Term
| Where are the kidneys located anatomically? |
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Definition
1) retroperitoneum
- below 12th rib (floating rib)
- evolved to protect kidney |
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Term
| What percent of cardiac output is sent through the renal arteries? |
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Definition
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Term
| Describe the arterial to venous supply of blood to the kidney |
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Definition
1) aorta
2) renal arteries
3) interlobar arteries
4) arcuate arteries
5) interlobular arteries
6) afferent arteriole
7) globeruli
8) efferent arteriole
9) peritubular capillaries
10) vasa recta
11) arcuate veins
12) interlobar veins
13) renal vein
14) inferior vena cava |
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Term
| What are the uretovesicular valves? |
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Definition
| 1) valves created by a diagnoal insertion of the ureters through the bladder wall that become compressed during micturation (bladder pressure increased) |
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Term
| What is the functional unit of the kidney? |
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Definition
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Term
| What are the 3 cell types that create the glomerulus? |
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Definition
1) endothelial cell - abundant fenestrations
2) epithelial cell - podocytes w/ interdigitating foot processes
3) mesangial cells - fibromuscular cells responsive to antiotensin II |
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Term
| What cell type lines the tubule of the nephron? |
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Definition
| 1) columnar epithelial cells (polarized fashion that allows for directional transport) |
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Term
| What are the unique features of the proximal convoluted tubule? loop of henle, distal convoluted tubule, collecting tuble? |
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Definition
1) brush border to increase surface area
2) dscending limb and ascending limb for countercurrent multiplier
3) water impermeable, solute permeable
4) hormone responsive |
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Term
| What are the two primary roles of the kidney? |
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Definition
1) maintain internal milieu (homeostasis)
2) remove toxins |
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Term
| Describe the homeostatic mechanisms at play for the maintenance of the extra-cellular fluid volume |
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Definition
1) filtration (GPP; AII)
2) proximal reabsorption
3) renin-angiotensin-aldosterone cascade for fine regulation of ECV |
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Term
| What percent of the sodium is reabsorbed in the proximal tubule, loop of henle, distal tubule, and collecting tubules? |
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Definition
1) 50-55%
2) 35-40%
3) 5-8%
4) 2-3% |
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Term
| Describe how the kidney maintains osmolality in the body |
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Definition
1) water is filtered w/ no secretion
2) countercurrent multiplier reates hypertonic medulla for reabsorption
3) ADH-sensitive water channels |
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Term
| How does the kidney maintain pH control? |
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Definition
1) bicarbonate reabsorption in proximal convoluted tubule
2) hydrogen ion secretion in the collecting tubule (aldosterone)
3) ammonia genesis for acid trapping |
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Term
| What are major mechanisms for clearance of toxins from the kidney? |
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Definition
1) filtration
2) secretion
3) reabsorption |
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Term
| How is the kidney involved in hemodynamics? |
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Definition
1) vascular tone (via RAAC)
2) sodium retention
3) pressure natriuresis
4) water retention |
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Term
| What are major mechanisms of endocrine function from the kidney? |
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Definition
1) renin from JGA macula densa due to luminal chloride and beta1 stim
2) erythropoietin
3) vitamin D |
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Term
| What is the result of increased 1,25-vitD? |
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Definition
1) decreased calcium and phosphate excretion from kidney
2) calcium and phosphate absorption from small intestine
3) increased osteoclast activity and bone turnover |
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Term
| What are the major functions of the kidney? |
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Definition
1) Homeostasis
2) clearance
3) hemodynamics
4) endocrine function |
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Term
| What is the effect of prostaglandin on the afferent arteriole? |
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Definition
| 1) vasodilation to preseve glomerular perfusion despite falls in kidney blood flow |
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Term
| What are the major components contributing to glomerular blood flow? |
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Definition
1) afferent arteriole
2) glomerular capillary
3) efferent arteriole |
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Term
| Describe how the proximal convoluted tubule is involved in volume regulation |
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Definition
1) Na isotonic, iso-electric reabsorption
2) reabsorption up-regulated by reduced tubular flow
3) Na/K-ATPase on basolateral membrane
4) Na-H countertransport
5) AA, glucose, phosphates, organic acid co-transport |
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Term
| Describe how the proximal convoluted tubule is involved in acid/base balance |
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Definition
1) H+ secretion, w/ HCO3 reuptake but NO NET H+ MOVEMENT
2) ammonia genesis (glu) for H+ trapping |
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Term
| Describe how the proximal convoluted tubule is involved in water balance |
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Definition
| 1) proximal tubule is freely permeable to water and water reabsorption following Na+ absorption |
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Term
| Describe how the proximal convoluted tubule is involved in clearance |
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Definition
| 1) solvent drag w/ Na+ reabsorption |
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Term
| Describe how the loop of henle is involved in volume regulation |
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Definition
| 1) Na/K ATPase w/ Na/K/2Cl co-transport to reabsorb Na |
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Term
| Describe how the loop of henle is involved in water balance |
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Definition
1) descending limb is freely permeable to water
2) ascending limb is impermeable to water |
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Term
| Describe how the loop of henle is involved in electrolyte homeostasis |
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Definition
| 1) K back-leak into lumen driving Ca, Mg and Na reabsorption via paracellular routes due to positive lumen |
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Term
| Describe how the loop of henle is involved in endrocrine function of the kidney |
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Definition
| 1) erythropoietin produced by interstitial cells in DEEP MEDULLA |
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Term
| Describe how the distal convoluted tubule is involved in volume regulation |
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Definition
| 1) Na/K ATPase w/ Na/Cl-cotransport |
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Term
| Describe how the distal convoluted tubule is involved in water balance |
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Definition
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Term
| Describe how the distal convoluted tubule is involved in hemodynamics |
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Definition
1) macula densa of the DCT due to Cl delivery
2) Low Cl stimulates macula densa to release renin from JGA |
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Term
| Describe how the distal convoluted tubule is involved in electrolyte homeostasis |
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Definition
1) Ca channels due to low Ca levels and net negative intra-cellular charge
2) Vit-D dependent Ca-binding protein
3) active transport of Ca across basolateral membrane by Ca-ATPase and Na/Ca-exchanger |
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Term
| Describe how the collecting tubule is involved in volume regulation |
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Definition
1) aldosterone (AII stim) increases activity of Na channels and Na reabsorption
2) ANP from cardiac myocytes inactivates Na channels |
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Term
| Describe how the collecting tubule is involved in water balance |
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Definition
1) anti-diuretic hormone (ADH) from posterior pituitary (hypothal/carotid body stim)
2) incorporation of pre-formed water channels
3) tubular/urinary concentration |
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Term
| Describe how the collecting tubule is involved in acid/base balance |
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Definition
1) secreted by H+ATPase and H/K exchanger from intercalated cells
2) enhances H secretion by aldosterone due to H-ATPase stim and Na reabsorption |
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Term
| Describe how the collecting tubule is involved in electrolyte homeostasis |
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Definition
1) K excretion from principal cells due to aldosterone
2) Na reabsorption down electro-chemical gradient, causing a lumen-negative force for K excretion |
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