Chakras are the foci within our bodies where the energy which makes up our life force is generated. Chakra is a Sanskrit word meaning wheel; a good representation of the spherical energy field the word refers to.
We have six Chakras which are sited along the spine and a seventh which is located above these, floating above the physical aspect of your body.
We think of these Chakras as being composed of energy; but it is very important to realize that the Chakras are closely related to and have influence over your physical body.

Having your Chakras in the proper alignment will also keep your physical, mental and spiritual health in good condition.
Muladhara

The Muladhara is the Chakra of your lower body.  This Chakra is responsible for your survival instinct and other related primal behaviors. Located in the perineum, the Muladhara relates to the potentiality of human life.
This is the Chakra which corresponds to the adrenal glands in the physical body and produces the fight or flight response.

Swadhisthana

The Swadhisthana is the reproductive Chakra, also known as the sacral Chakra. This Chakra corresponds to the genitalia and controls sexuality and the creative urge. This Chakra also governs the production of sex hormones and plays a role in producing mood swings.
This Chakra is symbolized by a six petal lotus.

Manipura

Located in the Navel, the Manipura or solar plexus Chakra is responsible for the transition from simple to comlex emotions. This Chakra is responsible for energy flow and digestion – it governs the conversion of food into energy. The Manipura corresponds to the pancreas in the physical body.
This Chakra is symbolized by a ten petal lotus.

Anahata

The Anahata is the heart.  This Chakra is responsible for love and other complex emotions, as well as your sense of equilibrium and well being overall. This Chakra corresponds to the thymus gland (located in the chest) and the immune system in the physical body.

This Chakra is symbolized by a twelve petal lotus

Vishuddha

The Vishudda is the throat.  This Chakra is responsible for your faculties of communication. This Chakra corresponds to the thyroid gland in the physical body. The Vishudda also governs the process of growth.
This Chakra is symbolized by a sixteen petal lotus.

Ajna

The Anja is your eyebrow or forehead. This Chakra is also known as the third eye. The Ajna  comtrols your visualization abilities and is the Chakra which has to do with time, light and awareness. This is the Chakra with the vital function of governing the sleep cycle.
This Chakra is symbolized by a two petal lotus.
Sahasrara

The Sahasrara is the seventh and final Chakra. The Sahasrara is the most important of all Chakras. This Chakra governs consciousness and as such, it is also important to every other Chakra and every system in the human body. This Chakra corresponds to the pituitary gland in the physical body.
This Chakra is symbolized by a thousand petal lotus.