Distribution of Body Solids & Fluids

Fluid Exchange

Processes in our body:

• Filtration

• Reabsorption

• Diffusion

• Osmosis

General barriers that separate intracellular fluid, interstitial fluid, and blood plasma:

1. Plasma membrane

2. Blood vessel walls

Fluid Homeostasis

Fluid Balance

1. Water

2. Electrolytes

Fluid Homeostasis

Regulate by:

1. Hypothalamus

2. Posterior pituitary (ADH)

3. Adrenal cortex

4. Kidney tubules

Sources of Body Water Gain & Loss

Dehydration

Hormonal Regulation of Na+ & Cl- Reabsorption

Series of events in water intoxication

                                                            

Electrolytes

• sodium (Na+)

• potassium (K+)

• chloride (Cl-)

• calcium (Ca2+)

• magnesium (Mg2+)

• bicarbonate (HCO3-)

• phosphate (PO42-)

• sulfate (SO42-)

Electrolyte and protein anion concentrations in plasma, interstitial fluid, & intercellular fluid

ElectrolytesHype???

• water, sucrose syrup, glucose-fructose syrup, citric acid, natural and artificial flavors, salt, sodium citrate, monopotassium phosphate, ester gum, sucrose acetate isobutyrate, red 40, blue 1

• Per 8 fl ozTotal fat 0gSodium 110mgPotassium 30mgTotal carbs 14gSugars 14gCalories 50

• water, dextrose, potassium citrate, sodium chloride and sodium citrate. Nonmedicinal ingredients: FD&C Blue #1 and Red #40 (grape flavor) and FD&C Red #40 (bubblegum flavor).

• Per 8 fl ozSodium 10.6 mg Potassium 4.7mg Chloride 8.3 mgDextrose 5.9gCalories 24

Acid-Base Balance

Removal of H+

1. Buffer systems

2. Exhalation of carbon dioxide

3. Kidney excretion of H +

Protein Buffering System

NH2 C COOH

H

R

NH2 C COO- + H+

H

R

NH2 C COOH + H+

H

R

NH3+ C COOH

H

R

CO2 + H2O ↔ H2CO3 ↔ HCO3- + H + ↔ CO3

2- + 2H+

By-product of respiration

carbonic acidbicarbonate

carbonate

The addition of CO2 makes blood acidic

Blood too basic:

H2CO3 HCO3- + H + pH drops

Blood too acidic:

HCO3- + H+ H2CO3 pH rises

Blood ave. pH = 7.4

Carbonic Acid-Bicarbonate Buffering System

Phosphate Buffering System

too basic: OH- + H2PO4

- H2O + HPO42-

too acidic:H+ + HPO4

2- H2PO4-

Exhalation of CO2

Exhalation of CO2

Exhalation of CO2

Negative feedback regulation of blood pH by the respiratory system

Exhalation of CO2

Kidney Excretion of H+

                                                            

Secretion of H+ by intercalated cells in the collecting duct