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42 Cards in this Set
- Front
- Back
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Amphibians have BLANK urine, while mammals BLANK urine
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amphibians have dilute, mammals concentrated
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A tubular structure that regulates blood volume and blood composition, producing urine
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kidneys
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Urine derived from...
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blood plasma, containing solutes and nitrogenous wastes
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Kidneys excrete H+ to
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regulate blood pH
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Kidneys excrete water to
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control osmotic pressure of blood
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Blood composition regulated by (2) excretions
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controlled excretions of blood solutes (including toxins) and water
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Basic unit of the kidney
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nephron, tubules that connect to collecting ducts that lead out of the body
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Primary urine is formed where?
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In Bowman's capsule of nephrons by ultrafiltration and secretion
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Ultrafiltration is accomplished by
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hydrostatic pressure in the glomerulus, forces fluid from blood into nephron
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GFR, glomerular filtration rate...
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rate of primary urine formation; humans it is about 120 mL/minute, or all plasma in 30 minutes
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Secretion (active solute secretion)...
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Active transport of a solute into the renal tubule, followed by osmosis and diffusion of other solutes into the tubule
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Definitive urine produced by?
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extensive modification, both in volume and composition, of the primary urine within renal tubules
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Filtrate leaves blood because of...
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a net filtration pressure caused by hydrostatic pressure
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Secretion via active transport of one solute...
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causes water and other solutes to follow
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Much of the filtrate in amphibians reabsorbed from
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proximal tubule into blood, including NaCl, HCO3, glucose, amino acids, producing isosmotic urine (U/P = 1)
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Amphibians: NaCl actively reabsorbed from...
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distal tubule
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Water reabsorption controlled by...
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altering permeability of the tubule to water; lower permeability = hyposmotic urine
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BLANK increases water permeability of distal tubule
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antidiuretic hormone (ADH) decreases water excretion
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ADH reduces BLANK and promotes BLANK reabsorption
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reduces glomerular filtration rate and promotes NaCl reabsorption
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Amphibians can store water in their bladder because
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urinary bladder responds to ADH by reabsorbing NaCl and increasing water permeability (and reabsorption)
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In amphibians and many reptiles, nephrons form
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messy knots, unlike mammals
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In all vertebrates, nephrons empty into a BLANK, which conveys urine to the ureter
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collecting duct
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Diuresis
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low ADH levels cause less water reabsorption
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Antidiuresis
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high ADH levels cause increased water reabsorption
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Vasopressin (ADH) causes
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aquaporins to be incorporated into apical membrane of collecting duct of epithelial cells via protein kinase
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Mammals produce BLANK urine, unlike amphibians
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produce hyperosmotic urine, because of the structure of the kidney and its tubules
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Concentrating urine involves
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going through collecting ducts through higher concentrations of NaCl as it leaves kidney, water pulled out of urine by osmosis
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BLANK generate the NaCl gradient above by active NaCl pumping out of ascending segment
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loops of Henle
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Urea is at high concentration in?
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high concentration in medulla and collecting duct, which is permeable to urea and contains concentrated urine
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Medulla blood supply is
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by the looped vasa recta
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Vasa Recta
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preserves NaCl concentration gradient by passive countercurrent diffusion exchange of solutes and gains of water by the blood via colloid osmosis
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The single effect
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driven by NaCl pumping
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How is the osmotic gradient established along length of the loop?
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By active NaCl transport and countercurrent urine flow
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In the rat kidney, osmotic pressure increases from
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cortex to outer medulla to inner medulla; this osmotic gradient drives water reabsorption from collecting duct
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The collecting duct becomes permeable to water during...
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antidiuresis, and water moves into interstitial fluid by osmosis
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Nitrogenous waste (urea) is in high concentration in both BLANK and BLANK
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duct and medullary interstitial fluid
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The collecting duct becomes less permeable to water during...
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diuresis, and water remains in the urine and is excretedl NaCl reabsorbed, making urine more dilute
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Proximal convoluted tubule
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NaCl and glucose reabsorbed, H+ excreted
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Ascending loop of Henle
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NaCl reabsorbed, H+ excreted
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Collecting duct
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Na+ reasorbing cell: NaCl reabsorbed
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Thickness of medulla correlation with urine concentrating ability
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positively correlated with urine concentration ability, reflects the length of the loops of Henle
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Sand rat vs lab rat
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long renal papilla, long loops of Henle define extent
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