Cardiac Output

Question 1

volume of blood ejected from one ventricle of the heart during one minute

Answer 1

cardiac output

Question 2

what is the equation for cardiac output

Answer 2

CO = HR + SV

Question 3

what is the equation for ejection fraction

Answer 3

EF = (EDV-ESV)/EDV

fraction of blood pumped each beat

Question 4

what is normal value of ejection fraction

Answer 4

55-67%

Question 5

what are the ways to regulate cardiac output

Answer 5

1. preload
2. afterload
3. inotropic state of cardiac muscle (amount of Ca2+)

Question 6

how does the heart modulate inotropic state

Answer 6

amount of calcium in SR

Question 7

90 percent of calcium comes for the

Answer 7

SR

Question 8

what are the physiological modulators of inotropic state

Answer 8

1. sympathetic via activation of cAMP-> phosphory of Ca channels-> faster AP conduction
2. parasympathetic via G activation-> low cAMP-> low phosphory of Ca

Question 9

what does phosphorylation of phospholambam do

Answer 9

reduces phospholambams ability to inhibitn SERCA 2 from storing Calcium ion SR

Question 10

what effect does a higher inotropic state have on ESV

Answer 10

decreases or lowers

Question 11

what effect does a higher inotropic state have on stroke volume

Answer 11

increases

Question 12

what are cardiac glycosides and how do they work

Answer 12

inhibit Na/K pump -> accumulation of Na in cell -> Na/Ca exchanger -> higher calcium inlfux, stronger contraction

Question 13

what doe methylxanthines do

Answer 13

(caffeine) inhibit PDE -> cAMP

Question 14

how can DHP channels become inhibited

Answer 14

ischemia (low ATP)

H+

Question 15

long resting length _____ velocity

Answer 15

increases

Question 16

stroke volume increases as _____ ______ increases

Answer 16

ventricular volume

Question 17

what does hypertension do to the afterload

Answer 17

increases the afterload

Question 18

T/F the length-tension relationship can compensate (in some situations) for an increase in preload

Answer 18

True

Question 19

LVEDV stands for

Answer 19

left ventricular end diastolic volume = full of blood with low pressure

Question 20

increased afterload, leads to a reduced SV, leads to a(n) _______ EDV

Answer 20

increased

Question 21

increase preload = _____ SV

Answer 21

increase

Question 22

positive inotrope = ______ SV

Answer 22

increase

Question 23

increase afterload = ______SV

Answer 23

decreased

Question 24

how do chronotropic effects increase the filling time

Answer 24

by reducing systolic time

Question 25

what do chronotropic agents do

Answer 25

increase speed conduciton

Question 26

effect of B1 on the heart

Answer 26

1. increase force of contraction
2. increase conduction velocity
3. increase speed of contraction/relaxation
4. increase rate of rise of pacemaker potential

Question 27

increasing the HR has what effect on stroke volume

Answer 27

decreases

Question 28

what is the most important limiting factor for CO

Answer 28

mean systemic filling pressure (Psf)