nitrogen MCAT - 51 Salt and Water Balance and Nitrogen...

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51 Salt and Water Balance and Nitrogen Excretion TEST FILE QUESTIONS Fill in the Blank 1. Organisms whose tissue fluids can have the same osmolarity as the environment are called _______. Answer: osmoconformers 2. An organism that maintains the osmolarity of its tissue fluids above that of the environment is known as a _______ regulator. Answer: hyperosmotic 3. Marine bony fishes actively excrete salt from their kidneys and gills, and nitrogenous wastes are lost as ammonia from the _______. Answer: gills 4. Tadpoles living in fresh water excrete nitrogenous wastes in the form of _______. Answer: ammonia 5. The Malpighian tubules of insects conserve water and excrete _______. Answer: uric acid 6. In the nephron of the vertebrate kidney, the glomerulus is a dense knot of thin-walled _______. Answer: capillaries 7. In humans, urine from the collecting ducts passes through the _______ to the urinary bladder. Answer: ureter 8. Resorption in the renal tubules is facilitated by _______, which provide extra surface area in the cells lining the tubule. Answer: microvilli 9. A normal kidney has several _______ mechanisms, which are adaptations to monitor and maintain kidney functions. Answer: autoregulatory 10. High levels of antidiuretic hormone cause the collecting ducts to become (more/less) _______ permeable to water, and highly concentrated urine is produced. Answer: more
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11. The human kidneys filter about 180 liters of blood per day, but they produce about 2– 3 liters of urine per day. Therefore, the percentage of fluid volume that ends up in urine is about _______. Answer: 1–2 percent (2–3 l/180 l) 12. Sharks and rays secrete salt from the _______. Answer: rectal gland 13. Renin is a regulatory enzyme released by the kidney. It acts on a circulating protein to begin converting that protein into an active hormone called _______. Answer: angiotensin 14. In addition to water and carbon dioxide, the metabolism of proteins and nucleic acids also produces nitrogenous waste found most frequently in the form of _______. Answer: ammonia (or NH 3 ) 15. Birds that eat marine animals ingest excess salt, which they excrete through their _______ glands. Answer: nasal salt 16. The hormone produced by the heart that influences kidney function is _______. Answer: atrial natriuretic hormone 17. Differences among tissues in water permeability relate to the presence or absence of proteins called _______. Answer: aquaporins 18. High levels of atrial natriuretic peptide (ANP) in the blood may indicate the condition known as _______. Answer: congestive heart failure Multiple Choice 1. The extracellular fluids in our bodies a. have the same composition as seawater. b. have a much higher osmotic concentration than fluids in cells have. c. contain no proteins.
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nitrogen MCAT - 51 Salt and Water Balance and Nitrogen...

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