Define vitamin?/Write down the types of vitamin/Classify vitamins

 Definitions: Vitamins are organic non-calorigenic nutrients that are required in small quantities for man different biochemical function, which generally cannot be synthesized by the body and must therefore, supplied by the diet.
Or Vitamin B- complex are chemical substance required by the body very small amounts, they do not yield energy but gives us protective manner.

Classification: According to solubility-Vitamins are classified into two main group.
1.       Water soluble vitamins-Vitamins B-Complex-Vitamins C.
2.       Fat soluble vitamins-Vitamin A, Vitamin E, Vitamin D & Vitamin K.
Difference vitamins between water soluble and fat soluble
Fat soluble vitamins.

Difference between fat soluble and water soluble vitamins

Fat soluble vitamins	Water soluble vitamins
1. Soluble in fat	1. Soluble in water
2. Bile salts & Fats are essential for their absorption	2. They are easily absorbed.
3. Are not precursor of co-enzymes ( except vit-k)	3. Many of them are precursors of co-enzymes.
4. significant amounts are stored in the Liver & adipose tissue	4. Small amounts are stored in the body.
5. They are not readily excreted in the urine.	5. When ingested in excess of the body’s requirement they readily excreted in the urine.
6. Excess amounts in the body is toxic (specially vit-A & D)	6. As excreted in the urine, excess amount is not toxic.

What are they ways of transmission of infactions diseases?

A. Direct transmission:
1. Direct- contact Infection may be transmitted by direct contact from skin to skin, mucosa to mucosa or mucosa to skin of the same or another person. Disease transmitted by direct contact include STD and AIDS, leprosy, skin and eye infection.
2. Droplet Infection- This is the direct projection of a spray of droplets of saliva and nasopharyngeal secretions during coughing scenting or speaking and spitting. The size of the particles are less than 5 mm and spread is limited to a distance of 30-60 cm between source and host. Disease transmitted by droplet infection include diphtheria whooping cough.
3. Contact with soil- The disease agent may be acquired by direct exposure to the disease agent in soil, compost or clearing vegetable matter e.g. Hookworm larval, Tetanus, mycosis etc.
4. Inoculation into skin or mucosa- The disease agent may be included directly into the skin or mucosa e.1g, rabies virus by dog bite hepatitis-B-Virus through needles and syringes.
5. Transplancental or vertical- Diseases transmitted transplacentailly are: Toxoplasma gondii, Rubella virus, Cytomegalo virus, Hepes virus, Varicella virus, Syphilis,-B, Cossacki-B, AIDS.
B. Indirect transmission- Mainly by 5 F.S-flies, fingers, fomites, fond and fluid.
1. Vehicle borne-
a. Water and food borne:  Acute diarrhoea, typhoid fever, cholera, polio, hepatitis-A, food poisoning.
b. Blood borne: Hepatitis-B, Malaria.
c. Organ transplantation: Cytomegalo virus infection.
2. Vector bone-
a. Mechanical transmission- Diarrhoea
b. Biological transmission- Plague, malaria.
3. Air borne-
a. Droplet nuclei- They are tiny particles (1-10 microns range) with represent the dried residue of droplets. They may be formed by i) evaporation of droplets coughed or sneezed into ari or ii) generated by atomizing devices (aerosols). Disease spread by droplet nuclei  include TH, influenza, chicken pox, measles.
b. Dust- They are larger droplets settle down by their sheer weight on the floor. Carpet clothes and become part of the dust. Diseased caused by dust are TB. pneumonia, Q fever etc.
4. Formite borne: Formites are inanimate articles or substances other than water or food contaminated by the infectious discharges from a patient. Formites include soiled clothes, towels linen. cups, spoons etc. Diseases transmitted by formites include diphtheria, typhoid fever, bacillary dysentery etc.
5. Unclean hands and fingers: The transmission takes place both directly and directly. Examples include typhoid fever, dysentery, hepatitis-A and intestinal parasites.