Topic7 Defense Against Infection

Question 1

How does our body prevent microbes getting in?

Answer 1

-eyes (tears contain enzymes that destroys pathogens)
-stomach (stomach acid)
-skin (acts as a barrier and causes scabs)

Question 2

What is the immune system?

Answer 2

-Destroys pathogens in our blood
-Contains white bloods cells phagocytes and lymphocytes

Question 3

What do phagocytes look like?

Answer 3

They have a lobed nucleus

Question 4

What do lymphocytes look like?

Answer 4

They have a large round nucleus

Question 5

How do bacteria cause disease?

Answer 5

-reproduce by dividing into 2 new cells every 20 minutes
-produce toxins that make us feel ill

Question 6

What is an antigen?

Answer 6

Proteins on the surface of all cells, specific to that cell.

Question 7

How do vaccinations prevent diseases?

Answer 7

• They inject small amounts of dead or inactive pathogen into your body
• the antigens in the vaccine stimulate your white blood cells into making antibodies
• the antibodies destroy the antigens without any risk of disease
• after this memory cells are made
• now you are immune to future infections