- Diencephalon: forms central core of forebrain, surrounded by cerebral hemispheres. Made of 3 paired structures: 1) thalamus, hypothalamus, and epithalamus.
- Thalamus: egg-shaped (known as the inner room) has midline connection called interthalamic adhesion
- ***EVERY part of the brain that communicated with the cerebral cortex must relay its signals through a nucleus of the thalamus.
- Hypothalamus: an inferior portion of the diencephalon. Lies between optic chiasma (point of crossover between cranial nerves II/ optic nerve) and the mammillary bodies (rounded bumps)
- Hypothalamus contains many nuclei and regulates activities of the visceral organs
Functions
- Control of ANS. Controls heart rate, blood pressure, movement of the digestive tube, secretion of sweat glands/ salivary glands.
- Control of emotional response. Lies at the center of the emotional part of the brain. (limbic system)
- Regulation of body temperature. Body’s thermostat
- Regulates hunger/ thirst sensations. Mediates feeling of hunger and thirst
- Control of motivational behavior. Controls behavior of rewarding/ pleasure. (i.e eating and sex)
- Regulation of sleep-wake cycle. (contains the suprachiasmatic nucleus)- body’s biological clock. Determines day and night cycle (circadian) rhythms.
- Controls endocrine system.
- Formation of memory.
- Control from the hypothalamus is carried through the periaqueductal gray matter/ medulla’s reticular centers
- Epithalamus: MOST dorsal part of the diencephalon. Contains pineal gland (hormone-secreting organ) This gland will secrete melatonin. Prepares the body for nighttime.
