Term
| What is the difference between edema and cerebral edema? |
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Definition
| Cerebral edema refers to expansion of brain volume due to intracellular expansion, whereas edema is regarded as expansion of the interstitial fluid. |
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Term
| What type of tissue are continuous capillaries found in and what is a tissue type that doesn’t have the typical loose tight junctions? |
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Definition
| Skeletal muscle, blood brain barrier |
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Term
| Where are fenestrated capillaries found and place are they found where they lack the typical sieve-like diaphragms in the fenestrae? |
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Definition
| Kidneys, intestines, choroids plexus, endocrine glands; glom capillaries |
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Term
| Where are discontinuouse capillaries typically found and what is unique about this type of capillary? |
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Definition
| Bone marrow, spleen, liver; gaps between junctions are so wide that there is no osmotic pressure gradient and proteins can readily leak across. |
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Term
| True or False: most capillary beds allow for significant amounts of albumin to cross the endothelium despite its large, non-selective permeability barrier. |
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Definition
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Term
| As a result of autoregulation adjustment to sphincter tone, mean capillary pressure is primarily a function of what? |
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Definition
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Term
| At what end of the capillary is hydrostatic driving force greater, arterial or venous? |
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Definition
| Arterial is large, venous small |
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Term
| True or False: when the rate at which water enters the interstitium increases relative to the rate at which colloid enters, oncotic pressure in the interstitium will decrease and cause the change in oncotic pressure to increase. |
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Definition
| True, this prevents edema |
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Term
| What aspect about hydrostatic pressure in the interstitium explains why its high resistance to fluid flow prevents edema initially but when it reaches a certain point it distends easily? |
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Definition
| The space behaves like a gel taking up space and giving the interstitium a negative pressure, P=-10; when P>0 you create runaway edema and pitting is palpable |
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Term
| Which of these are causes of edema - increased Pc, decreased capillary oncotic pressure, increased water conductivity and protein selectivity, lymphatic obstruction? |
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Definition
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Term
| True or false: since the net gradient for filtering fluid is small in the capillaries (<1mm Hg), a minor change in pressures has a large effect on fluid movement. |
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Definition
| False, a change of more than 15mm Hg is required because as filtration increases lymph flow increases, interstitial proteins get diluted which increases the change in oncotic pressure reducing filtration, and interstitial fluid is resistant to increases in flow. |
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Term
| What are the two problems with the kidney that can cause generalized edema? |
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Definition
| Volume receptors sensing inadequate flow(HF), or the kidney responds abnormally and retains salt and water(kidney disease). |
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Term
| Hemorrhage, third spacing, gastrointestinal losses, renal losses, and skin losses are all causes of initially __________ _______________? |
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Definition
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Term
| Since acute hyponatremia is less than 48 hours in duration what is the greatest risk and what are some examples of causes? |
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Definition
| The greatest risk is the brain not having time to RVD causing herniation, and example cause would be over-secreted ADH with a large intake of fluids. |
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Term
| Since chronics hyponatremia is greater than 48 hours and their aren’t symptoms of hypoosmolality what is the greatest risk and some causative examples? |
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Definition
| The greatest risk is overtreatment because the brain has already RVD and a return to normal osmolality can cause a brain shrinkage, with causes being increased ADH production due to stimulus or ectopic, potentiation of ADH action on kidneys, and CHF. |
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Term
| The causes of hypernatremia can stem from renal and non-renal water loss, list two reasons each could occur. |
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Definition
| Renal - diabetes insipidus, factors that affect concentrating mechanisms (osmotic diuresis, loop diuretics, renal failure); Non-renal - inability to access water or altered thirst mechanism. |
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Term
| What is the osmolality of these common solutions to treat hyper/hyponatremia - D5W(used for hypernatremia), normal saline, 3% saline(hyponatremia)? |
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Definition
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Term
| What is the Starling equation that is fundamental to understanding edema? |
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Definition
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Term
| What is the equation you use when you must figure out how much water to give or remove from a patient when the amount of solute is not changed? |
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Definition
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Term
| What is the equation to determine the amount of solute to add or remove when the amount of water is not changed? |
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Definition
| Added Na= TBW x ([Na2]-[Na1]) |
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Term
| What percentage of body K+ is in the intracellular pool, especially in skeletal muscle and what is the normal plasma [K+]? |
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Definition
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Term
| What two molecules stimulate K+ uptake into the skeletal muscle and liver which takes hours to effectively complete? |
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Definition
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Term
| What part of the nephron absorbs 90% of K+ regardless of diet? |
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Definition
| Proximal tubule and loops of Henle |
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Term
| Which segment of the nephron controls K+ excretion? |
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Definition
| Cortical collecting tubule |
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Term
| Since principal cells determine K+ reabsorption and secretion by changing their secretion rate what two factors affect this rate? |
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Definition
| Electrochemical gradient of K across membrane and K conductance (which is high luminally) |
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Term
| True or False: elevated plasma [K] directly stims aldosterone release from the adrenals and lowered [K] inhibits it. |
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Definition
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Term
| Through what two routes is K+ excreted from principal cells? |
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Definition
| Basolateral membrane Na/K pump and high luminal conductance of K |
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Term
| What are the two reasons why most diurectics are K+ wasting? |
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Definition
| High luminal flow rate allows more K to be carried away and Higher salt and water entering the nephron causes the Na/K pump in the collecting tubule to drive more K into the lumen. |
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Term
| Aldosterone stimulates Na/K pump in the collecting tubule thereby increasing Na reabsorption and K excretion, by what two mechanisms does it achieve this? |
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Definition
| Upregulating the Na/K pump and by upregulating the Na channels in the membrane which drives the pump due to elevated Na |
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Term
| What is the effect on K excretion when the diuretic amiloride blocks the Na channel in the collecting tubule and the Em becomes more negative? |
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Definition
| K secretion is severely inhibited. |
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Term
| Which of the following can result from hypokalemia - reduced neuromuscular activity due to hyperpolarization, life-threatening arrythmias, or reduced ability to concentrate urine and regulate acid-base balance? |
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Definition
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Term
| What are the effects of hyperkalemia? |
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Definition
| Membrane potential is reduced to near threshold making muscles irritable and hyperactive, causes difficulty in maintaining a normal sinus rhythym, membrane polarization is greatly accelerated. |
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Term
| How does arterial pH affect K+ excretion in the collecting tubule? |
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Definition
| H/K ATPase in the intercalated cells secretes H and reabsorbs K; therefore in low pH reduces K excretion, and high pH increases it. |
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Term
| Why is plasma [K] elevated in acidosis and depressed in alkalosis? |
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Definition
| Because during acidemia H+ enters the cells and K+ leaves to maintain electroneutrality, while the opposite is true for alkalemia. |
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Term
| How is it possible for K+ depletion to cause metabolic alkalosis? |
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Definition
| The kidneys try to increase K intake by dumping protons in the intercalated cells of the collecting tubule. |
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Term
| ___________ and __________ refer to blood pH’s that are acid and alkaline compared to normal. |
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Definition
| Academia and alkalemia, which differ from acidosis/alkalosis which refer to abnormal body processes that would change the arterial pH by themselves |
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Term
| What determines the effects of ingested acids on the acid-base balance? |
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Definition
| Their metabolic fates; acids that can be oxidized like citric acid causes a transient load whereas acids like benzoic and tartaric are not oxidized and are acidifying. |
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Term
| Acidosis resulting primarily from any cause other than accumulation of respiratory acid is defined as what? |
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Definition
| Metabolic acidosis, whether it is from protein, phospholipid, lactic acid, ketone metabolism, etc. |
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Term
| True or False: the following are the 3 mechanisms that respond to acid-base disturbances - chemical buffering, respiration, and GI tract. |
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Definition
| False, the last one is renal excretion; the GI is major abnormal route of acid-base excretion. |
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Term
| Respiratory compensation for high [H+] is almost never complete, so then what corrective mechanism is used to return the body to normal? |
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Definition
| Renal correction absorbs HCO3 and creates it from CO2 in the proximal cell to act as a blood buffer. |
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Term
| True or False: the isohydric principle states that all buffers are in equilibrium with H+ and with each other, therefore a change in one affects the others. |
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Definition
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Term
| In metabolic acidosis, as pH decreases what happens to [HCO3] and CO2 pressure in the blood? |
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Definition
| Both decrease, CO2 decreases due to respiratory compensation but is never complete |
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Term
| In respiratory acidosis, as pH decreases what happens to [HCO3] and CO2 pressure in the blood? |
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Definition
| Both increase, with renal compensation sometimes complete in mild cases |
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Term
| What mechanism determines whether respiratory acidosis is either acute or becomes chronic? |
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Definition
| Renal compensation, though not usually complete, increases [HCO3] |
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Term
| In metabolic alkalosis, as pH increases what happens to [HCO3] and CO2 pressure in the blood? |
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Definition
| Both increase, respiratory compensation is never complete |
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Term
| In respiratory alkalosis, as pH increases what happens to [HCO3] and CO2 pressure in the blood? |
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Definition
| Both decrease, with renal compensation rarely complete |
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Term
| The primary role of the kidneys in acid-base disturbances is to regulate pH by regulating extracellular __________. |
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Definition
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Term
| Since roughly 90% of H+ secretion occurs in the proximal tubule via the Na/H antiporter, where does the final acidification of the urine occur? |
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Definition
| In the collecting tubule via the H ATPase and H/K ATPase |
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Term
| The secretion rate of H+ can be directly regulate by intracellular concentration of _______? |
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Definition
| H+, it causes an upregulation of transport proteins. |
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Term
| Since the lumen and tight junctions are relatively impermeable to HCO3 in the proximal tubule and the a-intercalated cells how do they reabsorb the filtered bicarbonate? |
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Definition
| They exrecte protons in the lumen, shifting the equilibrium towards CO2 creation which is highly permeable, then intracellular carbonic anhydrase converts it back to H+ and HCO3, where each mmole of HCO3 is then absorbed for every H+ mmole excreted. |
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Term
| How does acidosis affect NH4 excretion in the proximal tubule? |
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Definition
| In the presence of acidosis the cell takes glutamine the resulting reactions create an NH4 molcule for every HCO3 molecule; the NH4 is then excreted into the lumen via the Na/H transporter in place of H. |
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Term
| How does the collecting tubule utilize ion trapping in acidosis in order to excrete NH4 and pull NH4 out of the interstitium that had been absorbed? |
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Definition
| The elevated levels of H+ drop the pH in lumen of the nephron, shifting the equilibrium of H+NH3->NH4+, pulling the membrane soluble NH3 out of the interstitium so that more NH4 can be excreted. |
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Term
| What are the two mechanisms by which bicarbonate is excreted in alkalosis? |
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Definition
| The reduced secretion of H+ halts the cycle of HCO3 formation in the nephron, and via active excretion of b-intercalated cells in the collecting tubule. |
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Term
| How does HCO3 filtration change in acute respiratory acidosis? |
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Definition
| Increased CO2 increases [HCO3], and increased [H+] produces extra HCO3 in the proximal tubule. |
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Term
| When there is decreased effective circulating volume why do some patients develop metabolic alkalosis? |
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Definition
| When volume is low body doesn’t reduce [HCO3] in order to conserve as much Na as possible (seen in the cotransporters of the basement membrane of proximal cell) |
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Term
| How is it that K+ depletion causes urinary acidification and metabolic alkalosis? |
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Definition
| The H/K ATPase in the a-intercalated cells drives excessive protons out of the body in order to conserve K+ |
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Term
| Understand this diagram and where the separations lead. |
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Definition
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