SC F3 CHAPTER 3

CHAPTER 3: EXCRETION

Process of removing waste material from our body

HUMAN

LUNG

1. carbon dioxide and water vaour

SKIN

1. largest organ in human body

2. water, urea and mineral salt

3. excrete waste product in form of sweating

KIDNEY

1. water, urea, mineral salt

2. eliminate as urine

3. bean shape

4. regulate amount of water and mineral

    salt, blood concentration

 

KIDNEY- filter and remove waste product

URETER- channel urine from kidney to urinary bladder

URINARY BLADDER- store urine

URETHRA- channel urine from urethra out of body

THE IMPORTANCE OF KIDNEYS

1. Removing excretory materials in the form of urine. Urine contains nitrogenous substances such as urea, ammonia and uric acid.

2. Urea is formed from carbon dioxide and ammonia while ammonia is the breakdown of protein in the liver. Therefore, the removal of urea can maintain the pH balance in the blood.

3. Reabsorbing materials such as mineral salts, glucose and amino acid required by the body from the blood and so control the blood concentration equilibrium.

4. Eliminating chemical compounds from blood for example, toxin, alcohol and drugs. The accumulation of toxic materials in the blood can result in death. 

LIVING WITH KIDNEY FAILURE

1. Kidney failure happens when they do not work properly. This could be due to infections caused by microorganisms.

2. A blockage in ureter and urethra can cause damage to the kidneys because urine cannot flow out of the body.

3. A person who has only one kidney still can live normally.

4. If both kidneys fail, the person will have to rely  on an artificial kidney machine called the dialysis machine to remove wastes from the blood.

DIALYSIS

1. The process of filtering and cleansing the blood using a dialysis machine.

2. Dialysis removes excess water and wastes through a  semi-permeable membrane.

3.  A semi-permeable membranes has pores which allow urea and salts to go through. Larger particles such as blood cells, bacteria, viruses or protein cannot pass through this membrane.

4. The common dialysis method is hemodialysis where waste products and excess water are separated artificially from the patient’s blood by diffusion and ultrafiltration

SKIN	WATER, MINERAL SALT, UREA	SWEATING
KIDNEY		URINATING
LUNG	CARBON DIOXIDE, WATER	EXHALING/ BREATHING

PLANT

1. no specify respiratory system

2. oxygen, carbon dioxide, water, mineral salt, nitrogenous waste

LATEX- RUBBER TREE- TYRE

RESIN- CASUARINA STEM- VARNISH AND GUM

GUM- ACACIA STEM- COUGH MEDICINE

TANNIC ACID- TEA, COFFE, MANGROVE BARK- INK

QUINNE- CINCHONA BARK- MALARIA MEDICINE

OIL- FLOWER OR LEAF- PERFUME AND INSECT BITE OINTMENT