2.5

Question 1

Pathogen

Answer 1

Organisms which can cause disease

Question 2

List of pathogens

Answer 2

Bacteria
Fungi
Viruses
Parasites

Question 3

Physical defences

Answer 3

Physical defences stop pathogens from entering the bloodstream by forming a physical barrier.

Question 4

What are epithelial cells

Answer 4

They line our nasal passages, airways and digestive tract to physically prevent pathogens in our air and food from entering the bloodstream.

Question 5

Physical defence example

Answer 5

Epithelial cells

Question 6

Chemical defence

Answer 6

Chemical defences sim to trap or kill microorganisms before they enter the bloodstream

Question 7

Examples of chemical defences

Answer 7

Tears
Saliva
Mucus
Stomach acid

Question 8

How do tears chemically defend

Answer 8

Contain chemical enzymes that destroy pathogens, and the liquid helps to wash pathogens away from eye.

Question 9

How is saliva a chemical defence

Answer 9

Contains antimicrobial proteins and enzymes that kill microorganisms

Question 10

Inflammatory response

Answer 10

If a pathogen manages to breach the physical and chemical barriers of the body the inflammatory response triggered

Question 11

Cell types involved in inflammatory response

Answer 11

Mast cells
Phagocytes
Platelets

Question 12

Mast cells function

Answer 12

Mast cells release histamine when injury is detected

Question 13

Histamine causes

Answer 13

Vasodilation of small arteries as well making capillaries more permeable. This sends surge of tissue fluid containing other cells to area: it also makes area red and swollen.

Question 14

Phagocytes function in defence

Answer 14

The increased blood flow brings phagocytes and they engulf pathogens via phagocytosis to destroy them using digestive enzymes called lysosomes.

Question 15

Lysosomes

Answer 15

Capsules held in phagocytes, merge with pathogens and release the enzymes inside them to break it doen

Question 16

Cytokines

Answer 16

Also released by phagocytes and are protein molecules that act as beacons to attract white blood cells of specific immune response to site of injury.

Question 17

Inflammation summary process

Answer 17

Mast cells at site of injury release histamine

Histamine dilates capillaries and increases permeability

Phagocytes arrive and engulf pathogens by phagocytosis

Phagocytes release cytokines to attract other white blood cells