Trans - Diencephalon Flashcards
components of diencephalon
- epithalamus
- thalamus
- subthalamus
- hypothalamus
ventricle associated with the diencephalon
3rd ventricle
relationship of epithalamus with 3rd ventricle
epithalamus forms the roof of the 3rd ventricle
pineal gland - function
produces melatonin that modulates the sleep-wake cycle
pineal gland - substance produced
melatonin
pineal gland is active during periods of:
darkness
pineal gland - importance in radiology
gland accumulates calcium (radiopaque), important marker for midline of brain
massa intermedia - define
interthalamic adhesion
percentage of people with massa intermedia
70-80%
massa intermedia - function
no known function
habenula - function
may be a center for integration of olfactory, visceral, and somatic afferent pathways
stria medullaris - define
horizontal ridge on the medial surface of the thalamus
subthalamic nucleus of Luys - function
inhibits uncontrolled movement
structure immediately anterior to thalamus
interventricular foramen
structure immediately posterior to thalamus
posterior commissure
structure immediately lateral to thalamus
internal capsule (posterior limb)
structure immediately superior to thalamus
part of lateral ventricle floor
thalamus - function
- translates prethalamic inputs into a form which can be interpreted by the cortex
- process sensory inputs
- relays sensory inputs selectively to areas in the cortex
- regulates sleep and consciousness
- provides sensory feedback to motor system, basal ganglia, cerebellum
what subdivides the thalamus
internal medullary lamina
thalamus - anterior nucleus - function
uncertain, probably memory and emotions
thalamus - anterior nucleus - major input from:
- mammillary nuclei
2. presubiculum of hippocampus
thalamus - anterior nucleus - has connections with:
- cingulate gyrus
2. frontal cortex
thalamus - medial group - which nuclei are present
dorsomedial nuclei
thalamus - dorsomedial nucleus - connections with:
prefrontal cortex
hypothalamus
thalamus - dorsomedial nucleus - function
memory
thalamus - pulvinar - subdivivisons and projections
- lateral - visual cortical association areas
- inferior - visual cortical association areas
- oral - somatosensory cortical association areas
- medial - cingulate, posterior parietal, prefrontal cortices
thalamus - pulvinar - function
main integrator and coordinator of stimuli
thalamus - lateral geniculate nucleus - function
optic radiation, connects optic tract with primary visual cortex in occipital lobe
thalamus - medial geniculate nucleus - function
auditory thalamus, relays auditory information from inferior colliculus to primary auditory cortex in superior temporal gyrus
what type of sensory signal is not directly processed by the thalamus
olfactory
thalamus - ventral lateral nucleus - major input from:
- substantia nigra
- globus pallidus
- cerebellum
thalamus - ventral lateral nucleus - function
learning of movement
thalamus - ventral lateral nucleus - major output to:
primary motor cortex
thalamus - ventral anterior nucleus - major input from:
- substantia nigra
2. globus pallidus
thalamus - ventral anterior nucleus - major output to:
supplementary motor cortex
thalamus - ventral anterior nucleus - function
planning movements - inhibition of unwanted movement, facilitation of wanted movement
thalamus - ventral posteromedial nucleus - function
relay facial sensation to somatosensory cortex
thalamus - ventral posterolateral nucleus - function
relay sensation from body to somatosensory cortex
structure immediately anterior to hypothalamus
optic chiasm & anterior commissure
structure immediately posterior to hypothalamus
mammillary bodies
structure immediately superior to hypothalamus
hypothalamic sulci
structure immediately inferior to hypothalamus
hypophysis
epiphysis
pineal gland
hypophysis
pituitary gland
posterior pituitary
neurohypophysis (pars nervosa)
anterior pituitary
adenohypophysis (Rathke’s pouch)
most rostral region of hypothalamus
preoptic
most caudal region of hypothalamus
posterior
what structure divides the hypothalamus into 3 parasagittal zones
fornix
dorsal longitudinal fasciculus is associated with what zone of the hypophysis
periventricular
thalamus - 3 diffuse projection nuclei
- intralaminar nuclei
- midline nuclei
- reticular nuclei
thalamus - intralaminar nuclei - example
centromedial nucleus
thalamus - centromedial nucleus - function
believed to influence consciousness, alertness, arousal
thalamus - midline nuclei - function
unknown
thalamus - reticular nuclei - function
regulation of other thalamic nuclei
what is the only thalamic nucleus that sends inhibitory input to other thalamic nuclei
reticular nucleus
hypothalamus - functions
- controls BP and electrolyte balance
- regulates temparature
- regulates energy metabolism - feeding, digestion, metabolic rate
- regulates reproduction
- directs responses to stress
hypothalamus - nucleus that mediates heat dissipation
anterior nucleus
hypothalamus - lesions in anterior nucleus may cause
hypothermia
hypothalamus - nucleus that mediates heat conservation
posterior nucleus
hypothalamus - lesions in posterior nucleus may cause
hypothermia when animal is placed in a cold environment
hypothalamus - nuclei that are sensitive to sex hormones
- preoptic nucleus
2. ventromedial nucleus
hypothalamus - lesions in preoptic or ventromedial nuclei may cause
menstrual cycle disturbance or precocious puberty
hypothalamus - nucleus that mediates circadian rhythm
suprachiasmatic nucleus
hypothalamus - nucleus that induces sleep
preoptic nucleus
hypothalamus - nuclei involved in cortical arousal
- lateral nucleus
2. posterior nucleus
hypothalamus - satiety center
- ventromedial nucleus
2. paraventricular nucleus
hypothalamus - lesion in ventromedial or paraventricular nuclei may cause
hyperphagia and obseity
hypothalamus - feeding center
lateral nuclei
hypothalamus - lesion in lateral nuclei may cause
aphagia and starvation
hypothalamus - 2 types of cells in paraventricular nucleus
- parvocellular
2. magnocellular
parvocellular neurons - characteristics
- medially - secrete hypothalamic releasing hormones (TRH, GHRH, CRH, GnRH, PRH)
- dorsally and ventrally - project and autonomically control medulla and spinal cord
magnocellular neurons - characteristics
control endocrine function by secreting vasopresin and oxytocin into the pars nervosa
secretion of magnocellular neurons
vasopresin, oxytocin
magnocellular neurons secrete their products into:
posterior pituitary
mammillary bodies - define
small round bodies on the ventral brain surface, part of hypothalamus
hypothalamus - anterior nucleus - sympathetic or parasympathetic?
parasympathetic (heat dissipation –> vasodilation and sweating)
hypothalamus - posterior nucleus - sympathetic or parasympathetic?
sympathetic (heat conservation –> vasoconstriction and shivering)
hypothalamus - nuclei involved in water balance
supraoptic and paraventricular nuclei
substance secreted by hypothalamic supraoptic and paraventricular nuclei
ADH
hypothalamus - nucleus responsible for rage responses
ventromedial nucleus
hypothalamus - nucleus responsible for somnolence
dorsolateral mammillary region (via ARAS)