Week 2 content (Diencephalon, Brainstem Region, Cerebellum) Flashcards
What part of the brain is the diencephalon in?
forebrain
parts of the diencephalon
thalamus, hypothalamus, epithalamus, subthalamus, pituitary gland, pineal gland
what is the largest subdivision of the diencephalon
thalamus
location of hypothalamus
inferior and anterior to the thalamus
location of epithalamus
posterior to thalamus
location of subthalamus
inferior to thalamus (coronal section)
location of pineal gland
posterior to thalamus
location of pituitary gland
inferior and anterior to thalamus
thalamus shape
large egg-shaped
what is the thalamus’s job?
regulates the flow of information, relay station; receives info from basal ganglia, cerebellum and all sensory systems except olfactory; processes info, relays info to the specific areas of cerebral cortex
anatomically, thalamus can be divided into 3 major groups
anterior, medial, lateral; lateral also divided into ventral and dorsal tiers
which sensory pathway is used for pain
spinothalamic pathway
which sensory pathway is used for touch and proprioception
dorsal column/medial lemniscus pathway (DCML)
Everything going into the brain goes through what portion of the brain
thalamus
thalamus relays information for every nerve except
olfactory
Relay nuclei convey info from the…
sensory systems (except olfactory), the basal ganglia, or the cerebellum to the cerebral cortex
all relay nuclei are found in the ________ of the lateral group
ventral tier
what is the relay nuclei’s job
to receive specific information and serve as a relay station by sending info directly to the localized area of the cerebral cortex
Association nuclei process…
emotional and some memory info or integrate different types of sensation
Association nuclei are found in the…
anterior thalamus, medial thalamus, and dorsal tier of the lateral thalamus
Nonspecific nuclei does…
it regulates consciousness, arousal, and attention
Relay nuclei is involved with
hearing and vision
Association nuclei is involved with
emotions/memory
Nonspecific nuclei is involved with
arousal and attention
Nuclei: ventral anterior
Function: motor
Afferents: globus pallidus
Efferents: motor planning areas
Nuclei: ventral lateral
Function: motor
Afferents: dentate
Efferents: motor cortex, motor planning areas
Nuclei: ventral posterolateral
Function: somatic sensation from body
Afferents: spinothalamic and medial lemniscus paths
Efferents: somatosensory cortex
Nuclei: ventral posteromedial
Function: somatic sensation from face
Afferents: sensory nucleus trigeminal nerve
Efferents: somatosensory cortex
Nuclei: medial geniculate
Function: hearing
Afferents: inferior colliculus
Efferents: auditory cortex
Nuclei: lateral geniculate
Function: vision
Afferents: optic tract
Efferents: visual cortex
Nuclei: medial group
Function: Emotions
Afferents & Efferents: reciprocal with emotion areas
Nuclei: anterior
Function: memory
Afferents & Efferents: reciprocal with memory areas
Nuclei: lateral dorsal
Function: Memory
Afferents & Efferents: reciprocal with memory areas
Nuclei: midline
Function: memory
Afferents: hippocampus
Efferents: prefrontal cortex
Nuclei: intralaminar
Function: arousal and attention
Afferents: ascending reticular system
Efferents: widespread areas of cortex
Thalamic lesions affect every sense except
smell
thalamic lesions involving the relay nuclei interrupt ascending pathways which
severely compromising or eliminating contralateral sensation
thalamic pain syndrome is also considered
unconsciousness
bilateral thalamic lesions affects
consciousness
hypothalamus regulates which hormones
pituitary, oxytocin, ADH
hypothalamus job
regulate homeostasis; essential for individual and species survival; integrates behaviors with visceral functions
functions orchestrated by hypothalamus include:
- endocrine regulation of growth, metabolism, and reproductive organs
- satiety and hunger center: water intake, eating
- emotional expression of pleasure, rage, fear, and aversion
- effects on autonomic nervous system: adjustment of body temperature, metabolic rate, blood pressure
- regulation of circadian rhythms (including sleep-wake cycles) in concert with other brain regions
what connects the hypothalamus to the pituitary gland
pituitary stalk
posterior pituitary hormones
oxytocin and ADH
oxytocin action
elicits milk expulsion in lactating females; uterus contraction, causing labor and delivery
ADH (anti-diuretic hormone) action
increasing the reabsorption of water in the kidneys and preventing excretion of large amounts of urine
Anterior pituitary hormones
FSH and LH, GH, prolactin, ACTH, TSH
FSH and LH action
synthesis of estrogen, progesterone, and testosterone
GH (growth hormone) action
overall growth
prolactin action
stimulates milk production
ACTH action
stimulates synthesis and secretion of adrenal cortical hormones
TSH action
stimulates synthesis and secretion of thyroid hormones
major structure of the epithalamus
pineal gland
pineal gland function
help regulate circadian rhythms (melatonin)
subthalamus function
regulating movement
location of brainstem
between cerebrum and spinal cord
portions of brainstem
medulla, pons, and midbrain
four functional groupings of brainstem
cranial nerve nuclei and related structures, long tracts, cerebellar circuits, reticular formation
sensory tracts travel _______ in the brainstem
up
motor tracts travel ________ in the brainstem
down
motor tracts are also known as
basilar (anterior)
sensory tracts are also known as
tegmentum (posterior)
tectum in midbrain includes structure that are involved in
reflexive control of intrinsic and extrinsic eye muscles and in movements of the head
CN I
Olfactory
CN II
Optic
CN III
Oculomotor
CN IV
Trochlear
CN V
Trigeminal
CN VI
Abducens
CN VII
Facial
CN VIII
Vestibulocochlear
CN IX
Glossopharyngeal
CN X
Vagus
CN XI
Accessory
CN XII
Hypoglossal
What CN are in forebrain
CN 1 & 2
What CN are in midbrain
CN 3, 4
What CN are in pons
CN 5, 6, 7, 8
What CN are in Medulla
CN 9, 10, 11, 12
if a CN has both motor and sensory functions, it is found that it has ________
2 nuclei (means the CN are not only in “specific” areas
function of CN I
sense of smell
Function of CN II
vision
Function of CN III
eye movements; eye up, down, and medial; constriction of pupils, tear ducts
Function of CN IV
eye movements; downward gaze
Function of CN V
biting down, muscles of mastication
Function of CN VI
eye movements; lateral
function of CN VII
expressions, taste
function of CN VIII
hearing, balance
function of CN IX
visceral sensation
function of CN X
motor control, autonomic functions of gut
function of CN XI
shoulder and neck muscles
function of CN XII
movements of the tongue
dorsal column/medial lemniscus system (touch) crosses over in
medulla
spinothalamic pathway (pain/temp) crosses over where
doesnt wait to cross over. happens where sensation was felt
what is a peduncle
tracts; bundle of axons
superior peduncle action
connects midbrain to cerebellum
middle peduncle action
connects pons to cerebellum
inferior peduncle action
connects medulla to cerebellum
summary of cerebellar functions:
coordination of movement, balance, and posture
what is the reticular formation
a complex neural network that includes the reticular nuclei, their connections, and ascending and descending reticular pathways
where is the reticular formation located
in brainstem tegmentum
Ascending Reticular Activating System (ARAS) consists of
midbrain and upper pons; maintain alert conscious state in the forebrain
Caudal reticular formation consists of
pons and medulla; motor, reflex, and autonomic
a coma is dysfunction of which reticular system?
ARAS; dysfunction of upper brainstem
What part of the brainstem is this?
upper midbrain; due to cerebral aqueduct, trigeminal lemniscus, red nucleus, oculomotor nucleus
What part of the brainstem is this?
junction of midbrain and pons
Tectum contains the
pretectal area and the colliculi
pretectal area is involved in
reflexes of the eye
inferior colliculi relays
auditory info from the cochlear nuclei to superior colliculus, medial geniculate body of thalamus, and reticular activating system
superior colliculi receives
sensory and motor information are involved in reflexive eye and head movements
reticular activating system
activates entire nervous system
what area is this?
upper pons
what area is this?
lower pons
stroke of the pons results in
loss of balance, facial drooping, no lateral eye tracking, difficulty chewing, and paralyzes.
What are the two vertical bulges of the medulla called
pyramids
what are the two small oval lumps on the medulla called
olives
what area is this
upper medulla
what area is this
inferior medulla
functions of the medulla
- contributes to control of head movements
- coordinates swallowing
- helps regulate cardiovascular, respiratory, and visceral activity
what is the cerebellum best at?
coordination!!!! of ongoing movement
where is the cerebellum located
posterior cranial fossa behind pons and medulla, inferior to occipital lobe
tentorium cerebelli separates
the cerebellum from the occipital lobe
what is this
vermis
spinocerebellum
(vermis and paravermal regions) integrates proprioceptive info
precentral gyrus –> cerebellum for coordination –> to person
cerebrocerebellum
(lateral hemisphere) coordinates precise distal voluntary movement
coordination of fine distal movements
vestibulocerebellum
(flocculonodular lobe; flocculus and nodulus) integrates visual and vestibular input to coordinate motor activities for posture, head, and eye movements
coordination of head and eye movements
