A Spot Question

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

Full Name: Hoai Thu GiangLecturer’s Name: Richard

Llopis GarciaSchool: 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 CO2 and Urea.

• This chemical waste must be removed. Otherwise it becomes a toxin.

remove excess CO2

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.

Þ 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 Reabsorption3. 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.

AB C

D

E

F

D irec tio no f b loo d flo w

(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

http://www.youtube.com/watch?v=aQZaNXNroVY

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,

http://schoolworkz.blogspot.co.uk/2011_01_01_archive.htm, accessed 10/2/2013

• No author, healthcare, 2007, “What Happens When Your Kidneys Slow Down or Stop Working” http://www.mykidneyplan.com/my-kidney-what-happens-when-your-kidneys-slow-down-or-stop-working, accessed 10/2/2013

Thank you for paying attention