Warm Question What are 7 Characteristics of Life? (Hint: Mrs Gren)

Full Name: Hoai Thu Giang Lecturer’s Name: Richard Llopis Garcia Excretion and The Kidneys

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

What is excretion? Chemical reactions in your body cells produce waste. This waste includes CO 2 and Urea These chemical wastes must be removed. Otherwise they become a poison.

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

What is Deamination? 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 Have bean-shaped Located against the dorsal body wall on either side of the backbone At the back of your body

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

Structure of the Kidneys Each kidney are thousands of tiny tubes called nephrons, where blood is filtered and urine is formed Nephron is 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 Reabsorbed The wall of this tuble 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

Secretion The process by which substances move into the distal and collecting ducts from blood in the capillaries around these tubules. 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

Thank you for paying attention

Reference Gareth Williams, 2002, Nelson Thornes, “Biology for you” Book, accessed 10/2/2013 Ben Aldiss, 2005, Nelson Thornes, “A2 Level Biology”, accessed 10/2/2013 Richard Llopis Garcia, 2013, City of Bath College, Material, accessed 10/2/2013 John parker and Ian Honeysett, 2005, “Revise Biology”, Letts educational, chapter 3, accessed 10/2/2013 No author, Blog, Illustration for Excretory System, ml, accessed 10/2/ ml