CARDIOVASCULAR 9

Question 1

Cardiac performance in Ventricles: values

1) ESV = End systolic volume
2) EDV = End diastolic volume

Answer 1

1) ~65ml

2) 135ml

Question 2

Stroke volume?

Formula

Answer 2

Amount of blood pumped by 1 Ventricle in 1 contraction

EDV-ESV

Question 3

Cardiac Output?
Formula?
Normal blood volume
Cardiac reserve?

Answer 3

Amount of blood pumped per ventricle per unit time
HR x SV
5L
Difference between resting and maximal CO

Question 4

What affects stroke volumes?

1) Preload
2) Afterload

Answer 4

1) An increase in venous return to the heart increases the filled volume (EDV) of the ventricle
2) Pressure that the ventricle must generate in order to eject blood into the aorta

Question 5

Critical factor in controlling stroke volume?

Frank-Starling Law?

Answer 5

Preload of cardiac muscle cell.

Stroke volume increases with EDV

Question 6

What effect does exercise have on SV?

Answer 6

Slow heartbeat and exercise increase venous return to the heart - increase SV

Question 7

What decreases SV?

Answer 7

Blood loss

Extremely rapid heartbeat

Question 8

Series of “bags’ with different compliances

1) Large arteries
2) Large veins

Answer 8

1) Low compliance & capacitance

2) High compliance & capacitance

Question 9

How does an increased DEV lead to increased SV?

Answer 9

Stretch increases a number of crossbridges and approaches optimal sacromere length

Question 10

What affects EDV

Answer 10

Venous return

Question 11

Three factors that affect venous return;

Answer 11

1) Skeletal muscle pump
2) Respiratory pump
3) Sympathetic innervation

Question 12

Extrinsic factors influencing stroke volume

What is contractility? (2 factors)

Answer 12

Increase in contractile strength

1) Independent of stretch
2) Independent of EDV

Question 13

3 things that increase contractility

Answer 13

1) Increased sympathetic stimuli
2) Certain hormones
3) Ca2+ and some drugs

Question 14

Innervation and heart control

1) Stimulation
2) Inhibition

Answer 14

1) Sympathetic cardioacceleratory center

2) Parasympathetic cardioinhibitory center

Question 15

Catecholamines Modulate ?

Answer 15

Cardiac Contraction

Question 16

Inotropic effect

Answer 16

increase in neorepinepherine on contracitily of the heart: increase in stroke volume

Question 17

Contractility
Any chemical that affects contractility is an ?
1) Positive effects chemical
What is the Negative effect?
2) Negative chemicals

Answer 17

1) inotropic agent, Epinephrine and norepineprine
Decrease in contractility
2) b-Blocker and Ca2+ ch. blocker