How many cells does a human have?
The human body consists of a make up of cells that serve different applications and organs. Some cells have he job of alerting other cells when an invasive host is present. Other cells eat bad cells. Each individual cell was created for a special purpose. Cells are always being created and destroyed in the human body and maintain a consistent cycle. It is very difficult to ascertain exactly how many cells exist in the human body because they are too numerous to count as well as the amount of cells present changes. For example: a person drinking a lot of alcohol kills off brain cells, burning your finger kills off some cells and puts others to work replenishing. The most current estimate is somewhere between 50 to 100 trillion cells.
The question is not very clear about whether it refers to number of types of cells in human body.
Like all bodies of all other living beings, human body is made up of cells. The cells in the human body are of about 210 different types, which are divides in cells of the following types of tissues or groups of cells. These are connective tissues, epithelial tissues, muscle tissues, and nervous tissues.
Connective tissues help to join and support various parts of the body. Epithelial tissues cover the body surface. This this type of tissues form among other things the external skin of the body. Muscle tissues are threadlike fibres that make movement of the body possible through contracting and relaxing. Nervous tissues perform the function of storing, processing information in the body. Each of these four types of tissues contain many different types of cells.
In another way of grouping human cell these can be classified in following groups of types of cells:
Keratinizing epithelial cells
Wet stratified barrier epithelial cells
Exocrine secretory epithelial cells
Hormone secreting cells
Metabolism and storage cells
Barrier function cells - kidney
Barrier function cells - others
Epithelial cells lining closed internal cavities
Ciliated cells with propulsive function
Extra cellular matrix secretion cells
Blood and immune system cells
Sensory transducer cells
Autonomic neuron cells
Sense organ and peripheral neuron supporting cells
Central nervous system neurons and glial cells
The exact number of cells in a human body cannot be counted accurately. However the total number of cells in an average adult human being is of the order of 10^13 to 10^14.