B5 Communicable Disease Flashcards
What chemicals are released from bacteria?
Toxins
What are the 4 components of the non-specific defence system?
- Skin
- Nose
- Lungs
- Stomach
Describe how the skin prevents pathogens from entering the body
- Forms a protective layer over the body
- The outer layer consists of dead cells which are
difficult for pathogens to penetrate - Produces an oily substance called Sebum which kills
bacteria - Scabs over when damaged
Describe how the nose prevents pathogens from entering the body
-Contains hair and mucus which trap pathogens before they enter the breathing system
Describe how the lungs defend against pathogens
Trachea and Bronchi are covered in Cilia which are covered in mucus that can trap pathogens, then waft the mucus up to the throat, where it is swallowed into the stomach
What are Cilia?
Tiny hairs on the Trachea and Bronchi
Describe how the stomach defends against pathogens
Contains HCL which kills pathogens which kills pathogens before they can make their way into the digestive system
Describe the 3 main ways that white blood cells prevent damage to the body from pathogens
- Phagocytosis (ingesting pathogens)
- Creating antibodies
- Creating antitoxins
What are the 2 main functions of the immune system?
- Destroys pathogens and any toxins that they produce
- Protects the body in case the same type of pathogen
invades it again
Describe the process of Phagocytosis
The white blood cell detects chemicals released from the pathogen, and then ingests the pathogen. Enzymes in the white blood cell now destroy the pathogen
Describe how antibodies are used to destroy pathogens
Antibodies are protein molecules produced by white blood cells, they stick to the pathogen, causing them to be destroyed
What are antibodies?
Protein molecules produced by white blood cells
Give one advantage and one disadvantage of antibodies
- They can remain in the blood for a long time, so they
can protect the body if the same pathogen ever
invades the body again - They’re extremely specific, e.g. if a person catches
measles and develop antibodies against the virus,
they will only protect against the measles virus and
not any other pathogen
Describe how antitoxins are used to destroy pathogens
White blood cells produce antitoxins which stick onto toxins and prevent them from damaging body cells
Name 2 infectious plant diseases
- Tobacco Mosaic Virus (TMV)
- Rose Black Spot
Describe the effects of TMV
Causes the leaves to discolour in a mosaic pattern
What are the effects of TMV on plant growth?
Rate of photosynthesis decreases, and growth of the plant is reduced