Hemodynamics

Question 1

What is vasculature?

Answer 1

the blood vessels of the body

Question 2

What is a circuit?

Answer 2

a network of blood vessels that begins and ends at the heart

Question 3

what circuits are the vasculature divided into?

Answer 3

pulmonary and systemic circuit

Question 4

What does the pulmonary circuit contain?

Answer 4

the blood vessels within the lungs, and those that transport blood bw the heart and lungs

Question 5

what does the systemic circuit contain?

Answer 5

blood vessels within all other organs, and those that transport blood between the heart and those organs

Question 6

What is series flow?

Answer 6

the movement of blood thru different types of blood vessels in sequence

Question 7

what are the 5 types of blood vessels?

Answer 7

arteries, arterioles, capillaries, venules, veins

Question 8

what is parallel flow?

Answer 8

movement of blood thru different organs at the same time

Question 9

What is blood flow?

Answer 9

the rate at which blood moves thru the vasculature

Question 10

what does blood flow measure?

Answer 10

the efficiency of blood movement to and from the tissues

Question 11

what are the determinants of blood flow?

Answer 11

pressure difference and vascular resistance

Question 12

What is pressure difference?

Answer 12

the force that drives blood thru the circuits

Question 13

What ventricle drives the blood thru the pulmonary circuit?

Answer 13

right ventricle

Question 14

What ventricle drives the blood through the systemic circuit?

Answer 14

left ventricle

Question 15

what are the units of pressure difference?

Answer 15

mmHg or kPa

Question 16

what does pressure difference calculation rely on?

Answer 16

mean arterial pressure (MAP)

Question 17

how does blood pressure vary during the cardiac cycle?

Answer 17

high during systole, low during diastole

Question 18

does the pressure difference vary between circuits? How so?

Answer 18

yes, pulmonary circuit is usually 15mmHg and 95 mmHg in the systemic circuit

Question 19

what is vascular resistance?

Answer 19

an impediment to blood flow; a measure of how much friction is encountered by blood as it moves thru the vasculature

Question 20

what are the 3 determinants of resistance in a single blood vessel?

Answer 20

length, radius of blood vessel, viscosity of blood

Question 21

what is blood viscosity affected by? what is it and what is its relationship with viscosity?

Answer 21

hematocrit; the percent of blood vol occupied by red blood cells; as hematocrit increases so does viscosity

Question 22

what factors increase resistance? decrease resistance?

Answer 22

increases with increasing length and viscosity; decreases with increasing radius

Question 23

what causes blood flow to increase and decrease?

Answer 23

increases with increased pressure difference and radius; decreased with increasing length and viscosity

Question 24

changes in radius have what kind of effect on flow? what does that mean?

Answer 24

disproportionate; small changes in radius will have a large effect on flow

Question 25

what is total peripheral resistance (TPR) and systemic vascular resistance (SVR)?

Answer 25

resistance in the systemic circuit

Question 26

what is pulmonary vascular resistance (PVR)?

Answer 26

resistance in the pulmonary circuit

Question 27

what is a typical TPR?

Answer 27

19 mmHg/L/min

Question 28

what is a typical PVR?

Answer 28

3 mmHg/L/min

Question 29

Why is PVR lower than TPR?

Answer 29

the pulmonary circuit is shorter, and arterioles are structured different from those in the systemic circuit

Question 30

what is the main source of resistance in the systemic circuit? what percentage?

Answer 30

resistance within the arterioles; 60%

Question 31

what happens to arterioles when the smooth muscle within it contracts?

Answer 31

decreases arteriole radius and increases resistance

Question 32

what happens to arterioles when the smooth muscle within it relaxes?

Answer 32

increase arteriole radius and decrease resistance