anatomy of the nervous system 2

Question 1

what does the peripheral nervous system consist of?

Answer 1

cranial nerves (12 pairs) and spinal nerves (31 pairs)

Question 2

what does the lateral horn consist of?

Answer 2

autonomic fibres

Question 3

describe the spinal tracts of white matter

Answer 3

1. ascending tracts — carry info to the brain from the periphery (sensory)
2. descending tracts — carry info from the brain to the periphery (motor)

Question 4

spinothalamic tracts

Answer 4

• lateral and ventral
• spine —> thalamus —> cortex

Question 5

name 2 dorsal columns (ascending tracts)

Answer 5

fasiculus gracilis — lower limb
fasciculus cuneatus — upper limb

Question 6

what is a fasciculus?

Answer 6

bundle of fibres

Question 7

describe the sensory pathway

Answer 7

Question 8

lateral vs ventral spinothalamic tract

Answer 8

lateral — pain and temperature
ventral — touch and pressure

Question 9

where does the 3rd order neuron go to in the spinothalamic tract?

Answer 9

homonculus

Question 10

describe the dorsal columns

Answer 10

Question 11

where are the corticospinal tracts?

Answer 11

lateral — at back
ventral — by fissure

Question 12

describe the somatic motor pathway?

Answer 12

• only 2 neurons
• most cross in medulla
• upper motor neurone states in precentral gyrus

Question 13

ventral vs lateral corticospinal tract

Answer 13

ventral stays ipsilateral at medulla then crosses, lateral crosses

Question 14

what are located in the brainstem?

Answer 14

sensory nucleus and motor nuclei

Question 15

how many nerves are there in a cranial pathway?

Answer 15

3

Question 16

what synapses on the sensory nuclei in the brain stem?

Answer 16

2nd order neurone

Question 17

where are the nerve cell bodies of CN V, CN VII, and CN IX & X?

Answer 17

in the PERIPHERY

CN V = trigeminal ganglion
CN VII = geniculate ganglion
CN IX & X = superior and inferior ganglia

Question 18

where is the nerve cell body of the 2nd order neurone in the general sensory pathways of cranial nerves?

Answer 18

trigeminal sensory nucleus of brainstem (regardless of cranial nerve). fibres decussate here

Question 19

ganglion vs nucleus

Answer 19

ganglion = collection of NCB outside CNS
nucleus = collection of NCB in CNS

Question 20

where is the NCB of the 3rd order neuron in the general sensory pathways of cranial nerves? where do axons project?

Answer 20

• NCB in VP thalamus
• axons project to primary sensory cortex

Question 21

what are the 3 subnuclei of the trigeminal sensory nucleus?

Answer 21

1. mesencephalic = in midbrain. proprioception
2. chief sensory nucleus = touch and pressure
3. spinal nucleus = pain and temperature

Question 22

from the trigeminal sensory nucelus, ______ fibres go the the _____ nucleus of the _____

Answer 22

trigeminothalamic fibres go to the ventral posterior nucleus of the thalamus

Question 23

some nerves in the corticobulbar tract are bilaterally innervated. what is the exception?

Answer 23

hypoglossal nerve CN XII

Question 24

which nerves are bilaterally innervated?

Answer 24

• oculomotor, CN III
• trochlear, CN IV
• trigeminal, CN V
• abducens, CN VI
• glossopharyngeal, CN IX
• vagus, CN X
• accessory, CN XI

Question 25

how is the facial nerve different?

Answer 25

- the facial motor nucleus is made up of 2 parts - superior part supplies muscles on upper half of the face — superior half is bilaterally innervated - inferior part supplies the muscles on lower half of the face — inferior part is contralaterally innervated

Question 26

what would be the effect of an UMN lesion in the facial nerve?

Answer 26

- superior parts of both sides of face still supplied - lower part not supplied of contralateral side to lesion — droopy face

Question 27

what 2 types of receptors are used in the parasympathetic nervous system? neurotransmitter?

Answer 27

Question 28

what 2 types of receptors are used in the sympathetic nervous system? neurotransmitter?

Answer 28

Question 29

how are postganglionic SYMPATHETIC neurones acting on sweat glands different?

Answer 29

release ACh which binds to muscarinic receptors

Question 30

label

Answer 30

Question 31

where are nerve cell bodies of preganglionic neurones located?

Answer 31

lateral horn of grey matter

Question 32

describe the route of the axon of preganglionic neurons?

Answer 32

axons passes in ventral root —> spinal nerve —> ventral rami —> white ramus communicantes then takes 1 of 3 options

Question 33

at what level is sympathetic outflow?

Answer 33

T1-L2

Question 34

what are the 3 options of the sympathetic preganglionic neurons?

Answer 34

1. synapses in paravertebral ganglion at own spinal level 2. passes up/down the chain to synapse in cervical or pelvic paravertebral ganglion 3. passes straight through chain to synapse in prevertebral ganglion

Question 35

if the preganglionic sympathetic neuron passes straight through the chain to synapse in a prevertebral ganglion, what is the preganglionic neuron called? where does the postganglionic neuron pass to?

Answer 35

splanchnic nerve post ganglionic neuron passes directly to the effector organ