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Week 3- Muscles - Coggle Diagram
Week 3- Muscles
Types
of
Muscles
Cardia Muscles: Walls of heart- Branching chain of cells/ uni/binucleate, striations
Smooth Muscles: Unit muscle (Walls of hollow visceral organs) multi unit muscle- eye muscles, airways, large arteries
Single fusiform, uninucleate, no striations
-
Neural communication:
Motor Unit:
Single neuron + muscle fibres it innervates
-Fixed amount
-
Theory of Sliding Filaments:
- Calcium needed to remove Blockage
-Calcium binds to Troponin--> Moves Tropomyosin--> Myosin heads can bind
Process:
1) Myosin Crossbridge attach to actin myofilament
( Myosin-head grab onto active sites--> E used--> hdyrolyse bound ATP= (ADP + Pi)
2) Power stroke ADP ABSENT, myosin head pivots and bends as pull on actin filament
3) Myosin-head detach from active site- ATP binding required (NOT USED)
4) Hydrolyse ATP= Myosin head "cocked" to bond with new active site
Myosin head binding:
- ATP-Bound (NOT USED)- Crossbridges broken/ myosin relaxes
- ADP- ATP Hydrolysed-ADP +Pi- Myosin head "Ready" position, new crossbridge formed
- Nothing-ADP released from Myosin- Powerstroke- pull acting towards M-Line
-
Functions
- Produce Body Movement
- Maintain Posture + Body position
- Stabilises Joints
- Generates heat
- Additional: Protect organs, form valves, control pupil size
Skeletal Muscle Structure
(B.F.F)
1) Muscle belly- wrapped in epimysium (entire muscle) 2) Muscle Fascicle- Bundle muscle fibres, wrapped in/separated by peri (Perimeter) mysium3) Muscle fibres- sheathed in endo(Inside) mysium, has capillaries/myostallite cells & acons of neurons
- composed of rows and rows of sarcomeres
4) Sarcomere- small contractile unit, in rows. pull + SLide over each other during contraction Summary:
Muscle, Fascicle, Muscle fibre, Myofibril, Sarcomere, Myofilament/filament
Characteristics of Muscles:
4:
1) Excitability (Responsiveness)- ability to receive and respond to stimulus
2) Contractility- ability shorted forcibly when stimulated
3) Extensibility-Ability to be stretched e.g. when relaxed)
4) Elasticity- ability recoil to resting length after stretch