Defense Mechanism

Question 1

What are the two qualities of specific defence mechanism?

Name two examples

Answer 1

slower response and specific to each pathogen

cell-mediated response ( T-lymphocytes)
Humoral response ( B-lymphocytes)

Question 2

Define pathogen

Answer 2

any microorganism that can cause disease

Question 3

Name the body’s defences to pathogens

Answer 3

Skin= physical barrier
hydrochloric acid
cilia/mucus
tears contain lysozymes

Question 4

Define immunity

Answer 4

the means by which the body prevents infection

Question 5

What are the two types of antigen and how does this occur?

Answer 5

self and non-self

each cell has specific proteins on its cell-surface
due to variety and a highly specific tertiary structure of proteins

Question 6

What can immune systems identify?

Answer 6

pathogens
non-self material
toxins
abnormal body cells

Question 7

Why are organ donations often unsuccessful and what medicine is used to stop this?

Answer 7

the body recognises the organ is non-self and attacks it

immunosuppressants help stop this

Question 8

How do lymphocytes recognise self cells?

Answer 8

When in the womb, infection is rare
lymphocytes collide only with bodies own material
lymphocytes with receptors that fit the bodies own cells are killed or suppressed

In adults, they are made in the bone marrow and initially only encounter self-antigens any that respond go through apoptosis

Question 9

Are phagocytes specific or nonspecific?

Answer 9

Non-specific

Question 10

What are the two types of white blood cells?

Answer 10

phagocytes and lymphocytes

Question 11

What are the two types of phagocytes and what makes them different?

Answer 11

Macrophage which presents

Neutrophil don’t

Question 12

How do damaged cells attract phagocytes?

Answer 12

damaged cells release histamine which dilates blood vessels so phagocytes can arrive easily

Question 13

What is pus?

Answer 13

dead pathogen and phagocytes

Question 14

Describe how phagocytes deal with pathogens?

Answer 14

chemical product of pathogen attracts the phagocytes, phagocytes move down a con. gradient 2 pathogen

phagocytes have several receptors in its cell surface membrane that attach to the pathogen antigens

the pathogen is engulfed to form a vesicle by phagosome
Lysosomes migrate and fuse with the phagosome

lysosome release lysozymes into a phagosome which hydrolysis the pathogen, particularly the cell walls

hydrolysed product is absorbed by phagocytes into the cytoplasm