Module 19 - Fluids, electrolytes and acid - base balance Flashcards
what does interstitial fluid mean?
fluid between the cells inside tissue
what composes trans-cellular fluid?
cerebrospinal fluid, synovial fluid in joints, vitreous and aqueous of the eye, and digestive secretions
what does intracellular fluid mean?
within the cell
what happens when osmolarity increases outside the cell?
water moves out of the cell and into the tissues
what happens when osmolarity decreases outside the cell?
water moves out of the tissue and into the cells
how does the body compensate for dehydration?
hypothamalus stimulates thirst
fluid excess
kidneys usually compensate by producing more urine, specific type of includes water intoxication
major cations
Na+, k+, Ca+, H+
major anions
Cl-, HCO3-, Pi
sodium
main electrolyte in extracellular fluid, determines the volume of total body water, influences how body water is distributed and plays a key role in depolarization
pH rises
more alkaline
pH drops
more acidic
phosphate participates in
carbohydrate metabolism, bone formation and acid -base balance
what mainly determine the amount and direction of flow of fluid?
concentration of solutes within each compartment
causes of acid gain (acidosis)
respiratory - retention of CO2 (hypoventilation)
metabolic - increased production of acids, consumption of acidic drugs, inability of the kidneys to excrete H+ ions, loss of bicarbonate
causes of acid loss (alkalosis)
respiratory- loss of CO2
metabolic - loss of gastric juices (vomiting or suctioning), excessive ingestion of bicarbonate
chemical buffers and 3 main chemical buffer systems
use chemical to bind h+ and remove it from the solution when levels rise too high and to release H+ when levels fall.
Bicarbonate buffer system, phosphate buffer system and protein buffer system
Physiological buffers
uses the respiratory and urinary systems to alter the output of acids, bases or CO2. This stabilizes pH
renal control of pH
kidneys are the only buffer system that actually expels H+ ions from the body. At the same time, they reabsorb bicarbonate, the predominant buffer in extracellular fluid. This double effect makes the renal system the most powerful of all buffer systems.
Potassium
Chief cation of intracellular fluid, crucial for proper nerve and muscle function.
Aldosterone regulates serum levels of potassium, just as it does sodium. Rising potassium levels stimulate the adrenal cortex to secrete aldosterone; aldosterone causes the kidneys to excrete potassium as they reabsorb sodium.
Calcium
plays a key role in muscle contraction, nerve transmission, and blood clotting. Plasma calcium levels are regulated by parathyroid hormone, which affects intestinal absorption of calcium and enhances the release of calcium from bones.
