Week 10 Lab Review

Question 1

Which of the following sets is accurately matched? (select all that apply)
A. Skeletal – striated
B. Cardiac – voluntary
C. Smooth – intercalated discs
D. Skeletal - multinucleate

Answer 1

A. and D.

Question 2

What does the term ‘Z disc’ refer to?

Answer 2

Ends of a sarcomere

Question 3

During contraction, to what structure does Ca2+ bind in the muscle?

Answer 3

Calcium binds to Troponin

Question 4

Place these layers in correct order from outer to inner most.
Perimysium… Endomysium… Epimysium

Answer 4

Epimysium 🡪 Perimysium 🡪 Endomysium

Question 5

What is the difference between F actin & G actin?

Answer 5

F = fibrous & is many connected actin

G = globular & is a single actin protein

Question 6

Indicate where these ions are most concentrated when cells are at rest.
Anionic proteins, Na+, Cl-, K+, & Ca2+

Answer 6

Inside = K & anionic proteins

Outside = Na, Cl & Ca

Question 7

What is the role of Ca2+ influx into the axon terminal?

Answer 7

Acts as signal to release ACh into synapse

Question 8

What is the function of tropomyosin when muscles are relaxed?

Answer 8

Blocks active sites on actin

Stops myosin from cross-bridging

Question 9

What specifically causes a voltage-sensitive channel to open?

Answer 9

The traveling action potential &/OR associated depolarization

Question 10

One more time, organize these structures from largest to smallest…
Fascicle, fiber, sarcomere, myofilament, myofibril

Answer 10

Fascicle –
fiber (cell) –
myofibril –
sarcomere -
filament

Question 11

What part of the sarcomere has ATPase enzymes?

Answer 11

Myosin heads

Question 12

What substance is not available when rigor mortis or potentially muscle cramps set in?

Answer 12

ATP

Question 13

What type of transport allows Ach (acetylcholine) to be released from axons?

Answer 13

Exocytosis of synaptic vesicles in the axon terminal

Question 14

What is the value in mV (millivolts) of resting membrane potential?

Answer 14

-70mV

Question 15

Which ion is associated with the action potential phase known as depolarization.

Answer 15

Na influx into the nerve or muscle cell causes depolarization

Question 16

Action potentials descending into T tubules stimulate what to happen next?

Answer 16

Voltage-sensitive channels on Sarcoplasmic Reticulum open and release Calcium

Question 17

When a new ATP binds to myosin, what step of muscle activity does this facilitate?

Answer 17

Release of actin by the myosin head

Question 18

What 2 enzymes catalyze phosphorylation of ADP to provide short term boost to ATP availability during initial muscle activity?

Answer 18

Creatine Kinase
Adenylate Kinase

Question 19

What is VO2max, & how do differences in body mass between individuals affect this value?

Answer 19

Greatest possible oxygen consumption during activity
Greater mass 🡺 Greater VO2max

Question 20

Which channel opens most slowly during an action potential in the motor neuron?

Answer 20

K channels are slower to open and stay open longer