Human performance

HEALTH-Physical mental and social well being

What is a disease?

Change in the body that produces a loss of health. Common terms:

Aetiology Symptom and Sign

Classification of siseases

By the organ or system affected. By persistence: acute or chronic or by transmissibility: infectious or non infectious

-infectious diseases. Caused by pathogens

-Non infectious diseases. Not caused by pathogens

TRANSMISSION OF INFECTIOUS DISEASES

Agent - pathogen that causes a disease

Reservoir. The place where pathogen lives

Vector. The person animal or microorganism that carries and transmits the agent or pathogen

Host. The organism that is infected

Transmission of pathogens

-Direct contact

-Indirect contact

Portals of entry into host

Skin, Respiratory tract, Digestive tract and genital tract

Endemic- disease continually present in a certain region

Epidemic- disease that spreads rapidly and affects a large number of people

Pandemic- disease that affects a large geographical area or reaches all parts of the world

The immune system

Responsible for protecting human body

Surface barriers

First line of defence:

Physical

Chemical

Biological

Non specific immune response

If pathogen crosses first line of defence then second line is activated. The response is carried out by phagocytes.

Specific immune response

When a non specific immune response does not stop a pathogen, a third line is activated. This response is carried out by lymphocytes

Lymphocytes recognize antigens entering the body. They are activated and respond by producing antibodies.

T cells- recognize antigens and destroy them

antigen receptor t-cell t-memory cells cytotoxic t-cells

B-cells- produce antibodies specific to the antigen that activated them

Antigen, receptor antibody, B-cell, Plasma cells, B-memory cells

Prevention

Personal and enviromental hygene Sexual health Food hygiene Vaccinations Preventive measures for travelling and pet care