Lecture 27- Somatotopy and Descending Pathways Flashcards
What does the post-central gyrus contain?
Somatosensory cortex
What does the pre-central gyrus contain?
Primary motor cortex
What is a motor unit?
The lower motor neuron and the group of muscle it innervates
What does somatotopy mean?
Particular brain regions correspond to particular parts of the body
In the Somatosensory cortex, what is the area innervated in the cortex proportional to?
Number of sensory inputs
What does the internal capsule contain?
Myelinated axons of upper motor neurons
Where are the cell bodies of upper motor neurons located?
Layer 5 of the primary motor cortex of the pre central gyrus
What is the descending pathway called?
The corticospinal tract (CST)
Where are the input and output regions of the corticospinal tract?
Input region- cortex
Output region-Spinal cord
What are the 2 neurons in descending and ascending pathways called?
Upper motor neurons (UMN) and lower motor neurons (LMN)
What is the decussation of the pyramids?
The region where upper motor neuron axons cross midline
What does the upper motor neuron synapse onto? Where does this occur?
Upper motor neurons crosses midline and synapses onto lower motor neuron in the ventral horn
What does corticospinal tract control
Voluntary motor function
For neurons whose conductile processes are in the corticospinal tract, protein synthesis would most likely occur in the _____ ______
Motor cortex
In regards to the spinothalamic tract, where does the second order neuron cross midline?
Spinal cord segment
