Advanced A&P - Unit 10 Study Guide: Fluid, Electrolyte, and Acid-Base Balance

45-70% of body weight

total amount of water in body

ICF

fluid w/in cells; 63% total body water, high in potassium and protein

ECF

fluid in body, but outside of cells; 37% of total body water, high in sodium, chloride, bicarbonate

osmotic pressure

water “pulling” force; water moves toward areas of greater osmotic pressure. plays a role in return of water into blood capillaries and movement of water between interstitial spaces and intracellular spaces

hydrostatic pressure

water “pushing” force; water moves from areas of higher to lower; causes fluid to leave capillaries from interstitial space and to drive fluid into lymphatic capillaries

why most of water leaves the blood plasma at arterial end and returns to plasma at venous end

• fluid leaves the plasma at the arteriole end of capillaries and enters interstitial spaces because of the net outward force of hydrostatic pressure

• fluid returns to the plasma from the interstitial spaces at venular ends of capillaries because of net inward force of colloid osmotic pressure due to plasma proteins

cell swells

decrease in sodium ion concentration causes net movement of water from ECF to ICF

cell shrinks

increase in sodium ion concentration causes net movement of water from ICF to ECF

regulation of water output

occurs in kidneys

role of hypothalamus, post. pit. gland, and ADH

when hypothalamus detects dehydration, impulses are sent to the post pit. gland to cause ADH release. ADH will cause increased water reabsorption in distal tubule and collecting duct

dehyrdation

ECF becomes hypertonic, cells shrink

water intoxication

ECF becomes hypotonic, cells swell and burst

causes of edema

• low blood protein levels

• lymphatic obstruction

• increased bp

• increased capillary permeability

  • if widespread, blood volume and pressure decrease

sodium

regulated thru aldosterone; will cause renal tubules to reabsorb _____ and secrete potassium

hyponatremia

• low sodium

  • increased sweating, vomiting, diarrhea, kidney disease, water intoxication

hypernatremia

• high sodium

  • dehydration and anything that causes excess water loss

hypokalemia

• low potassium

  • muscular weakness, mental confusion, cardiac arrhythmias

hyperkalemia

• high potassium

  • drugs that conserve potassium, nausea, fatigue, muscle weakness, tingling

hypocalcemia

• low calcium

  • cardiac arrithymias, tremors, convulsions, excessive bleeding

hypercalcemia

• high calcium

  • increased urination, kidney stones, weakness, increased drinking

acid

electrolytes that release hydrogen ions in solution

base

release hydroxide which can accept hydrogen and form water

acid-base imbalances

severely disrupt enzyme controlled metabolic reactions, shift distribution of other ions, or modify hormone actions

major sources of hydrogen ions in body

originate as by-products of metabolic processes, although digestive tract may direct absorb some

chemical buffers

moderate pH changes by converting strong acids/bases to weak acids/bases; can accept or release H+; first line of defense

respiratory mechanism buffer

excretion of CO2, will compensate for metabolic disorders

renal mechanism buffer

excretion of hydrogen ions, will compensate for respiratory disorders