Term
| What happens when the aortic valve opens during ventricular contraction? |
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Definition
- rapid outflow of blood
- increase in arterial pressure
- Aorta elasticity absorbs some pressure |
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Term
| What happens when the aortic valve closes during diastole? |
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Definition
- no blood flowing from ventricle
- elastic energy in aorta is released
- blood flow in vessels is then allowed to continue
- gradual decrease in arterial pressure |
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Term
| T or F: The sympathetic nervous system decreases heart rate |
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Definition
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Term
| Give a formula for calculating the Cardiac output |
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Definition
| Heart rate x Stroke volume |
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Term
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Definition
The volume of blood ejected per contraction
- End-diastolic Volume (EDV) - End-systolic volume (ESV) |
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Term
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Definition
a.k.a. The End-diastolic volume (EDV)
- the volume of blood present in the ventricles at the end of diastole |
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Term
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Definition
a.k.a. The End-systolic volume (ESV)
- the residual volume of blood contained in the ventricle after systole |
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Term
| If there is an increase in EDV, what happens to the stroke volume? |
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Definition
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Term
| What are the four components to the Frank-Starling Law? |
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Definition
1. As preload increases, contractility of the heart increases, and stroke volume increases
2. Increased stretch in cardiac fibers enhances Ca2+ binding to Troponin-C, inducing an increase in contractility
3. Under resting conditions, EDV stretches cardiac muscle to sub-optimal levels
4. The pericardium inhibits cardiac muscle from stretching beyond the optimum |
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Term
| What is the main factor affecting preload/EDV? |
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Definition
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Term
| What are some factors affecting venous return? |
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Definition
- Skeletal muscle pump
- respiratory activity
- blood volume
- Autonomic nervous system |
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Term
| What are the factors affecting afterload/ESV? |
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Definition
- the amount of resistance felt my the ventricles during ejection
- Total Peripheral resistance (TPR) or Arterial Vascular Resistance or Arterial vasomotor tone
- Blood pressure |
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Term
| Give a formula for blood pressure |
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Definition
| BP = Cardiac output x arterial resistance |
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Term
| What are the factors of blood vessels that affect blood pressure? |
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Definition
| diameter, elasticity, contractility |
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Term
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Definition
| volume of fluid transported per unit time |
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Term
| On what two factors is flow dependent? |
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Definition
| Difference in pressure between two points; resistance |
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Term
| Give an equation for Flow |
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Definition
| Flow (Q) = Pressure Diff.(delta P) / Resistance (R) |
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Term
| Is pressure higher in arteries or veins? |
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Definition
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Term
| What level of the arterial/venous system is referred to as the "bottleneck"? |
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Definition
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Term
| At what phase is starting/initial pressure measured? |
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Definition
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Term
| On what factors does resistance depend? |
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Definition
- length of vessel
- radius of vessel *** (most important)
- viscosity of blood |
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Term
| If radius is increased by a factor of 2, resistance decreases by a factor of... |
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Definition
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Term
| What is the mean blood pressure? |
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Definition
(MBP) The mean of the systolic and diastolic blood pressure
- less than half b/c diastolic takes longer |
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Term
| MBP is closer to diastolic under what condition? |
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Definition
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Term
| MBP is closer to systolic under what condition? |
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Definition
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Term
| What are the main variables involved in control of blood pressure? |
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Definition
heart rate
stroke volume
total peripheral resistance (TPR) |
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Term
| What components are involved in blood pressure reflex? |
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Definition
baroreceptors
sensory fibers
integration center
motor fibers
effectors |
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Term
| What are baroreceptors and where are they found? |
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Definition
receptors with free nerve endings; detect stretching of the arterial wall
found in sensitive areas e.g. aortic arch & carotid sinus |
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Term
| Sensory fibers ascend via the _____ _____ |
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Definition
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Term
| Sensory fiber stretch increases = _____ in AP frequency |
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Definition
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Term
| Where is the integration center for the control of blood pressure? |
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Definition
| cardiovascular center in the medulla oblongata |
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Term
True or False
Motor fibers controlling blood pressure are a part of the somatic nervous system |
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Definition
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Term
| What are the effectors involved in controlling blood pressure? |
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Definition
Heart rate & stroke volume (cardiac output)
Arterioles & veins (TPR) |
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Term
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Definition
| total peripheral resistance |
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Term
| What is postural hypotension? |
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Definition
| decrease in blood pressure as you change from lying down to standing up, causing blood to flow from the thoracic cavity to lower extremities |
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Term
| What is the immediate response to postural hypotension? |
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Definition
baroreceptor reflex compensates for the change
-stretch receptors slow down in firing
-parasympathetic activity decreases (increases heart rate)
-sympathetic activity increases (increases heart rate, stroke volume, vasoconstriction) |
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Term
| What is the atrial volume receptor reflex? |
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Definition
stretch receptors in wall of atria regulate blood volume via:
-autonomic nervous system activity
-neural input controlling thirst & hormone secretion (changes handling of sodium & water in the kidneys) |
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Term
| What hormone increases sodium excretion? Where is it synthesized? |
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Definition
Atrial Natriuretic Peptide (ANP)
synthesized in atrial wall |
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Term
|
Definition
-hormone synthesized in the kidney
-increases angiotensin II synthesis |
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Term
| What does angiotensin II do? |
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Definition
| promotes vasoconstriction |
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Term
| Angiotensin II can be converted into _____ which decreases _____ |
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Definition
aldosterone
sodium excretion |
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Term
| What hormone decreases water excretion at the kidney? |
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Definition
| antidiuretic hormone (vasopressin) |
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Term
| What is the diff b/w sys and diasolic pressure? |
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Definition
| Pulse pressure (measure of pressure on artery wall during systole) |
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Term
| What factors affect arterial pressure? |
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Definition
Elasticity
Cardiac Output
Respiration
Resistance
Blood volume |
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Term
| What is basal level of constriction? |
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Definition
myogenic tone (basal tone)
- makes it possible to decrease vessels contraction this increase diameter |
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Term
| How is vascular resistance controlled? |
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Definition
- arterioles' walls are less elastic, and have more smoos muscle fibers
- basal level of constriction
- diameter decreases, resistance increases
- autoregulation (local mechanisms)
- extrinsic control factor (neuro-hormonal) |
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Term
| Define myogenic (pressure) autoregulation |
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Definition
- vessels respond to changes in tone or stretch
- maintain blood supply virtually unchanged even with change in pressure |
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Term
| Define metabolic regulation |
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Definition
- response to changes in metabolism
- results in increase in diameter
- relative importance of factors depend on organ |
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Term
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Definition
(within organ or tissue) overrides extrinsic regulation
- control of flow in critical organs (therefore a protective mechanism) |
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Term
| Define extrinsic regulation |
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Definition
- regulate extrinsic pressure as a whole
- vasoconstrictive influences (sympathetic stimulation on a-adrenergic receptors, angiotensis II, arginin vasopressin)
- vasodilatory influences (mainly penish and clitorish) |
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Term
| During inspiration, as P in the thorax ______, pressure in the abdomen ________. (increases or decreases) |
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Definition
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Term
| T or F: veins have little resistance |
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Definition
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Term
| What draws venous blood back to the heart? |
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Definition
| Its low pressure after contraction |
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Term
| T or F: Veins possess smoos muscle |
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Definition
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Term
| When blood pressure in veins is too high, what happens? |
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Definition
| Flow is reduced and fluid leaks out/accumulates in tissue (edema) |
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