skeletal,smooth & cardiac muscle

Question 1

what is the main structural difference between skeletal & smooth muscle?

Answer 1

skeletal is striated , smooth is non-striated

Question 2

where is smooth muscle located?

Answer 2

located in the lining of hollow organs, and blood vessels

Question 3

where is skeletal muscle located & where is cardiac muscle located

Answer 3

skeletal= on the peripheral

cardiac= centrally (c for centrally in the word cardiac)

Question 4

compare the nucleus number in skeletal muscle & in cardiac

Answer 4

skeletal- multinucleated

cardiac- single nuclear

Question 5

how is skeletal muscle organised ?

Answer 5

bundles of muscles fibres encased in connective tissue sheaths

Question 6

after skeletal muscle injury, what cells are used to replace the damaged cells?

Answer 6

satellite cells

Question 7

do damaged skeletal muscle cells ever fully recover?

Answer 7

no
(satellite cells help replace damaged cells tho)

Question 8

what is hypertrophy?

Answer 8

increase in muscle size due to fibre size increase

Question 9

what is a sacromere

Answer 9

repeating unit(allows skeletal muscles to performs their function)

Question 10

describe the filaments actin & myosin in terms of there thickness

Answer 10

myosin= thick filament

actin= thin filament

Question 11

what are the 2 components of sacromere ?

Answer 11

actin & myosin filaments

Question 12

what is the difference between the Z-line of a sacromere & the M-line of a sacromere ?

Answer 12

Z-line: proteins which holds actin filaments in position

M-line: holds myosin filaments in position

Question 13

role of titan filaments in skeletal muscle

Answer 13

hold myosin filaments in the correct ALIGNMENT

Question 14

in skeletal muscle, when ATP binds to myosin, what happens?

Answer 14

detaches the cross bridge formed between actin & myosin

Question 15

in skeletal muscle, which 2 receprots are triggered that cause the release of Ca+ ?

Answer 15

DHP receptor first (small quantity released)

ryanodine receptor (larger quantity)

Question 16

what is sarcoplasm?

Answer 16

cytoplasm of muscle cell (sarcolemma is the cell membrane of skeletal muscle)

Question 17

how is Ca+ taken back up by the sarcoplasmic retiuculum in skeletal muscle ?

Answer 17

calcium ATPase

Question 18

which molecule is vital for muscle relaxation?

Answer 18

ATP

Question 19

what is a motor unit?

Answer 19

it is a motor neuron & all the muscle fibres it innervates

Question 20

why are motor units scattered about muscle?

Answer 20

if one motor unit fails, the other can compensate

Question 21

what is the difference between force of muscle and load on muscle?

Answer 21

force built up within a muscle is tension of muscle

load = force exerted on a muscle

Question 22

if a muscle contracts and the muscle length remains the same, what is the term used to describe this?

Answer 22

isometric contractions

Question 23

if a muscle contracts and the muscle length shortens, what is the term used to describe this?

Answer 23

isotonic contractions

Question 24

difference between isometric and isotonic contractions and give examples of each

Answer 24

isometric = muscle contracts but muscle length stays the same e.g weightlifting

isotonic = muscle contracts but muscle length shortens e.g running

Question 25

if a muscle contracts and the muscle length icnreases, what is the term used to describe this

Answer 25

lenghthening

Question 26

which contraction , isometric or isotonic has a faster response time ?

Answer 26

isometric (length stays the same)

Question 27

what does the time of contraction depend on?

Answer 27

speed of release of Ca+

Question 28

what is the LATENT period in muscle contraction?

Answer 28

time before myosin-actin cross bridge forms (time before excitation-contraction )

Question 29

what is optimal length, in terms of muscle contraction?

Answer 29

muscle length for greatest isometric tension

Question 30

what are the causes of fatigue during high intensity exercise then causes of faitgue in low intesity exercise

Answer 30

high intensity= increase in things low intensity= decrease in things (e.g decrease in glycogen)

Question 31

what makes a fast twitch muscle fast and a slow twitch muscle slow?

Answer 31

myosin has high ATPase activity slow twitch- myosin has low ATPase activity

Question 32

what colour of fibre are oxidative fibres and glycolytic fibres and how big is their diameters

Answer 32

oxidative= red fibres with low diameter glyoclytic fibres =white fibres with large diameter

Question 33

if a muscle is not used, what does this lead to?

Answer 33

disuse atrophy

Question 34

what does destruction of the nerve/NMJ lead to?

Answer 34

denervation atrophy

Question 35

what does exercise cause in terms of muscle mass?

Answer 35

hypertrophy (increase muscle mass and increase fibre mass)

Question 36

in smooth muscles, what are the filaments attached to?

Answer 36

dense bodies