Ch21 Body Fluids

Ch21 Body Fluids - 1 Body Fluids Body Fluids Body Fluid...

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Unformatted text preview: 1 Body Fluids Body Fluids Body Fluid Compartments: Body Fluid Compartments: ICF and ECF ICF and ECF Body Fluids Body Fluids s Intracellular fluid (ICF): ~ 63% of total body fluids s high in K + , phosphate and magnesium s Extracellular fluid (ECF): ~ 37% of total body fluids s high in Na+, Cl- Body Fluids Body Fluids s Extracellular fluid (ECF) is composed of: s Interstitial fluid s Blood plasma s Lymph s Fluid in special compartments s CSF, aqueous & vitreous humors of the eye, and the serous and synovial fluids Homeostasis of Body Homeostasis of Body Fluids Fluids Maintained by: s Hypothalamus (osmoreceptors & thirst mechanisms) s osmoreceptors = specialized neurons in hypothalamus which monitor osmotic pressure of blood, i.e. detect any changes in blood solute concentration (mainly Na + conc.) s Kidneys (renin-angiotensin mechanism) s Hormones (aldosterone from the adrenal cortex) s pH regulators (electrolytes, chemical & physical buffers) Importance of Water Importance of Water s Main solvent s Transport medium s Necessary in metabolic reactions s Body has ~ 40 liters (10.56 gallons) of body water s % of body water c as the amount of fat and age C s Highest in the young, the thin, and the muscular s Babies: 75% water s Men: 63 % s Women: 52% 2 Sources of Water Balance Sources of Water Balance Water intake = Water output Water Balance Water Balance s Constant fluid interchange between the 2 compartments s Fluids are transferred across semi-permeable membranes by diffusion or osmosis s osmosis is the primary method of water movement s Conc. of solutes (i.e. electrolytes) determines the direction of water movement s where sodium goes, water follows Water Balance Water Balance s Regulated by ADH, aldosterone, and the enzyme renin s If dehydration occurs (e.g. in hemorrhage or sever diarrhea) f c in blood volume & C in osmotic pressure s Osmoreceptors f hypothalamus f posterior pituitary f release of ADH f C water reabsorption by the kidneys f C blood volume, and c osmotic pressure If Dehydration Occurs: If Dehydration Occurs: s Water loss fc blood volume fc BP f renal cells produce...
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This note was uploaded on 05/04/2008 for the course HP 320 taught by Professor Islam during the Spring '08 term at USC.

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Ch21 Body Fluids - 1 Body Fluids Body Fluids Body Fluid...

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