F21-1

F21-2

F21-3  Anti Diuretic Hormone (ADH)  Renin-Angiotensin-Aldosterone  Atrial Natriuretic Hormone (ANH)  Urodilatin

↓ urine volume ADH OR BR OR ADH SECRETION F 21-4

F21-5

F12-6

F12-7

AgeIntracell ExtracellTotal Young Adult F21-8

F21-9

 Sources  Drinking  Food  Cellular metabolism  Losses  Urine  Evaporation  Sweating  Respiration and tongue  Faeces F21-10

 Water in oral mucosa  Mechanical distension of the stomach F21-11

 Passage of ions is regulated  Plasma membrane  Active transport  Electric charge  Water move by osmosis F21-12

 Detected by hypothalamic osmoreceptors  Increase in thirst sensation  Increase ADH secretion  Increase fluid intake  Increase permeability of renal cells  More water move into blood  Decrease blood osmolality  LOW OSMOLALITY  Detected by hypothalamic osmoreceptors  Decrease thirst sensation  Decrease ADH secretion  Decrease fluid intake  Decrease permeability of renal cells  Less water move into blood  Increase osmolality  HIGH OSMOLALITY F21-13

Increased BP in right atrium ANH Increased Na + and water excretion reduce BP Increased ANH in circulation F21-14