Cardio 8 Flashcards
Describe pulse pressure.
-amplitude of pressure pulsations in an artery
-each cardiac ejection = pressure increases
[pulse pressure = systolic pressure - diastolic pressure]
indicator of SV because the magnitude of pulse pressure reflects the volume of blood ejected from LV for each beat
Describe pulmonary circulation VS systemic circulation.
-pulmonary circulation = low pressure
-systemic circulation = high pressure
Describe systolic pressure.
-pressure at the top of each pressure pulsation
-highest arterial pressure during a cardiac cycle
-pressure in arteries after blood is ejected from LV
Describe diastolic pressure.
-pressure at the lowest point of each pulse
-lowest arterial pressure during a cardiac cycle
-pressure in arteries during ventricular relaxation
Describe compliance.
[compliance = volume/pressure]
-if arterial compliance is constant = arterial pressure depends on volume of blood the artery contains at any time (systole/diastole)
Describe MAP.
[MAP = diastolic pressure + 1/3 pulse pressure]
-the pressure that drives blood into tissues during cardiac cycle
-monitored & regulated by BP reflexes
Describe dumping of the pressure pulses.
-compliance & resistance of arterial system = imp in reducing pressure pulsations
-blood doesn’t need to flow to peripheral vessels only during cardiac systole
-blood flows continuously & reaches capillaries with no pulsation
-degree of dumping is directly proportional to the product of resistance x compliance
Describe how pressure pulses waves travel.
- from high compliance (elastic arteries) to high resistance arteries (muscular arteries)
- intensity of pulsations become less in smaller arteries, arterioles, & capillaries
Describe elastic arteries.
-high compliance
-elastin
-pulse smoothing
-EX: aorta & carotid artery
Describe muscular arteries.
-high resistance
-smooth muscle
-capable to vasoconstriction/dilation
-EX: femoral & mesenteric arteries
Describe the TPR.
‘total peripheral resistance’
-resistance of systemic circulation (pressure difference)
[MAP = CO X TPR]
if MAP is increased, its due to CO or TPR increasing (or both)
Describe venous pressure VS arterial pressure.
-venous pressure in systemic circulation is lower than arterial pressure
-close to 0
-the resistance & compliance is due to the fall in pressure
Describe the CVP.
‘Central venous pressure’
REGULATED BY:
-ability of heart to pump blood out of RA & ventricle into the lungs
-tendency for blood to flow from peripheral veins into RA
*right heart pumps strong = RA pressure decreases
*weakness of heart rises RA pressure
What are the factors that increase venous return & RA pressure (CVP)?
- Increase in blood volume
- Increase in large vessel tone in body
-increase peripheral venous pressure - Dilation of arterioles
-decreased peripheral resistance
-allows rapid flow of blood from arteries into veins
*the factors that regulate RA pressure also regulate CO
Describe pulmonary circulation VS systemic circulation.
-pressure in pulmonary circulation is lower than systemic circulation
-pulmonary vascular resistance is lower
>1/12 resistance of systemic circulation
>pulmonary blood vessels are compliant & distend to increase blood flow
-blood flow through lungs match amount of air delivered to alveoli = ventilation-perfusion matching
Describe the baroreceptor reflex steps from high BP to low.
strongest stimulus = rapid change in MAP
1. Increase in MAP detected & increase firing rate of afferent nerves
2. Afferent nerves synapse at medulla & coordinate responses comes from medullary cardiovascular centers
3. Increase in parasympathetic activity to SA node = decrease HR
4. Decrease in sympathetic activity to SA node also decreases cardiac contractility = decrease in CO
5. Decrease in sympathetic activity dilates arterioles (a receptor) & decrease TPR
6. Lead to decrease in MAP
Describe the response of baroreceptor reflex to hemorrhage.
Low BP to high BP.
