Lecture 5: Muscle

Question 1

The layer of connective tissue that surrounds muscle fascicles is ________________ that is made of _________________ .

a. Epimysium; dense irregular CT
b. Perimysium; dense irregular CT
c. Endomysium; dense irregular CT
d. Perimysium; loose irregular CT

Answer 1

b. Perimysium; dense irregular CT

Question 2

Skeletal muscle develops:

a. From myoepithelial cells
b. From epidermal precursors
c. From myoblasts
d. From a multinucleate cell

Answer 2

c. From myoblasts

Question 3

Type IIb fibers:

a. Have low myoglobin content
b. Have high myoglobin content
c. Have high mitochondria content
d. Have slower twitch

Answer 3

a. Have low myoglobin content

Question 4

In a sarcomere, thick filaments are linked by ____________ proteins of the _____________ .

a. a actinin and desmin; Z line
b. a actinin and desmin; M line
c. myomesin; Z line.
d. myomesin; M line.

Answer 4

d. myomesin; M line.

Question 5

The ion that is released by ACh at the NMJ to initiate a contraction is _____________.

a. Na+
b. Ca++
c. K+
d. Cl-

Answer 5

a. Na+

Question 6

The ion that triggers troponin movement of tropomyosin to create cross bridges is:

a. Na+
b. Ca++
c. K+
d. Cl-

Answer 6

b. Ca++

Question 7

Afferent receptors in muscle fibers are called:

a. Motor end fibers
b. Golgi organs
c. Muscle spindles
d. Ruffini corpuscles

Answer 7

c. Muscle spindles

Question 8

The junctions that make an intercalated disk are:

a. desmosomes
b. adherence junctions
c. gap junctions
d. all of the above

Answer 8

d. all of the above

Question 9

When a skeletal muscle fiber contracts,

a. the H bands and I bands get smaller.
b. the zones of overlap get smaller.
c. the Z lines get further apart.
d. the width of the A band narrows.

Answer 9

a. the H bands and I bands get smaller.

Question 10

Which of the following statements about smooth muscle contraction is TRUE?

a. Smooth muscle myosin has exactly the same arrangement of heads as skeletal muscle actin
b. Smooth muscle contracts using dense bodies
c. Smooth muscle actin uses ADP as a fuel source
d. Smooth muscle uses troponin

Answer 10

b. Smooth muscle contracts using dense bodies