Thalamus & Hypothalamus & 3rd Ventricle

Question 1

Mention dorsal & ventral parts of thalamus

Answer 1

D, thalamus, metathalamus (MGB & LGB), epithalamus (pineal body habenular nuclei & posterior commissure
V, hypothalamus & subthalamus
Divided by hypothalamic sulcus

Question 2

Describe ends of thalamus

Answer 2

Ant end, lies posterior to interventricular foramen of Monro
Post end, is edpanded to form pulvinar

Question 3

Mention surfaces of thalamus & their relations

Answer 3

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

Question 4

Sit, eff, aff & func of anterior nuclei

Answer 4

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

Question 5

Eff, aff & func of medial nuclei

Answer 5

A, from hypothalamus, amygdaka & olfactory cortex
E, via medial forebrain bundle to prefrontal cortex
F, forms part of limbic system responsible for thinking & mood

Question 6

Eff, aff and names of dorsal tier of lateral nuclei

Answer 6

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

Question 7

Mention eff and aff of following nuclei
1-VL & VI
2-VA
3-VPM
4-VPL

Answer 7

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

Question 8

Mention eff and aff of MGB AND LGB

Answer 8

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

Question 9

Describe aff, eff and func of (1)midline nuclei and (2)reticular nucleus

Answer 9

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.

Question 10

Describe blood supply of thalamus

Answer 10

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

Question 11

Describe the site & extent of hypothalamus

Answer 11

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)

Question 12

Mention parts of hypothalamus

Answer 12

Optic chiasma, tuber cinereum, mammilary body

Question 13

Enumerate nuclei of hypothalamus

Answer 13

Suprachiasmatic, supraoptic, infundibular, tuberal, paraventricular, mammilary nuclei

Question 14

Mention functions of hypothalamus

Answer 14

1. Controls autonomic & endocrine functions
2. Regulate fluid & food intake & body temp
3. Control emotions, reproduction & biological clock

Question 15

Describe connection of hypothalamus with prefrontal cortex

Answer 15

Periventricular system of fibers connects it with dorsomedial nucleus of thalamus (both ways)

Question 16

Describe connection of hypothalamus with limbic system

Answer 16

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

Question 17

Describe connection of hypothalamus with lower centers

Answer 17

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)

Question 18

Describe connection of hypothalamus with pituitary gland

Answer 18

-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)

Question 19

Subthalamus lies between……

Answer 19

Thalamus & tegmentum of midbrain

Question 20

Pineal body lies inferior to……, the base is formed of ……..(specify the content of each)

Answer 20

Splenium of corpus callosum
Superior lamina (habenular commissure) & inferior lamina (posterior commissure)

Question 21

Describe function of habenular nuclei

Answer 21

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.

Question 22

Mention nuclei of posterior commissure

Answer 22

Darkschwitscz nucleus & interstitial nucleus of Cajal

Question 23

Mention func of posterior commissure

Answer 23

Connects the two sperior colliculi, two MLF, pretectal nuclei of both sides

Question 24

Describe boundaries of third ventricles

Answer 24

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

Question 25

Mention recesses of 3rd ventricle

Answer 25

Optic recess, infundibular recess, pineal recess, suprapineal recess

Question 26

Mention functions of pineal gland

Answer 26

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