Somatic Motor System & Skeletal Muscle Flashcards
Skeletal Muscle Innervation
lower motor neurons are part of the PNS, they project onto skeletal muscle
Peripheral Pathway Originations (lower motor neurons)
1) Brain - cranial nerve nuclei
2) Spinal Cord - ventral horn cell bodies
Neuromuscular Junctions Parts
1) axon terminals
2) motor end plates
3) muscle membranes
4) Schwann cells
Schwann Cells function
secrete signals chemical signals used for maintaining the NMJ
Motor End Plate Details
specialized region of muscle membrane
- villi like structures to increase NAchR
NMJ Transmission
1) depolarized membrane
2) voltage gated Ca channel opens
3) vesicles release ACh into synaptic cleft
4) bind to NAChR
5) Acetylcholinesterase (AChE) metabolizes ACh
NAChR Channels
1) ACh binds to receptors
2) K leaves the cell, Na/Ca enters
3) influx causes depolarizing end plate potential
4) EPSP initiated
End Plate Potential, GP/AP?
end plate potential is a graded potential
Transverse Tubules Function
brings AP’s into the interior of muscle fiber
Sarcoplasmic Reticulum Function
stores Calcium
Myofibril Structure
where sarcomeres are found
- contains myosin/actin and proteins
H zone
only myosin
I band
only actin
Myosin Function
creates movement
- one actin binding site and one ATP binding site
Actin Details
myosin binding sites
