36) Unit 2 - Immune Response to Parasites

Question 1

name the 2 types of defence mammals have against parasites

Answer 1

• Non specific

* Specific

Question 2

List 5 types of non specific defence

Answer 2

• Skin
• Chemical secretion e.g. tears, mucus
• Inflammatory response
• Phagocytes
• Natural killer cells

Question 3

Describe how inflammatory response works to defend against parasites

Answer 3

• Inflammation occurs when blood rushes to a cut

* This increases the number of white blood cells to that area which can attack potential parasites from entering

Question 4

Describe how phagocytes defend against parasites

Answer 4

• Phagocytes recognise foreign antigens on the surface of parasites
• They engulf the parasite by enfolding their plasma membrane around the parasite
• The parasite is brought into the phagocyte in a vacuole/vesicle
• Lysosomes in the phagocytes fuse with the vacuole and release digestive enzymes which digest the parasite

Question 5

describe how natural killers defend against parasite

Answer 5

•These are lymphocytes responsible for destroying abnormal cells

Question 6

what types of cells carry out immune surveillance

Answer 6

white blood cells

Question 7

which white blood cells are used in specific defence against parasites

Answer 7

Phagocytes

Lymphocytes

Question 8

What role do phagocytes play in specific defence against parasites

Answer 8

phagocytes present foreign antigens on their surface to T lymphocytes

Question 9

why are endoparasites sucessful against the host immune system

Answer 9

• mimic the hosts antigens to remain undetected
• modify host immune system so it does not attack
• high antigenic variation

Question 10

why does high antigenic variation allow the parasite to be successful

Answer 10

allows them to evolve faster than the host immune system can respond to the new antigens

Question 11

why does high antigenic variation allow the parasite to be successful

Answer 11

allows them to evolve faster than the host immune system can respond to the new antigens

Question 12

what is epidemiology

Answer 12

the study off the outbreak and spread of infectious diesease

Question 13

what is herd immunity and what is herd immunity threshold

Answer 13

Herd immunity:
the protection that is offered to susceptible individuals by resistant individuals

Herd immunity threshold:
the density of resistant hosts in the population required to prevent an epidemic