Cardiac Muscle Contraction - Blue Book Flashcards Preview

My NBCE Part 1 - Cardiovascular Physiology > Cardiac Muscle Contraction - Blue Book > Flashcards

Flashcards in Cardiac Muscle Contraction - Blue Book Deck (27)
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1
Q

In resting state what ions are greater outside cell? Inside cell?

A
Outside  = Na+ and CA++
Inside = K+
2
Q

Phase O?

A

Na+ influx = rapid depolarization (rapid upstroke on graph)

3
Q

Phase 1?

A

Inactivation of Na+ influx

K+ efflux (notch of initial depolarization)

4
Q

Paste 2?

A

Plateau phase

Ca++ influx via (L-type Ca++ channels)

5
Q

Phase 3?

A

Inactivation of Ca++ influx

Continuation of K+ efflux (rest of repolarization)

6
Q

Phase 4?

A

Removal of excess Na+ and Ca++

Restoration of resting membrane potential using Na+/K+ pump (Na+ out, K+ in)

7
Q

What determines the force of the contraction in the myocardial cell?

A

Amount of intracellular Ca++

8
Q

No action potential can be initiated: called?

A

Absolute refractory period (ARP)

9
Q

What phase is the ARP?

A

Phase 1 through mid-3

10
Q

Why can their be no action potential during ARP?

A

Because Na+ channels are closed

11
Q

An action potential can be initiated but needs a greater stimulus?

A

Relative refractory period (RRP)

12
Q

RRP extends between which phases?

A

Mid-3 to start of phase 4

13
Q

Why is cardiac muscle incapable of tetani (sustained contraction) like in skeletal muscle?

A

b/c of relative long refractory period

14
Q

Cardiac output is directly proportional to the venous return. Law?

A

Frank Starling Law

15
Q

Frank Starling Law: force of contraction is _________ proportional to the length the myocardial fiber.

A

directly

16
Q

Frank Starling Law: the ___ the amount of blood entering the heart during diastole, the _____ the stretching of the cardiac myocytes.

A

Greater

greater

17
Q

Frank Starling Law: The greater the stretch, ?

A

The greater the force of contraction.

18
Q

1st heart sound is due to what? LUB

A

Closure of AV valves

19
Q

2nd heart sound is due to what? DUB

A

Closure of semilunar valves

20
Q

3rd heart sound: sound?

A

DUBup

21
Q

4th heart sound: sound?

A

deLUB

22
Q

3rd heart sound is heard in what condition?

A

Congestive heart failure

23
Q

4th heart sound is heard in what condition?

A

Hypertrophic ventricles

24
Q

3rd heart sound occurs after what?

A

2nd heart sound

25
Q

4th heart sound occurs when?

A

Before the 1st heart sound.

26
Q

Systole (contraction) occurs between what heart sounds?

A

1 and 2

27
Q

Diastole (relaxation) occurs between what heart sounds?

A

2 and 1