Biology 12 Notes

The Excretory frame Main functions of the excretory system be oto concentrate wastes and expel them from the body oto regulate precariouss and irrigate at heart the body Most metabolic wastes and toxins argon dissolved in the bodys internal surround, so the maintenance of the body fluids is essential for keeping the body free of waste products enabling it to function properly. liquidation in Incraniates and Non-mammaliam Vertebrates Single celled beings and simple multicellular organisms produce the same metabolic wastes and toxic compounds as much complex organism However wastes ar excreted directly from their cells since they arrest constant contact with the external environment. The greater challenge for simple organisms is affirming a fluid balance with their external environment An example is paramecium If they atomic number 18 not able to maintain a fluid balance they would continuously absorb pee from the environment and eventually burst oTo expel excess water sys tem, these protozoans have contractile vacuoles, which pump let out water to maintain osmotic balance More complex organisms face different challenges Some invertebrates such as earthworms have excretory organs called matanephridia that expel wastes from the body. oA fluid that serves as both interstitial fluid and bood known as hemolymph flows into a pair of metanphridia. oIons and wastes atomic number 18 reabsorbed from the hemolymph and secreted with water into a saclike organ called the bladder.General Biology Ii memorize Guide (Online Class)From there, the excess water and waste products are secreted to the external environment through a droning in the side of the worms body. Insects like grasshoppers excrete wastes uses a set of organs called malpighian tubules. oThe unappealing end of the organs are surrounded with hemolymph while open ends empty into intestines. oSubstances, such as uric acrid, and potassium and sodium ions are secreted into the tubules. oWhen assidui ty of the substances increases, water movies osmotically from the hemolymph into the tubule to orm a dilute waste resultant role and then it travels to the intestine of the insect where the cells reabsorb most of the K+ and Na+ venture into hemolymph oWater moves back and forrader using osmosis. oUric acid is left behind and casts crystals and is then expelled Terrestrial reptiles and most birds conserve water by excreting nitrogenous wastes in the form of an almost water free paste of uric acid crystals. oIts excreted into the cloaca (end of the digestive system) and removed from the body along with the digestive wastes oThe white substance in bird droppings is uric acid while the darker substance is feces. Those that live in or just about salt water take in large quantities of salt and rarely drink fresh water therefore they excrete excess salt through specialized salt glands in the head. oSalt glands remove salts from the relationship using active transport. oSalt is secret ed to the environment as a water solution oThe concentration of this is two to trinity times more than that in the body fluids. oSecretion exits through the nostril of birds and lizards and as salty tears from ocean turtles and crocodilians. The Human Excretory System All vertebrates used specialized tubules called uriniferous tubules to regulate water balance in the body and conduct excretion. They are located in the kidneys which are the major organs of excretory. The kidneys, ureters, bladder, and the urethra together desexualize up the human excretory system. Kidneys Play a critical role in oRemoving wastes oBalancing kin pH oMaintaining the bodys water balance Mammals have two kidneys on each side of the vertebrate column Human kidneys o150g oreceives 25% of cardiac output (1. 25 L/min. ) Blood is supplied through nephritic artery. Renal refers to the kidneys Kidney filters the wastes from the slant and clean blood exits the kidney through the renal veins. Outer layer of the kidney is called the renal cerebral cortex Inner layer is called the renal medulla A hollow cavity called the renal rose hip, connects the kidney to the ureter through which the peeing passes to the urinary bladder. Once the bladder is full, (300 to 400 mL of pee) the urine exits through the urethra Nephrons Each kidney contains about 1 000 000 nephrons They are the functional unit of a kidney Nephrons are differentiated into regions to perform a serioes of treads sensation end is the bowmans capsule which is a small folded structure that encircles a group of blood capillaries, the glomerulus in the cortex The glomerulus performs the first step of filtration of blood to form urine Blood is supplied to the glomerulus by the afferent arteriole and then after being filtered it exits via efferent arteriole and then called into interlock capillaries called the peritubular capillaries. They carry the urine and allow for reabsorption of essential ions and minerals back into bl oodstream. First Steps of Filtration Components of unfiltered blood pass from glomerulus into the bowmans capsule and enter a proximal problematic tubule which lies in the cortex The tubule descends into the medulla and forms a u shaped structure called loop of Henle before rising again to form a distal convoluted tubule The distal tubule drains the urine into collecting ducts that lead to renal coxa and then it is emptied through the ureter to the bladder The shaping of Urine Different sections of the nephron have specialized functions in the formation of urine and conservation of water Urine is hypoosmotic in ammals meaning that water tends to move from urine into the body fluids this is an adaptation that conserves water Three features of nephrons 1. Conserve nutrients and water 2. Balance salts 3. Concentrate wastes for excretion Urine formation is the result of trio interrelated processes oFiltration occurs when the body fluids move from the blood into the bowmans capsule o Reabsorption transfers essential solutes and water from the nephrons back into the blood oSecretion transfers essential solutes and water from the nephron back into the blood Filtration Urine formation begins in the bowmans capsule The cells of the bowmans capsule and the capillaries that surround it have a selectively permeable tissue layer that are wide enough to admit water, ions, small nutrient molecules ( glucose and amino acids), and nitrogenous waste molecules. The high twitch of blood in the glomerule drives the fuid that contrains these molecules and ions into the capsule. Blood cells, platelets and plasma proteins are too large therefore they are retain in capillaries Fluid enters the bowmans capsule contains only small molecules This is known as filtrationReabsorption The filtered fluid contains urea, water, ions, and former(a) molecules that are in the same concentrations as they are in the blood plasma. The fluid enters the proximal convoluted tubule where reabsorptio n occurs Water, ions, and nutrients are transferred back via passive and active transport Speclizied ion pumps transport postassium sodium and chlorine from the stress into the fluid surrounding the tubule. Active transport proteins in the walls of tubule reabsorb amino acids glucose and other nutrients urea and other unwanted compounds are not absorbed Microvilli in the inner walls increases surface area that is forthcoming for reabsorption of solutes All of the Reabsorption processes make the filtrate hypoosmotic to the interstitial fluid, this causes water to flow out of the tubule and into interstitial fluid by osmosis The movement of water is facilitated by tissue layer proteins called aquaporins or water channels They fancy that the maximum amount of water is removed from the tubule during reabsorption The remaining fluid has a high concentration of urea and other wastes moves into the loop of henle. More water is absorbed Then as it goes up the salary increase the Na an d Cl are out of the tubule Towards the top of the ascending segment ions are moved out by active transport Thus as the fluid flows through the loop og henle water nutrients and ions are conserved and returned to body fluids and urea and other nitrogenous wastes have become concentrated in the filtrate The distal convoluted tubule removes additional water and salts Ore ions and solutes more out of the fluid than into it Amount of urea and other nitrogenous wastes remain the same. Concentrated urea and wastes flow into the collecting ducts which concentrated the urine more compendium ducts decend from cortex through medulla Permeable to water but not to salt ions Concentration of solutes increases with discretion as fluid decends into the medulla Secretion Removal of waste products from blood and fluids Wastes are secreted at several(prenominal) points Some wastes are secreted rom interstitial fluid into proximal convoluted tubule H+ ions are actively secreted and the products of de toxified poisons from liver are passively secreted Ammonia secreted into the tubule Secretion of H+ ions into the filtrate helps to balance the acidity that is generated invariably hormones triggered by changes in salt concentrations vary the amounts of K+ and H+ secreted if acidity rises the excess H+ ions are secreted into collecting ducts and excreted when urine reaches the bottom of the collecting ducts it is roughly 4x as concentrate urine flows into the renal pelvis through the ureters and into the bladder Kidney Disease must function properly to maintain water balance and homeostasis they are affected by disease or injury in other parts of the body because in contact with blood and wastes from everywhere break down of kidney can impact any organ urinalysis contents of urine are analyzed for traces of metabolites and molecules that result from disease diabetes mellitus is caused by insufficient secretion of insulin causes blood sugar level to rise it can be detected in urina lysis kidney stone re an affliction of E. S. caused by the buildup of mineral solutes such as oxalates phosphates and carbonates. These combine with calcium to produce crystals that accumulate and form stones the can cause pain because they are sharp stones Broken up by high push sound waves in process called extracorporeal shoch wave lithotripsy ESWL Also can be removed by uteroscope or surgery Loss of kidney function requires the use of dialysis In dialysis blood is run through filtering machine and the harm of kidney function results to need of kidney transplant ? Definitions 1. Contractile Vacuole A structure in a single-celled organism that maintains osmotic equilibrium by pumping excess fluid out of the cell. . Metanephridium An excretory organ in both(prenominal) invertebrates that is used to reabsorb and eliminate wastes 3. Malpighian Tubule the main organ of exretion in insects, which is used to carry wastes to the intestines 4. Nephron the petite functional unit of the kidney that filters wastes from the blood 5. Bowmans Capsule a small folded structure in the human kidney that encircles the glomerulus 6. Glomerulus a network of capillaries within the Bowmans capsule that perform the first step in the filtration of blood 7.Afferent arteriole A vessel that supplies blood to the nephrons in the human kidneysRead also science lab 2 Biology8. Efferent arteriole A vessel that carries blood from the nephrons in the human kidneys 9. Peritubular Capillaries a net of capillaries in the nephrons that reabsorb essential ions and minerals from filtered blood 10. Proximal convoluted tubule the duct portion of a nephron that connects the bowmans capsule to the loop of Henle 11. Loop of Henle the U-shaped part of the duct that connects the proximal convoluted tubule to the distal convoluted tubule 12.Distal convoluted tubule the duct portion of a nephron that connects the loop of Henle to the ducts that lead to the renal pelvis 13. Filtration the process in wh ich blood and fluid pass through a selectively permeable membrane 14. Reabsorption the transfer of water, ions, and nutrients back to the interstitial fluid via passive and active transport 15. Aquaporin a membrane protein that passively transports water molecules 16. Secretion the removal of waste materials from the blood and intercellular fluid