Body Fluids content in anatomy and physiology

Body Fluids

1. Body Fluids 1 Sreenu Thalla Assistant Professor Department of Pharmacology

2. Total body fluids ≈ 60% (50-70%) of total bo d y w e i g ht ( T B W ) . S o l u t e s 60 % Water B o d y f l u i d s = w a t e r + d i ss o l v e d s o l u t e s . Electrolytes ( N a + , K + , C l - , HC O 3 - , M g + 2, Ca+2) Non-electrolytes ( g l u c o s e , u r e a , c r e a ti n i ne ) T o t a l bo d y w a t e r ≈ 60 % o f T B W . K g o f wa t e r = L o f W a t e r Body Fluid Content

3. Factors Affecting (TBW) Physiological: -Age -Sex - Body Fat Pathological: -Vomiting -Diarrhea - Di s e a s e s W i t h Exc e ss i v e l o s s o f w a t e r ( DM = Di a be t e s M e ll i t us , e xc e ss i v e S w e a t i ng …) -Blood loss -Burns Other: - Climate -Habits - P h ys i ca l Act i v i ty d i s t u r b a n c e s i n f l u i d balance 4

4. Low body fat L o w b o n e m a s s 73% or more water Higher body fat Smaller amount of skeletal muscles 40-50% water 60 % o f bo d y w e i g h t i s wat e r O n l y ab o u t 45 % of body weight is water 5 Body Fluid Content

5. C e ll s a r e l a r g e l y m a d e o f w a t e r a nd a r e s u r r o und e d b y a “ s e a ” o f w a t e r . W a t e r i s c o ns t a nt l y be i ng e xc ha ng e d be t w ee n t he c e ll s a nd s u r r o und i ng environment. K ee p i ng a c o ns t a nt v o l u m e o f w a t e r i s e ss e nt i a l f o r homeostasis. Water Balance 5

6. Fluid Intake = Fluid output the body modifies intake by thirst and output by kidney excretion 6

7. Input < o ut put . L e a d s t o : Hypovolemia Dehydration Physiologic regulation: 1 . A c t i v a t e s h y p o t h a l a m i c t h i r st c e n t r e → ↑ f l u i d i n t a ke T he h y p o t h a l a mi c t h i r s t c e nt r e i s a c ti v a t e d b y : ↓ EC F v o l um e ( 10 - 15 % ) ↑ ECF osmolarity (1-2%) 2 . ↑ ADH s e c r e t i on b y p o s t e r i o r p i t u it a r y → ↑ w a t e r r e a b s o r p t i on b y t h e k i d n e y . Water excess Input > o utput Le a d s t o : Hypervolemia. Edema. P h y s i o l o g i c regulation: ↓ ADH se c r e t i on → ↓ w a t e r r e a b s o r p t i on → ↑ w a t e r e x c r e t i on b y kidney . Decrease thirst 7 Regulation of Fluid Balance

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9. Fluid C o m p a r t m e n t s Plasma Ex t r a c e ll ul a r fluid(ECF ) In t e r s t i t i a l fl ui d Transcellular In t r a c e ll ul a r fluid(ICF) 9 Fluid Compartments

10. T o t a l B o d y WATER P l asma Interstitial fl ui d ICF Plasma is 25% of ECF 5 % o f T o ta l B o d y WEIGHT ICF is 40 % o f T o tal b o dy W E I G H T 2/ 3 o f T o tal Bo d y W A T E R Total body Water is 60% of Total Body Weight ECF ECF is 10 20 % o f T o tal Bo d y W E I G H T 1/ 3 o f T o ta l B o d y WATER Interstitial Fluid is 75% of ECF 15 % o f T o tal Bo d y W E I G H T

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12. Flui d b a thin g the cel l . 75% o f ECF 15% o f t o t a l b o d y weight Ul tra fi l tr ati o n o f plasm a . containe d i n a ge l - li k e extracellula r matrix . su r r ound s a l l ce l l s excep t bl oo d cells 12 P l a s ma : Fluid ci rculatin g i n the bl oo d vessels. 2 5 % o f ECF 5% o f t o t a l b o d y w ei g ht The r e i s High P r ote i n i n Plasma. T r a n s c ell u l a r fluid: sma l l amount. Examples: digestive sec r et i on s and CBS ( ce r eb r ospinal fluid) Extracellular fluid forms 1/3 of TBW and consists of: Interstitial fluid: Extracellular Fluid The main difference between plasma and interstitial fluids is the presence of protein in large quantities

13. Intracellular fluid forms 2/3 of TBW H i g h C o n c e n t r a t i o n o f p r o t e i n In s i d e T he c e l l 13 Intracellular Fluid ( ICF )

14. T r a n s c e ll u l a r F lu i d i s v e r y l itt l e D O N ’ T C O N F U S E T O T A L B O D Y W A T ER W IT H T O T A L B O D Y W EIG H T . 14

15. Ex t ra c e ll u l ar f l u i d s : Sod i u m i s t h e ch i e f c a t i o n ( + ) “Na” C h l o r i d e is t h e ch i e f an i o n ( - ) “Cl” In tr a c e l l u l a r f l u i d s : Potassium is t h e ch i e f cation(+)“K” P h o s p h at e is t h e ch i e f a ni o n ( - ) E l e c t r o - ne ut r a l it y : E a c h c o m p a r tm e nt m u s t H a v e a l m o s t t he s a m e c o n c e nt r a ti o n o f p os iti v e c h a r g e ( c a ti o ns ) a s o f ne g a ti v e c h a r g e ( a n i o n ) 15 C a l c i u m , c h l o r i d e , s o d i um , p r o te in , phosphate , potassium , glucose “IMPORTANT” Protein is highly concentrated in intracellular fluids and plasma Composition Of Body Fluids

16. Electrolyte Concentrations Memorize concentration level averages here rather than ranges: (as averages vary from book to book but the value in t he e xa m w i l l be v e r y c l o s e t o t he a v e r a g e he r e . ) 16

17. S o d i um ( N a ) : 135 – 145 m Eq /L C h l o r i d e ( C l ) : 98 – 107 m Eq /L P o t a ss i um ( K ) : 3 . 5 – 5 . 1 m Eq /L 24 Normal Ranges cont.

18. Does the composition of the compartments differ? (yes) 18

19. Abnormalities in electrolytes can change the osmolarity of E C F a nd c a n a f f e c t t he c e ll s . H y p e r n a t r e m i a ( ↑ N a c o n c . I n E C F ) H y p o n a t r e m i a ( ↓ N a c o n c . I n E C F ) Hyperkalemia ( ↑ K conc. In ECF) ( K is 60 – 100% above normal ) Hypokalemia ( ↓ K conc. In ECF) (1-2 mEq/L ) 19 How is it related to patient care?

20. A un i t o f c o n c e nt r a ti o n. d e s c r ibe s t he c o n c e nt r a ti o n o f one solution. It m e a s u r e s h o w c o n c e nt r a t e d o r d i l ut e d a s o l ut i o n i s . D e f i n e d a s = t he n um be r o f o s m o l e s o f a s o l ut e pe r l it r e o f s o l ut i o n. T he n o r m a l o s m o l a r it y o f b o d y f l u i d s is ≈ 300 mOsm/L 20 Terms of C oncen t r a t i o n O s m o l a r i t y : O s m / L O s m o l a li t y O s m / Kg Molarity M/L In b i o l o g i c a l s o l ut i o ns M i ll i m o l e s pe r l it e r ( m M / L ) M i ll i o s m o l e s pe r l it e r ( m O s m / L ) m = 1 / 1000 Osmolarity

21. What is Tonicity? ‘ r e m in d e r ’ O s m o l a r i ty d e s c r i be s t he c o n c e nt r a t i o n o f o n e solution. T on i c i ty i s us e d t o c o m pa r e be t w ee n t he osmolarities o f t w o o r m o r e s o l ut i o ns s e pa r a t e d b y a se m i - pe r m e a b l e m e m b r a ne 21 why it is important ? T he d i f f e r e n c e i n t o n i c i t y be t w ee n t w o d i f f e r e nt s o l ut i o ns s e pa r a t e d b y a semi-permeable m e m b r a ne d e t e r m i ne s t he m o v e m e nt o f w a t e r .

22. Isotonic solution : - (no swells or shrinking ) - 0.9% s o l u t i o n o f s o d i um c h l o r i d e - s a m e i n a nd o u t . 22 . 9 % - i n s i d e t he c e l l i s . 9 % - o u t s i d e t he H y po t o n i c s o l u t i o n : - ( s w e ll i ng ) h i g he r t ha n o u t s i d e t he c e ll . H y pe r t o n i c s o l u t i o n : - ( sh r i nk i ng ) c e l l i s h i g he r t ha n i n s i d e t he c e ll . Remember: the cell membrane functions as semi-permeable membrane Tonicity of Solutions: how does it apply to p hysiology ?

23. Movement of Water 23

24. I V F l u i d s A dm i n i s t ra t i o n 24 G l u c o s e a nd o t he r s o l u t i o ns a r e a d m i n i s t e r e d f o r n u t r iti v e pu r po s e s For people who can not take adequate amount of food. It i s a d m i n i s t e r e d s l o w l y in t o t he b l oo d s t r e a m . It i s p r e pa r e d i n i s o t o n i c s o l u t i o n. W a t e r i s e x c r e t e d i n t he p r o c e ss . Intravenous (IV) Fluids