Lecture 1

Question 1

What are the 3 types of muscles?

Answer 1

Skeletal
Smooth
Cardiac

Question 2

What are myofibrils?

Answer 2

Bundles of protein filaments

Question 3

What are sarcomeres?

Answer 3

Individual power of a muscle fiber, Basic contractile element of skeletal muscle

Question 4

What kind of bands/lines are included in a Sarcomere?

Answer 4

A-bands
I-bands
H-zone
M-line
Z-disk

Question 5

What is actin and where to find them?

Answer 5

Thin filaments - I-band contains only actin filaments

Question 6

What is Myosin & where to find them?

Answer 6

Thick Filaments - A-band contains both actin and myosin filaments, H-zone contains only myosin filaments

Question 7

What are globular heads?

Answer 7

Interact with actin filaments for contraction

Question 8

What are the 3 proteins that compose in actin?

Answer 8

Actin
Tropomyosin
Troponin

Question 9

What is titan?

Answer 9

(Third myofilament) - Acts like spring, Extends from Z-disk to M-band, Calcium binds to titan, stabilizes sarcomeres, prevents overstretching

Question 10

What is a motor unit?

Answer 10

Nerve and muscle fiber innervates

Question 11

If there are more operating motor units, what will happen to the contractile force?

Answer 11

There will be more contractile force

Question 12

What is a neuromuscular junction?

Answer 12

Space/junction of communication or neuron and muscle

Question 13

What do neuromuscular junctions do?

Answer 13

Serves as the site of communication between neuron and muscle, may connect to multiple muscle fibers

Question 14

What is excitation-contraction coupling?

Answer 14

The combined action of the nerve to contract the muscle - Look at images

Question 15

What is the role of CA2+ in muscle fibre?

Answer 15

AP arrives at SR from T-tubule
CA2+ binds to troponin on thin filaments

Question 16

In the sliding filament theory, how does the relaxed state happen?

Answer 16

No actin-myosin interaction at binding sites, myofilaments overlap a little

Question 17

In the sliding filament theory. how does the contracted state happen?

Answer 17

Myosin head pulls actin to sarcomere center, filaments slide past each other, sarcomeres-myofibrils-muscle fibre all shorten

Question 18

How does muscle relaxation happen?

Answer 18

AP ends; electrical stimulation of SR stops, CA2+ is pumped back into SR, with no CA2+ troponin and tropomyosin return to resting conformation

Question 19

What are the 3 types of fiber types?

Answer 19

Type 1, Type 2a, type 2x

Question 20

What is type 1 fibers?

Answer 20

Slow twitch (peak tension in 110 ms)

Question 21

Who uses the type 1 fibers the most?

Answer 21

Marathon Runners

Question 22

What are type 2 fibers?

Answer 22

Fast twitch (peak tension in 50ms)

Question 23

What does myosin ATPase do?

Answer 23

Help split into ADP and energy

Question 24

What is muscle biopsy?

Answer 24

Small piece of muscle removed, then frozen, slices, and examined with microscope

Question 25

What is gel electrophoreses?

Answer 25

The process separates types of myosin by size

Question 26

What does the Sarcoplasmic Reticulum do?

Answer 26

Hold calcium

Question 27

How many fibers are in a type 1 motor unit?

Answer 27

<300 fibers, smaller neuron

Question 28

How many fibers are in a type 2 motor units?

Answer 28

> 300 fibers, larger neuron