Bio 406 -Physiology - Practice Questions - Dr. Daley

Muscles & Neural Control of Muscles


1. A reflex action
A. is an automatic, involuntary response.
B. does not require the central nervous system.
C. is normally controlled consciously.
D. has no protective value.

2. In a knee-jerk reflex, the extrafusal fibers are stimulated to contract by
A. alpha motoneurons
B. gamma motoneurons
C. sensory neurons
D. autonomic neurons

3. Which of the following is required for the cross-bridges to be released at the end of a power
stroke?
A. Ca++
B. ATP
C. tropomyosin
D. troponin

4. During muscular contraction
A. both actin and myosin filaments move.
B. myosin filaments move but not actin.
C. actin filaments move but not myosin.
D. neither myosin nor actin filaments move.

5. Which of the following is responsible for inhibition of muscle contraction at rest?
A. ATP
B. Ca++
C. troponin-tropomyosin complex
D. creatine phosphate

6. A graded muscle contraction is produced by variations in the
A. size of action potentials
B. degree of contraction of individual muscle fibers
C. number of muscle fibers stimulated
D. lengths of the actin and myosin filaments

7. A muscle action potential
A. does not occur.
B. lags behind muscle contraction.
C. precedes muscle contraction.
D. indicates poor health.

8. Depolarization of a muscle fiber
A. causes the release of Ca++ from the sarcoplasmic reticulum
B. causes the uptake of Ca++ into the sarcoplasmic reticulum
C. directly results in movement of cross-bridges
D. directly results in sliding of the thick and thin filaments

9. Stimulation of gamma motoneurons directly results in
A. stimulation of sensory neurons
B. decreased length of the muscle spindle
C. contraction of extrafusal muscle fibers
D. increased sensitivity of the muscle spindle to passive stretch

10. Which muscle filament breaks down ATP?
A. myosin
B. actin
C. both
D. neither