L11: Skeletal Muscle Organ, Structure and Function

Question 1

what are the three types of muscles?

Answer 1

• cardiac
• skeletal
• smooth

Question 2

what makes up skeletal muscle tissue?

Answer 2

• muscle cells

- extracellular matrix (minimal)

Question 3

muscle cell/fibre are/consist of?

Answer 3

• multinucleated

- myofibrils

Question 4

what are myofibrils?

Answer 4

• bundles of myofilaments

Question 5

what are myofilaments?

Answer 5

• actin and myosin contractile proteins

Question 6

classification of type 1 skeletal muscle cells

Answer 6

• slow oxidative

- slow aerobic

Question 7

size of type 1 skeletal muscle cells

Answer 7

smallest

Question 8

function and power of type 1 skeletal muscle cells

Answer 8

• fatigue resistant

- least powerful

Question 9

classification of type 2a skeletal muscle cells

Answer 9

• fast oxidative

- fast aerobic

Question 10

size of type 2a skeletal muscle cells

Answer 10

• intermediate

Question 11

fatigue resistance of type 2a skeletal muscle cells?

Answer 11

• some fatigue resistance

Question 12

classification of type 2b skeletal muscle cells

Answer 12

• fast glycolytic

- fast anaerobic

Question 13

size of type 2b skeletal muscle cells

Answer 13

• largest

Question 14

Properties of type 2b skeletal muscle cells

Answer 14

• fatigue
• most powerful
• most common

Question 15

each muscle contains a combination of the fibre types

TRUE or FALSE?

Answer 15

• true

- %s vary according to function

Question 16

how many tissues present in skeletal muscle organs?

Answer 16

• 4 tissues

Question 17

what is a myotendinous junction?

Answer 17

• collagen fibrils of the tendon attach to the end of the muscle fibres

Question 18

what is ethesis?

Answer 18

• where a tendon or ligament attaches to bone

Question 19

what do collagen fibrils attach to?

Answer 19

• periosteum and/or anchor into the bone tissue

Question 20

what is a motor unit?

Answer 20

a single motor neuron and the muscle fibres it innervates

Question 21

what is an isometric contraction?

Answer 21

• muscle force matches load

- constant length

Question 22

what are isotonic contractions?

Answer 22

• concentric

- eccentric

Question 23

what is a concentric contraction?

Answer 23

• muscle force >load
• muscle shortens
• e.g lifting weight

Question 24

eccentric contraction?

Answer 24

• muscle force

Question 25

what is isokinetic?

Answer 25

constant speed

Question 26

what are sphincters

Answer 26

- fibres arranged concentrically around an opening | - circular

Question 27

example of sphincters?

Answer 27

- orbicularis oris | - orbicularis oculi

Question 28

what is parallel muscle architecture

Answer 28

- fascicles parallel to muscle

Question 29

example of fascicles parallel to muscle

Answer 29

- masseter - biceps brachii - rectus abdominis - sartorius

Question 30

what is convergent muscle architecture?

Answer 30

- fibres converge toward a common attachment site

Question 31

example of convergent muscles?

Answer 31

- pectoralis major | - latissimus dorsi

Question 32

what is pennate (feather) muscle architecture?

Answer 32

- fascicles at an oblique angle to the tendon

Question 33

what are the three different types of pennate muscles

Answer 33

- unipennate - bipennate - multipennate

Question 34

the extensor digitorum is what sort of pennate muscle?

Answer 34

unipennate

Question 35

the arrangement of fascicles in the rectus femoris is?

Answer 35

- bipennate

Question 36

the arrangement of fascicles in the deltoid is ?

Answer 36

multipennate

Question 37

function of parallel muscles

Answer 37

excursion

Question 38

function of pennate muscles

Answer 38

strength

Question 39

function of axial muscles

Answer 39

- stabilise or move elements of axial body

Question 40

function of appendicular muscles

Answer 40

- stabilise or move appendicular body

Question 41

3 compartments of the thigh?

Answer 41

- anterior - posterior - medial

Question 42

3 compartments of the leg?

Answer 42

- anterior - posterior - lateral

Question 43

what must a muscle cross in order to actively move a joint

Answer 43

- cross a joint

Question 44

what determines which movements are available?

Answer 44

joint structural and functional classification

Question 45

what helps predict a muscles general action relative to the joint it crosses

Answer 45

- the location of a muscle

Question 46

the amount of force that a muscle produces is a function of its?

Answer 46

physiological cross sectional area (PCSA)

Question 47

what is line of action?

Answer 47

when a muscle contracts concentrically it will pull its attachment site toward the centre of the muscle belly

Question 48

for a given force, the resultant moment will be affected by its?

Answer 48

- moment arm

Question 49

in biomechanics, bones are considered

Answer 49

levers

Question 50

in biomechanics, joints are considered

Answer 50

axes/ centre of rotation (COR)

Question 51

in biomechanics, muscles provide ?

Answer 51

force = pull

Question 52

what is moment of force?

Answer 52

- strength of rotation of body segment | - produced by force

Question 53

what is moment arm?

Answer 53

- perpendicular distance from the COR to the line of action of the force

Question 54

a force directed through the centre of rotation will produce a?

Answer 54

translation

Question 55

a force applied at a distance from the centre of rotation will produce a??

Answer 55

rotation called moment of force

Question 56

when a force acts on an object, and the object is fixed at some point, the object will?

Answer 56

- rotate around the fixed point | - results in a rotation called moment of force

Question 57

when a force (muscle pull) acts on an object (bone), and the object is fixed at some point (joint), the object will??

Answer 57

- rotate around the fixed point