PSYCH 3M03 Lecture Notes - Lecture 5: Area Postrema, Adrenal Gland, Classical Conditioning
1 Oct 2013
School
Department
Course
Professor
Document Summary
A major motivator, which rises to the top of priorities when an individual is deprived of water. Two physiological processes: extracellular water (1/3 of total) in blood, csf, other body cavities. Quickly lost (bleed, menstruation, perspiration: cellular water 2/3 of total) inside cells. Triggered by blood loss, perspiration, diarrhea, heavy menstrual bleeding. Baroreceptors in kidneys: renin angiotensin aldosterone conserve na, renin peptide hormone in the kidneys sets off extracellular thirst, angiotensin peptide produced in the blood in response to renin. Causes vasoconstriction, release of vasopressin (anti-diuretic hormone) in posterior pituitary and may stimulate thirst via actions in brain: aldosterone produced in adrenal cortices in response to angiotensin; signals for the conservation of na+ in kidneys. Cellular thirst: osmotic, osmometric or sodium thirst, osmotic force draws h2o from cells. Induced by excess salt consumption or severe thirst. Salt and water bind together high affinity salt draws water out of cells: osmoreceptors around hypothalamus regions by 3rd ventricle.
