HSM 330 Chapter Notes - Chapter 15: Optic Chiasm, Anterior Pituitary, Cerebellum
2 Apr 2013
School
Department
Course
Professor
Document Summary
The hypothalamus sits below the thalamus, along the walls of the third ventricle. This tiny cluster of nuclei makes up less than 1% of the brain"s mass. A tiny lesion can produce dramatic and often fatal disruptions. The hypothalamus integrates somatic and visceral responses in accordance with the needs of the brain. In mammals, the requirement for life include a narrow range of body temperatures and blood compositions: the hypothalamus regulates these levels in response to a changing external environment homeostasis. The pituitary has two lobes, posterior and anterior. The hypothalamus controls the two lobes in different ways. The kidneys secrete an enzyme into the blood called renin. This sets off a sequence of biochemical reactions in the blood. Angiotensinogen, released from the liver, is converted by renin to angiotensin i which breaks down to form angiotensin ii. Angiotensin ii directly effects the kidney and blood which increase blood pressure. The angiotensin ii is also detected by the subfornical organ.
