Test 2 - vascular hemodynamics

Question 1

study of blood pressure and blood flow throughtout the circulatory system

Answer 1

hemodynamics

Question 2

hydrostatic pressure measured within a given structure, either cardiac chamber, or a blood vessel

Answer 2

blood pressure

Question 3

capacity to contain a varying volume of blood

Answer 3

distensibility

Question 4

blood pressure is caused by

Answer 4

the recoil of the vessel walls against the blood, and its value is proportional to the stressed volume

Question 5

determines what the pressure will be, relative to the stressed volume

“reflects the underlying stiffness of the blood vessels”

Answer 5

compliance

P - blood pressure

V - blood volume

V_o - unstressed volume

C - compliance

(V-V_o) - stressed volume

Question 6

distension and recoil are ____ related in relationship with blood volume

Answer 6

inversely

distension: blood volume UP
recoil: blood volume DOWN

Question 7

encompasses both the unstressed volume (V_o) and the compliance (C) of blood vessels

“capacity of how much blood a region of the circulation may contain”

Answer 7

capacitance

Question 8

if you keep capacitance (V_o and C) constant:

blood pressure will then vary in _______ to changes in total blood volume

Answer 8

direct proportion

Question 9

for a given blood volume: blood pressure will then vary ________ to a change in capacitance

Answer 9

inverserly

Question 10

increased capacitance: compliance and/or V_o is ____

Answer 10

increased

Question 11

the capacitance of ______ is under reflex control

distributing arteries

or

collecting venules and distal veins

Answer 11

collecting venules and distal veins

Question 12

blood pressure is uniformly _____ throughout distributing arteries,

_______ within the collecting venules and veins

Answer 12

HIGH arteries

LOW venules and veins

Question 13

T/F: blood pressure at the distal end of arteries is almost >95% as high as the pressure within the ascending aorta

Answer 13

TRUE

Question 14

arterioles and capillaries present significant resistance to blood flowing through them

Answer 14

peripheral resistance (R_p) - reflexive control

Question 15

T/F: central venous blood pressure is approximately 10% of the central arterial pressure

Answer 15

TRUE

Question 16

vascular resistance is determined by the size of the blood vessel and by the viscosity of the blood

what law is this?

Answer 16

Poiseuille’s law

diameter - most important

viscosity - normally constant

length of vessel - constant

Question 17

determines how high the upstream pressure (P_up) must be (relative to the pressure downstream) to cause a given rate of flow (Q_out) through the distal resistance

Answer 17

resistance (R)

Question 18

T/F:

on average Q_out = Q_in = Q

Answer 18

TRUE

however, at any given instant, Q_out may not equal to Q_in

Question 19

if resistance is held constant:

Q_out is dependent upon, and varies in _______ to, upstream pressure

Answer 19

direct proportion

Question 20

if the upstream pressure is held constant:

Q_out varies ______ to changes in the distal resistance (R)

Answer 20

inverse

Question 21

pressure upstream from a point of resistance, dependent upon ______ and _______

Answer 21

reate of flow through the vascular region (Q)

and

value of resistance (R)

“ohm’s law”

Question 22

(P_up-P_down) measures the amount of pressure dissipated by flow across the ______

Answer 22

resistance

Question 23

flow of blood through the microcirculation

Answer 23

perfusion

“net flow of blood from arteries into veins”

Question 24

upstream arterial pressure:

P_a > ____mmHg

downstream venous pressure

P_v < _____mmHg

Answer 24

UPstream: >70mmHg

DOWNstream: <15mmHg

Question 25

for a given Q from the L heart into system arterial circulation, the arterial blood pressure (P_a) will _____ to whatever value necessary to maintain this rate of flow through the peripheral resis. imposed by arterioles and capillaries

Answer 25

RISE

Question 26

pressure-volume: volume needed to achieve a given upstream pressure is dependent upon the _______

Answer 26

vascular capacitance

(C and V_o)

Question 27

pressure-flow: upstream pressure needed to achieve a given rate of outlow is dependent upon the __________

Answer 27

downstream vascular resistance (R)

Question 28

Q_in: blood from the lungs is pumped into the disributing arteries as _______

Q_out: blood flows from the distributing arteries as ______ to perfuse the tissues

Answer 28

Q_in: blood from the lungs is pumped into the disributing arteries as cardiac output (Q_co)

Q_out: blood flows from the distributing arteries as peripheral runoff (Q_a->V) to perfuse the tissues

Question 29

the collective opposition (resistance) to blood flowing through the systemic arterioles and capillaries

Answer 29

peripheral resistance (R_p)

Question 30

“windkessel” network

FLOW IN: _____ from left ventricle

FLOW OUT: ______ through microcirculation

Answer 30

IN: cardiac output

OUT: peripheral runoff

Question 31

if arterial blood pressure remains constant: peripheral runoff _____ rate of cardiac output

Answer 31

matches

Question 32

if arterial blood pressure increases: peripheral runoff _____ rate of cardiac output

match

exceeds

less than

Answer 32

less than

Question 33

if arterial blood pressure decreases: peripheral runoff _____ rate of cardiac output

matches

exceeds

less than

Answer 33

exceeds