Muscles

Question 1

What are the 3 types of muscular tissue

Answer 1

1. Skeletal
2. cardiac
3. visceral

Question 2

Describe skeletal muscle

Answer 2

• long, thin, contractible fibres that are STRIATED (thick and thin filaments)
• voluntary muscles
• attach to bones via tendons
• allow movement (move bones)
• can allow heat production via friction
• respond to stimuli

Question 3

describe cardiac muscle

Answer 3

• heart muscles - very thick
• overlap (muscle fibres connect to each other for co-ordinated contraction (very important!!)
• involuntary movement

Question 4

describe visceral muscle

Answer 4

• involuntary
• smooth muscle = proteins spread out

Question 5

what are the functions of muscular tissues

Answer 5

• excitable and irritable - respond to stimuli
• contractible - shorten
• extensible - extend/relax
• elastic

Question 6

explain the structure of skeletal muscles (how does contraction occur?)

Answer 6

• muscle belly contains muscle fasicle which is made up of many muscle fibres (also surrounded by nuclei and mitochondria)
• a single muscle fibre contains bundles of thick and thin filaments called myofibrils (allow movement)
• myofibrils are made of a chain of repeating sacromeres that contain the actin and myosin
• within myofibrils, there are alternating strands of 2 proteins, myosin and actin. Myosin have globular heads that allow it to attach to overlapping actin
• when ATP available, myosin pulls away from actin and causes muscle contraction.
• ATP required for myosin to detach from actin at one point and grab onto the next point, pulling it towards itself

Question 7

define intrinsic muscles vs extrinsic

Answer 7

intrinsic - a muscle within a region (within a limb)
extrinsic - in between region (a muscle between bones)

Question 8

define origin vs insertion of a muscle

Answer 8

origin - the fixed/proximal muscle -> closest to trunk - usually join appendages to trunk
insertion - distal/mobile muscles -> move and far from trunk -> usually for movement of limbs between bones of limbs (e.g. at the elbow)

both attached to skeleton

Question 9

define Synergistic vs antagonistic muscles

Answer 9

synergistic - work together e.g. pull in the same direction -> e.g glutes
antagonistic - work against each other e.g. pull opposite direction -> e.g biceps, pectoral, triceps, quadriceps, hamstrings

Question 10

what are the different types of limb muscles

Answer 10

1. flexors - reduce the angle of the joint?
2. extensors - increase angle between bones

Question 11

explain the muscular anatomy of the arm and forearm

Answer 11

Divides into to sections/muscles:
1. anterior compartments (control upper arm) - biceps brachii on top, brachialis on bottom - flexors of elbow
2. posterior compartments control forearm - triceps brachi which has three parts, the medial head, lateral head and long head - extensors of elbow

*humerus bone in between muscles

Question 12

explain common names of muscles and their meanings

Answer 12

deltoid, rhomboid = shape
triceps, biceps = number of bellies/parts
pectoralis, brachii = location
major, minimus = size
rectus, obliquions = orientation

Question 13

Explain muscles as a lever system

Answer 13

1. axis of rotation/fulcrum = point the level rotates on
2. lever arm = distance between fulcrum and line of force - input force and output force are the arms

Question 14

how to calculate torque

Answer 14

torque = force x distance of lever/input arm

if two equal forces and equal arms, torque = 0

Question 15

first class lever system

Answer 15

equal forces and equal arm lengths e.g. keeping head in place with gravty vs neck muscles force equal

Question 16

second class lever system

Answer 16

output force arm is shorter than input force (pull one side upwards using effort)

Question 17

third class lever system

Answer 17

output force arm longer than input force e.g. gravity is stronger than muscle force to allow limbs to fall down/not move upwards

Question 18

what is torque

Answer 18

a measure of the force causing rotation around a point

Question 19

explain modifications that can be made to levers

Answer 19

1. increase in lever length = magnify the force
2. increase output lever = increase speed
3. move pivot closer to output to increase output force
4. move pivot closer to input to increase output speed

Question 20

what is masticatory muscle
what is latissimus dorsi

Answer 20

1. muscles that allow movement of the jaw e.g. masseter muscle
2. a muscle on the lower back/side that moves upper body and allows respiratory muscles to move

Question 21

need to add all jaw muscles to learn from lab