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31 Cards in this Set
- Front
- Back
4 main roles of maintaining homeostasis in kidneys
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1) Excretion of hydrophilic waste (i.e. toxins, nitrogenous substances, phosphate)
2) Maintain constant solute compostion 3) Maintain constant pH, ~7.4 4) Maintain constant fluid volume--important for blood pressure and cardiac output |
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What wedge-shaped structures of collecting ducts compose most of the medulla?
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Renal Pyramids (medullary pyramids)
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The most inner portion of the kidney
(Hint: extension of the ureter) |
Renal Pelvis located in the kidney's hilus
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The structural unit of the kidney
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Nephron
-more than a million units/kidney |
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The glomerulus is continuous with the distal convoluted tubule (T/F)
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False.
-Continuity begins at Bowman's capsule -Glomerulus is a capillary bed within the Bowman's capsule (together makes up the renal corpuscle) |
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Pathway of filtrate through excretory system
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1) Glomerulus (blood) -->Bowman's capsule (filtrate)
2) Nephron (PCT, ↑ & ↓ loop of Henle, DCT, collecting duct) 3) Papillary duct (where nearby collecting ducts merge) 4) Renal Pelvis-funnel-shaped sections called "calyces" 5) Ureter 6) Urinary Bladder 7) Urethra |
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3 elements renal corpuscle is comprised of:
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1) Glomerulus--tuft of capillaries
2) Glomuerular basement membrane 3) Bowman's capsule--surrounds glomerulus |
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Name pathway of blood flow from heart to kidney
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abdominal artery→renal artery→afferent arterioles (branch to individual corpuscles)→branch to form glomerular capillaries in Bowman's capsule→renal vein
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What are some causes that forces fluid to leave blood vessels and filter into Bowman's capsule?
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-afferent arterioles > efferent arterioles (↑ pressure)
-efferent arterioles can constrict creating high blood pressure in glomerular capillaries--↑ pressure forces fluid out of capillaries into ↓ pressure B's capsule |
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Glomerulus
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Network of branched capillaries sitting inside Bowman's capsule that is responsible for delivering blood into the nephron.
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Where does blood enter the kidney to become filtrate?
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Exits the glomerulus, supported by pressure differences, and enters the permeable visceral layer of Bowman's capsule.
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Proximal Convoluted Tubule (PCT)
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-Length of tubule proximal to the renal corpuscle
-Where most (~75%) reabsorption and secretion takes place through active transport proteins in apical membrane |
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What happens once a solute has reach its maximum in the proximal convoluted tubule?
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Solutes in the filtrate are then reabsorbed through passive or facilitative diffusion.
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What is the net result of the proximal convoluted tubule?
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To reduce the amount of filtrate in the nephron while changing the solute composition without changing the osmolarity.
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The nephron carries out its job in what 4 steps? Also name the transport method and selectivity of each step.
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1) Filtration: passive and non-selective
2) Secretion: active and highly selective 3) Reaborption: passive, active and selective 4) Excretion |
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Name the specialized cells in Bowman's capsule responsible for filtration. (3)
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-Slit Pores
-Podocytes -Basement Membrane |
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Descending Loop of Henle
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- water permeable but nearly impermeable to soultes
-Increasing [solute] gradient of medulla interstitium causes water to be reabsorbed into surrounding efferent capillaries (vasa recta)→renal vein |
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Ascending Loop of Henle
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-water impermeable, solute permeable
-At first, Na+ passively diffuses then actively transported to maintain interstitial concentration gradient |
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Solute concentration and volume of filtrate and is equal in cortical segments of the descending and ascending limbs. (T/F)
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False.
-Filtrate solute concentration in corresponding ascending limb is somewhat lower. -Filtrate volume is much lower |
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Distal Convoluted Tubule
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-Site of additional reabsorption and secretion that fine tunes and lowers filtrate concentration
-reabsorbs Na+ and Ca++ , secretes K+, H+, HCO3- (depending on blood [HCO3-]) |
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Where does aldosterone act on the nephron?
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-The distal convoluted tubule
-Increases Na+/K+ protein pump activity -Released when Na+ levels are low (and Ca++) |
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Where does the ADH act on in the nephron? (2)
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-On the collecting tubule (cortex) and collecting duct (medulla).
-Makes cells more permeable to water |
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Vasodilation of cardiovascular system increases blood filtration. (T/F)
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True.
-vasoconstriction decreases blood filtration |
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Juxtaglomerular Apparatus
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- Monitors filtrate pressure in the distal tubule
-specialized cells (granular) cells secrete renin, ultimately stimulates release of aldosterone |
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Renin
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Secreted by granular cells in juxtaglomerular apparatus (distal convoluted tubule) that initiates cascade of angiotensin I, II, and III → aldosterone
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Osmoregulation
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Management of the body's water an solute concentration.
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3 types of nitrogenous wastes and corresponding taxa of animals
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1) Ammonia: very soluble, highly toxic; organisms that live in the water i.e. hydra, fish, etc.
2) Urea: Not as toxic; earthworms and humans (liver processes ammonia--->urea) 3) Uric Acid: paste-like, non-toxic; excreted by insects, many reptiles, and birds--minimum water loss |
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Contractile Vacuole
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-protists
-unicellular algae |
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Flame Cells
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Simplest freshwater invertebrates--PLANERIA
-platyhelminthes (flat worms) |
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Nephridia OR Metanephridia
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Earthworms
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Malphighian tubules
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Insects
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