CARDIO PHYSIO

Question 1

what is flow directly proportional to? indirectly?

Answer 1

pressure

resistance

Question 2

how do we define the CO?

Answer 2

total amount of blood flow out of the left ventricle per minute which is the amount of blood pumped per minute by the right ventricle and equal to venous return

Question 3

T/F, CV is a closed or open system?

Answer 3

closed

Question 4

what is the equation for CO? how much does the healthy resting adult heart pump?

Answer 4

stoke volume x heart rate

4.9 L/min

Question 5

what is the equation for stroke volume?

Answer 5

EDV-ESV

120mL-50mL=70 mL
* 50mL is amount left in the ventricle

Question 6

what is the average drop in pressure per liter of flow in systemic circulation?

Answer 6

19 mm Hg

Question 7

affect of increased preload?

Answer 7

increase SV, increase CO

Question 8

affect of increased afterload?

Answer 8

decrease SV, decrease CO

Question 9

affect of resistance on increase in viscosity, increase in length of tube, increase radius of tube?

Answer 9

increase resistance

increase resistance

decrease resistance

Question 10

what is the affect of more vascular beds in parallel on resistance?

Answer 10

decrease resistances and so less work for the heart and lower pressure for same CO

Question 11

what is the difference in velocity and volume of blood?

units and definition

Answer 11

volume mLs/min
velocity meters/sec

volume of flow is in reference to amount of blood and velocity is speed of the blood

Question 12

what is velocity a function of?

Answer 12

total cross sectional area for vessel types

Question 13

velocity in aorta is less or more than capillary? if so, by how much or less? what about the aorta compared to the vena cava?

Answer 13

yes, 1000x

3x greater

Question 14

when do you read diastolic pressure?

Answer 14

when you stop hearing sound when using a blood pressure cuff

Question 15

what are the blood volume (young man, 65 y/o male) and distribution (heart, systemic circulation)?

Answer 15

6 L
5 L

heart 7%
systemic circ 84%
-veins 64%
-arteries 13%
-caps and arterioles 7%
pulmonary 9%

Question 16

how does the increase in pressure increase the flow? 2 ways

Answer 16

increase change in pressure

increase radius

Question 17

veins are how many times more distensible than arteries?

Answer 17

8x

Question 18

why is it much more difficult to have increase arterial pressure in the pulmonary system?

Answer 18

b/c is decreases the tendency to form edema in the lungs

Question 19

what is compliance?

Answer 19

measure of adaptability of a vessel in terms of how much blood it holds with increase pressure which is a change in volume with a change in pressure

Question 20

distensibility?

Answer 20

stretch dealing with cross sectional area

Question 21

a systemic vein is how much more distensible than an artery and contracts how much blood compared to it?1

Answer 21

8 times

3 times

Question 22

what are the effects of sympathetics on the heart?

why is this important

Answer 22

vasoconstrictor veins
decrease distensibility and compliance
increase venous return leading to increase EDV
increase stroke volume and increase cardiac output

its important to the body’s rapid response to severe blood loss or exercise

Question 23

what is the effect of the parasympathetic on the blood vessels?

Answer 23

vasodilate to decrease venous return

Question 24

what is the effect of vessels that are less distensible?

Answer 24

increase pulse pressure and peak systolic pressure increases to 160 mmHg and more

Question 25

what is pressure proportional too?

Answer 25

pressure x radius, leading to more stretching

Question 26

what happens when a weakened portion of a vessel is more easily stretched? what is a known syndrome that can cause this?

Answer 26

increased radius and tension leading developing an aneurysm

marfans syndrome

• weak collagen
• aneurysm
• rupture
• death

Question 27

what is CVP?

Answer 27

near zero as long as the right atrium doesn’t accumulate blood, so the right atrial blood stays low as long as the right ventricle pumps well

Question 28

what increases CVP?

Answer 28

increase venous return due to increase blood volume, venous constriction, arterial dilation

decrease right ventricular pumping

Question 29

what can cause venous return decrease?

Answer 29

hemorrhage due to negative pressure because of negative intrapleural pressure inside chest

Question 30

what is the effect of leg muscles contracting?

Answer 30

help to push blood upward through valves in the venous side and so if no contraction you increase pooling, decrease pooling return and so fainting occurs