Exam 3: Descending Tracts Flashcards
1
Q
Upper motor neurons =
A
corticospinal/corticobulbar
2
Q
Lower motor neurons =
A
brainstem and spinal cord (and cranial nerve nuclei), start in CNS and end in PNS
3
Q
Alpha motor
A
lower motor neurons to muscle
4
Q
Gamma motor
A
to muscle spindle (stretch receptor) part of reflex
5
Q
Renshaw cells are
A
interneurons, help control alpha motor neurons in a feedback loop
6
Q
Corticospinal tract is 60-80% from
A
primary motor cortex
7
Q
Corona radiata is __ brain
A
fore brain
8
Q
Crus cerebri is __ brain
A
mid brain
9
Q
Pontine corticospinal is part of which tract
A
corticospinal tract
10
Q
Pyramidal tract is in the
A
medulla
11
Q
80% cross as
A
lateral corticospinal
12
Q
10% cross as
A
anterior corticospinal (at ant. white commissure)
13
Q
10% remain
A
ipsilateral
14
Q
Lateral corticospinal
A
- distal limb motor neurons
- renshaw cells
- excitatory interneurons
- presynaptic inhibitory neurons
15
Q
Reticulospinal tract
A
- locomotion
- posture
