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APHY 201 Exam 3b
Ch. 14 Cardiac Output, Blood Flow, and Blood Pressure
| Question | Answer |
|---|---|
| What is end diastolic volume (EDV) also known as? | preload |
| How does an increase in EDV affect stroke volume? | Stroke volume increases because they have a directly proportional relationship. |
| What is total peripheral resistance also known as? | afterload |
| How does total peripheral resistance relate to stroke volume? | They are inversely proportional; as resistance increases, stroke volume decreases. |
| What effect do sympathetic norepinephrine and adrenal epinephrine have on contractility? | They increase contractility (positive inotropic effect) by making more Ca2+ available to sarcomeres. |
| What effect does parasympathetic acetylcholine have on heart rate at the SA node? | It decreases heart rate (negative chronotropic effect). |
| Why does a slower cardiac rate caused by the parasympathetic nervous system actually increase ventricular contraction strength? | It allows more time to fill between beats, which increases EDV and therefore increases contraction strength. |
| What are the six major factors that affect venous return? | Total blood volume, venous pressure, sympathetic nerve activity to veins, skeletal muscle pumps, pressure differences between abdominal and thoracic cavities (thoracic pump), and overall blood volume. |
| What is the highest and lowest pressure within the venous system? | Highest in the venules (10 mmHg) and lowest in the venae cavae into the right atrium (0 mmHg). |
| What is the equation for Starling Forces used to predict fluid movement across capillary membranes? | (pc + pii) - (pi + pip) |
| What are six possible causes of edema? | High arterial blood pressure, venous obstruction, leakage of plasma proteins into interstitial space, myxedema (hypothyroidism), decreased plasma protein concentration, and obstruction of lymphatic drainage. |
| How do the kidneys respond when increased blood volume stretches receptors in the atria? | Sympathetic stimulation to the kidneys decreases, causing kidney arterioles to dilate, which increases blood flow and urine production to lower blood volume. |
| What hormone is a physiological antagonist to aldosterone and increases the excretion of salt and water from the kidneys? | Atrial natriuretic peptide (ANP). |
| What three main effects does Angiotensin II have that result in a rise in blood pressure? | Vasoconstriction of small arteries/arterioles, stimulation of the thirst center in the hypothalamus, and stimulation of aldosterone production in the adrenal cortex. |
| Which organ receives the most blood out of all organs at rest? | The GI tract. |
| According to Poiseuille’s Law, which vessel physical constraint has the most profound mathematical effect on blood flow resistance? | Vessel radius, because it is raised to the fourth power |
| What paracrine molecules influence smooth muscle relaxation to produce local vasodilation? | Bradykinin, nitric oxide (NO), and prostaglandin I2. |
| What paracrine molecule stimulates smooth muscle contraction to produce vasoconstriction and raise total peripheral resistance? | Endothelin-1. |
| What is the difference between reactive hyperemia and active hyperemia? | Reactive hyperemia is vasodilation following the removal of a vessel constriction due to metabolic waste buildup, while active hyperemia is increased blood flow due to increased local metabolism during activities like exercise. |
| During heavy dynamic exercise, what does the ejection fraction increase to? | It increases from 60% at rest to 90% during heavy exercise. |
| What overall changes happen to total peripheral resistance and arterial blood pressure during exercise? | Total peripheral resistance decreases, and arterial blood pressure increases. |
| How does myogenic regulation protect cerebral blood vessels when blood pressure rises too high? | Cerebral vessels automatically constrict to protect small vessels from damage and stroke. |
| What chemical changes in the cerebrospinal fluid cause cerebral arteriole dilation and constriction? | Decreased pH (buildup of CO2) causes dilation, while increased pH (drop in CO2) causes constriction. |
| Where are the vasomotor and cardiac centers located in the brain? | In the medulla oblongata. |
| What is the formula used to calculate Mean Arterial Pressure (MAP)? | diastolic pressure + 1/3 pulse pressure |
| what are 2 possible causes of secondary hypertension that were bolded in your notes? | kidney disease, excess catecholamines (tumor of adrenal medulla) |
| what are 4 factors involved with essential hypertension? | high salt intake coupled with decreased kidney filtering ability, increased sympathetic nerve activity (HR up), responses to paracrine regulators from the endothelium (damage from stress-> not enough NO->excessive vasoconstriction), and increased TPR |
| what are 3 dangers of hypertension? | 1. vascular damage within organs (can lead to stroke in brain), 2. ventricular overload (high afterload due to high BP in aorta leading to hypertrophy->arrhythmias->cardiac arrest), 3. development of atherosclerosis in blood vessels |
| what are preload and afterload? | preload is the stretching of the heart muscle before it contracts, det by the amount of blood filling the ventricles at the end of diastole (relaxation). afterload is the resistance or pressure the heart must overcome to push that blood out into the body |
| what are 6 treatments to essential hypertension? | lifestyle modification (limit salt and vices/ lose weight/ exercise), K+ and even Ca2+ supplements, diuretics, beta blockers, ACE inhibitors, angiotensin II receptor blockers (ARBs) |
| what do beta blockers accomplish for hypertension? | block beta-1 sympathetic receptors in the heart--decreases cardiac rate |
| what do ACE inhibitors accomplish for hypertension? | block angiotensin II production, which would have caused vasoconstriction and increase BP |
| what do ARBs? | angiotensin II receptor blockers that inhibit actions of angiotensin II |
| what are the 2 most commonly prescribed drug for hypertension? | ACE inhibitors and ARBs |
| what do diuretics accomplish for hypertension? | increase volume of urine excreted, thus lowering blood volume |
| what is an example of a sympathoadrenal system inhibitor and what does it do? | atenolol blocks beta-adrenergic receptors, decreasing cardiac output and/or renin secretion |
| what are 2 early signs of blood pressure during shock and a late sign of shock as regards to BP? | decreased pulse pressure and increased diastolic pressure (BP normal but pulse pressure drops); late sign is decreased systolic pressure |
| what are 3 reflexes to compensate for circulatory shock? | heart: SNS stimulation produces increased cardiac rate and stroke volume; GI tract and skin: decreased blood flow due to SNS (alpha-adrenergic effect); kidneys: decreased urine production as a result of SNS constriction of renal arterioles |
| what does the body do to compensate for hypovolemic shock, and what does it include? | baroceptor reflex, which raises heart rate, raises peripheral resistance by vasoconstriction in the skin, viscera and muscles, and produces cold, clammy skin and low urine output |
| what condition occurs when cardiac output is not sufficient to maintain blood flow require by the body (usually on one side of the heart, backs fluid up to cause edema)? | congestive heart failure |
| (multiple choice, recognize for which is not) causes of congestive heart failure? | myocardial infarction, congenital defects, hypertension, aortic valve stenosis, or disturbances in electrolyte levels |
| congestive heart failure is characterized by what relative concentrations of what ions? | high K+ and low blood Ca2+. the high K+ depresses RMP of cardiac cells, and heart stops in diastole. the low Ca2+ reduces excitation-contraction coupling, and heart stops in diastole. |
| failure of which side of the heart is responsible for pulmonary congestion and edema? | left (atrium) |
| failure of which side of the heart is responsible for systemic congestion and edema? | right (atrium) |
| chronically low cardiac output due to congestive heart failure is associated with (choose between) elevated blood volume or decreased blood volume? | elevated, due to activation of RAAS and dilation/hypertrophy of the ventricles (extra blood overworks the heart) |
Created by:
elianayu
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