Motor Learning Lecture 1: Nervous System

What basic control system allows us to gather information, process it, and produce a response?

nervous system

What are the two main divisions of the nervous sytem?

CNS and PNS

What is the CNS comprised of?

brain and spinal cord

What part of the nervous system encompasses everything outside the CNS?

PNS

What are the two branches of the PNS?

sensory and motor

Which branch of the PNS is responsible for afferent information?

sensory division

Which branch of the PNS is responsible for efferent information?

motor division

What is the purpose of afferent neurons (information)?

carries information to the CNS

What is the purpose of efferent neurons (information)?

carries information away from the CNS

What type of neuron brings in sensory input from sensory receptors?

afferent

What type of neuron sends motor commands to muscles and glands?

efferent

What are the two subdivisions with the motor division of the PNS?

somatic and autonomic

Which subdivision of the motor division is responsible for voluntary action?

somatic

Which subdivision of the motor division is responsible fore involuntary action?

autonomic

What are the cells called that are long-lived, amitotic, long-length, and excitable?

neurons

What is the name of supporter cells in the PNS?

glial cells

What are Schwann cells (a glial cell) responsible for?

axon myelination

What are Satellite cells (a glial cell) responsible for?

regulation of chemical environment

What part of the neurons releases neuro transmitters across a synapse?

axon terminals

What part of a neuron receives signals from other neurons or sensory input?

dendrites

What part of a neuron conducts an action potential away from the cell body?

axon

What role does myelination play on the axon of neurons?

increases AP speed

How does myelination increase AP speed?

saltatory conduction

What role do the Nodes of Ranvier play along the axon of a neuron?

regenerates the AP

What is the name for 1 motor neuron and all the muscle fibers it innervates?

motor unit

Are motor neurons responsible for efferent or afferent information?

efferent

What size motor unit would be responsible for precise movement of the eye?

small

What size motor unit would be responsible for powerful broad movement of the quad muscles?

large

What is the resting membrane potential charge at?

-70mV

How is resting membrane potential maintained?

sodium potassium pumps

What is the charge for the membrane threshold?

-55mV

What happens at threshold (-55mV)?

Na+ gated channels open

What is the result of Na+ channels opening at threshold?

depolarization

Depolarization is categorized by what type of change in membrane potential?

net positive (less negative)

What is the membrane potential at during peak depolarization?

+30mV

What happens at peak depolarization (+30mV)?

K+ channels open as Na+ channels close

What is the result of K+ leaving the cell at after peak depolarization?

repolarization

Repolarization is categorized by what type of change in membrane potential?

net negative (less positive)

What is the result of K+ channels slowly closing during the repolarization phase?

hyperpolarization

What type is the charge of the membrane during hyperpolarization?

less than -70mV

What prevents an AP from moving backwards along an axon?

refractory period

How can the refractory period be bypassed to send AP’s in both directions of an axon?

artificial stimulation via electrodes

What two variables does conduction (AP) velocity rely on?

myelination and axon diameter

What is the first step of signal transition form one neuron to another?

release of ACh onto a soma

What is the effect of ACh on a soma?

a graded potential

What are graded potentials?

small, variable, local voltage changes on dendrites/soma

What phenomena describes adding up multiple graded potentials from the same presynaptic neuron firing repeatedly over time?

temporal summation

What phenomena describes adding up graded potentials from different presynaptic neurons firing at the same time?

spatial summation

What is the overall effect of both spatial and temporal summation?

reach threshold (-55mV) in the axon hillock