Chapter 26 Fluid, Electrolyte, and acid-base balance

Describe five hormones that are involved in regulating fluid output

ADH - from hypothalamus, response to solute, BP, or BV change AngioII - stimulates hypothalamus->Thirst. in response to low BP,BV or low NaCl in ECF Aldosterone - salt loving ANP/BNP - Increases urine, decreases BV/BP

List the factors that determine body water content and describe the effect of each factor

Age - 75-45% youth to eldery Body Mass - Males have more muscle mass, thus more water Body Fat - Females have more adipose tissue, which is hydrophobic, thus less water Hydration of tissues - adipose (20%) skeletal muscle (75%)

describe factors that determine fluid shifts in the body

Anything that changes solute concentration in the compartment that leads to net water flow Substances must pass through both plasma and interstitial fluid in order to reach the intracellular fluid

List the three major chemical buffer systems of the body and describe how they resist pH change.

Bicrabonate buffer system - Extracellular fluid, respiration based Phosphate buffer system - Urine/Intracellular fluid, similar to bicarbonate, Sodium dihydrogen phosphate: weak acid, monohydrogen phosphate: weak base Protein buffer system - Uses organic acids with carboxyl groups. Dissociate to release an H+ when pH is higher, or bind H+ when pH is too low

Describe the influence of the respiratory system on the acid-base balance

CO2+H2O -> Carbonic Anhydrase ->H2CO3 -> H+ +HCO3- Increased breathing rate if pH drops by modulating the respiratory center Decrease breathing rate if pH is high by modulating the respiratory center

List important sources of acids in the body

Carbonic, Lactic, Sulfuric, HCl, Phsophoric, ketosis(high fat/protein)

Describe how the kidneys regulate hydrogen and bicarbonate ion concentration in the blood

Directly can excrete or reabsorb H+ Kidneys can indirectly alter pH by changing the reabsorption or secretion of HCO3-

Explain the general role of electrolytes in fluid balance

Electrolytes are moved and water follows

Contrast the overall osmotic effects of the electrolytes and non-electrolytes

Electrolytes have a higher osmotic power

Compare and contrast the different types of fluid imbalances

Fluid imbalance with constant osmolarity - hemorrage, burns, chronic vomiting/diarrhea Fluid imbalance with chagnes in osmolarity Dehydration - Occurs when water output>intake Hypotonic hydration - Renal insufficiency or excessive water intake (Water intoxication) Edema - Fluid sequestration, fluid build up in the Interstitial space Hypoproteinemia - results in tissue edema because protein plasma has very low colloid osmotic pressure

List the routes by which water enters and leaves the body

Intake - Metabolism(10%), Foods(30%), Beverages(60%) Output - Feces (4%), Sweat (8%), Insensible (28%) Urine (60%) Obligatory water loss - 500mL, needed for nitrogenous wastes. Facultative water loss - potential (needs aquaporins) Regulation of water intake - Thirst, hypothalmus Intake increase BV -> Increase BP

Explain why Na+ is a critical electrolytes in the body and describe the mechanisms involved in regulating sodium balance, blood volume and blood pressure.

Na+ is 90% of the solute concentration in ECF Aldosterone - reclaims Na+, gets rid of K+ ANP/BNP - gets rid of salt Angiotensin II - RAAS

ID the main location, functions, and means of regulation for potassium and calcium

Potassium Location - Most abundant in cation in ICF (98%) Function - depolarization and hyperpolarization Regulation - Blood levels up -> sequestered into the cell; down -> released from cell Blood pH low -> H+ enters cells, and K+ exits Hypokalemia - muscle weakness, hyperpolarized, harder to depolarize Hyperkalemia - closer to depolarization, easily excitable, but unable to repolarize Calcium - PTH & calcitonin Blood clotting, Cofactor, nerve transmission, muscle contraction

Distinguish between acidosis and alkalosis resulting from respiratory and metabolic factors. Describe the importance of respiratory and renal compensations of acid-base balance

Respiratory Acidosis - falling pH and rising PCO2 (shallow breathing) Respiratory Alkalosis - CO2 is eliminated from the body faster than it is produced (hyperventilation, rare) Metabolic Acidosis - low blood pH and bicarbonate levels (excessive loss/ too much alcohol) Metabolic Alkalosis - rising pH and bicarbonate (vomiting/ excessvie base intake) Respiratory rate & depth increase with acidosis and decrease with alkalosis (too acidic more bicarb to buffer, too basic less bicarb) Renal compensation - respiratory acidosis: PCO2 and bicarb high, respiratory alkalosis pH high, PCO2 low.

Indicate the relative fluid volume and solute composition of the fluid compartments of the body

Rule of Thirds - 2/3: ICF, 1/3 ECF, 1/3 of EFC is plasma, 2/3 of ECF is IF. Composition Nonelectrolytes - organic molecules, urea, creatinine, glucose Electrolytes - inorganic salts, acids and bases (Higher osmotic power) ECF: Major Cation Na+, Major Anion Cl-; ICF: Major Cation K+, Major Anion P-

Differentiate among the salts, electrolytes and non-electrolytes

Salts dissociate in water ionic bonds, Electrolytes also dissociate, so acids/base/salts Non-electrolytes do not dissociate in water