Answer:
Option). about 20 percent of the calcium ion required for contraction comes from outside the cell.
Explanation:
Calcium ions play an important role in cardiac muscle physiology. Calcium ions influx is responsible for plateau phase after depolarization. Calcium ions also play role in muscle contraction with the help of troponin (regulatory protein).
For contraction, about 20 percent of calcium ions are supplied from outside of the cell, while rest of the calcium ions are released from SR (sarcoplasmic reticulum).
Thus, the correct answer is 'forth option.'
How should you use a heart rate monitor?
Measure your heart rate before, during, and after workouts
Answer:
Talking about dying or wanting to die
Talking about feeling empty, hopeless, or having no way out of problems
Mentioning strong feelings of guilt and shame
Talking about not having a reason to live or that others would be better off without them
Social withdrawal and isolation
Giving away personal items and wrapping up loose ends
Saying goodbye to friends and family
