muscle contractions: Flashcards
what are muscles for
muscles can contract or relax or can lengthen after being streched out
muscle cells covert atP into mechanical energy
3 types of muscle?
cardiac , skeletal, and smooth
skeletal muscle function
head production
muscle and posture tone
movement
it also attaches to the fascia , skin or bone, striated can see the light and dark bands wiht microscope
it is controlled voluntary - whenever we wants out muschle to work it will send signal from our brain
what happens during voluntary muscular movement
they are usually smooth , tremor and jerk free and muscles dont work alone but in teams
for movement . muscle pulls on bones and as muscle fibres shorten the bones to which they are attached move closer
insertion bone usually moves
how do movements occur
for movements to occur the muscle needs to work as agonist and antagonist
as the muscle which which is actively contracting is an agonist and the muscle which is relaxing and lengthening is an antagonist.
what happens to your arm when youre lifting weight
the bicep is contracting as you are lifting the weight so its the agonist however the tricep is relaxing so its the antagonist
What is a primer move
when muscles contract and the one muscle that is mostly causing the movements is called a primer move
what is a synergist
other muscles which are helping the primer move
what is a concentric?
this occurs when the length of the muscle shorten as tension is being generated
eccentric?
muscles lengthens as tension is being generated
isotonic?
muscles changes length whist generating tension
isometric?
muscle do not change length whilst generating tension
what are type 1 muscle fribres?
slow twitch fibres and resist fatigue. largely found in postural muscles as they can hold position for longer periods.
they are oxidative and aerobic in nature and also contains lots of mitochondria and myoglobin.
type IIb fibres?
are anaerobic and glycolytic.
they can produce rapid forceful contractions but fatigue very quickly .
they do not contain much myolglobin or mitochondria. mostly used for running, sprinting( fast twitch fibres)
appear white due to low myoglobin
type IIa fibres?
they have many mitochondria and many of myoglobins , however known as fast twitch fibers contract and break down atp very quickly.
less resistant to fatigue than type 1
red
what do muscles produce when contracting
muscles produce heat when contracting , shivering helps maintain body temperature when cold to maintain temperatures
what happens during excerise
when you lose heat or sweat this reduces the risk of muscles overheating and losing its function.
what is a cardiac muscle?
this forms the contractile tissue of the heart.
striated muscles
under involuntary control and autorhytmic.
what is a smooth muscle?
this is found in GI tract, walls of arteries, arterioles, venules , veins
non striated
involuntary control
what are the properties of muscles?
- excitability
2.. conductivity
3.contractility - extensibility
- elasticity
properties of skeletal muscle
they contain multiple nuclei, multinucleated
they are covered with a sarcolemma
what does sarcoplasm have
it contains lots of glycogen
what are t tubules
transerve tubules which run deep into the cells
they allows action potential to travel rapidly into the cell and also spread it evenly
what are myofibrils
they are made up of many sacromeres joint up together in chains
contractile part of muscle cell
what is the H zone
this only covers part of the thick filament
and doesnt cover the entirely of the thick filament
what is A band
it covers thin filament and a portion of thick filament too
what is the i band
it stretches over 2 sacromeres and only covers the thin filament
what is the z line
they are a boundry line of the sacromere
and give it a striated look
what protien is thick and thin filaments made from
thick- myosin
thin- actin
what do actins contains
they contain sites to which mysoin heads attach to
they have a strand called tropomyosin it spirals around the actin and a troponin which binded to acting and tropomyosin
what are myosin
they contain myosin head which contain Atp
they attach to the binding site of the actin
what are synaptic clefts filled with
basal lamina glyco protien
what are circular muscle fibres:
they are arranged in cocentric rings ,
convergend
wide orgin and converges towards a single tendon
parralel
long axis of the muscle runs parallel to the long axis of the muscle.
pennate.
muscle bundles which are short and attach to a central tendon
how many bones do humans have
206
axial skeleton contains 80 bones
what is the purpose of joints :
these are sits where two or more bones meet
it holds the skeleton together
and gives skeleton flexibilit
