Staying Healthy
Staying Healthy- Explain 2 different ways in which your immune system can destroy invading pathogens.
References
http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/understanding_organisms/staying_healthyrev4.shtml http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/understanding_organisms/staying_healthyrev5.shtml http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/defendingagainstinfectionrev4.shtml
How can your body stop pathogens getting into your body in the first place?
Body defences
The body has several defences against pathogens so that we do not fall ill with the diseases they cause.
The skin
Cross-section of skin
The skin covers the whole body. It protects the body from physical damage, microbe infection and dehydration. Its dry, dead outer cells are difficult for microbes to penetrate, and the sebaceous glands produce oils that help kill microbes.
Blood clotting
If microorganisms get into the body through a cut in the skin, the most important thing to do is close the wound quickly so that no more microorganisms can enter. A scab does just that. The blood contains tiny structures called platelets, and a protein called fibrin. A scab is basically platelets stuck in a fibrin mesh. The animation shows how this works.
Mucus
The respiratory system is protected in several ways. Nasal hairs keep out dust and larger microorganisms. Sticky mucus traps dust and microbes, which are then carried away by cilia. These are tiny hairs on the cells that line the respiratory system.
Stomach acid
Hydrochloric acid in the stomach kills harmful microorganisms that might be in the food or drink that we swallow.
What is your immune system?
Immunity
Once inside the body, pathogens reproduce. Viruses reproduce inside cells and damage them, while escaping to infect more cells. Bacteria produce toxins - poisons. Cell damage and toxins cause the symptoms of infectious diseases.
Once pathogens enter the body, the immune
References
http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/understanding_organisms/staying_healthyrev4.shtml http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/understanding_organisms/staying_healthyrev5.shtml http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/defendingagainstinfectionrev4.shtml
How can your body stop pathogens getting into your body in the first place?
Body defences
The body has several defences against pathogens so that we do not fall ill with the diseases they cause.
The skin
Cross-section of skin
The skin covers the whole body. It protects the body from physical damage, microbe infection and dehydration. Its dry, dead outer cells are difficult for microbes to penetrate, and the sebaceous glands produce oils that help kill microbes.
Blood clotting
If microorganisms get into the body through a cut in the skin, the most important thing to do is close the wound quickly so that no more microorganisms can enter. A scab does just that. The blood contains tiny structures called platelets, and a protein called fibrin. A scab is basically platelets stuck in a fibrin mesh. The animation shows how this works.
Mucus
The respiratory system is protected in several ways. Nasal hairs keep out dust and larger microorganisms. Sticky mucus traps dust and microbes, which are then carried away by cilia. These are tiny hairs on the cells that line the respiratory system.
Stomach acid
Hydrochloric acid in the stomach kills harmful microorganisms that might be in the food or drink that we swallow.
What is your immune system?
Immunity
Once inside the body, pathogens reproduce. Viruses reproduce inside cells and damage them, while escaping to infect more cells. Bacteria produce toxins - poisons. Cell damage and toxins cause the symptoms of infectious diseases.
Once pathogens enter the body, the immune