Author Question: What electrolyte inactivates troponin and allows actin and myosin to form a bridge enabling the ... (Read 77 times)

jCorn1234 · **on:** Jul 23, 2018

What electrolyte inactivates troponin and allows actin and myosin to form a bridge enabling the muscle fibers to contract?

A) Magnesium
B) Calcium
C) Potassium
D) Sodium

Question 2

The nurse is discussing the endocrine system with a class of nursing students. What substance would the nurse label as a hormone?

A) Acetylcholine
B) Norepinephrine
C) Nucleic acid
D) Serotonin

trog · **Reply #1 on:** Jul 23, 2018

Answer to Question 1

B
Feedback:
Calcium must be present to deactivate troponin so that actin and myosin can react to form actinomycin bridges. Potassium, sodium, and magnesium do not affect troponin.

Answer to Question 2

B
Feedback:
A hormone is secreted directly into the bloodstream and travels from the site of production to react with specific receptor sites to cause an action. Norepinephrine, which is a neurotransmitter, is a hormone when it is produced in the adrenal medulla, secreted into circulation, and travels to norepinephrine receptor sites to cause an effect. Acetylcholine and serotonin are neurotransmitters, but are not hormones. Nucleic acid is used to build deoxyribonucleic acid and ribonucleic acid.