Animal Primary Line Of Defence

Question 1

Skin

Answer 1

Physical barrier and contains skin flora which outcompete pathogens for space and resources on the skin

Question 2

Blood

Answer 2

Blood clots form if the skin is cut to create new barrier

Question 3

Mucous membranes

Answer 3

Line body tracts. Mucous is produced to trap pathogen and the cilia waft mucous away from lungs

Question 4

Lysosomes

Answer 4

Hydrolytic enzymes which digest pathogens

Question 5

Expulsion reflexes

Answer 5

Sneezing, coughing vomiting- methods which force pathogens out the body

Question 6

Histamines

Answer 6

Blood vessels dilate and increase blood flow. Increase temperature from blood and kills pathogen.
Makes walls of blood vessels more permeable so wbc can be delivered to site of damage

Question 7

Inflammation

Answer 7

In areas where damage to cells to be detected. Area becomes red, hot and ichy. Triggers release of histamines and cytokines

Question 8

Cytokines

Answer 8

Attracts phagocytes, which can engulf and destroy pathogens

Question 9

What are phagocytes what process do they undergo and what type of response is it?

Answer 9

-Phagocytes ( macrophages and neutrophils) travel in blood and squeezes out capillaries to engulf and digest pathogens
-phagocytosis
-secondary non-specific response

Question 10

How do you distinguish between neutrophils and macrophages?

Answer 10

Neutrophils- lobed nucleus
Macrophage- larger round nucleus

Question 11

Explain neutrophils

Answer 11

-lobed nucleus (helps squeeze out capillaries
-contains many lysosomes to digest pathogens
-die soon after ingesting pathogens

Question 12

Explain macrophagesnk

Answer 12

-larger than neutrophils
-round nucleus
-monocytes travel in bloodstreams and mature to macrophages
-engulf pathogens
-initiate specific immune response

Question 13

Explain Opsonins

Answer 13

-protein molecule- type of antibodies
-attach to antigen on surface of pathogen
-some opsonins not specific- attach to variety of pathogenic cells
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Question 14

What is the process of phagocytosis?

Answer 14

1)damaged cells and pathogens release cell-signalling chemicals (cytokines) that attract phagocytes
2)opsonin protein attach to pathogen to mark them and make it easier for neutrophils and macrophages to engulf them
3)phagocytes have receptors which can attach to chemicals on the surface of pathogen
4)the phagocyte then engulfs the pathogen into a vesicle to create a phagosome
5)lysosomes fuse with the phagosome, forming phagolysosome
6)enzymes break down pathogen and any soluble molecules is absorbed into cytoplasm
7) phagocytes will present the antigen of the digested pathogen on their surface- they are called antigen-presenting cells

Question 15

Explain Opsonins

Answer 15

-protein molecule- type of antibodies
-attach to antigen on surface of pathogen
-some opsonins not specific- attach to variety of pathogenic cells
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