Muscle Physiology Flashcards
3 types of muscles
Skeletal=single/bi nucleated
Cardiac =multi nucleated
Smooth =single nucleated
Cardiac muscle
Relatively short
30-200 um
Diameter:5-10um
No striations
Functions of skeletal muscle
• Movement of the skeleton
• Posture
• Support of visceral organs
• Body temperature
• Energy storage
Smallest anatomical structure in a skeletal muscle
(Smallest)functioal structure of the skeletal muscle
Sarcomere
The borders of the sarcomere and move closer together during contraction are
Z lines
Sarcomere
The main contractile,functional unit of the skeletal muscle fibres
The neuromuscular junction
-acetylcholine is released onto the neuromuscular junction
-it binds to acetyl choline receptor
-when acetyl choline receives an action potential(acetyl choline receptors are stimulated)sodium gated Channels open
-signal is carried along the nerve
Where are calcium ions stored
Stored in the sarcoplasmic reticulum
Where are ion channels located in
In the t-tubules
Actin
Muscle thin filament
Tropomyosin
Stiffens and stabilises actin,preventing actin binding at rest
Troponin
-where calcium binds
-has 3 subunits,each with a specific role
skeletal muscle contraction requires what form of sracoplamic reticulum
Calcium
Thin filament
Actin
Cross bridge model
-myosin head joins atp
-bound atp is hydrolysed= phosphate is released(still attached to myosin head)
-myosin head moves and grabs actin=phosphate is released
-power stroke
-atp is released(another myosin head binds to atp)
Watch lecture
What happens to atp in order for powerstroke to occur
Hydrolyse to form atp and inorganic phosphate
What affects the force of muscle
Developed due to the action of the cross bridges
What are isotonic contractions
-muscle contracts,shortening in length
-eg lifting an object which is easy to move
List types of muscle fibre types
-slow-twitch oxidative fibres(type 1)
-fast twitc oxidative glycolytic fatigue resistant muscles(type 2a)
-fast twitch glycolytic fatiguable fibres (type 2b)
Fastest contracting muscles in skeletal muscles are:
Type 2b
