CH 19 Pt 1 Flashcards
CNS
Analyze and organizes info
-motor system planning and commands
MAINLY SENSORY
PNS
Outputs CNS commands and sends sensory info to CNS
PRIMARILY MOTOR
Cerebellum
Primary motor cortex inside
-motor control centre
Afferent Neurons
Relay sensory info from peripheral to the CNS along posterior column
-away from muscles
Efferent Neuons
Relay info from CNS to the peripheral or away from the brain along the pyramidal tract
Somatic: voluntary
Autonomic: involuntary
Which brain region is associated with processing of sensory signals
Parietal love
Which art of brain is the primary motor cortex?
Pre -central gyrus
Which part connects each brain hemisphere via commisural fibers
Corpus callosum
Which part of the brain is known as the motor control centre
cerebellum
The what roots of the spinal cord contain what neurons that relay info back to the CNS?
The dorsal roots contain Afferent neurons
Voluntary Movements
Require integration at the cerebral cortex
-learned movements may become reflexive
-muscle memory
Reflexive Movements
Sensory input (vision, vestibular, muscle)
-can be modulated by higher brain centres
-involved in posture
Rhythmic Movements
Voluntary and reflexive
-initiated by cerebral cortex
-can be sustained without input from brain
CPG
Central Pattern Generator
-neural network in the lower part of the spinal cords that is thought to control locomotion
-doesn’t require input from higher brain
-output can be modified by input from brain or reflexes
Reflex Arc
Basic mechanism to process autonomic muscle action
-peripheral stimulus causes Afferent neuron impulses to enter spinal cords
Reflex Arc pathway
Afferent neurons interconnect (synapse) with interneurons in the spinal cord to relay info to CNS
Efferent signals return via anterior motor neurons to the muscles
Muscle responds
Motor Unit represents:
An alpha motor neuron and the fibers that it innnervates
Motor Neuron Pool represents
A collection of alpha motor neurons that innervate ONE muscle
Small Motor Unit
Only have a few fibers/ motor neurons
(small/ fine movements)
Large Motor Unit
May have hundreds or thousands of muscle fibers/ motor neurons
-simple, but gross movements
All muscle fibers within a given motor unit are:
The same fiber type (1, 2a, 2x)
Dendrites
Receive impulses and direct toward cell body
Cell body
Control centre
Schwaan cell
Covers bare axon
