Module 4 - health and disease Lesson 1
Health- state of physical,mental and social well-being and the absence of disease
Disease- condition affecting a body part,organ resulting from various causes,such as infection/genetic defect/environmental stress
Communicable disease- spread from one person to another , often happens by airborne viruses/bacteria, but also by blood/other bodily fluid. . The terms contagious and infectious are used to describe it.
Non Communicable disease- group of conditions not mainly caused by an acute infection, resulting in long term health consequences and often creates a need for long term treatment + care
Conditions: cancers, cardiovascular disease,diabetes and chronic lung illnesses
Groups of diseases
Parasites
Organism that lives in /on a host organism, takes shelter+ nutrients from the host, who gains no thing in return
Pathogen
Microorganisms including bacteria , fungus,protoctista+ viruses that cause disease
Vector
organism that transmits pathogens
Microorganisms
organism so small its microscopic
Bacteria Prokaryotes
All bacteria can be described as a microorganism but only a small proportion can be categories as pathogens.
Further classification within the kingdom Prokaryotes is done based composition of their cell wall and cell shape
Two types of cell walls which react differently to Gram staining.
Gram positive - Purple/blue (MRSA)
Gram Negative - red (E.coli)
Most bacteria produce toxins as a by-product of their normal functioning that poison or damage the host in some way causing the disease.
Toxins damage the host cells by either:
Breaking down the cell membranes
Inactivating the cells enzymes
Interfere with the host cell genetic material so the cells cannot divide.
Classified by:
Unicellular
Heterotrophic or autotrophic
Composition of cell wall
Cell shape
Viruses- often described as microorganisms but their lack of cell makes them a non - living infectious agents.
Unlike bacteria all viruses are pathogenic. Virus take over the cell metabolism and insert the viral DNA into the host cell and hosts DNA.
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Unicellular prokaryotic organism. Murein cell wall present, lacks nucleus and chloroplasts Organisms mainly heterotrophic