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Set 19 - Organ Systems - The Excretory System

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celine's version from 2018-03-17 19:24

Section

Question Answer
The excretory system filters waste compounds from the _________ and helps to maintain water balance (osmoregulation). Vessels transport blood to the _________, where wastes are filtered and water is returned to the circulatory system. Urine, consisting of waste compounds and some water, passes through the two _________ into the bladder, where it is stored until it can be eliminated through the _________.blood, kidneys, ureters, urethra
The task of the kidneys is to _________ while conserving water. This is accomplished by filtering a larger volume of water and solutes from the blood and then selectively reabsorbing water and other useful substances from the filtrate. While the first step requires little energy, the second relies on both _________ and _________ transport.eliminate waste, passive and active
The mammalian kidney is packed with functional units called _________.nephrons
Each nephron consists of a ball of capillaries called a _________, which is enclosed in one end of a long tube. The glomerulus and tube covering it form the _________. Extending from the Bowman’s capsule, the tube forms a hairpin at one point along its length, called the_________. The loop of Henle descends deeper into the center of the kidney and ascends back to the level of the Bowman’s capsule. Last, the tube feeds into a urine-collecting duct.glomerulus, Bowman’s capsule, loop of Henle
Water and small molecules pass from the _________ to the tube via _________ transport; cells and proteins are too large to pass into this filtrate. The filtrate contains glucose, salts, vitamins, and minerals that the body needs, as well as water that must be conserved. As the filtrate passes through the rest of the nephron, these substances are collected through both passive and active transport.glomerulus, passive transport
The_________ is key in the reabsorption of water and salt. This is accomplished by varying both the permeability of the membrane throughout the loop and the concentration of the fluid outside of the loop. As filtrate moves down the loop, it becomes more concentrated. However, the fluid surrounding the loop also increases in concentration, due to its location within the kidney. Therefore, water can still move out of the loop through passive transport. (Recall that water will move osmotically from an area of low solute concentration to an area of high solute concentration.)loop of Henle
The purpose of urine is to prevent a buildup of _________ from digested proteins and nucleic acids in the body. The simplest form of these nitrogen compounds is _________. However, ammonia is highly toxic and must be dissolved in large volumes of water for excretion. Mammals solve this problem by converting ammonia to a less toxic compound, _________. Urea can be excreted in a smaller volume of water.nitrogen compounds, ammonia (NH3), urea
Mammals produce urine that is _________ relative to the body’s fluids, a process that allows them to conserve water.hyperosmotic (more concentrated)
Desert mammals generally have longer _________, resulting in more concentrated urine.loops of Henle
Birds have short loops, but produce _________ instead of urea (which must be dissolved).uric acid (which is excreted as a paste)
Freshwater fishes, in contrast, can excrete large volumes of water; they _________ convert their ammonia to urea.do not
A long loop of Henle allows more water to be removed from the filtrate before it is excreted as urine. This causes the urine to be even more hyperosmotic and conserves water. This is an adaptation for an _________.arid environment
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