BIOL 1119 Lecture Notes - Lecture 35: Posterior Pituitary, Cerebral Cortex, Osmoreceptor

• School: Northeastern University
• Department: Biology
• Course: BIOL 1119
• Professor: Christopher Richardson

Document Summary

Functions: chemically reactive in metabolism, determine cell membrane potentials, affect osmolality of body fluids, a(cid:725)(cid:725)(cid:724)(cid:722)(cid:739) (cid:721)(cid:734)(cid:723)y"(cid:738) w(cid:720)(cid:739)(cid:724)(cid:737) (cid:722)(cid:734)(cid:733)(cid:739)(cid:724)(cid:733)(cid:739) (cid:720)(cid:733)(cid:723) (cid:723)i(cid:738)(cid:739)(cid:737)i(cid:721)(cid:740)(cid:739)i(cid:734)(cid:733) Responsible for the resting membrane potentials of cells, and its inflow is an essential event in nerve and muscle function. The principle cation of the ecf, for sodium, along with chloride, are about 85- Na acts like a non-penetrating solute: cannot pass through cell membranes. Sodium excreted is sodium filtered minus sodium reabsorbed. No receptors in body to detect total sodium levels. Short term regulation of total body sodium is mainly related to changes in bp. Thus, regulation of bp simultaneously regulates total body sodium. Long term regulation of sodium is through control of tubular sodium reabsorption: the major factor determining the rate of tubular sodium reabsorption in kidney is aldosterone (salt retaining hormone) Aldosterone stimulates sodium reabsorption from large intestine and ducts from sweat glands. Unlike adh, aldosterone does not change ecf sodium concentration.