Thalamus and hypothalamus
In the middle of the brain sit the two thalami, each about 3 centimetres long. Every sense except smell passes through a thalamus on its way to the cortex. The thalamus also relays the loops of the basal ganglia and the cerebellum back to the cortex.
The two thalami exposed from above, with the caudate nucleus curving round each, Gray's Anatomy, 20th edition, 1918, figure 716Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray716.png)
Below them lies the hypothalamus, less than 1 per cent of the brain. It holds the body at 37 degrees, drives hunger and thirst, sets the daily rhythm of sleep, and governs the pituitary gland that hangs from it on a stalk. The pituitary, half a gram to a gram, controls the thyroid, adrenal glands and gonads with its hormones.
Section through the pituitary gland in its bony seat, hanging from the infundibulum behind the optic chiasm, Gray's Anatomy, 20th edition, 1918, figure 1180Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray1180.png)
Sources
- Susan Standring (ed.), Gray's Anatomy, 42nd ed. (2020), chapter on the diencephalon.
- Arthur Guyton and John Hall, Textbook of Medical Physiology, 13th ed. (2016), ch. 59 and 76.
Prev: The basal gangliaNext: Memory