate.
What is the pulse pressure?
An important component of blood pressure; the difference between the systolic and diastolic blood pressures; reflective of the pulsatile nature of the arterial blood flow- typically about 40 mm Hg.
What are the two basic mechanisms for BP regulation?
Short term: regulation of blood vessel diameter, heart rate, and contractility.
Long term: regulation of blood volume, primarily via the conservation of body fluids through renal mechanisms and stimulation of water intake; involves renin-angiotensin-aldosterone mechanism and release of anti-diuretic hormone.
What factors are involved in the short term regulation of rising blood pressure?
Rising BP stretches the arterial walls, stimulating baroreceptors, which send impulses to the brain. Parasympathetic activity is then increased and the sympathetic activity is decreased, which in turn decreases the heart rate, relaxes the vascular smooth muscle, and increases the arterial diameter. BP is lowered as a result.
What factors are involved in the short term regulation of decreasing blood pressure?
Baroreceptors are inhibited by decreasing BP, parasympathetic activity is decreased, and sympathetic activity is increased due to decreased impulses to the brain; heart rate, contractility, and vasoconstriction are increased due to release of epinephrine and norepinephrine by the adrenal glands; BP is raised as a result.
What factors are involved in the long term regulation of low BP?
Renin is released by the kidney juxtaglomerular cells in response to a drop in BP. Renin binds to angiotensinogen, an inactive plasma protein, as it travels through the circulatory system. This binding process activates angiotensinogen to angiotensin I. Angiotensin I is converted to angiotension II as it passes through the lung, and angiotensin II travels to the adrenal glands where it stimulates the release of aldosterone. Aldosterone then increases sodium reabsorption from the DCT; water follows the movement of sodium into the bloodstream, and blood volume and BP are increased as a result. In addition, antidiuretic hormone is released by the posterior pituitary in response to increased osmolarity (dehydration). ADH promotes water reabsorption in the kidney and stimulates the thirst center, which decreases the osmolarity of the blood volume and increases blood pressure.
What types of blood vessels comprise the vascular system?
Arteries: carry oxygenated blood away from the heart thick walls of three layers.
Capillaries: are the site of exchange of water, macromolecules, metabolites,and waste products between blood and tissue; highly branched vessels of thin (single layer) walls.
Veins: carry deoxygenated blood from the capillary bed towards the heart; contain valves to prevent backflow of blood; contain 70% of circulating blood volume.
**The pulmonary artery and pulmonary veins are the exception to the rule regarding arteries carrying oxygenated blood and veins carrying deoxygenated blood; the pulmonary artery carries deoxygenated blood to the pulmonary vasculature for gas exchange, the pulmonary veins carry oxygenated blood back to the heart from the pulmonary vasculature.
How is the intensity of a murmur graded?
On a scale of I to VI over VI; for example, I/VI would indicate a murmur that's barely detectable to the examiner, while VI/VI would indicate a murmur that can still be heard when the stethoscope is completely off the chest.
What's an ejection murmur?
An abnormal heart sound theat results from the opening of the aortic and pulmonic valves during rapid ejection of blood out of the ventricles; an ejection murmur may be indicative of valve disease or intracardiac shunts.
What's a split S2?
The heart sound produced when the right and left ventricles contract at slightly different times; may be a normal variant in some persons, but it may also indicate left ventricular hypertrophy; and echocardiogram may be performed for further evaluation.
What is a gallop?
An abnormal heart rhythm marked by a low-pitched extra sound during diastole; usually referred to as S3 or S4.
What is an S3?
The low-pitched third heart sound that results from the rapid ventricular filling during diastole; also referred to as a ventricular gallop; may be normal in children, but is usually associated with heart failure in adults.
A left ventricular S3 is best detected using the bell of the stethoscope during expiration with the patient in the left lateral decubitis position, whereas a right ventricular S3 is best auscultated with the bell of the stethoscope over the left sternal border during inspiration.
What is an S4?
The low-pitched fourth heart sound that occurs secondary to atrial contraction against a noncompliant left ventricle; a presystolic heart sound best detected with the bell of the stethoscope; S4 is commonly associated with systemic hypertension, aortic stenosis, hypertropic cardiomyopathy, and ischemic heart disease; also referred to as an atrial gallop.
What is a click?
A high pitched abnormal heart sound auscultated at the apex during mid to late systole; commonly precedes a late systolic murmur.
What are palpitations?
Sensation of skipped heart beats or of pounding or racing of the heart.
What is a pericardial friction rub?
A harsh scraping or creaking sound auscultated over the left third intercostal space; may occur during systole, diastole, or both.
What is pulsus paradoxus?
An exaggerated inspiratory decrease in systolic blood pressure greater than 10mm Hg (normal inspiratory drop is < than 10 mm Hg); occurs in association with cardiac tamponade.
What is fibrillation?
An erratic, quivering of the myocardium that prevents the heart from effectively pumping blood.
What is flutter?
A disorder characterized by extremely rapid yet regular contractions of the atria or ventricles; may produce no symptoms.
What is ischemia?
Inadequate blood flow to tissues, resulting in oxygen deprivation; usually caused by a constriction or obstruction of an artery.
What is an infarction?
An area of dead tissue caused by the obstruction of blood flow.
What is a valvular stenosis?
The inability of a valve to open to its normal position.
What is valvular regurgitation or insufficiency?
The inability of a valve to effectively close and prevent the backward flow of blood.
What is mitral valve prolapse?
A mild abnormality of the mitral valve in which the valve leaflets flap backwards as the heart contracts.
What is Valsalva's maneuver?
A type of movement involving forcible exhalation while the mouth and nose remain closed (bearing down as if having a bowel movement), which causes an increase in intrathoracic pressure and a slowing of the heart rate; can be used to diagnose certain cardiac abnormalities and to correct certain rapid heart beats; usually taught to persons with MS to aid in fully emptying the bladder.
** Valsalva's maneuver should be avoided in patient's with severe coronary artery disease, a recent history of myocardial infarction, or a significant reduction in blood volume.
What is arteriosclerosis?
The loss of vessel elasticity; commonly known as hardening of the arteries.
What is atherosclerosis?
A form of arteriosclerosis characterized by the gradual accumulation of plaque or an atheroma, which causes the arteries to narrow and become less elastic; as a result, blood flow through the arteries is obstructed; a diet of high in fat and cholesterol, smoking, diabetes, and hypertension accelerate the process of plaque formation and are risk factors for atherosclerosis; coronary artery disease is a form of atherosclerosis.
What is an atheroma?
Atherosclerotic plaque consisting of deposits of fats, cholesterol, cellular debris, calcium and fibrin.
What's a bruit?
An abnormal, murmurlike heart sound associated with turbulent blood flow through a major vessel.
What's a thrill?
A vibrating sensation similar to a cat purring that frequently accompanies a bruit and is also indicative of turbulent blood flow.
What's a thrombus?
A blood clot consisting of platelets, fibrin, and possibly, other blood components that develop inside a blood vessel or within a cavity of the heart.
What's an embolus?
A clot that moves through the circulatory system until it becomes lodged in a narrowed blood vessel where it blocks blood flow, producing ischemia beyond the site of obstruction; most emboli arise from thrombi, although fat, air bubbles and plaque can also be considered emboli.
What's an aneurysm?
A bulging, ballooning, or abnormal enlargement of an artery that results from damage to or weakness of the blood vessel wall; most occur in the abdomen (abdominal aortic aneurysm) or brain (cerebral aneurysm).
What's vasculitis?
A condition characterized by an inflammation of blood vessels, commonly the arteries; thickening, weakeining, or scarring of the blood vessel wall can result; blood clots may develop.
What are varicose veins?
Veins that are swollen, torturous, and bulging above the skin surface as a result of congestion within the vein due to weakness of its valve; may be dark blue or purple and are found most commonly on the lower extremities; genetics, hormones, pregnancy, obesity, and prolonged standing are contributing factors to the development of varicose veins.
What's hypercholesterolemia?
A condition characterized by elevated serum cholesterol levels (240mg/dl or greater) that's associated with an increased risk for coronary heart disease and other atherosclerotic diseases such as thrombotic strokes.
Hypercholesterolemia occurs in association with a genetic predisposition and excessive intake of saturated fat, trans fatty acid, and cholesterol (believed to decrease low density lipoprotein receptors in the liver). Long term use of glucocorticoids, anabolic steroids, and progestins may also adversely affect cholesterol levels.
What's the pathophysiologic process of hypercholesterolemia?
Elevated serum cholesterol levels occur secondary to increased production of LDL or decreased catabolism of LDL; the excess lipids then promote atherogenesis by attaching to a site of vessel injury and attracting clusters of monocytes, which contribute to the formation of fatty streaks.
What are clinical manifestations of hypercholesterolemia?
Usually produces no symptoms and is typically found at the time of routing screening; xanthomas (slightly raised and yellow skin lesions that frequently are located on the eyelids) may indicated extreme hypertriglyceridemia.
What is a normal total cholesterol level?
Below 200mg/dl.
**A full lipid panel should be performed after the patient has fasted for 9 to 12 hours.
What are lipoproteins?
Fat-carrying proteins that encapsulate lipids for transportation in the blood; core contains cholesterol esters and triglycerides.
**Lipoproteins are classified according to the type and ration of proteins to fats they contain. The size and density of lipoproteins are also determined by their protein and fat content?
What are the classes of lipoproteins?
Chylomicrons: formed in the intesting; transport fats from intestine to liver and adipose tissue.
Very low density lipoprotein (VLDL): produced by the liver; carry largest amount of lipids (triglycerides); can be converted to LDL.
LDL: primary carrier of cholesterol, and as a result, are reflective of serum cholesterol level; "bad cholesterol;" normal levels are considered to be below 160mg/dl.
High density lipoproteins (HDL): cholesterol scavengers that remove excess cholesterol from peripheral tissues and carry it back to the liver for catabolism and excretion; HDL level above 40mg/dl is considered a risk factor for coronary artery disease.