Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular
Jessika Lee P.1 - Coggle Diagram
Muscular
Jessika Lee P.1
-
skeletal muscles
Upper half
- trapezius
- sternocleidomastoid
- deltoid
- pectoralis major
- serratus anterior
- bicep brachii
- tricep brachii
- Brachioradialis
- Flexor carpi radialis
- rectus abdominis
- external oblique
- infraspinatus
- teres major
- latissimus dorsi
- extensor carpi radialis
- flexor carpi ulnaris
- extensor digitorum
Lower half
- iliopsoas
- adductor longus
- sartorius
- gracilis
- rectus femoris
- vastus lateralis
- vastus medialis
- bicep femoris
- semitendinosus
- semimembranosus
- tibialis anterior
- extensor digitorum longus
- fibularis longus
- gastrocnemius
- soleus
Sliding filament theory
Sliding filament theory states that during contraction,thin filaments side past thick filaments causing actin and myosin to overlap more
- neither thick or thin filaments change length
Neuromuscular Junction
- skeletal muscles are stimulated by somatic motor neurons
- axon from central nervous system to skeletal muscle
- axon branches end of muscle fiber, forming neuromuscular junction
- axon terminal and muscle fibers separated by gel-filled space. synaptic cleft
-synaptic vesicles contain neurotransmitter acetycholine
- infoldings contain millions Ach receptors
Events at neuromuscular junction - AP arrives at axon terminal
- voltage gated calcium channels open, calcium enters motor neuron
- calcium entry causes release of Ach neurotransmitter into synaptic cleft
- Ach diffuses across Ach receptors on sarcomere
- Ach binding to receptors, open gates,results in end plate potential
- Ach degrade
Sarcomere
- smallest contractile unit of muscle fiber
- contains A band with half of an I band at each end
- consists of area between 2 discs
- individual sarcomeres align end to end along myofibril
-
Action Potential
- Action potential is caused by changes in electrical charges
- occurs in 3 steps
- generation of end plate potential
- depolarization
- re polarization
- Depolarization - generation and propagation of an action potential
- if end plate potential causes enough change, channels in membrane will open
- lead to muscle fiber contraction
- Re polarization - restoration of resting conditions
- refractory period
- muscle fiber cannot be stimulated for a specific amount of time
- End plate potential
- ach released from motor neuron bands to Ach receptors
- causes chemically gated ion channels to open
- results in local depolarization called end plate potential
Disorders
- Duchenne muscular dystrophy (DMD), most common and serious form of muscular dystrophies, muscle destroying diseases it generally appear during childhood
- appears between 2 and 7 years old
- disease progresses from extremities upward
- caused by defective gene for dystrophin
-inflammation follows and regenerative capacity is lost
-
-