Biology: Ch 44
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Created by:
loverlylaur on April 20, 2009
Description:
pg 928
pg 933-944
pg 939
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52 terms
Terms | Definitions |
|---|---|
 osmoregulation | regulation of solute and water concentrations in body fluids by organisms living in hyperosmotic, hypoosmotic, and terrestrial environments |
| excretion | disposal of nitrogen-containing waste products of metabolism |
| osmolarity | solute concentration expressed as molarity |
| isoosmotic | having the same osmolarity |
| hyperosmotic | solution with the greater concentration of solutes |
| hypoosmotic | solution with the lower concentration of solutes |
| osmoconformer | animal that does not actively adjust its internal osmolarity because it is isotonic with its environment |
| osmoregulator | animal whose body fluids have a different osmolarity than the environment and that must either discharge excess water if it lives in a hypotonic environment or take in water if it inhabits a hypertonic environment |
| stenohaline | referring to organisms that cannot tolerate substantial changes in external osmolarity |
| euryhaline | referring to organisms that can tolerate substantial changes in external osmolarity |
| anhydrobiosis | ability to survive in a dormant state when an organism's habitat dries up; also called cryptobiosis |
| transport epithelium | layer or layers of specialized epithelial cells that regulate solute movements |
| ammonia | small, very toxic molecule made up of three hydrogen atoms and one nitrogen atom; produced by nitrogen fixation and as a metabolic waste product of protein and nucleic acid metabolism |
| urea | soluble nitrogenous waste excreted by mammals, most adult amphibians, and many marine fishes and turtles; produced in the liver by a metabolic cycle that combines ammonia with carbon dioxide |
| uric acid | insoluble precipitate of nitrogenous waste excreted by land snails, insects, birds, and some reptiles |
| filtration | in the vertebrate kidney, the extraction of water and small solutes, including metabolic wastes, from the blood by the nephrons |
| filtrate | fluid extracted by the excretory system from the blood or body cavity. The excretory system produces urine from this after extracting valuable solutes from it and concentrating it |
| selective reabsorption | selective uptake of solutes from a filtrate of blood, coelomic fluid, or hemplymph in the excretory organs of animals |
| secretion | in the vertebrate kidney, the discharge of wastes from the blood into the filtrate from the nephron tubules |
| protonephridium | an excretory system, such as the flame-cell system of flatworms, consisting of a network of closed tubules having external openings called nephridiopores and lacking internal openings |
| metanephridium | in annelid worms, a type of excretory tubule with internal openings called nephrostomes that collect body fluids and external openings called nephridiopores |
| nephrostome | ciliated funnel surrounded a metanephridium |
| malpighian tubule | unique excretory organ of insects that empties into the digestive tract, removes nitrogenous wastes from the blood, and functions in osmoregulation |
| renal artery | blood vessel bringing blood to the kidney |
| renal vein | blood vessel draining the kidney |
| ureter | duct leading from the kidney to the urinary bladder |
| urinary bladder | pouch where urine is stored prior to elimination |
| urethra | tube that releases urine from the body near the vagina in females and through the penis in males; also serves in males as the exit tube for the reproductive system |
| renal cortex | outer portion of the vertebrate kidney |
| renal medulla | inner portion of the vertebrate kidney, beneath the renal cortex |
| nephron | tubular excretory unit of the vertebrate kidney |
| glomerulus | ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney |
| Bowman's capsule | cup-shaped receptacle in the vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood |
| filtration | occurs as blood pressure forces fluid from the blood in the glomerulus into the lumen of Bowman's capsule |
| proximal tubule | In the vertebrate kidney, the portion of a nephron immediately downstream from Bowman's capsule that conveys and helps refine filtrate |
| loop of Henle | the long hairpin turn, with a descending and ascending limb, of the renal tubule in the vertebrate kidney; functions in water and salt reabsorption |
| distal tubule | In the vertebrate kidney, the portion of a nephron that helps refine filtrate and empties it into a collecting duct |
| collecting duct | location in the kidney where filtrate from renal tubules is collected; the filtrate is now called urine |
| renal pelvis | funnel-shaped chamber that receives processed filtrate from the vertebrate kidney's collecting ducts and is drained by the ureter |
| cortical nephrons | nephrons located almost entirely in the renal cortex; have a reduced loop of Henle |
| juxtamedullary nephrons | nephrons with well-developed loops of Henle that extend deeply into the renal medulla |
| afferent arteriole | the blood vessel supplying a nephron |
| efferent arteriole | the blood vessel draining a nephron |
| peritubular capillaries | The network of tiny blood vessels that surrounds the proximal and distal tubules in the kidney |
| vasa recta | The capillary system that serves the loop of Henle |
| countercurrent multiplier systems | countercurrent system in which energy is expended in active transport to facilitate exchange of materials and create concentration gradients |
| antidiuretic hormone | hormone that is part of an elaborate feedback scheme that helps regulate the osmolarity of the blood |
| juxtaglomerular apparatus | specialized tissue located near the afferent arteriole that supplies blood to the glomerulus |
| angiotensin II | 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 |
| aldosterone | adrenal hormone that acts on the distal tubules of the kidney to stimulate the reabsorption of sodium (Na+) and the passive flow of water from the filtrate |
| renin-angiotensin-aldosterone system | part of a complex feedback circuit that normally partners with antidiuretic hormone in osmoregulation |
| atrial natriuertic factor | peptide hormone that opposes the renin-angiotensin-aldosterone system (RAAS) |
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