NURS 232 - Fluid & Electrolytes TEST (Graded A+ actual test)

Atrial natriuretic peptide role in the kidneys - ️️-Increases GFR by altering pressure in the glomerular capillaries -Reduces the reabsorption of sodium in the distal convoluted tubules through inhibition of ADH -Reduces renin secretion, inhibiting the RAAS ◦Result = fluid loss from the extra cellular compartment and lowered blood pressure Body mechanisms for fluid control - ️️-Thirst mechanism: osmoreceptors in the hypothalamus -Antidiuretic hormone (ADH): promotes reabsorption of water into blood from kidney tubules Osmolality - ️️-Concentration of fluid ◦Serum osmolality: normal = 280-300 mmol/kg ◦Hyper-osmolar means too many molecules ◦Hypo-osmolar means too dilute Total body water is __% of body weight, and formed components are __% of body weight - ️️60, 40 Total body water - ️️-60% of body weight -Intracellular: 40% of body weight -Extracellular: 20% of body weight Components of extracellular fluid - ️️-Interstitial fluid: 14% of body weight -Plasma volume: 5% of body weight -Transcellular volume: 1% of body weight Interstitial fluid - ️️Ultra filtrate of plasma, very little protein Transcellular fluid - ️️Lymph, synovial, intestinal, CSF, sweat, urine, pleural, peritoneal, pericardial, and intraocular fluids Which populations have lower water content and what is the risk of this? - ️️- Females have higher % of fatty tissue so have lower water content than males -Older adults and obese persons -Risk = more likely to be affected by any fluid imbalancePopulations at greatest risk for fluid and electrolyte imbalances - ️️Pediatrics -75% to 80% of body weight -Susceptible to significant changes in body fluids ◦Dehydration in newborns Aging -Decreased % of total body water ◦Decreased free fat mass and decreased muscle mass ◦Renal decline ◦Diminished thirst perception Capillary network - ️️-Blood flows from arterioles → metarterioles → capillary network -Venules drain network -Smooth muscle in arterioles, metarterioles, precapillary sphincters regulates blood flow Aquaporins - ️️Pores in the cell membrane that let water in and out Fluid and electrolyte balance - ️️The process of regulating the extracellular fluid volume, body fluid osmolality, and plasma concentrations of electrolytes Forces for movement of water and solutes - ️️-Filtration: ◦Capillary hydrostatic pressure (blood pressure) ◦Interstitial osmotic pressure (water-pulling) -Reabsorption: ◦Plasma (capillary) osmotic pressure (water-pulling) (↑ albumin), aka oncotic pressure ◦Interstitial hydrostatic pressure -Osmotic and hydrostatic pressure are opposing forces that keep the distribution of water constant When capillary hydrostatic pressure is greater than osmotic pressure... - ️️fluid leaves the capillary and enters the tissue When capillary hydrostatic pressure is less than osmotic pressure... - ️️fluid enters the capillary because it is pulled back into the bloodstream Organs involved in fluid and electrolyte balance - ️️Lungs, GI tract, kidneys Name three receptors that act on the hypothalamus - ️️1. Osmolality receptors (thirst perception) ◦Hyperosmolality and plasma volume depletion 2. Volume receptors3. Baroreceptors ◦Detect decreased blood pressure Renin-angiotensin-aldosterone (RAAS) system - ️️1. Dehydration, Na+ deficiency, or hemorrhage 2. Decrease in blood volume 3. Decrease in blood pressure 4. Kidneys produce renin 5. Renin converts angiotensinogen in the blood to angiotensin I 6. Angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II in the lungs 7. Angiotensin II stimulates vasoconstriction and the release of aldosterone 8. In kidneys, aldosterone promotes increased Na+ and water reabsorption and increased secretion of K+ and H+ into urine increased blood volume 9. Vasoconstriction and aldosterone cause increased blood pressure until it returns to normal Aldosterone - ️️Helps regulate blood volume, blood pressure, and levels of Na+, K+, and H+ in the blood Parts of a nephron - ️️Renal corpuscle → proximal convoluted tubule → nephron loop (aka, loop of Henle) → distal convoluted tubule → collecting duct