defence mechanisms and phagocytosis

Question 1

whats the function of an immune system?

Answer 1

a complex defence mechanism designed to protect from number of threats (pathogens, toxins, abnormal body cells, cells from other individuals - e.g. transplants)

Question 2

what is a pathogen?

Answer 2

a microorganism or infectious agent that causes communicable disease

Question 3

what is a cellular pathogen?

Answer 3

parasites (helmithes - tapeworm), protoza (plasmodia/ malaria), fungi (tinea - athletes foot), prokaryote (bacteria - leprosy)

Question 4

what is a acellular pathogen (non-living) ?

Answer 4

virus ( e.g. HIV/ aids), prion (CJD)

Question 5

what do membranes of all cells contain?

Answer 5

glycolipids and glycoproteins called antigens

Question 6

what can antigens be identified by the immune system as?

Answer 6

either self or non-self

Question 7

are antigens specific to each individual?

Answer 7

YES

Question 8

what happens once the immune system has identified a non-self antigen?

Answer 8

it will innitiate an immune response

Question 9

what happens once the immune system has identified a non-self antigen?

Answer 9

it will innitiate an immune response

Question 10

what are the two immune responses and wgat do they do?

Answer 10

non-specific (innate) responses (they do barrier defences and phagocytosis), specific (adaptive) response (they do cell-mediated responses and humoral responses)

Question 11

what are barrier defences for the body?

Answer 11

barrier defences are the first line of defence against a pathogen

Question 12

what else do barrier defences do?

Answer 12

block a pathogen entry into the body or destroy and inactivate those that get in

Question 13

what are the type of barrier defences?

Answer 13

1. digestive enzyme
2. skin
3. lysosomes

Question 14

what is the process of phagocytosis?

Answer 14

process carried by the white blood cell called a phagocyte

Question 15

whats the first step of phagocytosis?

Answer 15

phagocytes engulf and digest foreign cells or particles

Question 16

whats the second step of phagocytosis?

Answer 16

pathogen is engulfed and wrapped in a vesicle, forming a phagosome

Question 17

whats the third step of phagocytosis?

Answer 17

lysosomes within pagocyte fuse with the phagosome and Hydrolytic enzyme stored inside, break down the pathogen

Question 18

what happens in the fourth step of phagocytosis?

Answer 18

phagocyte then present the pathogens antigen on its plasma membrane, activates other immune cells.
it becomes an anitgen-presenting cell