Disease prevention

Question 1

What is the first line of defence?

Answer 1

Physical/chemical defences preventing the entry of pathogens

Question 2

Examples of first line of defence?

Answer 2

Skin, mucous membrane, chemicals e.g. lysosome

Question 3

What is an expulsive reflex?

Answer 3

A cough/sneeze, expelling irritants (including pathogens), from the upper part of the gas exchange system

Question 4

Physical defence?

Answer 4

Tissue acts as barrier to pathogens

Question 5

Cellular defence?

Answer 5

Cells alert body and produce substances to protect and digest pathogens

Question 6

Chemical defence?

Answer 6

Substances secreted by body trap them and cause them to burst

Question 7

Harmless bacteria and fungi defence?

Answer 7

Compete with pathogens to prevent infections

Question 8

How might hydrochloric acid protect us?

Answer 8

Secreted by cells in stomach lining kills bacteria

Question 9

What is the second line of defence?

Answer 9

Phagocytic cells and antimicrobial proteins, act when first line of defence hasn’t stopped a pathogen

Question 10

What are non-specific defences?

Answer 10

Present from birth, cannot distinguish between pathogens, give same response so quick but not always effective

Question 11

What is a rapid response to getting a wound of any kind?

Answer 11

Blood clotting

Question 12

How does the blood clot?

Answer 12

Platelets and cells release compounds which start a complex chain of reaction, involving many large plasma proteins

Question 13

Inflammation?

Answer 13

Response to tissue damage/infection, releasing chemical signalling molecules, increasing blood flow and movement of phagocytes

Question 14

Cytokines?

Answer 14

Small protein molecules that act as cell signalling compounds

Question 15

What do cytokines do?

Answer 15

Involved in stimulating events which occur in response to to infection e.g. inflammation

Question 16

What are interleukins?

Answer 16

A cytokine

Question 17

What are mast cells?

Answer 17

Increase chance of phagocytes going to the infected area

Question 18

How do mast cells respond to tissue damage?

Answer 18

Secretes histamine (cell signalling compound) stimulating responses

Question 19

How is vasodilation a response to the histamine released by mast cells?

Answer 19

It allows more blood flow through capillaries

Question 20

How does swelling occur?

Answer 20

Capillaries become leaky and fluid enters tissues

Question 21

How do phagocytes respond to histamine?

Answer 21

Leave blood, enter tissues and engulf foreign material

Question 22

What does histamine stimulate cells to secrete?

Answer 22

Cytokines

Question 23

How do stem cells help repair a scab?

Answer 23

Divide by mitosis

Question 24

How do platelets help repair a scab?

Answer 24

They secrete growth factors, initing cells to divide and grow

Question 25

What are formed as a stage of healing a wound?

Answer 25

New blood vessels

Question 26

What is produced as a stage of healing a wound?

Answer 26

Collagen

Question 27

What tissue forms and what does it do, when healing a wound?

Answer 27

Granulation tissue, fills wound so changes can occur underneath still

Question 28

What cells form and why when healing a wound?

Answer 28

New epithelium cells form by division of stem cells, to go to new tissue

Question 29

What are the two final steps of wound healing?

Answer 29

Wound contraction by contractile cells and death of unwanted cells

Question 30

What is a neutrophil?

Answer 30

Short lived phagocytic cell, produced in bone marrow (WBC)

Question 31

Monocyte?

Answer 31

Medium sized cell, circulates in blood till it leaves in the form of a macrophage, living in tissues for a long time

Question 32

Macrophage?

Answer 32

Large and long lived phagocytic cell, remains in tissues, they process pathogens presenting their antigens

Question 33

Dendritic cell?

Answer 33

Large phagocytic cell with long extensions, giving it a large SA to interact t with pathogens and lymphocytes

Question 34

What do neutrophils do?

Answer 34

Spread into tissue, rapid reaction, do not last long as die once engulfed bacteria

Question 35

What do monocytes do?

Answer 35

Only enter tissues to form into a macrophage, they process and present antigens to lymphocytes, they can remain there or migrate elsewhere

Question 36

What do dendritic cells do?

Answer 36

Ingest foreign material, migrate and take the material to the lymph nodes