Synaptic Transmission

Question 1

Point of attachment for actin

Answer 1

Z-disk

Question 2

Zone where only actin is present in cross section and is adjacent to the Z-disk

Answer 2

I-band

Question 3

Represents the cross-sectional area containing myosin

Answer 3

A-band

Question 4

Cross-section contains only myosin

Answer 4

H-zone

Question 5

Central region of myosin filaments are linked by proteins

Answer 5

M-line

Question 6

Long molecule that helps align actin

Answer 6

Nebulin

Question 7

Large, long elastic protein associated with myosin and anchors it with sarcomere. Also acts to return a stretched sarcomere to resting length.

Answer 7

Titan

Question 8

Huge protein that connects muscle cytoskeleton including actin the ECM

Answer 8

Dystrophin

Question 9

At the termination of the AP, SR begins sequestering Ca2+ via what pump?

Answer 9

SERCA (Ca2+/ATPase)

Question 10

contraction requires availability of ATP

• stores sources as phosphocreatine
• derived from glycolysis thus producing lactate
• derived from OXPHOS in mitochondria (requires constant O2)

Answer 10

peripheral fatigue

Question 11

perception of fatigue or loss of motivation brought on by increasing levels of byproducts of contraction

• H+ ion
• lactate

Answer 11

central fatigue

Question 12

• red: myoglobin and mitochondria
• small diameter
• uses O2
• fatigue resistance

Answer 12

slow-twitch oxidative

Question 13

• white
• large diameter
• uses phosphocreatine and glucose

Answer 13

fast-twitch glycolytic

Question 14

between the slow-twitch oxidative and fast-twitch glycolytic in characteristic

Answer 14

fast-twitch oxidative

Question 15

What does force of contraction depend on?

Answer 15

• starting length of sarcomere
  
  • max force near middle of length extremes
    
    • most efficient relationship b/w actin binding sites and myosin heads
    • distance between actin and myosin is less
• how rapidly fiber is stimulated by nerve

Question 16

What happens if the sarcomere is short?

Answer 16

• Myosin cannot pull actin far before it hits Z-line.
• Cross-sectional area is also increased thus pushing actin and myosin apart.

Question 17

What happens if a second twitch is initiated before complete relaxation?

Answer 17

second twitch requires a greater force

Question 18

What are some things that can cause greater force generation?

Answer 18

• neuron that innervates MORE fibers
• muscle with MORE glycolytic fibers (but fatigues quicker)
• MORE motor neurons and thus MORE motor units

Question 19

moving an object associated with muscle shortening

Answer 19

concentric contraction

Question 20

allowing an object to moe while muscle is lengthening

Answer 20

eccentric contraction (or controlled relaxation)

Question 21

when muscle shortening occurs without change in the load

Answer 21

isotonic contraction

Question 22

contraction in the absence of load movement

Answer 22

isometric contraction

Question 23

4 things that reflexes require:

Answer 23

• sensory receptor
• afferent input to CNS
• processing by CNS
• efferent output to approrpiate tissue

Question 24

resists change

Answer 24

negative feedback

Question 25

anticipates required change and prepares or activates appropriate tissue

Answer 25

feedforward mechanism