A3.4.2.Kidney - Belle Vernon Area School District



Name __________________________Spotlight on the Kidney – 40 Informal & 3 Formal for completing dissection (Additional 2 formal point bonus opportunity)IntroductionYou have probably heard urban legends about unsuspecting victims having a kidney stolen. You have most likely heard heartwarming stories of men and women donating a kidney to a dying loved one. But why are these two, bean-shaped organs so special and so valuable? We always hear about the wonders of the heart and the brain – how these two remarkable organs support life. But what about the kidney? Let’s give another amazing organ its moment in the spotlight. The kidneys are reddish-brown organs about the size of a bar of soap. Located on the posterior side of your body on either side of the spinal cord, these organs are responsible for producing urine and carrying liquid waste materials out of your body. The kidneys are made of millions of tiny little filters called nephrons. Like tiny sieves, these structures control which substances remain in your blood and which are filtered out in your urine. Each nephron receives a stream of blood that is delivered by the renal artery and returned to the body by the renal vein. But a lot happens to the blood along this path. Materials we need to survive are absorbed back into the blood while wastes are removed in urine. Without kidneys, the volume of your blood and the amount of ions, water, and waste in your system can not reach a balance.In this activity, you will take a look inside a kidney. You will work with a partner to dissect and explore the structures of the kidney and to investigate the location of nephrons, the specialized cells in the kidney that produce urine. As you complete your dissection, you will draw a map of the kidney that outlines the basic path of urine formation and identifies key structures. ProcedureWith your partner, use the Internet to find a clear picture or diagram of the inside of the kidney. Locate a simple diagram of the nephron and draw and label in the space below. Think about how these tiny units are organized inside of the kidney.A kidney cell:Research the structure and function of the following structures as well as their location in/on the kidney. Items marked with a * are specific parts of the nephron. You will not be able to see these exact structures in your dissection, but you should research where in the kidney (the pelvis, medulla or cortex) these parts of the nephron would be located. Fill in the table below to organize your information: Structure Function Location Renal PelvisThe major function of the renal pelvis is to act as a funnel for urine flowing to the ureter. Renal MedullaThe renal medulla contains the structures of the nephrons responsible for maintaining the salt and water balance of the blood.Innermost part of the kidney Renal CortexThe main function of a renal cortex is to filter blood and remove unwanted substances out of the body. Medullary PyramidThe pyramids consist mainly of tubules that transport urine from the cortical, or outer, part of the kidney, where urine is produced, to the calyces, or cup-shaped cavities in which urine collects before it passes through the ureter to the bladder. The point of each pyramid, called the papilla, projects into a calyx. UreterConnect the kidneys to the bladder CalyxUrine formed in the kidney passes through a renal papilla at the apex into the minor calyx; two or three minor calyces converge to form a major calyx, through which urine passes before continuing through the renal pelvis into the ureter. Renal CapsuleThe renal capsule is a tough fibrous layer surrounding the kidney and covered in a thick layer of perinephric adipose tissue. It provides some protection from trauma and damage.Site of the Glomerulus and Bowman’s capsule*Bowman's capsule is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac.Site of Collecting Ducts andLoop of Henle*The distal convoluted tubule and collecting duct have Na+ and water permeability regulated by the hormones aldosterone, antidiuretic hormone, and atrial natriuretic peptide. ... Since water is freely absorbed from the descending limb of the loop of Henle, filtrate concentration increases and water is reabsorbed. Locations are seen in the following diagram:Put on safety equipment. (Gloves, goggles, apron is optional) Obtain a pig kidney from your teacher and place it in a dissecting tray. Observe the external anatomy of the organ. Using a very sharp scalpel, carefully cut the kidney open lengthwise, like you were opening a book – leaving the two sides attached. This may be difficult – be careful and cut slowly. Explore the internal anatomy of the kidney and begin to connect specific structures with their role in the production of urine. Work with your partner to locate each of the listed structures.As you identify key structures, discuss and research the questions listed below. Write your answers in the space provided beneath each question. In which sections or section of the kidney is the urine formed?MedullaWhat section of the kidney collects the urine?Renal PelvisHow does the urine move from the kidney out of the body?Kidney Ureter Bladder UrethraIn which main regions of the kidney are the glomerulus and the Bowman’s capsule located?CortexIn which main regions of the kidney are the collecting ducts and the loop of Henle located?MedullaYou may want to use your cell phones or iPads to take pictures of your kidney. Make a record of your work. On a separate sheet of paper or poster board, draw a large “map” of your kidney. Draw and identify key structures from your dissection. Your map should allow a traveler to follow the path of blood entering the kidney and to observe and appreciate key landmarks along the way. Use arrows to show the path of urine formation and its departure from the body. Create road signs along the way that label key structures and provide a brief description of function. At one point in you map, show a magnified (zoom in) section highlighting the nephron. Identity key structures of the nephron. Do not worry about the function of each section at this point. You will study what happens to molecules and fluids across the nephron in the next activity.*Optional Bonus Opportunity: 2 Formal Bonus points (this is a quiz question and equivalent to nearly 7% on a quiz)- Create your drawing and map as described in #s 10 & 11 on poster board to be hung in room or in hallway- Neatly, color code everything and provide keys and descriptions where necessary- Also provide descriptions of the functions of each part of the nephron; Will be due at the end of the next activity after we have learned these; but think ahead and leave spaces for thisConclusion QuestionsOrder the following kidney structures to show the path of urine formation and its departure from the body: renal pelvis, glomerulus, ureter, renal artery, bladder, renal tubules (Loop of Henle and collecting ducts), calyx, urethra, Bowman’s capsule. Renal artery glomerulus bowman's capsule renal tubules (Loop of Henle and Collecting Ducts) calyx renal pelvis urethraHow will other body systems be affected if the kidneys begin to shut down? Explain your answer. All body systems are affected because the built up of toxins and waste is harmful. Can cause heart failure, shortened life span of red blood cells, nerve cell degeneration, as well as the calcification of your lungs.Neurons will not be able to carry impulses properly.Cells will become “sick” and function at a lower level or shut down all together.If you stretched the nephrons in a kidney from end to end, they would be over 40 miles long! Explain how this structure directly relates to the function of the kidney.Lots of surface area for absorption and excretion. (please refer to diagram in #11 to note which substances are absorbed and excreted in each location in a nephron)Suggest reasons why we can live with one kidney, but we are born with two.We actually do use both our kidneys to the fullest; two are needed to handle the volume blood the is constantly being filtered. However, one will compensate if the other fails so that if one fails we have a backup. If only one kidney is present, that kidney can adjust to filter as much as two kidneys would normally. In such a situation, the nephrons compensate individually by increasing in size-a process known as hypertrophy-to handle the extra load. This happens with no adverse effects, even over years! In fact, if one functional kidney is missing from birth, the other kidney can grow to reach a size similar to the combined weight of two kidneys!This also makes kidney donation possible with a living donor. Evolutionarily speaking, this helps the human species survive. ................
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