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Flashcards in Brain 4: Diencephalon Deck (27):

Diencephalon contains



What is Thalamus

relay station
Relays almost all sensory input to cerebral cortex
Paired oval masses of grey matter organized into nuclei with interspersed tracts with white matter


3 structures of thalamus

intermediate mass (interthalamic adhesion)
internedullary lamina
internal capsule


Intermediate mass (interthalamic adhesion)

joins the right and left halves of the thalmus in about 70% of human brain. A bridge of grey matter


Intermedullary lamina

A vertical Y-shaped sheet of white matter. Myelinated axons that enter and leave the various thalamic nuclei


Internal capsule

Thick band of white matter lateral to the thalamus


7 major groups of nuclei on each side of thalamus

1. anterior nucleus
2. medial nuclei
3. lateral group
4. ventral group (ventral anterior, lateral, posterior nucleus, lateral geniculate nucleus, medial geniculate nucleus)
5. intralaminar nuclei
6. midline nucleus
7. reticular nucleus


Anterior nucleus of thalamus

receives input from the hypothalamus and sends output to the limbic system. it functions in emotions and memory


Medial nuclei of thalamus

receives input from the limbic system and basal nuclei and send output to the cerebral cortex. They function in emotions, learning, memory and cognition (thinking and knowing)


Lateral group of Thalamus

receives input from the limbic system, superior colliculi and cerebral cortex and send output to the cerebral cortex. Lateral dorsal nucleus: expression of emotions. Lateral posterior nucleus and pulvinar nucleus help integrate sensory info.


Ventral anterior nucleus 1 of 5

receives input from the basal nuclei and sends output to motor areas of the cerebral cortex. It plays a role in movement control.


Ventral lateral nucleus (2 of 5)

receives input from the cerebellum and basal nuclei and sends output to motor areas of cerebral cortex. It also plays a role in movement conctrol


Ventral posterior nucleus 3 of 5

relays impulses for somatic sensations such as touch, pressure, vibration, itch, tickle, temperature, pain and proprioception from the face and body to the cerebral cortex


lateral geniculate nucleus 4 of 5

relays visual impulses for sight from the retina to the primary visual area of the cerebral cortex


Medial geniculate nucleus 5 of 5

relays auditory impulses for hearing from the ear to the primary auditory area of the cerebral cortex


Intralaminar nuclei

lie within the internal medullary lamina and make connections with the reticular formation, cerebellum, basal nuclei of the cerebral cortex. Function in arousal (activation of cerebral cortex from the brain stem reticular formation) and integration of sensory and motor information


Medline nucleus

forms a thin band adjacent to the third venticle and has a presumed function in memory and olfaction


Reticular nucleus

surrounds the lateral aspect of the thalamus, next to the internal capsule. This nucleus monitors, filters and integrates activities of other thalamic nuclei


4 regions of hypothalamus

Mammillary region
Tuberal region
Supraoptic region
preoptic region
hypothalamus controls many body activities and is one of the major regulators of homeostasis


where and what is mammillary region

adjacent to midbrain
most posterior part
mammillary bodies (relay station for reflexes related to smell)
posterior hypothalmic nuclei


where and what is tuberal region

widest part of hypothalamus
dorsomedial nucleus
ventromedial nucleus
arcuate nucleus
infundibulum and medial eminence - pituitary gland =hormone production


where and what is supraoptic region

in front of optic chiasm
paraventricular nucleus and supraoptic nucleus - post pituitary
anterior hypothalamic nucleus
suprachiasmatic nucleus - circadian rhythms = internal clock, sleep-wake cycles


where and what is preoptic region

regulates certain autonomic activities
contains medial and lateral preoptic nuclei


Hypothalamus 6 important function

1. Control of ANS (cardiac mm, smooth mm, glands)
2. hormone production
3. Regulation of emotional and behavioral patterns
4. regulation of eating and drinking
5. control of body temperature
6. regulation of circadian rhythms and states of consciousness


where and what is Epithalaums

consists of pineal gland and habenular nuclei
the pineal gland is part of the endocrine system because it secretes the hormone melatonin
habenular nuclei are Invovled in olafaction, especially emotional responses to odors


what does monitor chemical changes in the blood and what it doesn't have and where does it located

Circumventricular Organs (CVO) and it lacks blood brain barrier and it is part of hypothalamus, the penal gland and the pituitary gland in diencephalon


What is the function of circumventricular organs

coordination of homeostatic activities of endocrine and nervous system