Brainstem Region Spring

What is the only nerve that is not included in the brainstem?

spinal portion of spinal accessory

what 3 types of tracts travel through the brainstem?

sensory, autonomic, and motor vertical

brainstem acts as a

conduit

the brainstem is divided longitudinally into two sections which are

basilar and tegmentum

the midbrain has an additional section, posterior to the tegmentum which is called the

tectum

this area is involved in reflexive control of intrinsic and extrinsic eye muscles and in movements of the head

tectum

what are the 3 areas of the tectum?

pretectal area, superior and inferior colliculi

which area of the brainstem do the motor tracts mainly run?

basilar

which of the following are descending axons from the cerebral cortex?

1. corticospinal

2. corticobulbar

3. corticopontine

4. corticoreticular

what are the motor nuclei of the basilar section of the brainstem?

substantia nigra, pontine nuclei, inferior olive

what part of the brainstem is the cerebral cortex located?

basilar

includes the reticular nuclei, their connections, and ascending and descending reticular pathways

complex neural network

which of the following are functions of the reticular formation?

1. integrates sensory and cortical info

2. reulates somatic motor activity, autonomic function, and consciousness

3. modulates nociceptive info

what are the 4 major reticular nuclei?

1. ventral tegmental area (VTA)

2. pedunculopontine nucleus (PPN)

3. raphe nuclei

4. locus ceruleus and medial reticular area

what is the function of reticular nuclei and their transmitters?

regulate neural activity throughout the central nervous system

most neurons that produce dopmaine are located where?

midbrain

activation of VTA affects the ventral striatum/nucleus accumbens which produces feelings of what?

pleasure and reward

morphine is a habit forming drug because it inhibits

inhibitory inputs to the VTA

what is the neurotransmitter of the pedunculopontine nucleus?

acetylcholine

where is the pedunculopontine nucleus located?

caudal midbrain

PPN influences movement via the following connections

1. globus pallidus and subthalamic nucleus

2. limbic system

3. reticular nucleus that give rise to the retiulospinal tracts

most cells that produce serotonin and found along the midline of the brainstem in what nuclei?

raphe

this neurotransmitter helps to modulate neural activity throughout the cerebrum and spinal cord, and also assists with inhibiting nociceptive info

serotonin

what is the source for most norephinephrine in the CNS?

locus cereuleus and medial reticular zone

which of the following are functions of the locus ceruleus?

1. project throughout brain and spinal cord

2. more active when person is awake, less active when asleep

3. ability to direct attention

producing epinephrine and noepinephrine and regulating autonomic functions are functions of what nuclei?

medial reticular zone

awareness of self and surroundings

consciousness

governs alertness, sleep, and attention

consciousness system

the reticular formation and ascending reticular system activating (ARAS) are components of the

brainstem

what are the pyramids of the medulla?

vertical buldges

lateral oval lumps, lateral to the pyramids

olives

which cranial nerve connects to the medulla between the pyramid and the olive

XII (hypoglossal)

in the upper half of the medulla, the ______ _____ widens to form part of the fourth ventricle

central canal

what is the only tract in medulla that shifts between rostal and caudal medulla and which direction does it shift?

medial longitudinal fasiculus; posteriorly

most cranial nerve nuclei in the rostral medulla are clustered in the ______ section

dorsal

T/F: the central canal of the medulla is continous with the central canal of the spinal cord

true

what forms the pyramids?

descending axons of the corticospinal tracts

_______ medulla contains cranial nerve structures

lower

which of the following are functions of the medulla?

1. controlling eye and head movements

2. coordinating swallowing

3. helping regulare cardiovascular, respiratory, and visceral activity

4. speech articulation

this structure processes motor info from the cerebral cortex and forwards the inforamtion to the cerebellum

pons

pontine cranial nerve nuclei process sensory information from what area and which cranial nerve correlates to this area?

face; V (trigeminal)

which of the following does the pons control?

1. facial expression (VII)

2. lateral movement of the eye (VI)

3. chewing (V)

this structure connects the diencephalon to the pons

midbrain

what are the 3 regions of the midbrain?

basis pedunculi, tegmentum, tectum

this structure is a small canal through the midbrain and joins the third and fourth ventricles

cerebral aqueduct

what forms the basis pedunculi of the midbrain?

cerebral peduncles and substantia nigra

which of the following are located in the midbrain tegmentum?

1. ascending sensory tracts

2. superior cerebellar peduncle

3. red nucleus

4. PPN

5. nuclei of cranial nerve III

6. nuclei of cranial nerve IV

the inferior colliculi relays auditory info from the ________ nuclei to the superior _________ and to the _____ geniculate body of the thalamus

cochlear, colliculus, medial

the inferior colliculus is involved in ______ and the superior colliculus is involved in ___ __________

hearing, eye movement

this structure's function is entirely dependent on input and output connections with the brainstem

cerebellum

the cerebellum and brainstem share the tightly confined space of the _______ fossa

posterior

which of the following are the 3 main cerebellum functions?

1. coordination of movement

2. motor planning

3. cognitive functions, including rapid shifts of attention

T/F: single brainstem lesions may cause a mix of ipsilateral and contralateral signs

true

cranial nerves supply the ________ face and neck

ipsilateral

many tracts cross midline in the brainstem to supply the ___________ body

contralateral

T/F: lesions in the brainstem may interfere with vital functions and consciousness

true

which of the following connect the spinal cord with the contralateral cerebrum

1. lateral corticospinal

2. DCML

3. spinothalamic tracts

which tracts in the brainstem usually cause contralateral signs because they cross in the medulla?

lateral corticospinal and DCML

conveys motor signals from cerebral cortex to cranial nerve nuclei in the brainstem

corticobulbar lesions

neurons with axons in the corticobulbar tract serve as upper motor neurons to the motor neurons in cranial nerves

V, VII, IX, X, XI, XII

complete motor neuron lesion of the facial nerve prevents commands from reaching

ipsilateral facial muscles

what is the result of a motor neuron lesion of the facial nerve

flaccid paralysis of muscles in the ipsilateral face

single lesion in the upper anteromedial medulla of the left side can cause

1. paralysis of the right hand and foot

2. loss of discriminative touch and proprioceptive info on the right side of the body

3. paresis of the left side of the tongue

Disruption of vital functions secondary to brainstem damage may cause:

1. heart to stopt beating

2. BP flucuations

3. breathing to cease

which areas of the brainstem regulate vital functions?

medulla and pons

what are the 4 cardinal signs of brainstem dysfunction?

1. dysphagia

2. dysarthria

3. diplopia

4. dysmetria

what is dysphagia?

difficulty swallowing

what is dysarthria?

difficulty speaking

what is diplopia?

double vision

what is dysmetria?

Inability to control the distance of movements.

brainstem damage affecting the reticular formation and/or the axons of the ARAS interfere with

consciousness

damage to the cerebrum interfering with hypothalamic/thalamic activating areas or with the function of the entire cerebral cortex may impair

consciousness

unarousalbe, no response to strong stimuli

coma

arousable only by strong stimuli (pinching achilles tendon)

stupor

sleeping more than awake, drowsy and confused when awake

obtunded

complete loss of consciousness without alteration of vital functions

vegetative state

Brief loss of consciousness due to drop in BP

syncope

a vegeitative state is distinguished from a coma by the following signs:

1. spontaneous eye opening

2. regular sleep-wake cycles

3. normal respiratory patterns

which of the following are symptoms caused by increased intracranial pressure from a tumor in the cerebellum or brainstem?

1. headaches

2. nausea

3. vomiting

4. cranial nerve disorders

5. hydrocephalus

what is the most common sign of a tumor in the cerebellum?

ataxia

ischemia in the brainstem produces an aburpt onset of neurologic symptoms including

1. dizziness

2. visual disorders

3. weakness

4. incoordination

5. somatosensory disorders

vertebrobasilar artery insufficiency produces transient symptoms of the brainstem region ischemia when the neck is in what position?

extended and rotated