Diencephalon

what does the pineal gland do?

it is an endocrine organ. it synthesizes melatonin, controls sleep/wake cycle, and regulates the onset of puberty

two thalami are joined by the

massa intermedia

is the massa intermedia white or gray matter?

gray

what are the three broad areas of the thalamus? what are the separated by?

anterior, lateral, and medial. they are separated by the internal medullary lamina

what are the anterior and medial thalamus involved in?

visceral, emotional, and limbic systems

what is the lateral thalamus involved in?

somatic sensory and motor function

where are the reticular nuclei?

goes all the way around the thalamus

list the input, output, and the function: VPL

input: dorsal column/spinothalamic

output: postcentral gyrus

function: somesthesis (body perception)

list the input, output, and the function: VPM

input: trigeminal system

output: postcentral gyrus

function: somesthesis (body perception)

list the input, output, and the function: MGN

input: inferior colliculus

output: temporal lobe

function: hearing

list the input, output, and the function: LGN

input: retina

output: occipital lobe

function: vision

what are the specific sensory nuclei?

VPL (somesthesis), VPM (somesthesis), MGN (hearing), LGN (vision)

what are the specific motor relay nuclei?

VL, VA (both involved in motor planning; extrapyramidal)

what are the specific association nuclei of the thalamus?

anterior, DM, posterior, pulvinar

list the input, output, and the function: anterior

input: hypothalamus

output: cingulate

function: limbic

list the input, output, and the function: DM

input: amygdala

output: prefrontal cortex

function: limbic

list the input, output, and the function: posterior

input: anterolateral system

output: cingulate and association cortices

function: pain

list the input, output, and the function: pulvinar

input: superior colliculus

output: temporal, parietal, and occipital lobes

function vision

what are the non specific nuclei of the thalamus?

midline, intralaminar, and reticular

list the input, output, and the function: midline

input: reticular formation

output: entire cortex

function: arousal/limbic

list the input, output, and the function: intralaminar

input: motor cortex/basal ganglia

output: striatum and cortex

function: motor integration

list the input, output, and the function: reticular

input: cortex and brainstem

output: thalamus

function: thalamic modulation

pure sensory loss without weakness, pain. contralateral. pain on mild touch, made worse by stress, temperature, etc

thalamic infarction (Dejerine-roussy central pain syndrome)

which thalamic nuclei have inputs from the cerebellum?

VA/VL

the projection fibers that make up the corona radiata also radiate out of the brain stem via the ___

internal capsule

what are the ascending sensory pathways en route to the thalamus?

medial lemniscus, spinothalamic/trigeminothalamic tracts, cerebellothalamic fibers from dentate

what structure is the main highway to/from the cortex?

the internal capsule

which tract is associated with the genu of the internal capsule?

slurred speech, right sided weakness, dysarthria and right hemipledia. normal exam except right facial weakness sparing the forehead, dysarthria, right upgoing plantar response

internal capsular stroke

hallucinations and somolence. not drug,sleep, or psych related. what nucleus could be involved

pulvinar

describe pituitary development

a bulb grows upward from the roof of the mouth (rathke’s pouch) that develops into the anterior pituitary. another bulb grows from the diencephalon that becomes the posterior pituitary gland. in typical development, the rathke/anterior connection disconnects

benign, epithelium lined intrasellar cysts that are remnants of the rathke pouch. can present with headache, visual impairment, or hypothalamic dysfunction, but are usually asymptomatic

rathke’s cleft cyst

adenohypophysis vs neurohypophysis

adenohypophysis - anterior pituitary gland

neurohypophysis - posterior pituitary gland

what are the regions of the hypothalamus?

anterior/preoptic - supraoptic, suprachiasmatic, and paraventricular nuclei

tuberal region - ventromedial, dorsomedial, arcuate nuclei

posterior region - posterior nucleus and several mammillary nuclei

___ is a system of blood vessels in the microcirculation at the base of the brain connecting the hypothalamus with the anterior pituitary

hypophyseal portal veins

prolactin, gonadotropic hormones (FSH and LH), TSH, ACTH, and growth hormone are released by

anterior pituitary gland

oxytocin and vasopressin are released by

posterior pituitary

the fornix divides the hypothalamus into what regions

medial and lateral

what is the major output tract of the hippocampus?

the fornix

what are the functions of the hypothalamus?

autonomic ners

central diabetes insipidus, hyperprolactinemia, precocious puberty, and growth defects are all disorders of the

hypothalamus

how does the hypothalamus regulate the autonomic nervous system?

anterior area projects to the brainstem parasympathetic nuclei

posterior area influences sympathetic nuclei through projections to lateral horn

what are the hormone production functions of the hypothalamus?

supraoptic and paraventricular nuclei produce oxytocin and vasopressin, which is transported to the posterior pituitary for release

where are oxytocin and vasopressin produced?

in the hypothalamus (supraoptic and paraventricular nuclei)

circadian rhythm regulation

retina → suprachiasmatic nucleus (hypothalamus) → pineal gland

pineal gland function

produces melatonin, which affe

how does the hypothalamus regulate temperature?

posterior nucleus conserves heat (chills)

anterior nucleus dissipates heat (sweating)

how does the hypothalamus regulate feeding behaviors

arcuate nuc monitors

lateral nuc induces

ventromedial nuc inhibits

paraventricular nuc integrates

what area is the satiety center?

ventral medial hypothalamus

what area is the feeding center?

lateral hypothal

lesions to the ___ result in inability to stop eating, while lesions to the ___ result in refusal to eat

lesions to the ventral medial hypothalamus result in inability to stop eating, while lesions to the lateral hypothalamus result in refusal to eat

the ___ is the “AC” of the brain, while the "___ is the “heater”

anterior hypothalamus, posterior hypothalamus

lesions to the anterior hypothalamus results in

hyperthermia

lesions to the posterior hypothalamus result in

hypothermia (if in cold)

what is pituitary apoplexy?

bleeding into or impaired blood supply of the pituitary gland. can result in sudden sharp headache behind eyes. common during or after pregnancy

hypothyroidism (physical signs)

goiter. weight gain, tiredness, dry skin, depression, constipation due to slowed metabolism.

what results in goiter?

not enough iodine signals the thyroid to send less negative feedback to the pituitary, which results in excess TSH and thyroid growth

explain the hypothalamus-pituitary-thyroid feedback loop

the hypothalamus releases TRH to be received by the anterior pituitary

the anterior pituitary gland releases TSH to be received by the thyroid

if there is enough iodine present, the thyroid produces T3 and T4, which sends negative feedback to the anterior (keeps it from producing excess TSH)

what is acromegaly?

a hormonal disorder that results from too much growth hormone in the body after puberty. enlarged hands and feet, gradual changes in the face (larger jaw, brow, nose, lips, etc.

overeating causes inflammation in the ___, which inhibits neurogenesis

hypothalamus

NPY/AgRP neurons in the ___ nucleus stimulate appetite and lower metabolism/weight gain

arcuate

leptin/ghrelin

leptin - fullness

ghrelin - hunger

diencephalic syndrome

a rare neurological disorder seen in infants and children and characterized by failure to thrive and severe emaciation despite normal intake. strabismus, proptosis