Question

Immune System Worksheet

Line of Defense	Innate or Adaptive?	Overall Function	Structures/Cells/Mechanisms Involved And How Each Functions
1st Line of Defense
2nd Line of Defense
3rd Line of Defense

Answer 1

1st line of defence:

Innate system. Function- To keep pathogens out of the body physically and or kill them by chemical means. Non specific action.

Structures: Skin, mucous membrane (prevents physical entry of pathogens); sebum (kills pathogens); lysozyme (protects the eyes and kills bacteria in food); gastric juice (kills bacteria as it is highly acidic in nature)

2nd line of defence:

Innate system. Non specific action. Function - Engulf and kill bacteria non specifically (by certain cells) or kill bacteria by physical or chemical action.

Structures: Phagocytic cells (different macrophages, neutrophils) that engulf foreign pathogen and kills them; inflammation is an elaborate cellular response involving many cytokines that target pathogens; fever by which body raises temperature in order to kill bacteria.

3rd line of defence:

Adaptive system. Very specific. Function - to produce specific antibodies against specific pathogens in order to kill them and also store these antibodies as memories for future use.

Structures: T lymphocytes (produces antibodies against virus infected cells and cancerous cells in the body); B lymphocytes (produces soluble antibodies against foreign microbes and pathogens). They also produce memory cells for fighting a future infection.