PSYC 106 Lecture Notes - Lecture 18: Inverse Agonist, Neuropeptide Y, Ghrelin
Document Summary
Homeostasis of thirst- homeostasis disturbed by increased concentration of na+ in extracellular fluid (ecf), activating osmoreceptors. This causes increased adh release and increased thirst which leads to decreased urinary water loss and increased water gain. The water gained by these processes dilutes the ecf, causing water to reenter cells and increase cell volume to original size, restoring homeostasis. Also no blood brain barrier in capillaries: when dehydrated, high concentration of na+ in csf activates receptors and na+ flows into cells, elevating the sodium concentration in the cell. Lactate acts a gliotransmitter and activates gaba neurons which control the salt intake-controlling neurons. *conversion of atp is the important step in this process. Osmotic thirst mechanism: water flows to area of lower concentration (during dehydration, it flows outside cell because the ecf has too little water) extracellular osmolality in olvt and sfo increases.
