Non-specific Immune Response

Question 1

components of the non-specifc immune response

Answer 1

• lysozymes
• inflammation
• phagocytosis
• interferons
• blood clotting

Question 2

Lysozymes

Answer 2

An enzyme found in tears, saliva, sweat and nasal secretion which damages bacteria by hydrolysing the peptidoglycan in cell walls causing bacterial cell lysis

Question 3

Inflammation

Answer 3

1. Damaged tissues activate mast cells causing the release of histamine
2. histamine causes near by blood vessels to vasodilate which increases the blood supply to the area causing the area to feel hot or appear red.
3. histamine also makes the blood vessel walls more permeable to allow more blood plasma to leave the blood and form tissue fluid causing tissues to swell and become painful.

Question 4

Phagocytosis

Answer 4

1. phagocyte recognises non-self antigens on the pathogen and binds to them
2. phagocytes engulfs pathogens by endocytosis forming a phagosome
3. lysosomes fuse with phagosome and forms a phagolysosome
4. enzymes in lysozyme causes cell lysis which results in the phagocyte becoming an APC

Question 5

Interferons

Answer 5

produced by virus-infected cells and inhibits viral replication inside host cells.

Question 6

How is the body adapted to prevent pathogens entering

Answer 6

• mucus membrane containing cilia and mucus as well as releasing lysozyme which hydrolyses peptidoglycan in bacterial cell wall causing bacterial death
• Gut flora to compete with pathogens, also secretes lactic acid which is a useful defence against pathogens
• Skin and skin flora, the skins eperdermis is very tough due to the fibrous protein keratin so acts a physical barrier to pathogens and skin flora competes with pathogens on skin surface
• Stomach acid which has a very low pH so kills pathogens due to hydrochloric acid