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Genzyme-lesson.indd

Active Transport in Kidneys The kinetic theory of matter, sometimes cal ed the particle Active transport in the kidneys How do kidneys function? theory, is one of the most important foundations of modern The kidneys are multifunctional organs. One of their primary roles is in The kidneys operate by fi ltration and selective reabsorption. Blood is science. A theory is a hypothesis that through extensive excretion as part of homeostasis. Homeostasis is the maintenance of fi ltered as it passes through collections of capillaries called glomeruli. testing has produced experimental y reproducible results the internal environment of the body in a suitable state for effi cient Blood components smaller than the pores in these capillaries pass tissue cel metabolism. The main function of homeostasis is to keep the into microscopic tubules which lead to the pelvis of the kidney and on and therefore taken to be a reasonable explanation of blood in good condition. Every organ has a role in homeostasis, not just eventually to the bladder. The components are all the soluble components observations. In this lesson we wil look at how the kinetic the kidneys.
of blood plasma, except proteins, and water. Among the ‘escapees' are theory of matter has brought about advances in the treatment lots of useful substances such as glucose, amino acids, 99% of the water Genzyme is one of the worlds leading biotechnology companies of kidney failure. Excretion is the elimination of metabolic wastes from the body. A and about 90% of the salt. The water returns by osmosis and all the other with nearly 8500 employees worldwide. The company's goal metabolic waste is a substance – produced by the chemical activity useful substances are returned by active transport. is to make a major positive impact on the lives of people with of our cells – that is in excess, has no function or is toxic. The kidneys also eliminate other substances that have been absorbed into the body As we want these ‘good escapees' to return to the blood, they are What makes a solid, a liquid or a gas? debilitating diseases. The company designs and produces from food and drink, e.g. medicines, excess of water, salts and water- specifi cally selected – the wastes and excess will not be hindered in their innovative solutions for major unmet medical needs of patients According to the kinetic theory of matter, the movement of particles of a soluble vitamins. escape from the body; they are ‘deselected' and so are excreted. with genetic and chronic debilitating diseases. substance determines the state of that substance – whether it is a solid, The kidneys also maintain the correct concentration of the blood by a The major excreted substances are urea and water but there are over 200 Genzyme was founded in 1981 and has grown from a small start- a liquid or a gas. The particles of a solid vibrate on the spot, whereas process called osmoregulation and they also keep the pH at 7.4.
other substances eliminated by the kidneys from the body. Therefore, if up business to a diversifi ed enterprise with turnover in excess in a liquid the particles are speedily and randomly sliding across our kidneys fail, the internal environment of our body will deteriorate, as of $3 billion. Since its foundation, Genzyme has introduced a each other. In a gas, particles move in a very rapid, random motion the blood becomes polluted with unwanted materials.
number of breakthrough treatments in several areas of medicine, at relatively great distances from each other. This rapid movement of which have provided hope to patients throughout the world who liquid or gas particles provides an explanation for diffusion, osmosis and previously had no viable treatment options.
Brownian motion. How is kidney failure treated? Genzyme Ireland was established in Waterford in 2001. The Kidney failure, temporary or permanent, is treated by dialysis. In Waterford facility supplies the global market with Renagel tablets, How does molecular motion cause haemodialysis, blood is pumped from the body through a machine that a product used in the treatment of kidney dialysis patients in over has an array of semipermeable membranes. These membranes separate 40 countries worldwide. Renagel is a calcium-free, metal-free, the blood from a liquid, dialysate, which has the same composition as phosphate binder that reduces phosphorus levels in patients The movement of particles of a normal body fl uids. Wastes and excess of water are removed from with end stage renal disease who are on hemodialysis.
liquid or a gas explains diffusion the blood by fi ltration, as the blood and the dialysate fl ow in opposite and osmosis. Diffusion is the In 2005, Genzyme expanded its Manufacturing Process Research directions over these semipermeable membranes (counterfl ow).
passive movement of a specifi c and Development facility at Waterford to support clinical trial In certain cases of poisoning and drug overdose, dialysis can be used to substance in a fl uid from where work. This development facility allows Genzyme to expand its remove the life-threatening chemicals.
it is in higher concentration to capabilities to produce clinical supplies in sachet and liquid form, where it is in lower concentration. on top of the current tablet form.
Passive means that no external The Waterford site also has a facility where biological proteins energy has to be supplied to and enzymes are formulated, fi lled and fi nished. These dosage bring about the movement – the Blood enters the
forms are sterile and are fi lled into vials that are administered as substance spreads due to the dialyzer from your body.
small volume parenterals. The products processed in this plant Fig. 1 Random movement movement of its particles.
at Waterford are focused on treatment of rare genetic disorders, of water molecules Osmosis is the diffusion of water Dialysate is a special
transplant and immune diseases.
Fig. 2 Glomerulus in the kidney through a semipermeable membrane. A semipermeable membrane fluid that takes waste allows the small water molecules to pass through but holds back larger from the blood.
To fi nd our more about the work of Genzyme visit particles. As a result, water can pass through a barrier from an area of www.genzyme.com or www.sta.ie high water concentration (and lower solute concentration) to the region A membrane keeps
of lower water concentration (and higher solute concentration). Cell blood and dialysate membranes are semipermeable; they have ultramicroscopic pores, so from mixing, but lets small that only the water molecules can pass through in single fi le, but waste pass through. they do so at about a billion per second through each pore.
Waste moves
What is active transport? Active transport systems in cell membranes allow the movement of other substances actively against the concentration gradient. Using cellular the dialysate.
energy from aerobic respiration, molecules and ions move across membranes from regions of where they are in low concentration into Cleansed blood
regions of higher concentration. Every living cell of your body uses returns to your body.
active transport to maintain special ion concentrations on opposite sides of the cell membrane. Fig. 3 Structure of a glomerulus Fig. 4 Dialysis showing contrafl ow system Fig. 5 Patient undergoing dialysis Active Transport in Kidneys Syllabus Reference Examination Questions Leaving Certifi cate Biology Test a sample of the beaker water for reducing sugar (glucose), using • There are approximately 4000 to 11,000 white blood cel s in each 2006 Leaving Certifi cate Higher Level Unit 2.2.6 - Movement through Cel Membranes Benedict's reagent. Using your knowledge of the human vascular system and excretory Unit 3.4.6 – The Excretory System in the Humans Record any changes such as size, stiffness, in the dialysis tubing.
• We each have about 5 litres of blood, 55% of which is an aqueous systems to answer the following.
Unit H3.4.8 – The Nephron as a Unit of Kidney Function a) Did glucose diffuse out of the dialysis tube? Explain your answer.
solution cal ed plasma.
Explain the terms, plasma, glomerular fi ltrate.
b) Did starch diffuse out of the dialysis tube? Explain your answer.
• Urine consists of 95% water and 5% solutes.
Junior Certifi cate Science c) Is the dialysis tubing semipermeable? Explain your answer.
(i) Explain why red blood cells are normally absent from the glomerular Section 1A6 – Excretion • The yel ow colour of urine is due to urochrome, a chemical made d) Did water move by osmosis into the dialysis tube? Section 2A1 – Materials during the breakdown of haemoglobin when red blood cel s are Explain your answer.
(ii) The concentration of glucose is the same in plasma and glomerular being destroyed.
fi ltrate. Why is this? Investigative Activities • Urine is slightly acidic, having a pH of 6. A vegetarian diet leads to an (iii) Why is glucose normally absent from urine? Learning Objectives 1. Peel a fresh potato. Cut 18 ‘chips' from the potato – they do not have alkaline urine.
to be the same length. Make sure that the ends of the chips are cut (iv) Following a period of heavy exercise, an athlete may produce only a • The ‘fi lter' in our kidneys is 100 km long – the total length of the small volume of concentrated urine. Explain this observation and give On completing this lesson the student should be able to: at right angles. Divide the chips into three groups, each group of six glomerular capil aries.
chips. Then lay the chips of each group in a straight line, and measure an account of the process that concentrates the urine.
• Outline the kinetic theory of matter • The formation of kidney stones is an example of the total length of each.
crystallisation. To • Defi ne diffusion, osmosis, active transport and homeostasis avoid this problem, drinking adequately helps to avoid this problem, Place one group of chips in very salty (20% table salt) water. Place 2005 Leaving Certifi cate Ordinary Level. by keeping the urine dilute.
• Distinguish between passive and active transport the second group in ‘normal' saline solution (0.9% salt), and put the The diagram shows a section through a human • Suitably dilute urine is clear and almost without colour. third group in tap water. After 15 minutes, lay the chips of each group • Understand the essential features of a semipermeable membrane end to end and in a line. Again measure the total length of each group. • The fi rst successful human kidney transplant was done in 1954, over (i) Name A, B, C, D.
• Outline the many roles of the kidneys in homeostasis Compare these lengths to their original lengths. Try to explain the 50 years ago.
C (ii) To what structure does D connect the kidney? • Outline the two major processes in the formation of urine difference in the results between the three groups.
(iii) Filtration is an essential process in the • Outline how a dialyser or ‘artifi cial kidney' works.
2. Obtain young leaves from Elodea (i.e. pond weed). Make a slide of one of the leaves in water, and view under the microscope. Draw a label ed formation of urine. In what part does it take Biographical Notes diagram of three neighbouring cel s. Reabsorption of useful substances takes place in the kidney. In Marcello Malpighi 1628 – 1694 Now prepare another slide of a leaf in strong salt (20%) solution, General Learning Points and as before, view under the microscope. Draw a diagram of three what part does this occur? An Italian doctor, Malphigi was the fi rst scientist to use a microscope to neighbouring cel s. Try to explain the difference in appearance of the Name an excretory substance present in urine.
study animal and plant structures. His pioneering work resulted in him • The state of matter of a substance depends on the type of movement two drawings. (This procedure may also be carried out with onion producing the fi rst microscopic description of kidney structure, and many Name an excretory organ in the human body other than the kidney. of the particles in the substance.
microscopic anatomical structures, e.g., the Malpighian corpuscles in the Name a substance, other than the one you named in (v), excreted kidneys and spleen, are named after him. • Diffusion takes place in fl uids, i.e. liquids and gases.
3. Obtain the ‘stems' (i.e. fl ower stalks) of dandelions. Cut the stalks into • Barriers with tiny holes can be used to separate substances by 5 cm lengths. Split each stalk half way down its length. Immerse the fi ltration.
stalks for 15 minutes in tap water, and in different strength salt solutions. 2005 Leaving Certifi cate Ordinary Level Sir William Bowman 1816 – 1892 Then measure the distance between the tips of the split ends. Try to • Energy must be added to a system to move materials against their What is osmosis? A British surgeon, histologist and anatomist, Sir William Bowman is best explain the difference in degrees of curvature of the ‘stems' in the What is a selectively permeable (semipermeable) membrane? known for his work ‘On the structure and use of the Malpighian bodies of the kidneys', published in 1842, in which he identifi ed a key • Cel membranes al ow free passive movement of some material Draw a labelled diagram of the apparatus that you used to demonstrate component of the nephron of the kidney, which later became known as through them, but other materials can only pass through if ‘selected'.
Bowman's Capsule. • The energy for active transport across membranes comes from Describe how you carried out the experiment to demonstrate osmosis.
How were you able to tell that osmosis had taken place? Read more about other famous scientists at www.sta.ie • By keeping the blood in good condition, the immediate environment Indicate whether the following are true (T) or false (F) by For further examples of past paper questions of our al our living cel s is automatical y suitable for their effi cient drawing a circle around T or F.
operation. By taking care of one tissue (the blood), al the tissues are taken care of.
(a) The kinetic theory of matter is often cal ed the particle theory. T F(b) Solids and liquids are fl uids. • Our kidneys play a vital role in keeping our blood in good condition.
(c) Diffusion is an active process. • By knowing how the kidneys work, it has been possible to build Can you recall the meaning of these terms? Reviewing the (d) Osmosis is a particular example of diffusion. ‘artifi cial kidneys' to maintain the health and extend the lifespan of terminology is a powerful aid for recall and retention.
patients with failed or failing kidneys.
(e) Only special cel s in our kidneys carry out active transport. • Urea was the fi rst organic substance to be synthesised from simple (f) Homeostasis is keeping our internal environment Kinetic theory of matter; particle theory; hypothesis; solid; liquid; constantly good. • At room temperature the particles of water move at about 100 metres gas; passive; semipermeable membrane; Ultramicroscopic; active Practical Activities (g) Getting rid of undigested food from the gut is cal ed excretion. T F per second and col ide with their neighbours about two bil ion times a transport; concentration gradient; aerobic respiration; kidneys; (h) Filtration and selective reabsorption are how the second. In water vapour, molecules in air move at about 500 metres organs; excretion; homeostasis; cel metabolism; metabolic Mandatory Practical Activity - To demonstrate osmosis kidneys excrete. wastes; osmoregulation; pH; fi ltration; selective reabsorpiton; Soak dialysis tubing (Visking tubing) in warm water for fi ve minutes. Tie a (i) Filtration occurs at the glomerular blood capil aries. • One mil imetre cubed (1 mm3) of water consists of 3 x 1019 glomeruli; urea; kidney failure; dialysis; haemodialysis; dialysate; knot at one end of the dialysis tubing. Open the tubing at the free end and (j) Excreted materials are those deselected for reabsorption. fi l to within 5 cm of the top with a starch-glucose solution. Tie a knot at the hyperphosphatemia; molecules; mil imetre cubed; urochrome; (k) Kidney failure leads to pol ution of our internal environment. • The number of red blood cel s varies between about four and six free end. Place the tube into a beaker of tap water for 20 minutes. haemoglobin; crystal isation.
(l) Dialysis is a method of treatment for kidney failure. mil ion per mm3 of blood.
Test a sample of the beaker water for starch, using iodine solution. Check the Glossary of Terms for this lesson at www.sta.ie Check your answers to these questions on www.sta.ie

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