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cardiac output
chapter 14
35
Physiology
Undergraduate 4
05/09/2012

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Term
cardiac output
Definition
volume of blood pumped each minute by each ventricle
Term
regualting cardiac rate
Definition
spontaneous depolarization occurs at SA node allowing NA+ in
Term
Regulation of stroke volume
Definition
1. EDV end diastolic volume
2. Total peripheral resistance
3. Contractility
Term
EDV
Definition
amount of blood left in the ventricles after the diastole
Term
Total peripheral resistance
Definition
frictional resistance in the arteries
Term
contractility
Definition
strenght of ventricular contraction
Term
Frank starling law
Definition
Increased EDV results in increased contractility and thus increased stroke volume.
Term
edema
Definition
excessive accumulations of interstitial fluids
Term
regulation of blood volume by kidneys
Definition
The formation of urine begins with filtration of fluid through capillaries in the kidneys called glomeruli
Term
ADH
Definition
antidiuretic hormone:produced by hypothalamus and released when osmoreceptors there detect increased plasma osmolarity.
stiumulates water reabsorption
Term
Renin-angiotensin-aldosterone system
Definition
When blood pressure is low, cells in the kidneys (juxtaglomerular apparatus) secrete the enzyme renin
Term
angiotensin II effects
Definition
Vasoconstriction of small arteries and arterioles

Stimulates thirst center in hypothalamus

Stimulates production of aldosterone in adrenal cortex
Term
Atrial natriuretic peptide:
Definition
produced by the atria of the heart when stretch is detected

Promotes salt and water excretion in urine in response to increased blood volume
Term
laws regulating blood flow
Definition
Blood flows from higher concentration to lower concentration
Mean arterial pressure and vessel radius (r) are therefore the most important factors in blood flow.
Term
sympathetic nerves
Definition
norepinephrine, epeniphrine- vasoconstriction
acetylcholine-Vasodilation
Term
regulation of blood flow
Definition
Paracrine control: Molecules produced by one tissue control another tissue within the same organ
Term
cardiac tissue...
Definition
contains lots of mitochondria and respiratory enzymes, thus is metabolically active
Term
regulation of blood flow through skeletal muscles
Definition
Vasodilation is stimulated by both adrenal epinephrine and sympathetic acetylcholine
Term
circulatory changes during excercise
Definition
Increased cardiac output
Metabolic vasodilation
Diversion of blood away from viscera and skin
Term
cutaneous blood flow
Definition
the skin can handle the most fluctuation in blood flow
Term
thermoregulation
Definition
the skins way of regulating body temperature,
Term
blood pressure
Definition
Affected by blood volume/stroke volume, total peripheral resistance, and cardiac rate

Increase in any of these will increase blood pressure.
Term
sympathoadrenal system
Definition
The sympathoadrenal system stimulates vasoconstriction of arterioles (raising total peripheral resistance) and increased cardiac output
Term
baroreceptor reflux
Definition
Activated by changes in blood pressure detected by baroreceptors in the aortic arch and carotid sinuses

Increased blood pressure stretches these receptors, increasing action potentials to the vasomotor and cardiac control centers in the medulla
Term
baroreceptor reflux mechanism
Definition
Fall in blood pressure = ↑ sympathetic and ↓ parasympathetic activity, resulting in increased heart rate and total peripheral resistance
Term
blood pressure cuff
Definition
A blood pressure cuff produces turbulent flow of blood in the brachial artery, which can be heard using a stethoscope; called sounds of Korotkoff
Term
pulse pressure
Definition
The difference between blood pressure at systole and at diastole
Term
hypertension
Definition
high blood pressure

increased risk of cardiac diseases and stroke
Term
essential hypertension
Definition
Increased salt intake coupled with decreased kidney filtering ability
Increased sympathetic nerve activity, increasing heart rate
Responses to paracrine regulators from the endothelium
Term
dangers of hypertension
Definition
Vascular damage within organs, especially dangerous in the cerebral vessels and leading to stroke

Ventricular overload to eject blood, leading to arrhythmias and cardiac arrest

Contributes to the development of atherosclerosis
Term
treatments of hypertension
Definition
Lifestyle modification: limit salt intake; limit smoking and drinking; lose weight; exercise
K+ (and possibly calcium) supplements
Diuretics to increase urine formation
Beta blockers to decrease cardiac rate
ACE inhibitors to block angiotensin II production
Term
circulatory shock
Definition
occurs when there is inadequate blood flow to match oxygen usage in the tissues
Term
hypovolemic shock
Definition
Due to low blood volume from an injury, dehydration, or burns
Term
septic shock
Definition
Dangerously low blood pressure due to an infection (sepsis)
Term
other types of circulatory shock
Definition
anaphalactic shock-allergic reaction, buildup of histamine, and vasodilation

neurogenic shock- results from spinal cord injury, due to loss of sympathetic stimulation

cardiogenic shock-due to significant to myocardial loss
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