Ch. 22

Question 1

Diastole

Answer 1

1. interval between closing of aortic valve and closing of mitral valve
2. Interval between closing of the pulmonary valve and closing of tricuspid valve

Question 2

Systole

Answer 2

1. interval between closing of mitral valve and closing of aortic valve
2. Interval between closing of the tricuspid valve and closing of pulmonary valve

Question 3

List the 3 pathways that lead to VSMC contraction.

Answer 3

1. increase Ca2+ –> increase Ca2+-CaM –> increase MLCK activity –> increase phosphorylation of MLC –> VSMC contraction.
2. decrease cAMP –> decrease PKA –> decrease phosphorylation of MLCK –> increase MLCK activity –> increase phosphorylation of MLC –> VSMC contraction
3. decrease cGMP –> decrease PKG –> decrease phosphorylation of MLCK –> increase MLCK activity –> increase phosphorylation of MLC –> VSMC contraction

Question 4

List the 3 pathways that lead to VSMC relaxation.

Answer 4

1. decrease Ca2+ –> decrease Ca2+-CaM –> decrease MLCK activity –> decrease phosphorylation of MLC –> VSMC relaxation.
2. increase cAMP –> increase PKA –> increase phosphorylation of MLCK –> decrease MLCK activity –> decrease phosphorylation of MLC –> VSMC relaxation
3. increase cGMP –> increase PKG –> increase phosphorylation of MLCK –> decrease MLCK activity –> decrease phosphorylation of MLC –> VSMC relaxation

Question 5

Vasomotion

Answer 5

Spontaneous contractions

Question 6

Is ventricular pressure higher in the left or right ventricle?

Answer 6

Significantly greater in the left ventricle.

Question 7

Draw pressure and volumes of the cardiac cycle for the left and right heart.

Answer 7

How’d you do?

Question 8

The aorta is i similar to what concept of physics?

Answer 8

Capacitor

Question 9

How is stroke volume affected by contractility, preload, and afterload?

Answer 9

Increased by: increase contractility and preload, decrease afterload

Question 10

Preload

Answer 10

Load present prior to contraction

Approximated by EDV

Depends on venous tone and circulating blood volume

Question 11

Afterload

Answer 11

Force resisting outflow from ventricle or shortening

Approximated by MAP

Arterial blood pressure is a measure of afterload

Question 12

Isovolumic Contraction

Answer 12

Endocardium (Clockwise)

Initial shortening of endocardial fibers causes stretching of epicardial fibers

Question 13

Ejection

Answer 13

Epicardium (Counterclockwise)

All layers activate and shorten causing contraction

Question 14

Isovolumic Relaxation

Answer 14

Endocardium (Clockwise)
Endocardium has postsystolic shortening, causing stretch in epicardial fibers and starting rotation in opposite direction, causing expansion

Question 15

Filling

Answer 15

Passive phase where all fibers being stretched to allow maximum filling

Question 16

Depolarization (Muscle Shortening)

Answer 16

Endocardial –> Epicardial (inside –> outside)

Question 17

Repolarization (Muscle Stretch)

Answer 17

Epicardial –> Endocardial (Outside –> inside)