Download Worksheet for 10/2 SI Session Muscle System 3

Muscle System 3
Supplemental Instruction
Iowa State University
SI Session
Leader:
Course:
Instructor:
Date:
Chelsea P
AnS 214
Dr. Adur
10/2/16
1. Number the following 1-6 in the order that they occur during a muscle contraction.
ADP and Pi are expelled from the myosin head, allowing it to return to the relaxed
90º state.
1
The myosin head is in the relaxed state, at 90º. Bound to it is an ATP molecule.
Myosin heads bind to the now exposed binding sites on actin.
The flexion of a relaxing myosin head pulls its attached actin strand in towards the
center of the sarcomere.
ATP on the myosin head is cleaved into ADP and Pi, forcing myosin heads into the
high energy, 'cocked', position.
The myosin head binds an ATP molecule, allowing it to release actin.
1. How do muscles relax?
2. Explain what happens in the muscle cells of an organism after it dies.
3. Describe the length-tension relationship. Include an explanation of what a sarcomere
looks like at the extremes and optimal position.
4. What are the 3 phases of a twitch?
1060 Hixson-Lied Student Success Center  515-294-6624  [email protected]  http://www.si.iastate.edu
5. What is the difference between unfused tetany and fused tetany?
6. What enzyme shuts off the stimulation to a muscle cell and starts the repolarization
of the sarcolemma and T-tubules?
7. Where is calcium stored in a muscle cell?
8. What does calsequestrin do? And where is it located?
9. What are the two sub-types of isotonic contractions? Define each.
Eccentric contractions:
Concentric contractions: