Muscles

Question 1

What is the normal cellular equivalent of the sarcolemma

Answer 1

Cell membrane

Question 2

What is the normal cellular equivalent of the sarcoplasm

Answer 2

Cytoplasm

Question 3

What is the normal cellular equivalent of the sarcoplasmic reticulum

Answer 3

Endoplasmic reticulum

Question 4

What proteins make up the thin filament

Answer 4

Globular actin (G actin)
Tropomyosin
Troponin

Question 5

What is the sliding filament theory

Answer 5

Thin and thick filaments slide over each other when muscle contracts

Question 6

Where is the I band

Answer 6

Between the A bands of two sarcomeres

Question 7

How do the bands change during contraction in the sliding filament model

Answer 7

Only I changes - shortens

Question 8

What is the first stage of the cross bridge cycle

Answer 8

ATP binding causes myosin to disconnect

Question 9

What is the second stage of the cross bridge cycle

Answer 9

ATP is hydrolysed, triggers myosin hinge to move and bind to next G actin

Question 10

What is the third stage of the cross bridge cycle

Answer 10

Pi pisses off and causes myosin head to move back to 45 degrees, moving the actin filament

Question 11

What is the power stroke

Answer 11

The third stage of the cross bridge cycle

Question 12

What is the fourth stage of the cross bridge cycle

Answer 12

ADP fucks off too, resets

Question 13

What is the role of Ca+ during contraction

Answer 13

An increase in cytosolic Ca+ causes tropomyosin to move, exposing G actin for myosin to bind

Question 14

What is the flow of events that leads to muscle contraction

Answer 14

1. Action potential at neuromuscular junction
2. Excitation-contraction coupling
3. Ca2+ released
4. Cross bridge cycle
5. Sliding filament / muscle twitch

Question 15

What are the characteristics of an isometric contraction

Answer 15

no muscle shortening, but sarcomeres shorten and elastic elements stretch maintaining total muscle length

Question 16

What are the characteristics of an isotonic contraction

Answer 16

sarcomeres shorten but elastic components are already stretched to the muscle shortens

Question 17

What is a neurogenic contraction

Answer 17

stimulated from action potentials from neurons

Question 18

What is a myogenic contraction

Answer 18

stimulated from spontaneous contractions

Question 19

Is skeletal muscle contraction an example of neurogenic or myogenic contraction

Answer 19

Neurogenic

Question 20

Is cardiac muscle contraction neurogenic or myogenic

Answer 20

Myogenic

Question 21

Is smooth muscle contraction neurogenic or myogenic

Answer 21

Myogenic

Question 22

What are the 5 factors that influence force generation in skeletal muscle

Answer 22

1. initial length of muscle
2. degree of activation
3. rate of contraction from fibre types
4. frequency of stimulation (twitch vs tetanus)
5. size of muscle

Question 23

What muscle type isn’t striated

Answer 23

Smooth

Question 24

How are muscle fibres arranged in skeletal and cardiac muscle

Answer 24

Sarcomeres

Question 25

How are muscle fibres arranged in smooth muscle

Answer 25

Oblique bundles

Question 26

What anatomical structures are absent or significantly reduced in smooth muscle

Answer 26

T tubles and sarcoplasmic reticulum

Question 27

What muscle type has the slowest contraction speed

Answer 27

smooth muscle

Question 28

What 2 types of organisation do smooth muscle fibres have

Answer 28

Single and multi unit organisation

Question 29

What structures do smooth muscle have that the others don't

Answer 29

Cavaeloae

Question 30

What signalling methods does single unit muscle fibres use

Answer 30

Neuron and gap junctions

Question 31

What signalling method does multi unit fibres use

Answer 31

Neuron only

Question 32

Give an example of multi unit contraction

Answer 32

Muscles in eye

Question 33

Give an example of single unit contraction

Answer 33

Intestinal smooth muscle

Question 34

What 2 second messengers are involved in contraction and relaxation of smooth muscle

Answer 34

Ca2+ and calmodulin

Question 35

What are the stages in relaxation of smooth muscle

Answer 35

1. Ca2+ decreases 2. Ca2+ unbinds from calmodulin 3. Myosin phosphatase removes phosphate - decreasing myosin ATPase activity 4. decreased muscle tension

Question 36

What is the role of caveolae

Answer 36

Ca2+ stores

Question 37

What are the M lines in sarcomeres

Answer 37

the attachment site for myosin thick filaments

Question 38

Where are the M lines located in the sarcomere

Answer 38

Bang in the middle

Question 39

What is the H zone in a sarcomere

Answer 39

zone within the A band that only contains the thick myosin filaments

Question 40

What is the A band in a sarcomere

Answer 40

part of the sarcomere that contains the whole thick myosin filament contains the H zone and M line