313 FINAL 3 Flashcards
What can and cannot individual reflex inputs do?
Can summate, but do not reach the threshold for APs to occur
What type of input comes down with repetitive EPSPs and why?
Tonic input
to change the membrane potential to bring it close to threshold
Combining the ___ input and adding the ____ bursts does what?
combing tonic input and adding the reflexive bursts summates the EPSPs, creating occasional AP if they summate enough.
Tonic input =
increasing membrane on the neuron
When can you change how excitable a MN is?
when its not excitable and not close to threshold
how do inputs form the brain/BS come down and impact reflexes?
through axons, EPSPs, IPSPs and interneurons
1a afferents connect _____ to the motor neuron and____ to the 1a inhibitory interneuron
monosynaptically, disynaptically
How can you remove reciprocal inhibition? ex: how can you activate tri and bi at the same time
Bias both MN pools, have input come down and remove the inhibitory 1a IN bilaterally –> inhibit the inhibition
describe supraspinal input during walking
A muscle spindle feedbacks into the spinal cord (or the CPG for simple reflexes), goes to the cerebellum that coordinates some visual guidance and adjustments (balance wise)
parts of the NS involved in walking + their role:
Visual cortex is the visual aspect obviously
Motor cortex: visual guidance
Cerebellar pathways: fine tuning, coordination
Brainstem centers: activates and controls speed
roles of CPG, feedback, tonic signals and supraspinal input during walking
CPG can handle walking on its own, downloaded into the spinal cord and not dependent on the brain
Feedback coming in helps to tune/adapt to the environment (afferent feedback)
Tonic signals come from brainstem for timing (time to walk, time to move)
Supraspinal control helps with: stability, task selection, navigation, obstacle avoidance
3 directions of vestibular movement
Pitch - anterior/posterior (rotation around y axis)
Roll - coronal (rotation around x axis)
Yaw (rotation around z axis)
components of the vestibular system
semicircular ducts (canals): horizontal, posterior and superior
vestibule (containing otolith organs: saccule and utricle).
ampulla =
membranous labyrinth =
ampulla = a swelling at the end of each semicircular canal before reaching the vestibule
with a membranous tissue running inside of it (membranous labyrinth)
perilymph and endolymph =
The liquid on the outside is called perilymph which helps float the membranous series of ducts, and balloon animal in the middle, and the other structures
Inside the duct, there is another fluid (endolymph)
ampullae =
the bulges at the end of the semicircular ducts
Semicircular canals contain..
semicircular ducts: anterior, posterior, lateral
2 types of hairs:
1 kinocilium: the tallest hair sticking on 1 edge of the hair, very thick compared to other hairs)
40-70 stereocilia: sticking straight upwards, they get shorter as you move away from the kinocilium
the top of the hair cell is ____
polarized
what happens if you push the stereocilia towards the kinocilia?
it could cause the hair cells to depolarize, become less negative, release more neurotransmitter –> the axon would fire more
what happens if you pushe the stereocilia away from the kinocilia?
the hair cells hyperpolarized, become more negative, releasing less neurotransmitter –> the axon would fire less
hair cells are _______, and drop ______ to the ____ causing it to ____ and giving the ____ a ____ _____ _____
hair cells are chronically leaky, and drop neurotransmitter to the axon causing it to fire and giving the axon a resting discharge rate
Bend stereocilia towards kinocilia => _____ of hair cell, hair cell becomes less _____, ______ neurotransmitter release, increase in ____________
Bend stereocilia towards kinocilia, depolarization of hair cell, hair cell becomes less negative, more neurotransmitter release, increase in firing frequency in axons
Bend stereocilia away from kinocilia => ______ of hair cell, hair cell becomes more ____, _____ neurotransmitter release on axon, decrease in ____________
Bend stereocilia away from kinocilia, hyperpolarization of hair cell, hair cell becomes more negative, less neurotransmitter release on axon, decrease in firing frequency in axons
The hair cells are like a tap that is always leaking a small amount of water (_______) onto the ___________. Bending the cilia either makes the hair cells more or less ______.
The hair cells are like a tap that is always leaking a small amount of water (neurotransmitter) onto the 8th nerve afferents. Bending the cilia either makes the hair cells more (depolarization) or less leaky.
For the hair cells in the ampullae of the semicircular ducts the hair cells are all oriented ______. For the otolith receptors, the sensory region (macula) the hair cells are oriented ________.
For the hair cells in the ampullae of the semicircular ducts the hair cells are all oriented in the same direction. For the otolith receptors, the sensory region (macula) the hair cells are oriented in different directions.
