Forebrain, diencephalon.
Meninges of the brain.
Cerebro-spinal fluid.
The diencephalon
• The diencephalon is the region of the embryonic
vertebrate neural tube that gives rise to posterior
forebrain structures including the thalamus,
hypothalamus, posterior portion of the pituitary
gland, and pineal gland.
• The hypothalamus performs numerous vital
functions, most of which relate directly or
indirectly to the regulation of visceral activities by
way of other brain regions and the autonomic
nervous system.
THE DIENCEPHALON
• EPITHALAMUS
• THALAMUS
• SUBTHALAMUS
• HYPOTHALAMUS
Diencephalon
Hypothalamus
Thalamus
•Command for the
•Chief relay centre for
control of autonomic
directing sensory messages functions such as heart
Helps regulate awareness
rate, blood pressure,
•Relays commands going
hunger, thirst.
to the skeletal muscles
•Role in emotions and
from the motor cortex.
motivation (e.g., thoughts
about fear get translated into
arousal through hypothalamus.)
THE HYPOTHALAMUS
• Lateral zone
• No discrete nuclei
• Regulation of food and water
intake
•Medial zone
•Well defined nuclei
•Chiasmatic region (anterior region)
•hormone release• SO,PV)
•Cardiovascular function (Ant.)
•Circadian rhytms (SCH)
•Body temperature (Preoptic nc.)
• Tuberal region (middle reg.)
•
•
VM – satiety center (lesion
produces hyperphagia + obesity)
Arcuate nc. - delivers peptides to
the portal vessels
• Mamillary region (posterior
reg.)
•
•
Posterior nc.- elevating of blood
pressure, pupillary dilatation, body
heat conservation
Mammillary ncc. – memory
formation (fornix)
Vasopresin (Antidiuretic h.),
Oxytocin (uterus,ejection of milk)
Somatotropin, Prolactin, Folitropin,
Lutropin, thyrotropin, ACTH
Diencephalon3rd ventricle
Surrounded by cerebrum
Intermediate
mass
Hypothalamus
Pituitary gland
Mammillary body
Thalamus
Pineal body
Epithalamus
epithalamus Located at dorsal part of the diencephalons, it includes the
pinieal body. It secretes melatonin which signals the nighttime stage of the
sleep-wake cycle.
pineal body — internal secretion gland
habenular triangle— habenular nucleus
habenular commissure
thalamic medullary stria
posterior commissure
subthalamus
subthalamic nucleus
participate in the function of extracorticospinal tract