Non-specific body defences

Question 1

Pathogens

Answer 1

Bacterium, virus, or other organisms that cause disease.

Question 2

First line defence

Answer 2

Non-specific - physical or chemical barriers

Question 3

Skin

Answer 3

Closely packed epithelial cells to stop infection - cut quickly scabs and heals.

Question 4

Epithelial cells

Answer 4

Skin also found in lining of stomach and respiratory systems

Question 5

Nose

Answer 5

Internal hairs as physical barrier. cells produce musics that traps pathogens before they can enter lungs. When blown mucus is removed and any pathogens are trapped within it.

Question 6

Trachea

Answer 6

runs from nose towards lungs - cells that line trachea also have hairs called cilia

Question 7

Ciliated cells

Answer 7

Waft their hairs in motion to move mucus and pathogens upwards to throat where is swallowed to stomach

Question 8

Goblet Cells

Answer 8

Create mucus in order to trap pathogens - the production of mucus is a physical barrier

Question 9

Chemical barriers

Answer 9

stomach acid
tears
saliva
mucus

Question 10

Stomach acid

Answer 10

Chemical barrier - HCL strong enough to kill pathogens that are caught in mucus in airways or consumed in food or water

Question 11

Tears and Saliva

Answer 11

Have enzymes that destroy bacterial cells by breaking down their cell walls. These enzymes are called lysozymes.

Question 12

Enzyme that breaks down cell walls

Answer 12

Lysozyme

Question 13

Mucus

Answer 13

Sticky substance secreted by goblet cells in trachea. Foreign particles and pathogens adhere to surface and cilia sweep them away from lungs.

Question 14

Inflammatory response

Answer 14

Localised defence mechanism used following physical injury or infection.

Specialised immune cells called mast cells release histamine.

Question 15

Mast cell

Answer 15

Inflammatory response - release histamine

Question 16

Histamine

Answer 16

Causes blood vessels to widen (vasodilation) increasing blood flow to area. Increased blood flow leads to accumulation of phagocytes and clotting elements at site of infection.

Question 17

5 Stages of inflammatory response?

Answer 17

1. physical injury or infection
2. mast cells release chemical histamine
3. histamine stimulates blood vessels to vasodilate and increases permeability of capillaries
4. this causes increased blood flow
5. phagocytes and clotting elements accumulate at site of injury or infection

Question 18

Second line of defence

Answer 18

Immune system - phagocytes and lymphocytes

Question 19

2 types of WBC

Answer 19

Phagocyte

Lymphocyte

Question 20

Phagocyte

Answer 20

70% wbc

Ingest and destroy pathogens

Recognise pathogens and destroy by phagocytosis

Question 21

Phagocytosis

Answer 21

Engulfing of pathogens and their destruction by digestive enzymes contained in lysosomes

Phagocyte membrane surround pathogen and engulfs it in a vacuole. enzymes then break it down - non-specific

Question 22

Cytokines

Answer 22

Phagocytes release cytokines (proteins that act as signalling molecules) which attracts more phagocytes to site of infection