Cardio S20

Question 1

P-wave

Answer 1

depolarization of atria

• start: atria are still in full relaxation
• end: atria are still in contraction

Question 2

QRS Complex

Answer 2

depolarization of ventricles (also repolarization of atria; masked by large QRS complex)

• start: ventricles are still in full relaxation
• end: ventricles are still in contraction

Question 3

T-wave

Answer 3

repolarization of ventricles

• start: ventricles still in contraction
• end: no electrical or mechanical activity
• completion of cardiac cycle.

Question 4

U-wave

Answer 4

unknown; possible repolarization of papillary muscles or purkinje fibres.

Question 5

In the cardiac cycle… ________ comes before _________.

Answer 5

electrical, mechanical

Question 6

AV valves

Answer 6

allow flow from atria to into the ventricles

Question 7

semilunar valve

Answer 7

one way valves that existsbetween the ventricles and outflow artery

Question 8

ventricular systole

Answer 8

• isovolumic contraction

- ejection (rapid then reduced)

Question 9

ventricular diastole

Answer 9

• isovolumic relaxation

- filling (rapid then reduced)

Question 10

isovolumic contraction

Answer 10

• closure of AV mitral valve
• LUB
• blood volume=EDV or preload

Question 11

ventricular ejection

Answer 11

• opening of semilunar valve (AV valves closed)
• sharp increase in ventricular and aortic pressure (rapid)
• reduced ejection (end of closure of semilunar valves)

Question 12

isovolumic relaxation

Answer 12

• closure of semilunar
• DUB
• blood volume in ventricle = ESV

Question 13

stroke volume

Answer 13

difference between EDV & ESV

-the amount of blood pumped out of the ventricular per beat

Question 14

ventricular filling

Answer 14

• opening of the AV valve (semilunar are closed)
• majority of filling (rapid and passive)
• followed by reduced + active filling

Question 15

ventricular pressure-volume loop

Answer 15

dynamic changes in the left ventricle for one complete cardiac cycle
-left ventricular pressure vs left ventricular volume

Question 16

mitral valve

Answer 16

AV valve

Question 17

aortic valve

Answer 17

semilunar valve

Question 18

cardiac output

Answer 18

heart rate x stroke volume

-output of heart per unit time

Question 19

normal value of stroke volume

Answer 19

70 ml

Question 20

normal value for cardiac output

Answer 20

5-6 L/min

Question 21

cardiac index (CI)

Answer 21

a value used to minimize the influence of body size on cardiac output
-defined as CO per body surface area (BSA)

Question 22

increasing HR

Answer 22

• inverse effect on SV b/c ventricular filling time is decreased as diastolic period decreases
• increase CO

Question 23

exercising and heart rate

Answer 23

• reduction in vascular resistance
• increase of sympathetic activity
• enhanced venous return

Question 24

3 parameters that affect SV

Answer 24

• preload (affecting EDV)
• afterload
• contractility
• heart rate to a lesser degree

Question 25

preload (EDV)

Answer 25

ESV + venous return

Question 26

increase in preload will increase..

Answer 26

SV

Question 27

What affects preload?

Answer 27

the degree of stretching of the cardiac myocytes prior to contraction and the sarcomere length at the end of diastole

Question 28

preload is directly related too..

Answer 28

end diastolic ventricular blood volume and the intra-myocardial wall stress of ventricle at the end of diastole

Question 29

preload is indirectly related to…

Answer 29

ventricular end diastolic pressure

Question 30

preload is determined by..

Answer 30

• ventricular compliance
• venous return
• length-tension relationship
• HR (to a lesser extent)

Question 31

compliance

Answer 31

the change in volume divided by change in pressure

Question 32

high compliance

Answer 32

heart can be easily stretched during diastole (enhanced venous return)

Question 33

low compliance

Answer 33

heart will resist expansion during diastole (stiff)

Question 34

end-diastolic pressure-volume relationship (EDOVR)

Answer 34

reciprocal of compliance; reciprocal of slope is ventricular compliance

Question 35

steeper slope of EDPVR

Answer 35

• increases in ventricular volume

- centricle becomes les compliant or stiffer

Question 36

thick ventricular walls =

Answer 36

decreased compliance, decreased venous return, decreased EDV, decreased SV