Pathophysiology Exam #3 - University of Cincinnati question and verified answers graded A+

Pathophysiology Exam #3 - University of Cincinnati question and verified answers graded A+ How does fluid movement work? - ANSWER - Arterial end = capillary hydrostatic pressure = pushing pressure --- filtration - Venous end = higher capillary oncotic pressure -- pulling pressure --- reabsorption What is oedema? - ANSWER accumulation of fluid into interstitial space What causes edema? - ANSWER 1. increased capillary hydrostatic pressure (venous obstruction) 2. Decreased plasma oncotic pressure (losses or diminished production of albumin) 3. Increased capillary permeability (inflammation and immune response) 4. Lymph obstruction (lymphedema) 5. Sodium retention Pathophysiology = increase in forces favouring fluid filtration from the capillaries or lymphatic channels into the tissues. A person with heart failure has edema in the lower legs and sacral area. The nurse suspects this condition is due to a(n): - ANSWER Increase in capillary hydrostatic pressure What is the role of sodium in fluid balance? - ANSWER Is the primary ECF cation. Regulates the fluid balance Key ion in transport of other ions across the membrane Sodium and Chloride react the same (both go up, both go down) EXCEPT for bicarb Regulates osmotic forces, thus water Roles include: Neuromuscular irritability, acid-base balance, cellular reactions, and transport of substances Is regulated by aldosterone and natriuretic peptides. • 136-145mEq/L What is the hormonal regulation of fluids? - ANSWER -It is mediated by aldosterone (first control of sodium in the body) -A mineralocorticoid steroid synthesized and secreted from the adrenal cortex -increases the blood pressure and volume • Influenced by both plasma concentrations of sodium and potassium in circulating blood • Secreted when sodium levels are depressed, potassium levels increases, or renal perfusion is decreased • Acts on the distal tubule of the kidney to increase reabsorption of sodium. • Leads to sodium and water reabsorption back into the circulation and potassium and hydrogen secretion to be lost in urine Explain the Renin-Angiotensin-Aldosterone System. - ANSWER A negative feedback system The second control of sodium in the body • Sympathetic nerve stimulation and decreased perfusion/blood pressure in the renal vasculature leads to the release of the enzyme renin juxtaglomerular cells of the kidney • Renin stimulates release of angiotensin I, inactive polypeptide, which is then converted to angiotensin II by ACE in pulmonary vessels • 2 major functions of angiotensin II 1. Stimulates the secretion of aldosterone - Aldosterone stimulates reabsorption of sodium and water restoring fluid balance 2. Causes vasoconstriction - Vasoconstriction rises systemic blood pressure restoring renal perfusion • Restoration of sodium levels, fluid volume, and renal perfusion leads to inhibition of the release of renin = negative feedback because end result is opposite of initiating stimulus What are natriuretic peptides? - ANSWER Third regulation of sodium in the body They work opposite of RAAS system Negative feedback system • Hormones that include atrial natriuretic peptide (ANP) and brain natriuretic peptide 1. ANP produced by myocardial atria - Urodilatin is ANP analog that is released by kidney cells with increased renal blood flow 2. BNP produced by myocardial ventricles, and • Natural antagonist to RAAS 1. Decreases blood pressure 2. Increase sodium and water excretion • Released when there is increased atrial pressure (increased volume); e.g.. CHF • Decrease in BP decrease atrial pressure therefore inhibiting release of ANP and BNP What is the role of the antidiuretic hormone (ADH)? - ANSWER - Is released when there is an increase in plasma osmolality, decrease in circulating blood volume, or decrease in BP which all result in decrease atrial pressure and ultimately secretion of ADH • Is also called arginine vasopressin. • Increases water reabsorption. 1. Increases permeability of renal tubules and collecting ducts of kidneys 2. Reabsorption of water mediated by ADH then promotes restoration of blood volume • Increase in blood volume returns to heart, increasing atrial pressure, ultimately stopping release of ADH A person reports severe diarrhea for 2 days. The practitioner understands this stimulates a(n): - ANSWER Increase in antidiuretic hormone secretion What is an isotonic solution? - ANSWER Contains equal concentrations of solutes on both sides. What is a hypotonic solution? - ANSWER the solution has a lower solute concentration than the cell -lysed cells What is a hypertonic solution? - ANSWER The solution has a higher solute concentration than the cell -shrivelled cells What are isotonic alterations? - ANSWER Total body water change with proportional electrolyte change (no change in concentration) - Isotonic volume depletion (hypovolemia) - Isotonic volume excess (hypervolemia) What are hypertonic alterations? - ANSWER 1. Hypernatremia • Serum sodium 147 mEq/L • Related to sodium gain or water loss • Water movement from the ICF to the ECF • Intracellular dehydration • Manifestations: Intracellular dehydration, convulsions, pulmonary edema, hypotension, tachycardia 2. Hyperchloremia • Serum chloride levels exceed 105mEq/L • Occurs with hypernatremia or a bicarbonate deficit. • Is usually secondary to pathophysiologic processes. • No specific symptoms are associated with hyperchloremia 3. Water deficit • Dehydration- isotonic dehydration • Pure water deficits -Are hypertonic dehydration. It is rare and seen in comatose and paralyzed patients • Renal free water clearance -Common cause is result of impaired tubular function or inability to concentrate urine, DI • Manifestations = Tachycardia, weak pulse, and postural hypotension, Elevated hematocrit and serum sodium levels, Headache, dry skin, and dry mucous membranes