Health and Disease

Health- Physical, mental and social well being, not merely the absence of disease or imfirmity.

Disease-anything that impairs the normal functioning of the body and causes physical, mental or social systoms.

Parasite:an organism that lives in close assosication with its host, and causes it harm. parasites takes the nurtirtions away from the host.

Pathogen: an organism that causes diesase, pathogens are a type of parasite. can cuase infection via: host to host, enter of the hosts tissue, reproduce and causes damage to the host tissue.

Transmission of the disease: the passage of a pathogen from a infected to a unifected person:

Vector: organism carries the diease, Physical contact, droplet infection.

(Malaria is caused by a protocist PLASMODIUM, It is transmitted via a vector: Anopheles femal mosquito, injecting saliva inot host. The site of acvtion is the red blood cells. Can be controled via: mosquito nets, pestidies, drugs.

Aids is caused by a virus RETROVIRUSHIV is transmitted via odily fluids. Unprotected sex, unscreened blood transfusion, sharing needles, across the placenta, breat milk. Site of action: T lymphocyte (WBC), contolled via: using condoms, screening blood products, needle exchange schemes, he4alth education about sex.

TB is caused by a bacterium, mycobacterium tuberculosis. Transmitted via droplet infection: poor diet, overcrowed, poor health (aids) Site of action: affects lungs. control: antibiotics, BCG vaccination.

Primary defence:

The skin: outer layer of the epidermis, consists of dead cells, which act as a phyical barrier to pathogens.

Commensal flora: harmless bacteria which lives on the surface of the skin competes with pathogenic bacteria.

Mucous membranes: in the gut, anus, ears, nose and respiraroty passages. An epithelial layer of cells, mucus producing goblet cells. sticky mucus lining the passages traps pathogens. In the respiratory tract contains cilliated cells which waft mucus to the top of the tranchea, swallowed and passes into the stomach.

Eyes: produces tears, contains antibodies and lysosomes. Ear: produces wax, traps pathogens. Vagina: lactic acid.