Define isometric contraction

the tension generated does not overcome the load, so there is no visible shortening of the muscle fiber (although crossbridge cycling is happening)

define isotonic contraction

the tension generated DOES overcome the load, so there is measurable shortening of the fiber.

What is another word for "thick filaments"

Myosin

What is another word for "thin filaments"

Actin

During sarcomere contraction, which of the following does NOT change length?

a) the distance between the Z-lines

b) the length of the I bands

c) the length of the A-bands

d) none of the above change length

c) the length of the A-bands

During sarcomere contraction, Ca binds to ______________ , which allows ______________to move and reveal the ______________ active sites for crossbridge formation.

troponin; tropomysin; actin

Order of Crossbridge Formation:

1. AP reaches T-tubules

2. Ca is released from the SR

3. Ca binds to troponin

4. Tropomyosin moves to reveal active sites

5. Crossbridge Forms

Which one of the following components stimulates contraction of a skeletal muscle?

a) muscle fiber

b) motor neuron

c) acetylcholinesterase

d) synaptic cleft

b) motor neuron

Which structure of the neuromuscular junction is a chemically-gated ion channel that the neurotransmitter binds to?

a) voltage-gated sodium channel

b) voltage-gated calcium channel

c) acetylcholine receptor

d) synaptic vesicle

c) acetylcholine receptor