week 4 quiz

Question 1

what is the membranous network that surrounds each myofibril?

Answer 1

The sarcoplasmic reticulum

Question 2

the command to contract is conducted throughout the muscle fibre by the ______ tubules.

Answer 2

transverse

Question 3

what is the part of the sarcomere that contains thick filaments but no thin filaments?

Answer 3

the H zone

Question 4

what do Z lines mark?

Answer 4

the boundaries between adjacent sarcomeres

Question 5

Strands of elastic protien ___________ extend from the tips of the thick filaments to attachment sites at the z line

Answer 5

titin

Question 6

What happens when the myosin head splits ATP into ADP and a phosphate group

Answer 6

myosin reactivation

Question 7

Name the 5 stages of the contraction cycle

Answer 7

1. active site exposure
2. cross bridge attachment
3. pivoting
4. cross bridge detachment
5. myosin reactivation

Question 8

Action potentials must travel along which structure internal to the sarcolemma to cause the release of calcium ions from the sarcoplasmic reticulum?

Answer 8

t tubules

Question 9

In which part of the sarcomere are myosin heads able to form crossbridges with actin?

Answer 9

zone of overlap

Question 10

The pivoting of the myosin head towards the m-line is called the _______.

Answer 10

myosin