Where does the vagus nerve originate and what pathway does it involve
Axon varicosities open what channel and use what neurotransmitter in response to an action potential
Calcium channel, NE
What is the function of AChE?
Breaks down ACh
NAChR is permeable to what ions?
Na and K
What is the role of Troponin and Tropomyosin?
Troponin is bound by Ca and moves Tropomyosin which exposes the myosin-binding site on the actin
What is the role of Titin and Nebulin
Titin provides stability and elasticity to myosin Nebulin helps align actin
what is the composition of myosinn?
2 coiled heavy chain tails with 2 heads
What part of the sarcomere gets shorter during contraction?
the I band
Describe the power stroke steps to muscle contraction.
Tight binding in the rigor state, ATP binds to myosin which causes myosin to release actin, ATP hydrolized (ADP + Pi) myosin head binds in cocked position, Release of Pi initiates the power stroke, ADP falls off and myosin resumes the rigor state.
Function of DHP receptors
responds to the action potential in the T-tubules, opens ryanodine receptors which let Ca out of the Sarcoplasmic reticulum
Slow twitch oxidative, long periods of contraction, small cell diameter
Intermediate muscle fibers
fast twitch oxidative, less fatigueable, both oxidative and glycolytic processes
fast twitch glycolytic, quick fatigue, anaerobic, large cell diameter (recruited last due to fatigue)
Group of muscle fibers controlled by a single somatic motor neuron. (small motor units for fine movements and large units for gross movements) (all fibers are of the same type)
What component is found in skeletal but not smooth muscles?
Single unit smooth muscles
numerous gap junctions, unified contraction (found in blood vessels, intestinal tract)
Multi unit smooth muscle
No gap junctions, fine, graded contractions (found in iris, male reproductive tract)
Molecular events of smooth muscle contraction.
Ca channels open causing Ca release from SR, Ca binds to CaM, Ca-CaM activates MLCK, MLCK phosphorylates myosin heads (ATP), phosphorylated myosin heads increase muscle tension (no ATP needed to hold contraction)
Autonomic reflexes are monosynaptic or polysynaptic. Where are the synapses
Polysynaptic. at least one in CNS and another in an autonomic ganglion.
Muscle spindle function
sends information about muscle stretch to the CNS
Golgi tendon organ function
detects strain in the tendon (sensory nerve endings interwoven among collagen fibers)
What 2 regions control voluntary movements
Cerebral Cortex, Basal Nuclei
What 2 regions control postural reflexes and hand and eye movements
Brain stem, Cerebellum
what relays information from spinal cord, basal nucleus, and cerebellum to the Cortex
What integrates porprioception?
What maintains posture subconciously
Lateral corticospinal tracts cross in the ____ while Anterior CST cross in the ______