muscles

Question 1

what is the connective tissue layer surrounding the muscle?

Answer 1

epimysium

Question 2

describe a muscle

Answer 2

fascicles (bundles of muscle fibres) surrounded by the epimysium

Question 3

what is the connective tissue layer that surrounds each fascicle?

Answer 3

the perimysium

Question 4

what does calcium bind to during muscle contraction?

what does this result in?

Answer 4

binds to troponin

rolls tropomysin away from binding sites of actin filaments

Question 5

skeletal muscle histology

Answer 5

very long
multinucleated
striated
cylindrical

Question 6

what is the connection between the nervous system and the skeletal muscle fibre?

what neurotransmitter is released here?

Answer 6

neuromuscular junction

ACh

Question 7

what gives skeletal muscle its striated appearance?

Answer 7

alternating bands of actin and myosin

Question 8

what are the steps in initiating muscle contraction?

Answer 8

1. ACh released, binds to receptors
2. action potential reaches T-tubule
3. sarcoplasmic reticulum releases calcium
4. active site exposure, cross bridge formation
5. contraction begins

Question 9

describe the regeneration ability of muscle

Answer 9

poor regenerative ability

damage leads to fibrosis (scar tissue)

no regeneration in cardiac muscle

Question 10

how do cardiac muscles store oxygen?

Answer 10

in myoglobin

Question 11

smooth muscle features

Answer 11

uni-nucleated

spindle shaped

non-striated

Question 12

which type of muscle cells are branched?

Answer 12

cardiac muscle

Question 13

which type of muscle cells are not striated?

Answer 13

smooth muscle

Question 14

ER-like organelle in muscle cells?

Answer 14

sarcoplasmic reticulum

Question 15

what are the three types of muscle cells?

Answer 15

cardiac muscle
smooth muscle
skeletal muscle

Question 16

what is the functional unit of contraction called?

Answer 16

the sarcomere

Question 17

what is atrophy?

Answer 17

decrease in size/shrinkage of muscle size due to lack of use

Question 18

give an example of an isometric contraction

Answer 18

carrying a bag of groceries

holding head up

Question 19

what is the connective tissue layer that surrounds each muscle fibre?

Answer 19

the endomysium

Question 20

what are the roles of muscles in the body?

Answer 20

1. movement
2. support soft tissues
3. maintain posture and body position
4. thermoregulation
5. storage of nutrients
6. guards body entrances and exits

Question 21

during exercise, haemoglobin releases more oxygen to active skeletal muscles than when those muscles are at rest. why?

Answer 21

more heat generated
more acidic wastes generated.

both make haemoglobin release more oxygen

Question 22

what is a muscle cell also known as?

Answer 22

a muscle fibre

Question 23

what is the point of attachment that doesn’t change when muscle contracts

Answer 23

the origin

Question 24

name the three types of myofilaments

Answer 24

actin
myosin
titin

Question 25

cytoplasm of a muscle

Answer 25

sarcoplasm

Question 26

point of attachment of a muscle: the end that is freely moveable

Answer 26

insertion

Question 27

define circumduction

Answer 27

movement of arm in a circular motion

movement of hand in a circular motion without moving arm

Question 28

what is muscle tone? what does it do?

Answer 28

degree of contraction or undertone in resting muscles

posture
joint stabililty
ready response state

Question 29

what are the movements in the anterior-posterior plane?

Answer 29

flexion (smaller angle - hand towards inner arm)

extension - hand in a line with arm

hyperextension - wrist bending back towards forearm

Question 30

what is agonist /antagonist with reference to muscles?

Answer 30

the contracted muscle is the agonist

the relaxed muscle is the antagonist

Question 31

what’s the cell membrane of a muscle called?

Answer 31

the sarcolemma

Question 32

the russian doll of muscle organisation

Answer 32

muscles each contain:

many fascicles which each contain:

many muscle fibres which each contain:

many myofibrils which each contain:

many myofilaments.

Question 33

what is the thin myofilament called? the thick? the elastic?

Answer 33

actin (thin)

myosin (thick)

titin (elastic)

Question 34

define hyperplasia

Answer 34

increase in cell number

occurs in skeletal muscle subjected to persistent increased workload (eg. weights, bodybuilding)

Question 35

how are myosin heads activated in the muscle contraction process?

Answer 35

ATP binds to myosin head and breaks into ADP and P

myosin head is now cocked and can bind with actin when troponin binds wuth calcium

when it binds, it pulls the actin along

Question 36

what is ATPs role in muscle contraction?

Answer 36

attaches to myosin head and releases it from the actin

ATP then breaks into ADP and P and the head is activated again

Question 37

steps in initiating muscle relaxation?

Answer 37

1. ACh broken down by AChE at neuromuscular junction
2. sarcoplasmic reticulum recaptures calcium
3. active sites covered, no cross bridge formation
4. contraction ends
5. relaxation occurs, passive return to resting length

Question 38

what happens to actin and myosin, and to the sarcomere, during muscle contraction?

Answer 38

actin and myosin overlap, which shortens the sarcomere, causing contraction