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Physiology Exam 1 Semester 1 > Lecture 7 > Flashcards

Lecture 7 Flashcards

(45 cards)

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1
Q

What are the special requirements of cardiac action potential?

A
  1. Must be self generating
  2. Must be prolonged
  3. Propagate from myocyte to myocyte
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2
Q

In terms of cardiac muscle action potential phase 4 is what?

A

Resting potential

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3
Q

In terms of cardiac muscle action potential phase 0 is what?

A

Rapid depolarization

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4
Q

In terms of cardiac muscle action potential phase 1 is what?

A

initial, incomplete repolarization

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5
Q

In terms of cardiac muscle action potential phase 2 is what?

A

Plateau or slow decline of membrane potential

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6
Q

In terms of cardiac muscle action potential phase 3 is what?

A

Repolarization

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7
Q

What are the characteristics of fast type contractile myocytes? What is an example?

A
  • Large Diameter
  • High Amplitude
  • Rapid onset of action potential
    EXAMPLE: Ventricle
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8
Q

What are the characteristics of fast type non-contractile myocytes? What is an example?

A
  • Very large diameter
  • Very rapid upstroke
    EXAMPLE: Purkinje Fibers
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9
Q

What are the characteristics of slow type non-contractile myocytes? What is an example?

A
  • Small diameter
  • Low amplitude
  • Slow rate of depolarization
    EXAMPLE: SA or VA node
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10
Q

What is it called when it is impossible to generate another action potential?

A

Absolute Refractory Period

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11
Q

What is it called when a stronger than normal stimulus can generate an action potential?

A

Relative Refractory Period

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12
Q

The triceps muscle while lowering down into the floor during pushup is eccentric or concentric?

A

Eccentric

  • Pull up:
    Triceps: UP: Eccentric DOWN: Concentric
    Biceps: UP: Concentric DOWN: Eccentric
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13
Q

What maintains optimum calcium concentration gradient to facilitate return of calcium to SR?

A

Calsequestrin

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14
Q

What happens after ATP binds to the myosin?

A

Release of the myosin head from the actin binding site.

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15
Q

What is the order of the make up of a muscle? Start with muscle –>

A

Muscle–> fasicle –> myofibers –> myofibrils –> actin and myosin

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16
Q

What makes up a sarcomere?

A

Actin and myosin (myofilaments)

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17
Q

Long chain or sarcomeres is what?

A

Myofibrils

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18
Q

What does not go with change in length during a contraction?

A

A band

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19
Q

What bands are composed entirely of actin filaments?

20
Q

DHP is composed of what?

21
Q

What causes an action potential in the ventricular fiber action potential?

Study These Flashcards
A

Opening of fast sodium channels and slow calcium sodium channels

22
Q

Source of calcium necessary for electrical mechanical coupling from the T tubules via diffusion through voltage dependent calcium channels is called what?

Study These Flashcards
A

Dihydropyridine receptors

23
Q

L type calcium channels are found in the t tubule membrane are called what?

Study These Flashcards
A

Dihydropyridine receptors

24
Q

During the absolute refractory period is it impossible to generate another action potential? T or F

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A

True it is impossible

25
During the relative refractory period what can generate an action potential?
A stronger than normal stimulus.
26
What is considered the pacemaker of the heart?
SA node
27
The resting membrane potential of SA node fiber are fast sodiums channels that are already what?
inactivated (block)
28
If only slow sodium calcium channels can open the atrial node action potential is what? And repolarization is what?
Is slower to develop with slower repolarization
29
At resting potential the membrane potential approaches what?
K+ equil. potential.
30
Action potentials originating in the SA node generates what?
A sinus rhythm
31
Compared to skeletal muscle cardiac muscle has far fewer what?
calcium induced calcium release channels
32
What are the two transporters for relaxation?
SERCA and sodium calcium exchange in the sarcolemma
33
What is SERCA and what does it do?
Sarcoplasmic reticulum calcium ATPase, return calcium to the sarcoplasmic reticulum during diastole
34
What does the sodium calcium exchanger in the sarcolemma do?
Transport calcium out of the cell.
35
What valves are closed during systole?
AV valves
36
What happens at the end of ventricular systole?
AV valves open at the end of systole because of increased pressures in the atria
37
What happens in atria as a primer pump?
About 80% of blood flows from the atria to the ventricles before the atria contract
38
What happens during the first third diastole?
Rapid filling
39
What happens during the middle third of diastole (diastasis)
Small amount of blood flows into the ventricles representing blood that continues to flow into atria during diastole
40
What happens in the last third of diastole?
Atria contract to push last 20% of blood into the ventricles
41
What happens in isometric contraction?
Ventricles contract but semilunar valves do not open
42
What happens during the period of rapid ejection?
Occurs when left ventricular pressure is a little above 80mmHg, semilunar valves open, occurs during the first third of ejection
43
What happens during the period of slow ejection?
Remaining 30% of blood is ejected from the ventricles, occurs during the last two-thirds of ejection
44
What are the Frank-Starling Law?
The greater the heart muscle is stretched during filling, the greater the force of contraction and the greater the quantity of blood pumped into the aorta
45
What does the stretching of the cardiac muscle do?
Brings the actin and myosin filaments to a more nearly optimal degree of overlap for force generation

Physiology Exam 1 Semester 1 (7 decks)

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