1. Unit 4 - Immunology and Public Health

2. Unit 4 – Immunology and Public Health
1. The Immune System
2. Infectious Diseases and immunity
Non-specific defences
Specific cellular defences
Transmission and control
Active Immunisation and Vaccination and the evasion of immune responses

3. Can you now ….
Name some of the body’s physical and chemical defence barriers
Explain the role of epithelial cells in defence
state when an inflammatory response might occur
describe the steps and cells involved in the inflammatory response
describe the role and process of phagocytosis
describe the action of natural killer (NK) cells

4. Quick Question
Complete the sentences below using the letters or words in the box below:
A. Pathogen
B. Skin
C. Airways
D. Non-specific
E. Specific
F. Epithelial
A microbe that could cause us harm is known as a _________
The ___________cells that line our ______ and ____________act as a physical barrier to pathogens.
This is an example of _____________defence.
A or Pathogen
B or Skin
F or Epithelial
C or airways
D or non-specific

5. Quick Question 1. Cytokine 3. Phagocyte 4. Mast Cell
Match the immune factor to it’s function
1. Cytokine
A. Triggers the inflammatory response.
2. Complement antimicrobial proteins
B. Attract phagocytes
3. Phagocyte
C. Amplifies the immune response.
4. Mast Cell
D. Engulfs pathogens.

6. Quick Question
Events in the inflammatory response are described below.
1 Clotting elements coagulate the blood
2 Phagocytes engulf pathogens
3 Blood capillaries dilate and increase in permeability
4 Healing
5 Mast cell releases cytokines and histamine
The sequence in which these events occur following is
A 2, 3, 1, 5, 4
B 2, 1, 3, 4, 5
C 5, 3, 2, 1, 4
D 5, 2, 1, 3, 4.

7. Questions
Decide whether each of the following statements is true or false. If it is false, correct the word in bold to make it true. COPY THE CORRECT SENTENCES IN YOUR JOTTER
The process of programmed cell death of a pathogen infected cell is called phagocytosis
If white blood cells detect tissue damage, they release cytokines which attract other white blood cells to the site of injury
A phagocytes cytoplasm contains ribosomes full of digestive enzymes
Following injury, mast cells in connective tissue release histamine which causes vasodilation
Decreased capillary permeability occurs at an infected site showing inflammation. F T F T F

8. Quick Question 1. Which white blood cell secretes histamine?
Phagocytes
Mast cells
Complement
Natural killer cells

9. Quick Question
2. Which of the following is NOT an affect brought on by histamine at the site of an infection?
Vasodilation
Clotting of blood
Attraction of phagocytes to site of infection
Increased capillary permeability
Trick!! There are only 2 effects of histamine presence

10. Quick Question
3. Cytokines are secreted at the site of infection. What effect does this have?
Antimicrobial protein / clotting element is drawn to the site of infection of the skin (cut)

11. Quick Question
4. Which of the following describes the action of phagocytes?
Stimulates inflammatory response
releases histamine
Causes programmed cell death
Engulfs pathogenic cell

12. Causes cell to self destruct
Quick Question
5. Describe the action of Natural Killer cells
Causes cell to self destruct

13. Extended Answer Question
Describe non-specific defences that the body uses to protect itself from pathogens. (8 marks)
Higher Human Biology Revised 2013

14. The skin prevents the entry of pathogens / is a physical barrier.
Epithelial cells (in cavity linings) produce (protective chemical) secretions
Description of one non-specific defence e.g. mucus in windpipe / acid in stomach / lysozyme or anti-bacterial substances in tears / coughing or sneezing / blood clotting
The inflammatory response is caused by the release of histamine from mast cells
Vasodilation / increased capillary permeability / increased blood flow (occurs)
Increased blood flow / secretion of cytokines results in the accumulation of phagocytes
It also results in the delivery of antimicrobial proteins / clotting elements to the site
Phagocytes recognise surface antigens or protein markers on pathogens
They then destroy the pathogen by engulfing it / by phagocytosis
Natural killer (NK) cells induce the pathogen to destroy itself / apoptosis
(The NK cells cause) the pathogen to produce digestive / self-destructive enzymes
Phagocytes / NK cells release cytokines that stimulates the (specific) immune response
8 marks