Question

physiology of muscle contraction, select the correct description of the step from the following three options

step 1

a. Ca moves out of the synaptic knob triggering exotyosis of acetylcholine

b. Ca moves into synaptic knob, triggering exotyosis of acetylcholine

c. Ca moves into synaptic knob triggering endocytosis of acetylcholine

step 2.

a. acetylcholine binds to CG-NA channels, Na moves into myofiber

b. acetylcholine binds to CG-NA channels, Na moves out of myofiber

c. acetylcholine binds to CG-NA channels, Ca moves out of myofiber

step 3

a. an action potential propagated down sarcoplasmic reticulum

b. action potential propagated down t-tubules

c. action potential propagated down sarcomere

step 4

a. Ca diffuses into sarcoplasm through VG-NA channels

b. Ca diffuses to sarcomere through CG-Ca channels

c. Ca diffuses into sarcoplasm through Ca release channels

step 5

a. Ca binds to troponin

b. Ca binds to tropomyosin

c. Ca diffuses into sarcoplasm through Ca release channels

step 6

a. troponin moves away from myosin binding sites

b. cross bridge forms

c. tropomyosin moves away from myosin binding sitea

step 7

a. myosin binds actin

b. mtosin binds tropomyosin

c. sctin binds troponin

Answer 1

Step 1 answer is Option b ye sit will cause movement of Calcium into synaptic knob causing exocytosis of Ach.

Step 2 is Option b acetylcholine binds to CG-NA channels, Na moves into myofiber that is entry from ECF

Step 3 is Option b action potential propagated down t-tubules

Step 4 is Option a Ca diffuses into sarcoplasm through VG-NA channels in the t tubule

Step 5 is a that is Calcium bind with troponin to change position

Step 6 is Option c as tropomyosin moves away from myosin binding sites

Step 7 is myosin bind to actin