Cardiac Muscle Flashcards Preview

FBS1 > Cardiac Muscle > Flashcards

Flashcards in Cardiac Muscle Deck (7)
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1
Q

What is the difference in cellular structure between skeletal and cardiac muscle?

A

In skeletal muscle endoplasmic reticulum forms triads, and in cardiac muscle its dyads.

2
Q

How is a negative charge on the inside of a cardiac muscle cell relative to the outside maintained while a high [k] is maintained relative to the outside?

A

The concentration gradient of K balances with the electrical gradient

3
Q

How does cardiac muscle avoid temporal summation of contraction?

A

The refractory period is long enough so that the muscle twitch is over before another action potential can be generated.

4
Q

What is the refractory period of cardiac muscle?

A

The window of time in which another beat cannot be generated

5
Q

What is the relative refractory period of cardiac muscle?

A

The window in time in which another beat cannot be generated unless the pacemaker gives a strong stimulus

6
Q

How is Ca2+ released in cardiac muscle cells for contraction?

A

By Ca-induced-Ca-release

When calcium enters the dyadic cleft it causes the release of more Ca via L-type Ca channels

7
Q

What is the length-tension relationship/Frank-Starling law of the heart?

A

Increased sarcomeric length leads to increased force and Ca2+ sensitivity.

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