Fluid Distribution

olanjones's version from 2016-02-04 00:55

Section 1

Question Answer
What % of total body weight is water for an adult?60%
What % of total body weight is water for pediatrics75-80%
How is fluid distributed between ICF/ECF compartments?2/3 of TBW is in ICF, 1/3 of TBW is in ECF
What is the break down of fluid in ECF compartments?75% Interstital, 25% Plasma (vascular), 0.5 L Transcellular (CSF)
How does aging result in a decreased % of TBW?Increased adipose tissue, decreased muscle mass, diminished thirst perception, decreased renal function

Section 2

Question Answer
Isotonic alterationstotal body water change with proportional electrolyte/water change
Isotonic fluid loss hypovolemia results in rapid heart rate, flattened neck veins, decreased BP
Isotonic fluid excesshypervolemia results in weight gain, distended neck veins, increased BP, diluted plasma proteins. Can lead to edema
Hypertonic alterationsincreased osmolality either caused by increase in solute or decrease in ECF water, will stimulate thirst to increase water intake, ADH release to reabsorb water from urine
Hypertonic hypernatremiaresults in intracellular dehydration (ICF moves into ECF towards higher solute concentration), leads to hypervolemic symptoms
Hypertonic water deficitresults in hypovolemic symptoms, hemoconcentrated labs (can be caused by Diabetes Insipidous)
Hypotonic alterationsdecreased osmolality either caused by decrease in solute or by water excess, will result in a lack of thirst to decrease water intake, decrease in ADH to release water in urine
Hypotonic hyponatremiaresults in intracellular edema (ECF move into ICF towards higher solute concentration), leads to symptoms of hypovolemia
Hypotonic water excessresults in hypervolemic symptoms/water intoxication, hemodilute labs (can be cause by Syndrome of inappropriate ADH - SIADH)

Section 3

Question Answer
What is the Starling hypothesis?forces favoring filtration - forces opposing filtration = net filtration
capillary hydrostatic pressurevolume pressure that pushes fluid out of the capillary into interstitial space (blood pressure) - favors filtration
interstitial oncotic pressureproteins in the interstitial space pulling fluid out of capillary (proteins pull) - favors filtration
capillary oncotic pressureproteins within capillary pulling fluid into capillary (proteins pull) - favors reabsorption
interstitial hydrostatic pressurevolume pressure that pushes fluid out of interstitial space into capillary - favors reabsorption
edemaaccumulation of fluid within the interstitial space, results in swelling of tissue under the skin, pitting when skin is depressed, shortness of breath
What are the causes of edema?increased capillary hydrostatic pressure; decreased plasma oncotic pressure; increased capillary permeability; lymph obstruction
dehydrationdeficit of total body water, results in dry mucus membranes, decreased skin turgor, headache, confusion, low blood pressure, rapid heart rate
What are the causes of dehydration?vomiting, diarrhea, increased urination, excessive sweating, fever

Section 4

Question Answer
Antidiuretic Hormone (ADH)released by the posterior pituitary to increase fluid retention
Reninreleased by the kidney to convert angiotensinogen (produced by the liver) into angiotensin I, starting the RAAS pathway to cause fluid retention
Aldosteronereleased by adrenal cortex to cause increased renal fluid retention via sodium retention
Natriurectic Peptides (ANP and BNP)released by atria and brain tissues to function as aldosterone antagonists and promote fluid and sodium loss via renal secretion
What is the RAAS system?a series of hormone releases to increase fluid volume in the body, triggered by dehydration, Na+ deficiency, or total volume loss.
How does the RAAS system work?low BP triggers the kidneys to release Renin, this converts angiotensinogen to angiotensin I which is converted by ACE in the lungs to angiotensin II (see functions of angiotensin II)
What are the functions of angiotensin II?stimulate vasoconstriction of arterioles, stimulate the release of aldosterone, stimulates release of ADH (all of which work to increase blood pressure)

Recent badges