DEFENCE AGAINST INFECTIOUS DISEASE

6.3.1 DEFINE PATHOGEN

Pathogen: an organism or a virus that causes a disease.

Examples: Viruses: HIV Bacteria: Cholera Protozoa: Malaria Fungi: Ringworm Flatworms: pork tapeworm Roundworms: Hookworm

Also we can add physical factors that could tigger an inmunological response such as: weather changes, dust, polen and radiation.

6.3.2 EXPLAIN WHY ANTIBIOTICS ARE EFFECTIVE AGAINST BACTERIA BUT NOT AGAINST VIRUSES

Antibiotics are drugs which kill or slow the growth of bacteria. Antibiotics block metabolic pathways of bacteria, inhibiting cell wall formation and protein synthesis, or respiration, resulting in the death of foreign bacteria. However, viruses are not alive and utilize the organisms host cells to replicate, which are not targeted by antibiotics. In order to kill a virus by any kind of drug, human cell has to be killed as well .

 

6.3.3 OUTLINE THE ROLE OF SKIN AND MUCOUS MEMBRANES IN DEFENCE AGAINST PATHOGENS

Non-specific inmunity

6.3.4 Outline how phagocytic leucocytes

(macrophages) ingest pathogens in the blood and

in body tissues

6.3.5 Distinguish between antigens and antibodies

6.3.6 Explain antibody production

For these three points check the following

diagram…

PRIMARY SPECIFIC INMUNE RESPONSE

Fig. 2

Non-specific response. Pathogen has not been determined, just the fact

that is not-self.

Specific Response, each type of antibody recognises a type

of antigen.

FOR ANTIBODIES PRODUCTION…

Check the other ppt of antibodies production

and remember: the natural reaction of

antibodies is polyclonal …

6.3.7 OUTLINE THE EFFECTS OF HIV ON THE INMUNE SYSTEM

HIV attacks T-cells which are part of the immune system that are important for the formation of B-lymphocytes.

The virus enters the T-Cells and replicates there. As reproduction increases, the cell breaks up and the virus RNA is spread to other T-cells.

The virus keeps infecting and killing other T-cells, paralyzing the immune system.

This enables other organisms usually kept under control by the immune system to be able to affect the body. (opportunistic diseases)

6.3.8 DISCUSS THE CAUSE, TRANSMISSION AND SOCIAL IMPLICATIONS OF AIDS AIDS or Acquired Immunodeficiency Syndrome is

a collection of symptoms and infections caused by infection with the human immunodeficiency virus (HIV).

Transmission: HIV is transmitted via direct contact of the mucous membrane with a bodily fluid containing HIV such as blood, semen, or breast milk. The transmission could be through anal or penetrative sex, blood transfusion, contaminated needles, or during pregnancy. Most researches think that the virus originated from the Sub-Sahara, but the exact cause is unknown.

Social Implications Fear and apprehension for those associated with the disease, the lifestyle associated with the disease is attacked, trouble getting a job or even getting health insurance- distanced from society