Muscles

Question 1

origin

Answer 1

where the muscle begins, less moveable attachment

Question 2

insertion

Answer 2

where muscle ends, more moveable attachment

Question 3

muscle attachments

Answer 3

when muscle contracts, insertion moves towards origin

Question 4

what do skeletal muscles consist of

Answer 4

fascicles

Question 5

what are fascicles

Answer 5

bundle of muscle fibres running parallel to one another

Question 6

what does fascicle arrangement tell us

Answer 6

action of muscle

Question 7

what does arrangement of fascicles determine

Answer 7

range of motion and power

Question 8

what determines muscle power

Answer 8

the number of muscle fibres in the muscle and the length of the fibres

Question 9

how much power do longer muscle fibres provide

Answer 9

less

Question 10

how much power to short muscle fibres provide

Answer 10

more

Question 11

types of muscle arrangement

Answer 11

• circular ex. around the mouth
• triangular/convergent ex. pectoralis major
• parallel: fusiform (large central body) ex. biceps brachii
• parallel: straplike (thin) ex. sartorius
• multipennate (feather-shaped) ex. deltoid
• bipennate (2 insertions) ex. rectus femoris
• unipennate (1 insertion)

Question 12

interactions of skeletal muscles in the body

Answer 12

a muscle cannot reverse the movement it produces, another muscle must undo the action and muscles with opposite actions lie on opposite sides of a joint

Question 13

muscle functional groups

Answer 13

• prime mover/agonist
• antagonist
• synergist (fixator)

Question 14

prime mover/agonist

Answer 14

has major responsibility for a certain movement

Question 15

antagonist

Answer 15

opposes or reverses a movement

Question 16

synergist

Answer 16

helps prime mover by adding extra force or by reducing undesirable movements

Question 17

fixator

Answer 17

type of synergist that holds a bone/joint firmly in place to stabilize the prime mover to act more efficiently

Question 18

mechanisms of contraction

Answer 18

• concentric
• eccentric
• isometric

Question 19

concentric contraction

Answer 19

muscle shortens and does work (positive work)

Question 20

eccentric contraction

Answer 20

more strenuous than concentric, muscle generates force as it lengthens which is essential for controlled movements and resistance to gravity i.e. acts like a brake (negative work)

Question 21

isometric contraction

Answer 21

force generated with no change in muscle length

Question 22

what is a muscle compartment

Answer 22

a group of skeletal muscles that arose from a common embryonic origin

Question 23

muscles in opposing compartments

Answer 23

are agonist and antagonist pairs, share a common blood and nerve supply

Question 24

muscle compartments of the arm

Answer 24

anterior compartment muscles flex the shoulder or elbow, posterior compartment muscles extend the shoulder or elbow

Question 25

muscle compartments of the thigh

Answer 25

posterior: extend hip and flex knee anterior: flex hip and extend knee medial: adduct from thigh lateral: abduct from thigh

Question 26

ways muscles can be named

Answer 26

- location - shape - relative size - direction of fascicles and muscle fibres - location of attachments - number of origins - action