Biology 2 Notes Chapter 41
Biology 2 Notes Chapter 41 BIOL 1040
Popular in General Biology II
Popular in Biology
This 4 page Class Notes was uploaded by Courtney Luber on Thursday February 25, 2016. The Class Notes belongs to BIOL 1040 at Clemson University taught by Dr. William Surver in Fall 2016. Since its upload, it has received 22 views. For similar materials see General Biology II in Biology at Clemson University.
Reviews for Biology 2 Notes Chapter 41
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/25/16
Osmotic Regulation and Excretion Water/Salt Balance o Osmoregulation is the homeostatic control of the uptake and loss of water and solutes such as salt and other ions o Osmosis is the process utilized o REVIEW OSMOSIS; MEMBRANE TRANSPORT; SOLUTE CONCENTRATION; HYPERTONIC, HYPOTONIC, ISOTONIC o Hypertonic solution—concentration is greater outside cell than inside o Isotonic—concentration is the same inside & outside of cell o Hypotonic solution—concentration is greater inside cell than outside o Osmoconformers Have body fluids with a solute concentration equal to that of seawater Face no serious challenges in water balance Many marine animals o Osomoregulators Have body fluids whose solute concentrations differ from that of their environment Must actively regulate water movement Include: Many land animals Freshwater animals Marine vertebrates such as sharks o Saltwater fish – live in a hypertonic environment Have a water conservation problem Lose water by osmosis Drink seawater Use their gills and kidneys to excrete excess salt o Freshwater fish – live in a hypotonic environment Gain water by osmosis (mainly through gills) Lose salt by diffusion to the more dilute environment Take in salt through their gills and in food Excrete excess water in dilute urine o Land animals Face risk of dehydration Lose water by evaporation and waste disposal How can we reclaim water & substances we lose? Gain water by drinking and eating and cellular respiration Conserve water by reproductive adaptations, behavior adaptations, waterproof skin, and efficient kidneys o The urinary system Forms and excretes urine Regulates the amount of water and solutes in body fluids o In humans the kidneys are the main processing centers of the urinary system Highly associated with the circulatory system Pair of organs toward the back of the body o Our kidneys extract about 180 L of fluid called filtrate that consists of Water Urea A number of valuable solutes including glucose, amino acids, ions, and vitamins o Our kidneys refine the filtrate Concentrating the urea Recycling most of the water and useful solutes to the blood o In a typical day we excrete only about 1.5 L of urine, the refined filtrate containing wastes o Water conservation is one of the primary functions of the kidneys o During filtration the pressure of the blood forces water and other small molecules through a capillary wall in the start of the kidney tubule forming filtrate Materials are forced into the kidney o Urine the final product of filtration leaves each kidney through a duct called a ureter o Both ureters drain into the urinary bladder o During urination urine is expelled from the bladder through a tube called the urethra o Blood enters the nephron through the renal artery and flows into a bed of capillaries called the glomerulus o Nephron—the functional unit of the kidney. The glomerulus and convoluted tubules are located in the kidney cortex, while collecting ducts are located in the pyramids of the medulla Loop of Henle (ascending) reabsorbs Na and Cl from the filtrate into the interstitial fluid (descending) aquaporins allow water to pass from the filtrate into the interstitial fluid Distal—further away from something Proximal—closer to something o Glomerulus doesn’t select what gets into the nephrons; up to the kidneys o The filtrate forced into Bowman’s capsule flows into the nephron tubule where it is refined o Two processes refine the filtrate Reabsorption water and valuable solutes such as glucose, salt, and amino acids are reclaimed from the filtrate Secretion excess H+ and toxins are added to the filtrate o The Loop of Henle acts as a countercurrent multiplier that uses energy to create concentration gradients. The descending limb is water permeable. Water flows from the filtrate to the interstitial fluid, so osmolality inside the limb increases as it descends into the renal medulla. At the bottom, the osmolality is higher inside the loop than in the interstitial fluid. Thus, as filtrate enters the ascending limb, Na and - Cl ions exit through ion channels present in the cell membrane. Further up, Na is actively transported out of the filtrate and Cl follows. Osmolarity is given in units of milliosmoles per liter (mOsm/L). o nephron filtration, secretion, reabsorption increasing concentration gradient towards bottom of nephron distal tubule—sodium chloride is actively transported out of the filtrate o Excretion urine is expelled o Nitrogenous waste a toxic by-product of metabolism o Nitrogenous wastes are toxic breakdown products of proteins and nucleic acids o Animals dispose of nitrogenous wastes indifferent ways o An animal disposes of metabolic wastes by converting them to chemicals that can be extracted through an opening in the body o The type of waste product produced and how the animal disposes of it depends on Adaptations Habitat o Ammonia—type of nitrogenous waste Too toxic to be stored in the body (most toxic waste) Highly soluble in water Easily disposed by aquatic animals o Urea Produced in the vertebrate liver by combining ammonia and carbon dioxide Less toxic than ammonia A soluble form of nitrogenous waste o Uric acid Excreted by some land animals (birds, insects, land snails and many reptiles Relatively nontoxic Water –insoluble Excreted as a semisolid paste thus conserving water More energy expensive to produce o Hormones regulate the urinary system Antidiuretic hormone (ADH) regulates the amount of water excreted by the kidneys by signaling nephrons to reabsorb water from the filtrate returning it to the blood and decreasing the amount of water excreted o Diuretics Inhibit the release of ADH Alcohol and caffeine
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'