Neuromuscular Control Flashcards
what are the divisions of the CNS
afferent and efferent
what types of neurons are in the afferent division
sensory neurons
what types of neurons are in the effere division
motor
what are the divisions of afferent nervous system
somatic and visceral
what are the divisions of the efferent nervous system
autonomic and somatic
what makes up a motor unit
motor neuron and all the fibers it innervates
what does the somatic nervous system innervate
skeletal muscle
what carries the AP along the membrane
voltage gated sodium channels
what is end plate potential
stimulation of Ach nicotinic receptors leads to change in membrane potential in skeletal muscle
what does end plate potential cause
AP
what does Ach nicotinic receptor allow through
sodium
what structure does AP move down
t- tubules
where do t-tubules carry AP
into the belly of the muscle
what receptors are on T-tubules that get activated with AP
DHPRs
what is the AP mechanism leading to calcium release
AP CAUSES DHPR TO CHANGe conformation withc makes contact with sarcolemma, Ca leaves Sarcoplasmic reticulum and calcium is involved in actin-myosin interaction
what is CICR
Ca release triggers neighboring sarcoplasmic reticulum to release Ca
how is calcium returned to the SR
Through the SERCA pump
how does calcium induce muscle contraction
via interaction of myosin and actin
what is the mutation resulting in dechenne muscular dystrophy
DMD gene encoding dystrophin
what does dystrophin do
connects cytoskeleton of the fiber to the ECM
how is contraction terminated (acetylcholine mechanism)
AChE breaks down ACh into choline and acetic acid. choline gets transported back into presynpatic neuron via sodium co transporter. choline combines with acetyl CoA by ChAT which makes ACh then it is repackaged into a vesicle for release. acetic acid is degraded
how is contraction terminated (Calcium mechanism)
calcium is pumped back into the SR via the SERCA pump.
- using gradient of sodium pump calcium out of cell by NCX
- calsequestrin
what stops vesicles from fusing with membrane
botulinum toxin
what stopd VGNa+ channels
tetrodotoxin, lidocaine
what blocks the nicotinic receptor
crurare
what is physostigmine
a reversible muscle contraction inhibitor
what are the causes of myasthenia gravis
-autoimmune disease
- antibody production to Ach ninoctinic receptors
what is the major symptom of myasthenia gravis
weakening of skeletal muscles
