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25 Cards in this Set
- Front
- Back
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Electrolytes are the ionic components of the body fluids. TRUE/FALSE
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TRUE. The most notable are;
Na+/K+/Cl-/HCO3-/H+/Ca+/ PO4-3. |
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What are the 4 important phases of renal function?
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1. Filtration
2. Reabsorption 3. Secretion 4. Synthesis |
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What are the three layers that comprise the glomerular membrane?
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a. capillary endothelium
b. inner wall of Bowman's capsule c. basement membrane |
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Does the inner wall of Bowman's capule contain specialized cells?
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Yes. Podocyte cells
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Where does the basement membrane lie?
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It lies between the capillary endothelium and podocyte layers.
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What are mesangial cells?
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These are found as well in the glomerulus. These have contractile properties(partly stimulated by catecholamines and angiotensin 11, inhibited by atrial natriuretic factor).
When mesangial cells contract or relax, this reduces or increases the surface area of the glomerulus, thereby altering the capacity for glomerular filtration. |
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The outer and inner layers of the glomerular membrane leak, since the cells do not tightly adhere to one another. TRUE/FALSE
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TRUE. Infact slit like spaces between the cells allow the passage of small molecules.
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Most large molecule resistance is met with where?
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The basement membrane. Even with spatial considerations ionic charge relationships within the glomerular membrane render it particularly difficult for large negatively charged particles to pass through(most proteins are negatively charged).
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What does polarity nhave to do with reabsorption or excretion within the tubule lumen?
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Molecules that are nonpolar are reabsorbed more easily through the renal tubular membrane.
If one wishes to increase the excretion of a drug that is a weak acid(aspirin overdose) it may help to alkalinize the urine. This will drive the reaction to the left. H+ + DRUG- = HDRUG. |
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The more polar form of the drug produced by this reaction will then be excreted. TRUE/FALSE
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TRUE. Alternatively, one could acidify the urine to cause more of a weak acid medication to be reabsorbed.
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What do Thiazide diuretics do?
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They block the reabsorption of sodium in the distal convoluted tubule, sodium is then excreted along with water, which passively follows sodium.
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What is Probenecid?
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It inhibits the tubular reabsorption of urate and is used in the treatment of hyperuricemia in gout. It inhibits as well the tubular secretion of penicillin and is used to maintain plasma levels of penicillin.
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How is sodium absorbed?
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Sodium is actively transported from the renal tubular cell into the interstitial fluid and peritubular capillaries, a process that occurs throughout the length of the renal tubule.
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How does this affect intracellular sodium?
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This depltes the concentration of intracellular sodium in the renal tubules cells, leading to passive diffusion of Na+ from the renal tubular lumen into the tubular cell.
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How much sodium is reabsorbed in the PCT?
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About 65% of filtered Na+ and H2O is reabsorbed in the PCT.
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What else does the PCT reabsorb?
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Bicarbonate and many organic substances(glucose, amino acids, lactate, water soluble vitamins, ketones various Kreb cycle products).
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What are carrier proteins?
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Different carrier proteins are important in the transportation of certain groups of these organic molecules during reabsorption.
Different kinds of molecules are reabsorbed or secreted in different areas of the tubule, depending on which carrier is present. |
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One type of carrier protein carries arginine, lysine and ornithine. TRUE/FALSE
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TRUE. Another may carry aspartate and glutamate. Various diseases of amino acid transport may selectively affect the reabsorption of one or more amino acids.
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Give an example(s) of amino acid defect transportation.
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Cystenuria is a defect in the transport of cystine, lysine, arginine and ornithine in the proximal renal tubule and jejunal mucosa.
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What is Hartnup disease?
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here, there is a defect in the reabsorption of neutral amino acids.
some diseases may alter reabsorption, others, secretion. |
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What happens in renal tubular acidosis?
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H+ cannot be properly secreted by the renal tubule. Sodium is then reabsorbed along with chloride(Cl-) rather than through exchange with H=, and the result is a hyperchloremic acidosis develops.
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How and why does reabsorption occur?
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It occurs partly because the hydraulic pressure in the peritubular capillaries is very low, due to the passage of blood through the glomeruli.
The osmolality in the peritubular capillaries is relatively high since proteins do not filter at the glomerular level. |
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What happens to molecules that do not filter through the glomerulus?
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They pass on into the efferent renal arteriole to the peritubular capillaries. There, the molecules may be secreted into the tubular lumen, from which they are excreted or reabsorbed.
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Is albumin absorbed?
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Some molecules are neither filtered nor secreted significantly, such as albumin, whereas others may be both filtered and secreted(potassium).
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Can the kidney synthesize molecules?
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Yes. Renin, vitamin D, prostaglandins, kinins, glucose, bicarbonate, ammonia(a byproduct of amino acid metabolism that may be secreted and excreted by the kidney).
Erythropoietin is synthesized as well. |
