L14 - Myocyte Contraction Coupling

Question 1

What is the syncytium?

Answer 1

groups of muscle myofibrils connected by intercalated discs.

Question 2

What are gap junctions?

Answer 2

Electrical links between cells.

Question 3

Where does the calcium come from for cardiac contraction?

Answer 3

• Influx from the ECF via L-Type calcium ion channels (Cav1.2)
• Activation of ryanodine receptor type 2 on SR - CICR (largest contribution)

Question 4

How is the removal of calcium mediated

Answer 4

By a number of proteins

Question 5

How does SERCA2 aid in the removal of calcium?

Answer 5

Its an ATPase which uses energy from ATP to pump calcium back into the sarcoplasmic reticulum.

Question 6

How does PMCA aid in the removal of calcium?

Answer 6

Its an ATPase which pumps calcium out of the cell along the electrochemical gradient in exchange for H+

Question 7

How does NCX1 aid in the removal of calcium?

Answer 7

It brings 3 sodium into the cell in exchange for calcium.

Question 8

How does MiCa aid in the removal of calcium?

Answer 8

the channels open so that the calcium moves into the mitochondria.