Cardiac Output And Control Of Cardiac Function

Front 1

Cardiac output is

Back 1

the volume of blood pumped by each ventricle per minute

Front 2

The unit for cardiac output is

Back 2

L/min

Front 3

Average cardiac output is approximately

Back 3

5 L/minute

Front 4

Stroke volume is

Back 4

The amount of blood ejected by each ventricle with each beat

Front 5

The equation for cardiac output (CO) is

Back 5

SV x HR

Front 6

The total blood volume in a normal individual is approximately

Back 6

5 liters

Front 7

The SA node is innervated by

Back 7

parasympathetic and sympathetic postganglionic nerve fibers

Front 8

Parasympathetic activity to the SA node causes

Back 8

decrease in rate of firing and HR decrease

Front 9

Sympathetic activity to the SA node causes

Back 9

increase in rate of firing and HR increase.

Front 10

At rest, _______ activity to the SA node dominates

Back 10

parasympathetic

Front 11

Increasing sympathetic activity to SA node increases heart rate by

Back 11

increasing number of F-type sodium and T-type calcium channels that open, which reaches threshold faster.

Front 12

Increasing parasympathetic activity to SA node decreases heart rate by

Back 12

decreasing number of F-type sodium and T-type calcium channels that open and hyperpolarizing ell, which reaches threshold slower.

Front 13

In addition to norepinephrine, sympathetic activity to SA node is also increased by

Back 13

epi from adrenal medulla.

Front 14

The AV node is innervated by

Back 14

parasympathetic and sympathetic postganglionic nerve fibers

Front 15

Increasing the relative amount of sympathetic activity to the AV node

Back 15

increases velocity of conduction of AP through AV node.

Front 16

Increasing the relative amount of parasympathetic activity to the AV node

Back 16

decreases velocity of conduction of AP through AV node.

Front 17

Other than ANS innervation, factors that can affect resting HR include

Back 17

body temperature, alterations in serum electrolyte concentrations, and adenosine.

Front 18

Stroke volume can be altered by changing

Back 18

EDV (preload), ESV, aortic blood pressure (afterload), sympathetic activity

Front 19

Ventricles contract more forcefully if

Back 19

they have been filled to a greater degree during preceding diastole

Front 20

The Frank-Starling mechanism is

Back 20

as EDV increases, stroke volume increases.

Front 21

The Frank-Starling mechanism is due to

Back 21

length-tension properties of cardiac muscle

Front 22

In general, increase in initial fiber length in cardiac muscle will

Back 22

increase contractile force.

Front 23

Sympathetic nerves don’t just innervate SA and AV, they innervate

Back 23

myocardium

Front 24

Cardiac contractility is

Back 24

strength of contraction at any given ventricular EDV.

Front 25

Increased activity in sympathetic nerves increases

Back 25

cardiac contractility

Front 26

Changes in contractility are independent of

Back 26

changes in EDV.

Front 27

Stroke volume is ______ at any given EDV during sympathetic stimulation compared to without sympathetic stimulation.

Back 27

greater.

Front 28

Resting ejection fraction is

Back 28

60%

Front 29

Mechanisms responsible for increases in cardiac contractility are

Back 29

1. Opening more plasma membrane L-type ca2+ channels during plateau phase increases amount of Ca2+ released from SR, 2. Stimulation of active Ca2+ reabsorption into SR, 3. Altering in binding of Ca2+ to troponin.

Front 30

The effect of parasympathetic activity on cardiac contractility is

Back 30

little to none

Front 31

Increases in cardiac contractility are the result of

Back 31

increases in amount of free Ca2+ in cytosol during contraction and increases in rate of removal during relaxation.

Front 32

Afterload is

Back 32

magnitude of aortic pressure or pulmonary artery pressure against which ventricle must eject its load of blood

Front 33

Increases in afterload without operation of any compensatory actions will cause

Back 33

SV to decrease

Front 34

Cardiac output is increased by

Back 34

1. increasing SV through increase in EDV, sympathetic activity, or plasma epinephrine, 2. Increasing HR through increase in sympathetic activity, plasma epinephrine, or decrease in parasympathetic activity.