Biology

Name: Lab Section:

1. (2.8 pt, 0.2 ea) Match the following confusing terms with the appropriate definition or description.

endomysium epimysium

perimysium myosin

myofilament myoglobin

myoblast myofibril

tropomyosin troponin

sarcomere sarcoplasm

sarcoplamic reticulum sarcolemma

a. fibrous connective tissue that surrounds muscle fascicles

b. muscle cytoplasm

c. muscle stem cell that can fuse to form muscle fibers

d. muscle plasma membrane

e. oxygen binding protein in muscle

f. muscle fiber thick filament

g. the smallest contractile unit of a muscle fiber

h. regulates internal Ca++ levels

i. a complex of three peptides that binds actin and calcium

j. contractile elements of striated muscle - there are two types, thin & thick

k. a rod-shaped protein that blocks actin active sites in a resting muscle

l. dense irregular connective tissue surrounding whole muscle

m. fine sheath of connective tissue that surrounds muscle fibers

n. a rod shaped bundle of contractile proteins that extends the length of a muscle fiber

2. (2.4 pt, 0.3 ea) Circle all the structures that decrease in size during a contraction.

A) myofilaments B) Z-disk

C) A band D) H zone

E) zone of overlap F) sarcomere

G) I band H) triad

3. (2.1 pt, 0.3 ea) Circle all the correct statements about the neuromuscular junction.

A) Breakdown of acetylcholine (ACh) by acetylcholinesterase removes ACh from the synaptic cleft.

B) Calcium diffuses across the synaptic cleft and causes voltage gated Na+ channels to open.

C) Acetylcholine gated channels (ACh receptors) allow Na+ to enter the muscle causing depolarization.

D) In a resting muscle the sarcoplasmic side of the sarcolemma is more negative than the extracellular side.

E) During an action potential Na+ rushing out of the cell is responsible for depolarization.

F) Movement of K+ ions out of the muscle is...