brainstem

what serves as a conduit for ascending and descending tracts

brainstem

what houses most cranial nerve nuclei

brainstem

what regulates consciousness, breathing, CV function, swallowing, posture, and eye-head coordination

brainstem

what integrates sensory and motor information

brainstem

where is brainstem located

inferior to diencephalon, superor to spinal cord

anterior to cerebellum

what is composed of the midbrain, pons, and medulla

brainstem

where is the cerebellum attached to brainstem

posteriorly through cerebellar peduncles

what is the crossroads for neural communication and regulation

brainstem

all CN are in brainstem except

1 & 2 (olfactory and optic)

what CN connect with midbrain

3 (oculomotor) and 4 (trochlear)

what CN connect with pons

5 (trigeminal)

6 (abducens)

7 (facial)

8 (vestibulocochlear)

what CN connect with medulla

9 (glosseopharyngeal)

10 (vagus)

12 (hypoglossal)

vertical tracts travel

through the brainstem

what are the 3 types of vertical tracts

sensory

motor

autonomic

some tracts continue through brainstem

without alteration

brain acts as a conduit

brainstem divided longitudinally into 2 sections

tegmentum

basilar

what is the additional longitudinal section in midbrain

tectum

where is tectum location

posterior to tegmentum

what is in tectum

includes structures involved in reflexive control of intrinsic and extrinsic eye muscles and head movement

pretectal area

superior and inferior colliculi (corpora quadrigemina)

basilar section of braintstem location

anteriorly

basilar section of braintstem contains

primarily descending motor systems and motor nuclei

tegmentum location

anterior to ventricular space

between the basis pedunculi and the tectum

tegmentum contains

reticular formation

sensory nuclei and ascending tracts

CN nuclei (3&4)

medial longitudinal fasciculus

red nucleus

pedunculopontine nucleus

tectum location

present in midbrain only

what is the reticular formation

complex netlike neural network

reticular formation extends from _____ and runs _______

midbrain to medulla

throughout entire tegmentum

what does the reticular formation contain

nuclei involved in NT production

nuclei involved with CN

descending tracts involved in modulating sensory and motor functions

ascending tracts integral to arousal and consciousness

major reticular nuclei

ventral tegmental area (VTA)

pedunculopontine nucleus (PPN)

raphe nuclei

locus coeruleus

NT released by reticular nuclei all act via

slow transmission

either by indirect opening ion channels or by a cascade of cellular events

what NT does the ventral tegmental area produce

dopamine

most dopamine producing neurons are located

in the midbrain

what are the two production areas of dopamine

ventral tegmental

substantia nigra

what is ventral tegmental

part of recticular formation between red nucleus and substantia nigra

what is substantia nigra

part of basal ganglia circuit

activation of VTA affects the

ventral striatum (nucleus accumbes (NAcc), olfactory tubercle)

what does VTA influence

decision-making, motivation, pleasure, reward

dopamine is associated with

pleasure/satisfaction

rewards and motivation

reinforcement

memory

sleep/arousal

vasodilation (low) and vasoconstriction (high)

slows GI movement

movement

what does the pedunculopontine nucleus produce

acetylcholine

where is pedunculopontine nucleus located

caudal midbrain

what does PPN contain

ascending axons from PPN project to inferior frontal cerebral cortex and thalamus

PPN influences movement via connections to

globus pallidus and subthalamic nucleus (STN)

emotion system

reticuar areas that give rise to reticulospinal tracts

deep brain stimulation to PPN imrpoves

gait (freezing) and posture in parkinson's disease

Acetylcholine is the

main NT of the parasympathetic nervous system

Acetylcholine involved in

regulating cardiac contraction

regulating blood pressure

intestinal peristalsis

memory/learning

what is a common NT at the neuromuscular junction

ACh

what NT is markedly dec in Alzheimers

Ach

what does raphe nuclei produce

serotonin

most serotonin producing cells are in the

midline brainstem

brainstem raphe nuclei

modulate neural activity throughout the brainstem and cerebellum

modulate pain

regulate sleep-wake cycles

mood regulation

raphe-spinal endings in anterior horn (spina cord)

activate nonspecific interneurons and motor neurons

interventions acting on the raphe nuclei =

acupuncture and SSRIs

serotonin influences

mood (happiness, focus, calmness)

cognition

reward

learning

memory

physiological processes of serotonin

GI function

sleep

breathing

body temperature

where is norepinepherine produced

locus coeruleus and medial reticular zone

medial reticular zone produces both

norepinepherine and epinepherine

locus coeruleus produces

norepinepherine

where is locus coeruleus

pons near floor of 4th ventricle

norepinepherine function

mobilizes the brain and body for action

medial reticular zone function

regulates autonomic functions

regulates attention

inhibits pain at spinal cord level

how does medial reticular zone regulate autonomic functions

through projections to the hypothalamus, brainstem nuclei and spinal cord lateral horn

locus coeruleus function

projects to most areas of the brain except the basal ganglia

regulates arousal and attention

learned behaviors

operant conditioning

reward, attention to task

ascending tracts

carries messages between the reticular system and cortex

descending tracts

carries messages between the reticular system and the spinal cord and motor neurons

consciousness

awareness of self and surroundings

consciousness system

governs alertness, sleep, attention

consciousness system relays information about

respiration rate

cough response

cardiac rhythm

mastication

chewing may maintain cognitive function

by stimulating the reticular activating system

sleep is actively induced by

activity of areas within the ascending reticular activating system

uppermost part of midbrain

connects diencephalon and pons

the cerebral aqueduct connects

3rd and 4th ventricles

crus cerebri

cerebral peduncles

what is in the crus cerebri

corticospinal

corticobulbar

corticopontine fibers

degeneration of substantia nigra is involved with

parkinsons disease

how does the substantia nigra change with parkinsons disease

appears lighter, not as black due to dec dopamine

substantia nigra recives input from

dorsal striatum (caudate and putamen)

basis pedunculi formed by

cerebral peduncles - descending tracts from cerebral cortex

substantia nigra

tegmentum is

periaqueductal gray

in tegmentum, edinger westphal nucleus

parasympathetic CN III

cilliary mm

sphincter pupillae

in tegmentum, medial longitudinal fascicles

integrates head and eye movement

optokinetic reflex and VOR

pretectal area is involved in

pupillary, consensual and accomodation reflexes of the eye

inferior colliculi relay auditory information from the

cochlear nuclei to the superior colliculus and to the medial geniculate body of the thalamus

superior colliculi and involved in

reflexive eye and head movements

basilar (anterior) section of pons contains

corticospinal, corticobrainstem and corticopontine axons

pontine nuclei

pontocerebellar axons

pons processes motor information from the

cerebral cortex and forwards te information to the cerebellum

corticopontine tracts synapse with

pontocerebellar fibers

pontine tegmentum (posterior) section of pons contains

sensory tracts, reticular formation, autonomic pathways, medial longitudinal fasciculus, CN nuclei

pontine CN nuclei process sensory information from

the face (CN 5)

about sound, head position, head movement (CN 8)

CN nuclei control contraction of muscles involved in

lateral movement of the eye (CN 6)

chewing (CN 5)

facial expression (CN 7)

CN 5

trigeminal n and nuclei

process sensory information from the face

controls contraction of muscles involved in chewing

ponto medullary junction

between pons and medulla

what is in are in ponto-medullary junction

CN 6, 7, 8

cerebllopontine angle

vestibular schwannoma (acoustic neuroma)

tumor CN VII vestibular portion

facial paralysis, hearing loss, tinnitus, vertigo, balance impairments

in medulla, anteriorly there are two verticle bulges

pyramids

in medulla, lateral to the pyramids are two small oval lumps

olives

CN 12 connects with the medulla b/t

the pyramid and the olive

in the groove lateral to the olive, axons of

CN 9 and 10 enter and exit the medulla

in upper medulla the central canal

widens to form part of the 4th ventricle

in upper medulla, most CN nuclei in rostral medulla are

clustered in the dorsal section

in upper medulla, from medial to lateral the CN are

hypoglossal (CN 12)

dorsal motor nucleus of vagus (CN 10)

solitary nucleus (taste from CN 7 & 9; autonomic afferents from CNs 9 & 10)

vestibular (CN 8)

in upper medulla nucleus ambiguous is

located more anteriorly

motor fibers to striated muscles in larynx, pharynx, upper esophagus