Diencephalon and Third Ventricle Flashcards
Ends of thalamus
Anterior: Narrow. Posterior boundary of interventricular foramen
Posteior: Pulvinar. Overhangs medial, lateral geniculate bodies, sup. colliculi
Surfaces of thalamus
Sup: Lateral part forms floor of lateral ventricle. Medial part has tela choroidea of 3rd ventricle
Inf: Anterior part fused with subthalamus
Med: Lateral wall of 3rd ventricle
Lat: Medial boundary of internal capsule
White matter of thalamus
External and Internal medullary lamina
Nuclei in anterior part of thalamus
Anterior nucleus
Nuclei in medial part of thalamus
Medial dorsal
Medial ventral
Nuclei in lateral part of thalamus
Craniocaudally Dorsal: 1. Lateral dorsal 2. Lateral posterior 3. Pulvinar Ventral: 1. Ventroanterior 2. Vetro intermediate 3. Ventroposterior
Connections and functions of VPM
Aff: Trigeminal lemniscus
Eff: Post central gyrus
Func: Relay for face, head, taste bud impulses
Connections and functions of VPL
Aff: Medial lemniscus, Spinal lemniscus
Eff: Postcentral gyrus
Func: Relay for exteroceptive, proprioceptive
Connections and functions of VA
Aff: from globus pallidus
Eff: Premotor cortex
Func: Relay for striatal impulses
Connections and functions of VI
Aff: Dentatothalamic
Eff: Motor and premotor cortex
Func: Relay for cerebellar impulses
Connections and functions of Medial Geniculate body
Aff: Auditory fib. from inf. colliculus
Eff: Primary auditory area
Func: Relay for auditory impulses
Connections and functions of Lateral Geniculate body
Aff: Optic tract
Eff: Primary visual cortex
Func: Relay for visual impulses
Connections and functions of Anterior nucleus
Aff: from Mamillary body
Eff: Cingulate gyrus
Func: Attention, recent memory
Connections and functions of Medial dorsal nucleus
Aff: Hypothalamus
Eff: Prefrontal area
Func: Mood, Emotional balance
Connections and functions of Lateral dorsal nucleus
Aff: Thalamic n.
Eff: Cingulate gyrus
Func: Integrate sensory info
Connections and functions of pulvinar nucleus
Aff: Thalamic n.
Eff: Association area
Func: Coorelation of senses
Connections and functions of reticular nucleus
Aff: Brainstem reticular formation
Eff: Cerebral cortex
Func: RAS
Functions of thalamus
- Integration and relay station of all impulses
2. Poor recognition of pain, temp.
Thalamic syndrome
- Pain, temp., touch treshold decreases contra.
2. Emotional instability
External features of pineal gland
- occupies vertical groove b/w sup. colliculi
- has a stalk
- stalk divides into 2 laminae
- Inf. lamina contd. with posterior commissure
- Sup. lamina contd. with habenular commissure
- supplied by nervus cornii
Structure of pineal gland
- contains pinealocytes and neuroglial cells
- Pinealocytes secrete melatonin
- Ca phosphates and crabonates get deposited with age to for CORPORA ARENACEA (brain sand)
Functions of pineal gland
- Neuroendocrine activity
- Biological clock
- Melatonin inhibits secretion of GnRH
Unique features of pineal gland
No nerve cells
Only part of brain supllied by nervus conarii that arises outside brain
Habenular nucleus
- lies beneath habenular triangle
- habenular triangle is above sup. colliculus medial to pulvinar of thalamus
- with its connections, forms part of limbic system
Habenular commissure
- connects habenular nucleus on both sides
- crosses midline by passing thru sup. lamina of stalk of pineal gland
Posterior commissure
- connects MLF, interstitial nuclei, sup. colliculus, pretectal n. of both sides
- crosses midline by passing thru inf. lamina of pineal stalk
Boundaries of hypothalamus
Ant: Lamina terminalis Post: Subthalamus Inf: Floor of 3rd ventricle Sup: Thalamus Lat: Internal capsule Med: Cavity of 3rd ventricles
Hypothalamic nuclei
- Preoptic
- Supraoptic
- Anterior
- Arcuate
- Ventromedial
- Dorsomedial
- Posterior
- Mamillary
- Lateral
Functions of Preoptic n.
Regulates release of Gn releasing hormones
Functions of Supraoptic n.
- Produces ADH, oxytocin
2. Regulates water balance
Functions of Anterior n. of hypothalamus
- Regulates body temp.
2. Stimulates parasym. NS
Functions of Arcuate n. of hypothalamus
Produces hypothalamic releasing factors
Functions of Ventromedial n. of hypothalamus
Satiety centre
Functions of Dorsomedial n. of hypothalamus
Stimulation causes obesity and savage behaviour
Functions of Posterior n. of hypothalamus
- Regulates body temp.
2. Stimulates Symp. NS
Functions of Mamillary n. of hypothalamus
Receives info from hippocampus thru fornix
Afferent connections of hypothalamus
- Fornix connects hippocampus to mamillary bodies
- Stria terminalis: amygdala to preoptic, anterior
- Mamillary peduncle: spinal cord to lateral
- Thalamus
- Corpus striatum
Efferent connections of hypothalamus
Mamillothalamic tract Mamillotegmental tract (midbrain reticular formation)
Anterior wall of 3rd ventricle
Up to down
- Anterior column of fornix
- Anterior commissure
- Lamina terminalis
Posterior wall of 3rd ventricle
Up to down
- Pineal gland
- Posterior commissure
Roof of 3rd ventricle
Ependyma
Floor of 3rd ventricle
Front to back
- Optic chiasma
- Tuber cinerum
- Pituitary stalk
- Mamillary bodies
- Posterior perforated substance
- Tegmentum of midbrain
Lateral wall of 3rd ventricle
Hypothalamic sulcus
Recesses of 3rd ventricle
From front below to back
- Infundibular
- Optic
- Anterior
- Suprapineal
- Pineal
Blood vessels contributing to choroidal plexus of 3rd ventrilce
Anterior choroidal arteries