Term
| contributors to venous return to the heart |
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Definition
1) skeletal muscle contractions (major)
2) respiratory pump (minor)
3) hydrostatic pressure (minor) |
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Term
| function of respiratory pump |
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Definition
| expands thoracic cavity during inhalation which increases venous return by lowering pericardial cavity pressure |
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Term
| hydrostatic pressure [description] |
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Definition
1) very low pressure gradient in venous system
2) valves in place to prevent back flow of blood below heart |
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Term
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Definition
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Term
|
Definition
| smooth blood flow occurring in parallel, concentric layers |
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Term
|
Definition
| rough, chaotic blood flow |
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Term
| resistance of laminar flow |
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Definition
| little resistance to blood flow |
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Term
| resistance of turbulent flow |
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Definition
| increases resistance of blood flow |
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Term
| where does turbulent flow occur? |
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Definition
| occurs at the areas of blood vessel branching |
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Term
| turbulent flow contributes to |
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Definition
| atherosclerosis by causing inflammation of blood vessels |
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Term
| what contributes to turbulent blood flow? |
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Definition
| atherosclerosis and thrombi |
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Term
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Definition
| describes the flow of blood in a vessel |
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Term
| greatest effect on resistance to blood flow |
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Definition
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Term
| arterial radius is affected by |
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Definition
1) sympathetic tone
2) local factors |
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Term
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Definition
| decreases blood vessel radius |
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Term
|
Definition
| increases blood vessel radius |
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Term
|
Definition
| measure of the thickness of a fluid |
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Term
| what happens if viscosity is increased? |
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Definition
|
|
Term
| how is viscosity increased? |
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Definition
| increasing substances in blood |
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Term
| factors that increase viscosity |
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Definition
1) increase in hematocrit
2) dehydration
3) high cholesterol and/or triglyceride levels
4) stasis |
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Term
| control of blood flow is done by |
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Definition
controlling smooth muscle tone by
1) vasomotor centers
2) local factors |
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Term
| local factors that cause smooth muscle relaxation (vasodilation) |
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Definition
1) arginine
2) histamine
3) decrease in pH
4) increase in CO2
5) decrease in O2 |
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Term
| local factors that cause smooth muscle contraction (vasoconstriction) |
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Definition
1) thromboxanes
2) ADH/vasopressin
3) increase in pH
4) decrease in CO2
5) increase in O2 |
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Term
| output of vasomotor centers in brainstem via |
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Definition
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Term
| stimulation of vasomotor centers |
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Definition
| causes smooth muscle contraction (vasoconstriction) |
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Term
| inhibition of vasomotor centers |
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Definition
| causes smooth muscle relaxation (vasodilation) |
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Term
| blood pressure is measured in |
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Definition
|
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Term
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Definition
| measure of the force that blood exerts against blood vessel walls |
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Term
| mean arterial pressure (MAP) |
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Definition
| average blood pressure in the arterial circulation |
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|
Term
| what type of average is MAP |
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Definition
| weighted average because heart spends 1/3 in systole and 2/3 in diastole |
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Term
|
Definition
1) arterial radius
2) viscosity
3) friction |
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Term
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Definition
| opposing force to blood flow |
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|
Term
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Definition
| abnormally low blood pressure when the blood pressure gradient for flow is diminished |
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Term
| critical closing pressure |
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Definition
| pressure below which a blood vessel collapses |
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Term
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Definition
| severe decreases in blood pressure which leads to inadequate blood flow |
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Term
| types of circulatory shock |
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Definition
1) hypovolemic shock
2) vasodilatory shock
3) cardiogenic shock |
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Term
|
Definition
| loss of blood volume decreases blood pressure |
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|
Term
|
Definition
| vasodilation decreases blood pressure |
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|
Term
|
Definition
| inadequate cardiac output decreases blood pressure |
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Term
| reasons for circulatory shock |
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Definition
1) hemorrhagic shock
2) anaphylactic shock
3) septic shock
4) emotional shock
5) neurogenic shock |
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Term
| hemorrhagic shock (hypovolumic) |
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Definition
| bleeding that causes loss of blood volume |
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Term
| anaphylactic shock (vasodilatory) |
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Definition
| severe allergic response that causes the massive release of inflammatory chemicals (causes severe vasodilation) |
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Term
| septic shock (hypovolumic, vasodilatory, and cardiogenic) |
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Definition
| systemic blood infection that releases toxins in the blood |
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Term
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Definition
1) bleeding caused by damaged capillary beds
2) vasodilation
3) decreases heart rate and contractility |
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Term
| emotional shock (vasodilatory and cardiogenic) |
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Definition
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|
Term
| symptoms of emotional shock |
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Definition
1) causes strong parasympathetic stimulation which decreases heart rate
2) causes strong sympathetic inhibition which causes vasodilation and decreases heart rate and contractility |
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Term
| neurogenic shock (vasodilatory and cardiogenic) |
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Definition
| causes strong inhibition of sympathetics which causes vasodilation and decreases heart rate and contractility |
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