Muscles Flashcards
What are the 3 types of muscular tissue
- Skeletal
- cardiac
- visceral
Describe skeletal muscle
- 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
describe cardiac muscle
- heart muscles - very thick
- overlap (muscle fibres connect to each other for co-ordinated contraction (very important!!)
- involuntary movement
describe visceral muscle
- involuntary
- smooth muscle = proteins spread out
what are the functions of muscular tissues
- excitable and irritable - respond to stimuli
- contractible - shorten
- extensible - extend/relax
- elastic
explain the structure of skeletal muscles (how does contraction occur?)
- 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
define intrinsic muscles vs extrinsic
intrinsic - a muscle within a region (within a limb)
extrinsic - in between region (a muscle between bones)
define origin vs insertion of a muscle
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
define Synergistic vs antagonistic muscles
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
what are the different types of limb muscles
- flexors - reduce the angle of the joint?
- extensors - increase angle between bones
explain the muscular anatomy of the arm and forearm
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
explain common names of muscles and their meanings
deltoid, rhomboid = shape
triceps, biceps = number of bellies/parts
pectoralis, brachii = location
major, minimus = size
rectus, obliquions = orientation
Explain muscles as a lever system
- axis of rotation/fulcrum = point the level rotates on
- lever arm = distance between fulcrum and line of force - input force and output force are the arms
how to calculate torque
torque = force x distance of lever/input arm
if two equal forces and equal arms, torque = 0
first class lever system
equal forces and equal arm lengths e.g. keeping head in place with gravty vs neck muscles force equal
