Thalamus & Hypothalamus & 3rd Ventricle Flashcards
Mention dorsal & ventral parts of thalamus
D, thalamus, metathalamus (MGB & LGB), epithalamus (pineal body habenular nuclei & posterior commissure
V, hypothalamus & subthalamus
Divided by hypothalamic sulcus
Describe ends of thalamus
Ant end, lies posterior to interventricular foramen of Monro
Post end, is edpanded to form pulvinar
Mention surfaces of thalamus & their relations
Sup: free related to choroid plexus forms part of floor of lateral ventricle
Inf: separated by hypothalamic sulcus from ventral structures
Med: forms lateral wall of 3rd ventricle both med walls are connected by interthalamic adhesions (connexus)
Lat: separated from lentiform nucleus by internal capsule
Sit, eff, aff & func of anterior nuclei
S, between 2 limbs of Y-shaped internal medullary lamina
A, mammilo-thalamic fibers
E, anterior thalamic radiation to cingulate gyrus
F, part of limbic system (Papez circuit) responsible for recent memory & emotions
Eff, aff & func of medial nuclei
A, from hypothalamus, amygdaka & olfactory cortex
E, via medial forebrain bundle to prefrontal cortex
F, forms part of limbic system responsible for thinking & mood
Eff, aff and names of dorsal tier of lateral nuclei
A, recieve from other thalamic nuclei and integrate signal (multisesnory processing unit
E, to sensory association areas of the cortex
Lateral-dorsal, lateral-posterior and pulviminar
Mention eff and aff of following nuclei
1-VL & VI
2-VA
3-VPM
4-VPL
1- from cerebellum to premotor and motor areas, relays motor planning for voluntary movement
2- from basal ganglia to supplememtary motor area, relays motor circuits
3- from medial amd spinal leminsci to upper 2/3 of cortex
4-from trigeminal leminiscus and solitario-thalamic fibers to lower 1/3 of cortex
Mention eff and aff of MGB AND LGB
MGB, recives auditory input from inferior colliculus sends, projects auditory radiation to auditory cortex
LGB, recieves visual input from optic tract, projects visual radiation to visual cortex
Describe aff, eff and func of (1)midline nuclei and (2)reticular nucleus
1, recieves input from modbrain relicular formation and projects non-specificalltly to whole cortex increasing its activity, part of RAS.
2, recives input from whole cortex and ends on thalamic nuclei, inhibit thalamic nuclei during sleep.
Describe blood supply of thalamus
Arterial, medial and ant regions by posteromedial group of posterior cerebral artery. Lat and post regions by posterolateral group of posterior cerebral artery (thalamogeniculate art)
V, by thalamostriate vein
Describe the site & extent of hypothalamus
Ant, lamina terminalis
Post, till a vertical plane posterior to mammilary bodies
Sup: extends till hypothalamic sulcus
Inf: it forms base of brain beneath 3rd ventricle (the floor of interpeduncular fossa)
Mention parts of hypothalamus
Optic chiasma, tuber cinereum, mammilary body
Enumerate nuclei of hypothalamus
Suprachiasmatic, supraoptic, infundibular, tuberal, paraventricular, mammilary nuclei
Mention functions of hypothalamus
- Controls autonomic & endocrine functions
- Regulate fluid & food intake & body temp
- Control emotions, reproduction & biological clock
Describe connection of hypothalamus with prefrontal cortex
Periventricular system of fibers connects it with dorsomedial nucleus of thalamus (both ways)
Describe connection of hypothalamus with limbic system
Medial forebrain bundle connects central grey of brain stem to the hypothalamus, amygdala & septal areas. It contains mostvserotonergic & noradrenergic fibers
Fornix connects hippocampus to mamillary bodies which send efferent to thalamus (Papez circuit)
Stria terminalis: afferent fibers from amygdala to preoptic nucleus
Describe connection of hypothalamus with lower centers
A. Tegmentum of midbrain: mammillary peduncle (afferent), mammillo-tegmental tract (efferent)
B. The posterior longitudinal fasciculus (in central grey) carries efferents to the vital autonomic nuclei of brain stem & spinal cord (LHCs)
Describe connection of hypothalamus with pituitary gland
-Hypthalamic-hypophyseal tracrs, supraoptic-hypophyseal (vasopressin) & paraventricular-hypophyseal (oxytocin)
-Infundibular (arcutae) secretes the release and release inhibiting hormones taken up by superior set of capillaries to inferior set of capillaries in anterior pituitary (portal vein between them)
Subthalamus lies between……
Thalamus & tegmentum of midbrain
Pineal body lies inferior to……, the base is formed of ……..(specify the content of each)
Splenium of corpus callosum
Superior lamina (habenular commissure) & inferior lamina (posterior commissure)
Describe function of habenular nuclei
Recieves olfactory input via habenular stria & sends output to brainstem visceral nuclei (salivatory, dorsal vagal & ambiguus) via fasciculus retroflexus. Which is why smell of food stimulates salivation, gastric secretions & motility.
Mention nuclei of posterior commissure
Darkschwitscz nucleus & interstitial nucleus of Cajal
Mention func of posterior commissure
Connects the two sperior colliculi, two MLF, pretectal nuclei of both sides
Describe boundaries of third ventricles
Lat, thalamus & hypothalamus
Roof: epedyma covered by tela choroidea. Choroid plexus of 3rd ventricle hangs as 2 longitudinal elevations from the roof
Floor: mostly hypothalamic structures (optic chiasma, infundibulum, tuber cinereum, mammilary bodies), posterior perforated substance + tegmentum of midbrain
Ant: lamina terminalis, column of fornix, anterior commissure
Post: posterior commissure, pineal body, suprapineal recess
Mention recesses of 3rd ventricle
Optic recess, infundibular recess, pineal recess, suprapineal recess
Mention functions of pineal gland
It is an endocine gland that inhibits pituitary, pancreas, adrenals, gonads, parathyroids. It secretes melatonin
After puberty it becomes calcified forming brain sand which is a landmark in skull x-rays
