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eliminate nitrogenous wastes; osmoregulation; include filtration, reabsorption, secretion, and elimination
a small, very toxic molecule (NH3) produced by nitrogen fixation or as a metabolic waste product of protein and nucleic acid metabolism
a soluble nitrogenous waste produced in the liver by a metabolic cycle that combines ammonia with carbon dioxide
a product of protein and purine metabolism and the major nitrogenous waste product of insects, land snails, and many reptiles; this is relatively nontoxic and largely insoluble
in excretory systems, the extraction of water and small solutes, including metabolic wastes, from teh body fluid; nonselective; blood pressure in afferent arterioles forces material into Bowman's capsule
(simple tubes) an excretory system, such as the flame bulb system of flatworms, consisting of a network of closed tubules and lacking internal openings
(tubes + capillaries) an excretory organ found in many invertebrates taht typically consists of tubules connecting ciliated internal openings to external openings
a cup-shaped receptacle in teh vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood
a ball of capillaries surrounded by Bowmans capsule in teh nephron and serving as the site of filtration in vertebrate kidney
Proximal convoluted tubule
in the vertebrate kidney, the portion of a nephron immediately downstream from Bowman's capsule that conveys and helps refine filtrate; reabsorption of materials (from tubules into intertitial fluid and capillaries, water follows by osmosis); secretion of materials (especially for adjusting pH)
Loop of Henle
the hairpin turn, with a descending and ascending limb, between the proximal and distal tubules of the vertebrate kidney; functions in water and salt reabsorption
Distal convoluted tubule
in the vertebrate kidney, the portion of a nephron that helps refine filtrate and empties its into a collecting duct; regulate Na+, K+, Cl-; regulate pH (H+, bicarbonate); urine relatively dilute
the location in the kidney where processed filtrate, called urine, is collected from teh renal tubules; NaCl reabsorbed; water reabsorbed by osmosis (hyperosmotic interstitial fluid); urea becomes more concentrated (most is excreted, some is reabsorbed from lower permeable tubule)
funnel-shaped chamber that receives processed filtrate from teh vertebrate kidney's collecting ducts and is drained by the ureter
Loop of Henle: descending limb
impermeable to NaCl; permeable to water >>> water is reabsorbed by osmosis
Loop of Henle: ascending limb
permeable to NaCl (thin segment - Nacl diffuses out; thick segment - NaCl actively pumped out); impermeable to water >>> reabsorption of NaCl
Interstitial fluid osmotic gradient
increasingly concentrated from cortex deeper into medulla; important for water reabsorption (water moves by osmosis from tubuel into interstitial fluid and capillaries)
in mammals and birds, a nephron with a loop of Henle located almost entirely in the renal cortex
in mammals and birds, a nephron with a loop of Henle that extends far into the renal medulla
release of renin stimulated by low blood pressure, low blood volume; angiotensinogen -----(renin)---> angiotensinogen II
Renin-angiotensin II-aldosterone system (RAAS)
a hormone cascade pathway that helps regulate blood pressure and blood volume
a specialized tissue in nephrons that releases teh enzyme renin in response to a drop in blood pressure or volume
a peptide hormone that stimulates constriction of precapillary arterioles and increases reabsorption of NaCl and water by the proximal tubules of the kidney, increasing blood pressure and volume; stimulates the release of aldosterone from the adrenal gland
a steroid hormone that acts on tubules of the kidney to regulate teh transport of sodium ions and potassium ions; increases NaCl reabsorption and water reabsorption
a peptide hormone, also knowns as vaspressing, that promotes water retention by the kidneys; prodcued in teh hypothaliamus and released from teh posterior pituitary, ADH also has activities in teh brain; released if blood osmolarity > 300mosm; increases water permeabllity of distal convoluted tubules and collecting ducts; alcohol inhibits release of ADH
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