Exam #3 Page 4

Question 1

Axonal Ends

Answer 1

Terminal ends of motor neurons of the somatic nervous systems. Requires influx of calcium to release the neurotransmitter, “acetylcholine” (ACh)

Question 2

Synaptic Cleft

Answer 2

Space between the axonal end and the sarcolemma of the muscle

Question 3

Motor End Plate

Answer 3

Segment of sarcolemma which contains ACh receptors for binding of the neurotransmitter

Question 4

Acetylcholinesterase

Answer 4

Enzyme responsible for breakdowns of ACh to prevent continued muscle fiber contraction

Question 5

Action Potential

Answer 5

Depolarization of the sarcolemma and propagation of the electrical event down the muscle fiber

Question 6

Depolarization

Answer 6

Changing the polarity (charge) across the sarcolemma membrane

Question 7

Muscle metabolism

Answer 7

ATP energy necessary for contraction. Phosphorylation releases the cross-bridge connection between the myosin heads and their binding sites on the actin filaments.

Question 8

Aerobic Respiration

Answer 8

With Oxygen. 38 ATP produced for each “glucose” molecule

Question 9

Anaerobic Respiration

Answer 9

Without oxygen. 2 ATP produced per glucose. Lactic acid is produced when in an anaerobic condition.

Question 10

Muscle Fatigue

Answer 10

Physiological inability to contract due to decreased ATP, lactic acid accumulation, and/or ionic imbalances

Question 11

Oxygen Debt

Answer 11

Insufficient oxygen supplies to maintain aerobic respiration

Question 12

Myasthenia Gravis

Answer 12

A disease characterized by drooping upper eyelids, difficulty swallowing and talking, and generalized muscle weakness. Involves a loss of ACh receptors because the ACh receptors are attacked by their own antibodies - “Autoimmune Disease’’

Question 13

Rigor mortis

Answer 13

Intracellular calcium levels increase because ATP is no longer being synthesized. Results in persistent cross-bridge formation.

Question 14

Cross-bridge detachment

Answer 14

ATP is needed. Myosin head staying bound to actin, causing a constant state of contraction. Muscles stay contacted until muscle proteins break down, causing myosin to release.

Question 15

Muscle Dystrophy

Answer 15

Inherited, muscle-destroying diseases, where cells enlarge due to deposits of fat and connective tissue

Question 16

Duchenne Muscular Dystrophy (DMD)

Answer 16

most common and severe type. Caused by defective gene for “Dystrophin”

Question 17

Dystrophin

Answer 17

a cytoplasmic protein that links the cytoskeleton to the extracellular matrix, stabilizing the sarcolemma. Loss of the dystrophin protein leads to damaged contractile fibers, inflammation of the cells, and loss of contractile physiology and muscle mass declines

Question 18

Regeneration of muscle cells

Answer 18

Cardiac and skeletal muscle cells become amitotic but can still lengthen and thicken. Smooth muscle cells can regenerate themselves by mitosis.