A Spot Question What are 7 Characteristics of Living things? (Hint: Mrs Gren)

Full Name: Hoai Thu Giang Lecturer’s Name: Richard Llopis Garcia School: City of Bath College Excretion and The Kidneys Coursework One: Presentation

Outline Excretion What is Excretion? What are Human Excretory organs? What is Deamination? The Kidneys The Location, Functions and Structure of the Kidneys Nephrons

What is excretion? Chemical reactions in your body cells produce waste. This waste includes CO 2 and Urea. This chemical waste must be removed. Otherwise it becomes a toxin.

remove excess CO 2 removes excess water, salt, urea and uric acid produces urea and uric acid as a by-product of the breakdown of proteins filter the blood to form urine, which is excess water, salt, urea and uric acid Human Excretory Organs j Lungs: Skin: Liver: Kidneys:

What is Deamination? The body cannot store excess amino acids. So they are broken down in the liver to make a waste chemical called urea.  Deamination The urea is taken from the liver to the kidneys. The kidneys excrete the urea

(i ) Why are protein molecules considered to be polymers? (ii) Name process C

Kidneys Location of the Kidneys Are bean-shaped Located against the dorsal body wall on either side of the spine

Excretion – the removal of toxic Nitrogenous waste products from the blood, including urea and creatine Homeostasis – the kidneys regulate the water content, ion composition and pH of the body fluids. Functions of the Kidneys

Structure of the Kidneys Each kidney contains millions of tiny tubes called nephrons, where blood is filtered and urine is formed. Nephrons are responsible for urine formation by 3 main processes: 1. Ultrafiltration 2. Selective Reabsorption 3. Tubular Secretion

Nephron

The glomerulus is enclosed by the Bowman’s capsule. Blood flowing through the glomerulus exerts pressure. Only small molecules pass out of the glomerulus and into the nephron. 1. Ultrafiltration

Ultrafiltration in the capillary and renal capsule membranes 1. Pores in the capillary wall – squamous endothelium. 2. A basement membrane made up of collagen fibres and glycoprotein. 3. A specialised epithelium of the renal capsule, made up of cells called podocytes.

2. Selective Reabsorption The wall of this tubule is made of epithelium with microvilli facing the filtrate to increase the surface area. Glucose and salts are needed by the body. They are reabsorbed by active transport. Water is reabsorbed by osmosis. Some urea is reabsorbed to the blood by diffusion.

Secretion Certain substances are secreted by actively transported from the blood into the filtrate through the distal convoluted tubule. Secretion is regulated by hormones. Substances secreted are Hydrogen ions, Potassium ions and Ammonia.

(a)Name the major artery of which A is a branch (b)Name the process that takes place in the part of the nephron labelled B (c)Give the letter or letters which represent the region or regions of glucose reabsorption

In the first convoluted tubule of a human nephron, sodium ions, glucose molecules and water molecules are reabsorbed into the blood plasma. Figure 3 illustrates how these substances are reabsorbed. i) Explain the large number of the organelles labelled X in these cells ii) Explain the importance of the structures labelled Y on the epithelial cells

Further practice Exercises file:///F:/Biology%20CD%20- %20UoB/chapter44/deluxe.html Video clip for summary ZaNXNroVY

Bibliography Gareth Williams, 2002, Nelson Thornes, “Biology for you” Book. Ben Aldiss, 2005, Nelson Thornes, “A2 Level Biology”. Richard Llopis Garcia, 2013, City of Bath College, Material. John parker and Ian Honeysett, 2005, “Revise Biology”, Letts educational, chapter 3 No author, Blog, Illustration for Excretory System, accessed 10/2/ No author, healthcare, 2007, “What Happens When Your Kidneys Slow Down or Stop Working” when-your-kidneys-slow-down-or-stop-working, accessed 10/2/ when-your-kidneys-slow-down-or-stop-working

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