diencephalon
DESCRIPTION
DIENCEPHALON. 05.05.2014 Monday. Kaan Yücel M.D.,Ph.D. 1. Diencephalon. Prosencephalon [ Forebrain ] Telencephalon Diencephalon. 2. Diencephalon is composed of…. ( 1) thalamus (2) subthalamus [-sub: 'inferior to”] ( 3) epithalamus [- epi : “superior to”] - PowerPoint PPT PresentationTRANSCRIPT
DIENCEPHALON
Kaan Yücel M.D.,Ph.D.05.05.2014 Monday
1. DiencephalonProsencephalon [Forebrain]
1. Telencephalon2. Diencephalon
2. Diencephalon is composed of…(1) thalamus (2) subthalamus [-sub: 'inferior to”](3) epithalamus [-epi: “superior to”](4) hypothalamus [-hypo: “under” ]
posteriorly where 3rd ventricle becomes continuous with the cerebral aqueduct anteriorlyinterventricular foramina
A midline structure with symmetrical right and left halves
2. Diencephalon extends...
• Only area exposed to the surface in the intact brain.
• Formed by hypothalamic and other structures, which include, from anterior to posterior:o optic chiasma o infundibulum with the tuber cinereum [x]o mammillary bodies
2. Diencephalon’s inferior surface
[x]
• Concealed by the fornix.
• The actual superior wall of the diencephalon is formed by roof of the third ventricle.
• A pair of vascular processes, choroid plexuses of the third ventricle, project downward from the midline into the cavity of the third ventricle and CSF is produced here.
2. Diencephalon’s superior surface
Bounded by the internal capsuleoconsists of nerve fibers oconnect the cerebral cortex with parts of the brainstem and spinal cord. MRI of the brain, T1-weighted axial cut
2. Diencephalon’s lateral surface
1. Insula2. Internal capsule3.Caudate nucleus4. Putamen5. Internal capsulePosterior limb 6. Splenium, corpus callosum 7.Thalamus
2. Diencephalon’s medial surfacea.k.a. Lateral wall of the third ventricle
Superior part by medial surface of thalamus hypothalamic sulcus Inferior party by hypothalamus
stria medullaris thalami •Afferent fibers to the habenular nucleus
•Forms a ridge along the superior margin of the medial surface of the diencephalon
3. Thalamus L. thalamus "inner chamber," from Gk. thalamos "inner chamber, bedroom"
Large ovoid mass of gray matter that forms the major part of the diencephalon.
On each side of the third ventricle.
3. Thalamus
The superior surface of the thalamus is covered medially by the tela choroidea and the fornix
The inferior surface is continuous with the tegmentum of the midbrain.
3. Thalamus The medial surface of the thalamus forms the superior part of the lateral wall of the third ventricle
Usually connected to the opposite thalamus by a band of gray matter, interthalamic connection (interthalamic adhesion- adhesio interthalamica- massa interrmedia)
Found in 70-80% of humans
Axial T2-weighted MR image C = caudate nucleus G = globus pallidus L = lentiform nucleus (G+P) P = putamen T = thalamus
Important station that receives the main sensory tracts (except the olfactory pathway).
A station where much of the information is integrated and relayed to the cerebral cortex and many other subcortical regions.
A key role in the integration of visceral and somatic functions.
3. Thalamus Anterior thalamic nuclei, which receive the mammilothalamic tract from the mammillary nuclei.
Associated with of that of the limbic system and is concerned with emotional tone and the mechanisms of recent memory.
3. Thalamus Medial part of the thalamus large dorsomedial nucleus and several smaller nuclei. 2 connections with the whole prefrontal cortex and hypothalamic nuclei.
Responsible for
integration of a large variety of sensory information
relation of this information to one’s emotions
3. Thalamus
Stria terminalis: Runs @ lateral margin of thalamusFrom amygala to hypothalamusMajor output of amygdala
4. Hypothalamus
CHIEF OF THE HORMONES
from the region of the optic chiasma to the caudal border of the mammillary bodies
4. Hypothalamus four distinct groups in the rostral-caudal plane of the third ventricle: 1. preoptic (above and in front of the optic chiasm - telencephalic
extension of the basal forebrain, but functionally diencephalonic)
2. chiasmatic (above and around the optic chiasm)
3. tuberal (above and around the "tuber cinereum", i.e. pituitary stalk)
4. posterior region which includes the mammillary bodies.
4. Hypothalamus When observed from below, the hypothalamus is seen to be related to the following structures, from anterior to posterior: (1) optic chiasma(2) tuber cinereum & infundibulum(3) mammillary bodies
5. SubthalamusInferior to thalamusBetween thalamus-midbrainAnteriomedially- hypothalamusImportant connections with the striatumFxn: Control of muscle activity
AC
Adhesiointerthalamica
Septum pellicidum
Thalamus
Hypothalamus
Cerebral aqueduct
Mamillary body
Optic chiasm
Anterior commissure Posterior
commissure
Pineal gland
Pituitary gland
Corpora quadrigemina
6. Pituitary gland SIDEKICK OF THE HYPOTHALAMUS
Hormone Stimulated by the hypothalamic hormone
Does
Anterior pituitary gland (Adenohypoysis)
Growth Hormone (GH) Growth Hormone-Releasing Hormone (GHRH)
Growing
Thyroid-stimulating hormone (TSH)
Thyrotropin-Releasing Hormone (TRH) Metabolism of the body
Adrenocorticotropic hormone (ACTH)
Corticotropin-Releasing Hormone (CRH) Production and release of corticosteroids from the adrenal glands
Prolactin (PRL) Long list of chemical substances, inhibited by dopamine
Stimulation of milk production in breasts
Luteinizing hormone (LH) Gonadotropin-Releasing Hormone (GnRH)
Triggers ovulationICHS production of testosterone
Follicle-stimulating hormone (FSH)
Gonadotropin-Releasing Hormone (GnRH)
Regulates the development, growth, pubertal maturation, and reproductive processes of the body
Posterior pituitary gland (Neurohypoysis)
Oxytocin Secreted from the hypothalamus and carried to the pituitary gland
Distension of the cervix and uterus during labor, facilitating birth, and after stimulation of the nipples, facilitating breastfeeding.
Antidiuretic hormone (ADH)
Secreted from the hypothalamus and carried to the pituitary gland
Increases water absorption in the the kidney
7. Tuber CinereumInterthalamic adhesion
Septum pellicidum
Fornix
Thalamus
PC
Mammillary bodies
AC
Pituitarygland
Opticchiasma
Hypothalamus
Optic chiasm
Pituitary gland
Thalamus
HypothalamusAC
PC
Lamina terminalis
Pineal glandTuber cinerum
Infundibulum
Habenula
Interthalamic adhesionFornix
8. Epithalamus Pineal gland+habenular nucleus+stria medullaris thalami
Haber SN, Knutson B. The reward circuit: linking primate anatomy and human imaging. Neuropsychopharmacology. 2010;35(1):4-26.
Pineal gland:Inhibition of hormonesCircadian rhythm day & nigh timeMelatonin
Habenula:potential importance ofthe lateral habenular nucleus in regulating the dopamine reward signal
Anterior commissure (AC)Connecting temporal lobesPosterior commissure (PC)Pupillary eye reflex