ch 36 - second A

Question 1

equation for cardiac output

Answer 1

CO =HR x SV

Question 2

Determined by myocardial contractility, cardiac afterload and preload

Answer 2

stroke volume

Question 3

the amount of tension (stretch) applied to a muscle before contraction

Answer 3

Preload

Question 4

the load a muscle must overcome in order to contract

arterial pressure that the left ventricle must overcome to eject blood

Answer 4

Afterload

Question 5

if Afterload increased, _____ will decrease

Answer 5

SV (stroke volume)

Question 6

If afterload falls, _____ will rise

Answer 6

SV

Question 7

the force of ventricular contraction is proportional to muscle fiber length (up to a point)

Answer 7

Starling Law

Question 8

most important factor that determines venous return

Answer 8

systemic filling pressure (force that returns blood to the heart)

Question 9

what raises filling pressure?

Answer 9

constriction of veins

increase in blood volume

Question 10

formula for arterial pressure

Answer 10

AP = PR x CO

PR is peripheral resistance
CO is cardiac output

Question 11

Arterial pressure is regulated by what 3 systems

Answer 11

Autonomic NS
RAAS
Kidneys

Question 12

The Autonomic Nervous System regulates Arterial pressure by adjusting

Answer 12

Cardiac output and Peripheral resistance

Question 13

Baroreceptor reflex

Answer 13

Baroreceptors sense BP in the aortic arch and carotid sinus and relay info to the medulla

1-When Arterial pressure drops, vasoconstriction of all arterioles which increases Peripheral Resistance
2-Constriction of all veins, increases venous return
3-Accelerated HR

1-When Arterial pressure rises, dilation of arterials which decrease peripheral resistance
2-Dilation of all veins, decreases venous return
3-slows HR

Question 14

RAAS supports arterial pressure by

Answer 14

1) constricting arterioles and veins

2) retention of water by the kidneys

Question 15

In the RAAS system, Vasoconstriction is mediated by what hormone

Answer 15

Angiotensin II

Question 16

In the RAAS system, water retention is mediated in part by what hormone

Answer 16

aldosterone through retention of sodium

Question 17

what is the fastest way the RAAS works

Answer 17

Vasoconstriction (hours)

Question 18

what is the slowest way that RAAS works

Answer 18

Water retention (days)

Question 19

when AP remains low for a long time, the kidneys respond by

Answer 19

retaining water which in turn causes Arterial pressure to rise. (fluid retention increases blood volume )

Question 20

Reduction in AP causes the kidneys to

Answer 20

retain water, because low AP reduces renal blood flow (RBF), which in turn reduces GFR

Question 21

reduction in AP that can occur when we move from a supine or seated position to an upright position

Answer 21

orthostatic hypotension

Question 22

when postural hypotension occurs, the baroreceptor reflex can restore AP by

Answer 22

1) constricting veins and arterioles

2) increasing HR

Question 23

Drugs that reduce arterial pressure by relaxing veins can trigger what which causes what

Answer 23

the baroreceptor reflex and cause reflex tachycardia

Question 24

Natriuretic peptides serve to protect

Answer 24

the cardiovascular system in the event of volume overload

Question 25

Natriuretic peptides work primarily by

Answer 25

1) reducing blood volume

2) promoting dilation of arterioles and veins

Question 26

what are the 3 main members of Natriuretic peptides

Answer 26

Atrial Natriuretic peptide (ANP)
B- or brain natriuretic peptide (BnP)
C-natriuretic peptide (CNP)

Question 27

when are the natriuretic peptides released

Answer 27

when blood volume is excessive

Question 28

How does ANP and BNP work

Answer 28

reduce blood volume
increase venous capacitance

which decreases preload

Question 29

what is the main action of CNP

Answer 29

promote vasodilation

Question 30

If afterload is increased what happens to the stroke volume?

Answer 30

decreases

Question 31

Beta 1 adrenergic agents help increase the hearts stroke volume by

Answer 31

increasing myocardial contractility

Question 32

if arterial pressure decreases what happens to HR

Answer 32

increases