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24 Cards in this Set
- Front
- Back
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What is the difference between osmoregulation and excretion?
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1. Osmoregulation: regulating solute concentrations and balancing the gain and loss of water. Excretion: methods used to get rid of waste
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what are osmoregulators. Give examples
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Osmoregulators expend energy to control water uptake or loss. Hypersomotic environments- marine invertebrates and some marine invertebrates, they have dehydrating environments, they constantly loose water so they drink in water, NaCl actively transported out in gills. In hyposomatic environments- freshwater fish, constantly gain water and lose salt, their metabolism is adapted to interstitial fluid with lower salts, many excrete large amounts of dilute urine, acquire salt from food and uptake in gills.
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what are osmoconformers, give example
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Osomconformers do not actively adjust internal osmolarity. They do not gain or lose water. Examples are all marine invertebrates.
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Where do tetrapods fit in these categories? osmoregulators and conformers
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Layer of dead keratinized skin in tetrapods.
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Why is nitrogen such a common waste product? Why is there a need to regulate nitrogenous waste?
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Nucleic acids and proteins broken down to make CHO’s or fats or to get energy. Ammonia is toxic.
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What is the advantage/disadvantage of ammonia Give example of animals that use each.
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4. Ammonia- soluble, tolerated only in low concentrations, animals that excrete NH3 must dilute it in lots of water. Example- freshwater fish, they loose ammonia across their gills and in urine from kidneys
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What is the advantage/disadvantage of urea Give example of animals that use each.
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Urea- combination of NH4 and CO2. Not toxic and is produced in the liver, can travel in the circulatory system until filtered out of the kidneys. Disadvantage is that energy is spent to make it. It is secreted by mammals, amphibians, sharks, and few fish.
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What is the advantage/disadvantage of uric acid Give examples of animals that use each.
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Uric acid- non toxic, insoluble, excreted as a semi solid paste, less water loss. Disadvantage is that requires most energy to make. Secreted by most reptiles, including birds.
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•What are the 4 key functions of an excretory system?
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1. Filtration- pressure filtering of body fluids.
Reabsorption- reclaiming valuable solutes. Secretion- adding toxins and other solutes from the body fluids to the filtrate. Excretion- removing the filtrate from the system. |
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Describe the mammalian excretory system
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1. Diverse, depends inn habitat and ancestors, variations on a tubular theme. Amount of waste produced depends on metabolic rate.
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Describe the anatomy of a kidney
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Centered on paired kidneys, also the principal site of water balance and salt regulation. Each is supplied with blood from the renal artery and drained by the renal vein. Urine exits the kidney by a duct called the ureter, which drains in to the bladder, stores urine until it exits the urethra. Kidneys have two distinct regions the outer renal cortex and the inner renal medulla. Nephron is the functional unit of excretion.
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what is the nephron
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Nephron is the functional unit of excretion. consists of a long tubule with a cup shaped area at one end (bowmans capsule) and a ball of caplliareies (golomerulus)that sits inside the capsule
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What are the two types of nephrons and how are they different? Do the relative concentrations of each differ amoung animals, if so, why?
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3. Coritcal nephron- located in the outer, renal cortex.
Juxtameduallary nephrons- 20% of human nephrons, have much longer tubules. Extend down into the renal medulla. Only mammals and birds have them. Enable production of urine that is hypersomotic to other body fluids. |
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What is the function of the proxmial tubule?
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Reabsorbs water and salt , HCO3 nutrients such as glucose. Sends these molecules into the interstitial fluid. Also secretes drugs and other poisons into the filtrate. Adjusts PH (controls secretion or reabsorption of H+, can activilty secrete ammonia).
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what is function of loop of henle? descending loop
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Descending limb- transport eplithelial here are freely permeable to water, but not salt. water exits b/c as the loop descends the intersitial fluid that baths it is increasnigly hypersomotic. The filtrate becomes incresingly condensed.
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what is function of loop of henle? ascending loop
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Transport epithelia here are permmeable to salt, but not water. as fluid ascends, sal diffuses out, these creates the hypersomotic environment of the medulla, the fluid become dilute and moves up.
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what is the function of distal tubule?
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epithelia here secretes varying amounts of potassium into the tubule, reabsorbs varying amount s og slat, regualtes H+ and HCO3 uptake.
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what is the function of the colecting duct?
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carries the filtrate to the renal pelvis. transport the epithelia 1. activiley absorb salt, regulates how much salt ends up in urine.
2. can reabsorb water, under hormonal control. The collecting duct traverses the gradient of osmolarity established in the kidney. |
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Upon what is the concentrating ability of the kidney dependent?
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The concentrating ability of the kidney is completely dependent on the precise arrangement of the tubules and collecting ducts. Form Fits Function.
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Describe the 2 solute model for the concentration of urine.
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. The 2 solutes contribute to the interstitial gradient of osmolarity in the medulla. NaCl is maintained by the loop of henle. Urea is maintained by the collecting duct. The filtrate makes 3 trips between the cortex and medulla. As filtrate flows down the collecting duct, pat the interstitial fluid of increasing osmolarity- more water moves out and concentrates the urine.
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What is ADH? Describe how it regulates urine volume.
How does alcohol affect this? |
Antidiuretic hormone- Increases the transport epithelia to water. 1. Alcohol disturbs water balance, inhibits the release of ADH, results in water loss though urine and dehydration.
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what is a kideney stone
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1. A mass that develops in the urinary tract (commonly calcium and phosphate or oxalate).
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how might kideny stones form, is genetics involved?
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Not completely understood, inherited forms, inability to make chemicals that inhibit formation, other metabolic disorders, infection.
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what is treatment for kideny stones
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most pass or surgery
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