Cardiac Muscle Physiology T Tubules and Calcium-induced Calcium Release

The video tutorial discusses the physiology of voltage gated sodium channels and their role in propagating action potentials along muscle cell membranes. It highlights the challenge of reaching deeper myofibrils for muscle contraction and introduces the T tubule system as a solution. The tutorial explains the propagation of action potentials through sodium channels and the role of calcium channels, specifically the DHP receptor and ryanodine calcium channel, in muscle contraction. The concept of calcium-induced calcium release and positive feedback is also covered.

What is the primary function of voltage-gated sodium channels in muscle cells?

• To release calcium ions

• To propagate action potentials

• To store energy

• To contract the muscle

What is the role of T-tubule systems in muscle cells?

• To produce energy

• To transmit action potentials to deeper myofibrils

• To release acetylcholine

• To store sodium ions

Which channel is activated after the voltage-gated sodium channels in the muscle cell membrane?

• Potassium channel

• L-type calcium channel

• Chloride channel

• Magnesium channel

What is the specific L-type calcium channel discussed in the video?

• Acetylcholine receptor

• Dihydropyridine receptor

• Ryanodine receptor

• Sodium-potassium pump

What is the function of the ryanodine calcium channel in muscle cells?

• To generate ATP

• To store calcium in the sarcoplasm

• To release calcium from the sarcoplasmic reticulum

• To transport sodium ions

What triggers the ryanodine calcium channel to release calcium?

• Potassium efflux

• Calcium influx through the DHP receptor

• Magnesium influx

• Sodium influx

What is the result of calcium-induced calcium release in muscle cells?

• Increase in cytosolic calcium concentration

• Decrease in sodium concentration

• Decrease in cytosolic calcium concentration

• No change in calcium levels