KNES 259 Study Guide - Final Guide: Myoglobin, Agonist, Golgi Tendon Organ

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orchidcrab540

17 Dec 2016

School

University of Calgary

Department

Kinesiology

Course

KNES 259

Professor

Ronald Reed Ferber

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Document Summary

Action potential arrives at the neuromuscular junction (axon terminal end meets the muscle end plate) Acetylcholine is released from the axon end and binds to receptors on the muscle endplate: creating an epp (end-plate potential or muscle graded potential) Epp travels to the side of the end plate and triggers a muscle action potential. The ap moves down the t-tubules to the inner core of the muscle. The ap voltage change in the t-tubules triggers the release of ca+ from the sarcoplasmic reticulum: ap activates the dhp receptors and opens ryanodine gates to release ca+ from the s. r. Ca+ binds to troponin, which shifts the tropomyosin to expose the myosin binding site. The myosin head pivots, increasing the overlap of actin and myosin: sarcomere shortening. Myosin binds atp so that the head can release from actin. Atp hydrolyzes into adp + p: allowing the myosin to re-pivot. Myosin is now re-energized and ready to attach to another actin molecule.

Related Questions

Describe the process of skeletal muscle contraction by assembling the following 10 events in the proper order. Your answer must be written in complete sentences- do not just list the letters or the events- write it out. Begin your description with an action potential traveling down a motor neuron and end with the muscle in it's relaxed state.

A) T and T system undergoes a conformational change, exposing the myosin binding sites on actin

B) myosin heads/cross bridges bind to actin and flex, shortening the sacromere

C) the motor neuron triggers an action potential at the neuromuscular junction

D) calcium ions bind to the T and T system

E) actin filaments are pulled toward the center of the sacromere, shortening the muscle fiber

F) muscle fiber is stimulated at the neuromuscular junction

G) myosin head/cross-bridges bind to actin

H) APs travel down the T-tubules to the sarcoplasmic reticulum

I) in response to an AP, calcium ions are released into the cytosol/space around the myofibrils

J) calcium ions actively transported into the sarcoplasmic reticulum

K) myosin head continues to attach, flex, release, extend, and reattach as long as calcium ions are present

lilacporcupine860

1.If the supply of ATP to a shortening muscle is completelydepleted, what will happen to the cross-bridge cycle? What is thename if the phenomenon that results from complet ATP depletion?

2.Order the following 10 events that summarize musclecontraction. Remember that a muscle contraction begins with thetransmission of a nerve impulse to a muscle fiber

a. the power stroke

b. Opening of ryanodine Ca2+ channels in the sarcoplasmicreticulum

c. Binding of mysosin cross-bridges to actin

d. release of acetylcholine into the neuromuscular junction

e. confromational change in tropomyosin troponin complex

f. binding of ca2+ to troponin

g. binding of atp to myosin cross-brisges

h. depolarization of the muscle fiber

i. hydrolysis of atp bound to myosin cross-bridges

j. action potential propagation along the transverse tubules

pearpig306

1. Which of the following structures is NOT a part of the musclefiber?

A. transverse tubule
B. motor end plate
C. sarcolemma
D. synaptic knob
E. sarcoplasmic reticulum

2. You briefly apply a high concentration of acetylcholine (ACh)directly to the motor end plate and observe no contraction of thefiber. Since muscular dysgenesis only affects one type of cell inthe body you would suspect that the motor neurons of dysgenic micework normally. True or False?

A. True
B. False

3. Arrange the events at the neuromuscular junction in the propersequence from first to last

1. arrival of the action potential at the synaptic knob
2. generation of action potential in sarcolemma
3. binding of ACh to ACh receptors in the motor end plate
4. release of ACh into the synaptic cleft
5. removal of ACh from the cleft by acetylcholinesterase

A. 1, 2, 3, 5, 4
B. 2, 3, 1, 4, 5
C. 1, 4, 3, 2, 5
D. 2, 5, 1, 4, 3

4. After you apply acetylcholine to the muscle fiber you find thatan action potential is generated in the sarcolemma. This resultproves that certain events or conditions occur normally within theneuromuscular junction. Which event or condition is NOT PROVED bythe above result?

A. ACh receptors are present in the membrane of the motor endplate
B. ACh receptors bind to ACh
C. Sodium permeability of the end plate membrane is increased
D. Acetylcholinesterase breaks down ACh

5. Arrange the events of excitation contraction coupling in theproper sequence from first to last

1. cross-bridge cycling
2. action potential in the sarcolemma reaches the triads
3. release of calcium from the sarcoplasmic reticulum
4. exposure of active site on the thin filaments
5. binding of calcium to troponin

A. 2, 3, 5, 4, 1
B. 5, 3, 4, 2, 1
C. 5, 1, 3, 2, 4
D. 3, 5, 2, 4, 1

6. You artificially raise the calcium concentration within thesarcoplasm of the muscle fiber and observe that the cell contractsnormally. From this observation you conclude that the defect inmuscular dysgeny occurs at which step in control of the musclefiber?

A. Exposure of the active site on thin (actin) filaments
B. Binding of calcium to troponin
C. Release of calcium ions from the sarcoplasmic reticulum into thesarcoplasm
D. Repeated cycles of crossbridge binding, pivoting, anddetachment

7. Where in the muscle fiber do you suspect that the normal proteinmade by the mdg gene functions in normal mice?

A. motor end plate
B. triad
C. myofibrils
D. thin filaments

8. All of the following conditions would have same effect onmuscles (flaccid paralysis) as muscular dysgeny with a singleexception. What is the EXCEPTION?

A. botulism
B. poisoning with atropine
C. poisoning with military nerve gas
D. myasthenia gravis

9. You would expect the muscles from an animal afflicted withmuscular dysgenesis to exhibit:

A. hypertrophy
B. atrophy

10. You would expect that a dysgenic mouse dies shortly after birthbecause:

A. the heart fails to beat
B. vasoconstriction of the carotid artery prevents blood flow tothe brain
C. vasodilation of the systemic blood vessels causes the bloodpressure to drop to lethal levels
D. the respiratory muscles are unable to contract

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KNES 259 Study Guide - Final Guide: Myoglobin, Agonist, Golgi Tendon Organ

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