somatosensory 1

Question 1

in the descending pathway cell bodies are located in the

Answer 1

primary motor cortex

Question 2

axon fibers descend to the

Answer 2

corticospinal tract

Question 3

most descending fibers decussate in the

Answer 3

medullary pyramids (90%)

Question 4

fibers synapse on to the LMN in the

Answer 4

ventral horn of the spinal cord

Question 5

in the descending pathway cell bodies in the ventral horn can be found in this laminae

Answer 5

9

Question 6

LMN will always use __ as their Neurotransmitter

Answer 6

Ach

Question 7

Ach binds to the ___ receptors

Answer 7

excitatory nicotinic

Question 8

When ACh binds to the receptor, the channel opens, allowing for ion exchange and __

Answer 8

muscle fiber depolarization.

Question 9

Excess ACh in the synapse is degraded locally by

Answer 9

Excess ACh in the synapse is degraded locally by acetylcholinesterase (AChE).

Question 10

A motor unit is defined

Answer 10

A motor unit is defined as a motor neuron and all the fibers it contacts.

Question 11

small motor units vs large motor units

Answer 11

Smaller motor units regulate fine motor activity, while large motor units control more gross movements.

Question 12

gamma motor neurons and alpha

Answer 12

alpha: tells muscle to contract

gamma : intrafusal fibers that control the length/tension of muscle spindles

Question 13

what happens When alpha motorneurons cause shortening of the extrafusal fibers?

Answer 13

sensory input is loss

Question 14

polysynaptic vs monsynaptic

Answer 14

poly: indirect
mono: direct. These afferent proprioceptive sensory neurons directly synapse onto
ipsilateral lower motor neurons.

Question 15

in reciprocal pathway :Afferent proprioceptive sensory neurons directly synapse onto

Answer 15

ipsilateral lower motor neurons to cause quadriceps contraction
and
interneurons that inhibit the lower motor neurons innervating the hamstring muscle.

Question 16

interneurons are usually

Answer 16

inhibitory

Question 17

reciprocal inhibition

Answer 17

activate one and relax other muscle ..

Question 18

CROSSED EXTENSOR aka

Answer 18

(WITHDRAWAL) REFLEX’

Question 19

explain withdrawl reflex

Answer 19

Afferent nociceptive sensory neurons cause contraction of the ipsilateral hamstring and reciprocal inhibition of the ipsilateral quadriceps, for flexion of the ipsilateral leg

Sensory neurons also cause extension of the contralateral leg

Question 20

cerebellum

Answer 20

The cerebellum receives and integrates information about balance, body position, motor intention

The cerebellum is also involved in fine motor memories such as typing or playing the piano.

Question 21

vestibulocerebellum

Answer 21

The vestibulocerebellum helps maintain balance and controls eye movements.

Question 22

The spinocerebellum

Answer 22

The spinocerebellum enhances muscle tone and helps coordinate voluntary movements, especially fast, phasic motor activities

Question 23

The cerebrocerebellum

Answer 23

The cerebrocerebellum plays a role in initiating voluntary movement

Question 24

function of basal ganglia

Answer 24

Inhibiting muscle tone throughout the body – prevent unintentional movement
Monitoring and controlling slow, sustained contractions

Question 25

Rubrospinal

Answer 25

- Integration of cortical and cerebellar information. Distal musculature preferentially.

Question 26

Reticulospinal

Answer 26

Reticulospinal - excite motorneurons to proximal extensors for postural control

Question 27

Tectospinal

Answer 27

Tectospinal - Head movement in response to stimuli

Question 28

Vestibulospinal

Answer 28

Vestibulospinal – Postural control

Question 29

Corticobulbar axons innervate the

Answer 29

Corticobulbar axons innervate the cranial nerve motor nuclei Ipsilateral system

Question 30

in descending pathway Axons exit the spinal cord via the

Answer 30

Axons exit the spinal cord via the ventral root and project in spinal nerves to innervate target muscles.

Question 31

parkisons is a Neurodegenerative disease of the

Answer 31

nigrostriatal dopamine pathway

Question 32

BROWN-SEQUARD SYNDROME spinal cord hemisection ipsilateral defects

Answer 32

Loss of fine touch, vibration, proprioception Loss of function-upper motor neurons Spastic paralysis Hyper-reflexia

Question 33

BROWN-SEQUARD SYNDROME spinal cord hemisection contralateral defects

Answer 33

loss of pain and temp

Question 34

NEUROMUSCULAR JUNCTIONMYASTHENIA GRAVIS

Answer 34

Autoimmune disorder. Targets nicotinic receptors at the neuromuscular junction. Muscle weakness, ptosis Treated with acetylcholinesterase inhibitors