3. Immune system

Question 1

What is a Pathogen

Answer 1

Disease causing agent

Question 2

What is an Antigen

Answer 2

Specific surface marker on pathogens that can be detected by WBC

Question 3

What does Self mean

Answer 3

A surface marker which is detected as belonging to the human body

Question 4

What does Non-self mean

Answer 4

A surface marker which is detected as foreign to the body

Question 5

Function of Neutrophils

Answer 5

First responder of immune cells

Question 6

What are Lymphocytes

Answer 6

B and T cells that defend against specific invaders

Question 7

Immune system function

Answer 7

To protect the body against infection, illness and disease
-prevent entry then trap them and then destroy / kill them

Question 8

Describe the First line of defence

Answer 8

Physical and chemical barriers which aim to prevent pathogens from entering the body

Question 9

How does the skin provide protection

Answer 9

-Act as physical/ Intact barrier
-Dead cells constantly slough off
-Sebum→contain bacteriacidal / fungicidal properties
-Sweat containing salt→hostile environment for pathogens
-Hair prevents foreign bodies from entering

Question 10

List the Physical barriers

Answer 10

Hair- ears, nose, eyelashes
Ear wax
Mucous
Skin

Question 11

Identify Mucous membranes locations

Answer 11

Respiratory tract
Alimentary tract
Genitourinary tract

Question 12

Structure of mucous membranes

Answer 12

Surface layer of epithelial cells over a deeper layer of connective tissue

Question 13

Function of mucous membranes

Answer 13

Produces mucous which provides a dense barrier to trap foreign particles that can later be removed

Question 14

List the Chemical barriers

Answer 14

Tears
Saliva
Stomach acid

Question 15

Tears and saliva function

Answer 15

Contain lysozymes (enzymes) which break down bacteria

Question 16

Stomach acid function

Answer 16

Contains HCl (ph of 2) which destroy pathogens that have entered the stomach eg via food

Question 17

Where do Microbial barriers exist

Answer 17

Skin
Stomach
Vagina

Question 18

How do microbial barriers work

Answer 18

The presence of of normal (healthy) microbes means that there is limited resources (space) for bacterial growth

Question 19

What does non specific mean

Answer 19

Response will be the same for all invading pathogens

Question 20

What does the second line of defence do

Answer 20

Traps pathogens by inflammation and phagocystosis

Question 21

What is the mucocilliary escalator

Answer 21

cilia on bronchial wall that helps trap pathogens which enter via the respiratory tract (in respiratory system)

Question 22

Describe the PROCESS of inflammation

Answer 22

-the skin is penetrated which triggers a innate, non specific response

-blood capillaries increase permeability (leakiness) and hence more WBC’s leak out into surrounding tissues // vasodilation also occurs

-Increased leakiness of capillaries means that swelling occurs (traps pathogens and may cause pain)
-Increased leakiness of capillaries means that more phagocytes migrate to the site of injury and the further release of cytokines if triggered

-Vasodilation means that there increased blood flow to site of injury (causing redness and heat)

Question 23

What is the purpose of inflammation

Answer 23

protect, isolate and inactivate cause of (and) damaged tissue

Question 24

Describe the PROCESS of phagocytosis

Answer 24

-Phagocyte recognises bacteria as ‘non self’
-phagocyte engulfs bacteria or pathogen
-phagosome and phagolysosome form
-enzymes within the lysosome breaks down pathogens
-unwanted cellular material is removed from the cell

Question 25

Whats fever and its purpose

Answer 25

Fever is often a sign that the body is suffering an infection -an increase in temperature creates a hostile environment for the pathogen to survive

Question 26

Outline what is meant by specific immunity

Answer 26

-reacts in a specific way to each infection -triggered by a specific antigen -delayed at first -greater (faster, sustained, significant ) response on 2nd encounter -develops over time

Question 27

Distinguish between cell mediated and humoral response

Answer 27

-The cell mediated response involves T lymphocytes whereas the humeral response involves B lymphocytes (antibodies)

Question 28

Which lines of defence have memory

Answer 28

3rd

Question 29

Which lines of defence are specific

Answer 29

3rd

Question 30

Which line of defence has different levels of response

Answer 30

3rd

Question 31

How do b cells vs t cells work

Answer 31

B cells secrete antibodies whereas T cells secrete cytokines

Question 32

Where do B cells vs T cells attack invaders

Answer 32

B cells outside of cells whereas T ells attack inside of cells

Question 33

How does the process of antibodies work

Answer 33

-Antibody and antigen bind (deactivates the pathogen) -Forms lattice and agglutination occurs which triggers phagocytes for phagocytosis (engulf and destroy) -Signals release of cytotoxins which kills cells -Immobilise the pathogen

Question 34

Distinguish between active and passive immunity

Answer 34

Active immunity is where antibodies are produced within the body Antibodies are produced in one person and then introduced into another for passive immunity

Question 35

eg of natural active

Answer 35

-infected with pathogen

Question 36

eg of induced active

Answer 36

vaccine

Question 37

eg of natural passive

Answer 37

breastmilk and placenta

Question 38

eg of induced passive

Answer 38

plasma donations

Question 39

define autoimmune disease

Answer 39

-condition in which immune system attacks own body as it is unable to differentiate between self and non self antigens eg MS, MND