Cardiac Muscle Flashcards
What is the difference in cellular structure between skeletal and cardiac muscle?
In skeletal muscle endoplasmic reticulum forms triads, and in cardiac muscle its dyads.
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?
The concentration gradient of K balances with the electrical gradient
How does cardiac muscle avoid temporal summation of contraction?
The refractory period is long enough so that the muscle twitch is over before another action potential can be generated.
What is the refractory period of cardiac muscle?
The window of time in which another beat cannot be generated
What is the relative refractory period of cardiac muscle?
The window in time in which another beat cannot be generated unless the pacemaker gives a strong stimulus
How is Ca2+ released in cardiac muscle cells for contraction?
By Ca-induced-Ca-release
When calcium enters the dyadic cleft it causes the release of more Ca via L-type Ca channels
What is the length-tension relationship/Frank-Starling law of the heart?
Increased sarcomeric length leads to increased force and Ca2+ sensitivity.
