Brainstem I

Question 1

What is brainstem

Answer 1

conduit for info flow between brain and spinal cord

Question 2

describe branches of neurons in anterolateral pathway in brainstem

Answer 2

Branches come off in brainstem = have other functions, aspects of physiological responses like pain
Go to brainstem, not spinothalamic fibers

Question 3

define fiber tract

Answer 3

bundle of axons in cns

Question 4

define nerve

Answer 4

Bundle of axons in pns

Question 5

define projections

Answer 5

Axons that extend from one region of nervous system to another

Question 6

what is brainstem comprised of

Answer 6

Medulla (most caudal)
Pons
Midbrain

Question 7

name important parts of brainstem

Answer 7

4th ventricle
Cerebral aqueduct
Superior and inferior colliculi
Pineal gland

Question 8

describe 4th ventricle

Answer 8

Space inside brain filled with csf

Question 9

what does cross section through caudal medulla show = gen

Answer 9

Dorsal colum and anteriolateral fiber tracts
Medulla = looks similar to spinal cord
See axons = fibers of dorsal neurons and 2nd order neurons of anterolateral

Question 10

what does cross section through caudal medulla show = stain

Answer 10

White matter = dark
Gray matter = white

Question 11

what does cross section through caudal medulla show = 3 features

Answer 11

Fasciculus gracilis = legs = medial
Fasciculus Cuneatus = arms = lateral
Spinothalamic tract = anterolateral

Question 12

describe what tract names correspond to

Answer 12

To where they start and where they end
(Spinothalamic = spinal cord —> thalamus)

Question 13

name features of section high up in medulla = 3 things

Answer 13

Nucleus gracilis = legs
Nucleus cuneatus = arms
Spinothalamic tract

Question 14

what do dorsal column axons do in medulla

Answer 14

sysnpse with 2nd order neurons in dorsal columns nuelci of medulla (dorsal column nuclei = organized collection of cell bodies, dendrites and synapses in cns)

Question 15

descrive nucleus gracilis

Answer 15

Receives Input from legs and lower body

Question 16

describe nucleus cuneatus

Answer 16

Receives inputs from arms and upper body

Question 17

why are fasiculus replaced by nuclei

Answer 17

White matter disappears and replaced by gray matter

Question 18

desribe what else is found in section of higher up medulla

Answer 18

White matter = coticospinal tract = output going down
Cerebral cortex —> spinal cord = produces movement

Question 19

what happens in Rostral medulla

Answer 19

Axons of dorsal column nuclei have crossed to contralateral side of brainstem = form a fiber tract called medial lemniscus

Question 20

where are we cutting in rostral medulla

Answer 20

Above cell bodies
= cutting through axons of 2nd order neurons

Question 21

describe all features = when cut through rostal medulla

Answer 21

Fiber tracts = medial lemniscus
Somatotopic organization
Arms, legs, 2nd order neurons
Spinothalamic tract
Inferior olive = involved in cerebellum/connected to it
Crossed over = axons on left correspond to right side of body

Question 22

Describe section off when cut through pons = features

Answer 22

Ascending somatic sensory tracts
Medial leminscus
Spinothalamic tract
Arms, legs
Many myelinated axons = bundles, huge going into cerebellum
Movement pathway down from brain visible

Question 23

Describe section fo cutting through midbrain

Answer 23

Ascending somatic sensory tracts
Legs, arms
Spinothalamic tract
Medial lemniscus
Cerebral aqueduct

Question 24

what is cerebral aqueduct

Answer 24

Replaced 4th ventricle
Connects 4th ventricle to other ventricles in brain

Question 25

define cranial nerves

Answer 25

12 cranial nerves Continuation of spinal nerves = innervate head

Question 26

what are all spinal nerves

Answer 26

mixed

Question 27

are The functions listed of cranial nerves the ONLY functions

Answer 27

nOOOO Esoteric functions = like how facial connected to stapedius muscle Lesser known and secondary

Question 28

CRANIAL NERVE I = olfactory = type of input and function

Answer 28

Sensory Olfaction - smell Special sense unique to head (Axons connect nose —> brain, axons through roof of nose = holes= synapse in olfactory bulb —> nose)

Question 29

CRANIAL NERVE II = optic = type of input and function

Answer 29

Sensory Vision Special sense unique to head

Question 30

CRANIAL NERVE III = oculomotor = type of input and function

Answer 30

Motor = only axons leaving brain to eye msucles Eye movements = 4/6 eye msucles, eyelids, pupillary constriction

Question 31

CRANIAL NERVE IV = trochlear = type of input and function

Answer 31

Motor Eye movements

Question 32

CRANIAL NERVE V = trigeminal = type of input and function

Answer 32

Mixed = somatic sensory nerve of head = touch, pain, headache, tooth ache Cutaneous and proprioceptive sensation in face and mouth, innervation of teeth, muscles of mastication

Question 33

CRANIAL NERVE VI = abducens = type of input and function

Answer 33

Motor Eye movement = lateral rectus, moves eyes laterally

Question 34

CRANIAL NERVE VII = facial = type of input and function

Answer 34

Mixed Msucles of facial expression, taste sensation from tongue, bells palsy*

Question 35

CRANIAL NERVE VIII = vestibulocochlear = type of input and function

Answer 35

Sensory Hearing, equilibrium (2 nerves stuck together= input from cochlear and vestibular system)

Question 36

CRANIAL NERVE IX = glossopharyngeal = type of input and function

Answer 36

Mixed Swallowing, sensations form plate and back 1/3 of tongue

Question 37

CRANIAL NERVE X = vagus = type of input and function

Answer 37

Mixed Autonomic sensory and motor functions of body, visceral sensation s of pharynx and larynx (Main preganglionic psns output that innervates visceral organs, also sensory information in from viseral organs)

Question 38

CRANIAL NERVE XI = spinal accessory = type of input and function

Answer 38

Motor Trapezius and sternocleidomastoid muscles

Question 39

CRANIAL NERVE XII = hypoglossal = type of input and function

Answer 39

Motor Muscles of the tongue

Question 40

describe basic organization of cranial nerves nuclei = gen

Answer 40

Axons in, cell bodies motor neurons —> out Middle = autonomic neurons Basic organization preserved all the way up into brainstem which also has central gray matter core

Question 41

Describe what 4th ventricle does as go though brainstem

Answer 41

As go up through brainstem = everything gets pushed out to side

Question 42

Where is somatic sensory nuclei

Answer 42

Dorsal and lateral

Question 43

where is visceral sensory nuclei

Answer 43

Autonomic sensory and motor in middle

Question 44

where is visceral motor nuclei

Answer 44

Autonomic sensory and motor in middle

Question 45

where is somatic motor nuclei

Answer 45

Ventral and medial

Question 46

describe somatic sensory nuclei

Answer 46

Trigeminal= somatic sensory = ex —> sensory neuron axons start in face teeth and head = form trigeminal nerve —> brainstem and synapses with 2nd order neurons in brainstem Nuclei = organized groups of neurons found in cns, somatic sensory - receiving inputs

Question 47

describe visceral sensory nuclei

Answer 47

Autonomic neurons = sensory inputs that are autonomic and have preganglinic psns outputs that are autonomic Nuclei receiving visceral sensory inputs

Question 48

describe visceral motor nuclei

Answer 48

Autonomic neurons = sensory inputs that are autonomic and have preganglinic psns outputs that are autonomic Nuclei containing cell bodies of preganglionic neurons that go to innerate visceral organs

Question 49

desribe somatic motor nuclei

Answer 49

motor neurons with cell bodies in brainstem = send axons out to skeletal msucles = somatic motor outputsv

Question 50

describe cranial nerve nuclei in brainstem = gen

Answer 50

View = if remove cerebellum and cerebral cortex and look down on top of brain stem Nuclei = stretched out across regions of brain, some span almost entire brainstem

Question 51

describe cranial nerve nuclei in brainstem = pattern special

Answer 51

Lateral Concentrated between pons and medulla Vestibulocochlear nerve = sensory axons coming in and synapse with cranial nerve nuclei here

Question 52

describe cranial nerve nuclei in brainstem = pattern somatic Sensory

Answer 52

2nd most lateral Span whole brainstem = cervcial cord —> medulla —> pons —> midbrain Vagus Nerve

Question 53

describe cranial nerve nuclei in brainstem = pattern visceral sensory

Answer 53

3rd most lateral Concentrated in medulla Vii, ix, x (vagus = inputs coming in, terminate here in this nucleus)

Question 54

describe cranial nerve nuclei in brainstem = pattern visceral motor

Answer 54

4th most lateral Midbrain = III Rest near medulla mostly, entering into pons a bit (VII) III Vii Ix X

Question 55

describe cranial nerve nuclei in brainstem = pattern somatic motor

Answer 55

5th most lateral = medial Midbrain = III, IV Pons = V, VI, VII Medulla = IX, VII Cervical cord = XI Cell bodies of motor neurons going out to control eye msucles, jaw msucles etc