Performance Objectives for Second Test

Performance Objectives For Second Test

For the test on the muscular system you should be able to:

1. Describe the sliding filament mechanism of muscle contraction.

2. Explain the role of calcium ions in skeletal muscle contraction including:

a. location of calcium

b. mechanism of release

c. binding site

e. mechanism of removal

3. Compare a relaxed and contracted muscle fiber in terms of:

a. length of sarcomeres

b. overlapping of thick and thin filaments

c. movement of Z lines

4. Define the motor unit and explain size and number of muscle fibers per motor unit in different muscle types.

5. Label the latent period, contraction period and relaxation period of a twitch contraction.

6. Define:

a. recruitment

b. minimal stimulus

c. maximal stimulus

d. supramaximal stimulus

e. subminimal stimulus

f. summation

g. tetanus

h. incomplete tetanus

i. treppe

j. isometric contraction

k. isotonic contraction

7. Describe the sources of energy for muscle contraction under the following conditions:

a. a powerful burst of activity

b. sustained strenuous activity

c. continued activity of long time periods (marathon)

8. Describe lactic acid and alactic oxygen debt and Cori cycle.

9. Describe the structures of the neuromuscular junction:

a. sole foot

b. motor end plate

c. calcium channels

d. axon terminal

e. acetycholine receptors

f. myoneural (synaptic) cleft

g. cholinesterase

10. Describe the effects of curare, TTX (tetrodotoxin), nerve gasesand toxin from Botulinusbacteria on the neuromuscular junction.

11. Explain excitation coupling, that is, the events of muscular contraction from nerve impulse through cross-bridge detachment.

12. Explain the length tension relationship of a typical muscle.

13. Explain the characteristics of fast-twitch and slow-twitch fibers and their primary fuel sources.

14. Describe in detail the following structural components of thick and thin filaments:

a. troponin

b. tropomyosin

c. G-actin

d. F-actin

e. myosin

15. Describe the effects of changing stimulus intensity and rate of stimulus on a isolated muscle (lab experiment)

Try the following sample test questions:

1. The striated appearance of skeletal muscle is due to the

(a) regular orderly arrangement of the T tubules.

(b) regular orderly arrangement of the lateral sacs of the sarcoplasmic reticulum.

(d) regular orderly arrangement of the motor units.

(e) presence of white and red muscle fibers within the muscle.

2. An action potential rapidly spreads to the central portions of a muscle cell by means of the

(a) Z lines.

(b) sarcoplasmic reticulum.

(d) pores in the membrane surface.

(e) T tubules.

3. The T tubules

(a) store Ca2+.

(b) provide a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fiber.

(d) run longitudinally between the myofibrils.

(e) have expanded lateral sacs.

4. Which is not characteristic of cross bridges?

(a) they are a component of thin filaments.

(b) they are comprised of myosin.

(d) they have an ATPase binding site.

(e) they provide power stroking.

5. Cross bridge interaction between actin and myosin in skeletal muscle is directly blocked by

(a) acetylcholine.

(b) triads.

(d) calcium.

(e) tropomyosin.