Animal SurvivalAnimal SurvivalAnimal SurvivalAnimal Survival

Water and WasteWater and Waste

• G1: Identify the ways in which a mammal gains and loses water

Water Gain• Food• Drink• Chemical

Reactions*

Water Loss• Urine (Urea in

water)

• Faeces• Sweat• Breathing

*Respiration = how the body releases energy from food.Oxygen + Food Carbon Dioxide + Water + Energy

• The kidneys make sure that the amount of water gain equals the amount of water loss

Water Balance

Water In = Water Out

• G2: State that the kidneys are the main organs for regulating the water content in a mammal.

This is called OSMOREGULATION

• G3: Identify the position and state the functions of the kidney, renal arteries, renal veins, ureter and bladder.

water regulate/control

Name Function

Kidney Filter blood. Remove excess water and urea

Renal Arteries

Supply blood to the kidneys

Renal Vein

Take filtered blood away from the kidneys

Ureter Take urine (urea and water) from the kidneys to the bladder

Bladder Stores urine until it is passed out of the body

G4: State that the kidneys work by filtration of blood and reabsorption of useful materials such as glucose.

G5: State that urea is a waste product removed in the urine.

• FILTRATION

• As blood flows through the kidneys, a lot of water and most of the substances dissolved in the plasma are filtered out. This includes urea, glucose, amino acids and salt.

• RE-ABSORPTION

• Many of these substances are needed by the body, so are RE-ABSORBED back into the blood.

• Urea and just the right amount of water that the body needs to lose are NOT re-absorbed. They pass out of the kidneys, down to the bladder and are excreted in the urine

C1: Explain the process of urine production using a simple diagram of the nephron.

Glomerulus

Bowman’s capsule

Kidney

tubuleCapillaries

Collecting Tube

Part of Nephron Function

Glomerulus Blood is filtered and collects in the Bowman’s Capsule

Kidney Tubule Useful substances are re-absorbed (eg, glucose, amino acids) and pass back into the capillaries.

Collecting Duct Final re-absorption of water occurs here. The amount re-absorbed is controlled by ADH (anti-diuretic hormone).

C2: State the source of urea in the body and describe how urea is transported to the kidneys.

• Urea is a poisonous nitrogenous (contains nitrogen) waste. It is made in the liver when surplus amino acids are broken down.

Amino Acids Glycogen + UreaUseful carbohydrate stored in the liverUrea passes into the bloodstream

and is transported to the kidneys where it is removed from the blood.

New term …… diuretic• A diuretic is a substance which causes an

increase in the production of urine.

• Opposite terms• eg, clockwise/anti-clockwise• social/anti-social• anti-viral

Don’t copy this!!!!!!!

Diuretic• A diuretic is a substance which causes an

increase in the production of urine.

Anti-diuretic• An anti-diuretic will reduce the

production of urine.

C3: Explain the role of ADH (anti-diuretic hormone) in the regulation of water balance

• Anti-diuretic hormone = decrease production of urine

• Anti-diuretic hormone is released by the pituitary gland (part of the brain).

• Body can either produce lots of ADH or a little ADH

• Lots of ADH = less urine

Releases little ADH

• Scenario 1: Drank too much water

Blood too diluteDrink

too much

Low volume of water reabsorbed by kidney

Large volume dilute urine to bladder

Water conc. in blood normalWater conc. in blood normal

Releases lots ADH

• Scenario 2: Body has lost too much water

Blood too concentrated

sweating

High volume of water reabsorbed by kidney

Small volume concentrated urine to

bladder

Water conc. in blood normalWater conc. in blood normal

G6: Explain the implications of damage to the kidneys by accidents or disease

• People can live with only one kidney, but if both kidneys become damaged, urea will build up and will eventually cause death if not treated.

• Treatment• Dialysis (kidney machine)• Kidney Transplant

C4: Describe the benefits and limitations of replacement and “artificial” kidneys.

C4: Describe the benefits and limitations of replacement and “artificial” kidneys.

Page 50 Biology Booklet

Complete pages 43-51

Textbook 130-137Read/Revise/Take Notes/Answer Questions

Last page of booklet – past paper questions/book

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