Monday, 2nd, May, 2011

An Introduction to Our Nervous SYSTEMOur Nervous system is

responsible for the communication in our body, it helps us feel and sense the stimulus, analyze the received messages and react by the help of nervous messages so that we can adapt to our environment and survive.

The nervous system is made up of many cells called NEURONS.

The Nervous CellA neuron has three parts:

1-"Dendrites" receive messages that are coming into the neuron from the receptors or from other neurons.

2- The cell body, or "soma," acts as the primary maintenance station, conducting metabolic activities that are necessary to keep the neuron alive.

3- The "axon" extends from the soma

to carry an electrical message

to the muscles if it is a motor nerve fiber, or to the central nervous system

if it is a sensory nerve fiber. Axons can be very long.

How can we taste freshness in our mouth ? Sensory neurons take information

from the eyes, ears, nose, tongue, and skin to the brain. Motor neurons carry messages away from the brain and back to the rest of the body. They are connected muscle fibers, gland cells, or other neurons.

There are receptors found in our mouth and especially on the tongue to let us taste the flavor and to feel the temperature of the food. They are of two types:

Chemo-receptors and Thermo-receptors.

How can we taste freshness in our mouth ?1- The chemo-receptors are parts of

the sensory neurons that are able to bind to the chemical particles of the food and create a nervous message to be transmitted to the brain to feel the food taste.

2- The thermo-receptors are parts of other sensory neurons that are able to create a nervous message when they are exposed to a change in the temperature of food then this nervous message is transmitted to the brain to realize the temperature of food.

The thermo-receptors receptors are also of two types:

a- If the receptors responsible for the cold sensation are activated, we feel the freshness in our mouth or the cold sensation.

b- If the receptors responsible for the hot sensation , we feel the chilly flavor or hotness in our mouth.

Where does freshness / cold sensation occur in the mouth ?

Freshness occur, notonly on the tongue butin the roof of the mouthand at the back of thethroat. Taste buds arethought to be located inconcentrated areas onthe tongue.

How does our mouth detect the temperature of food?We feel temperature with two different sets of

nerve cells:

One set called TRP-M8 will detect increases in temperature and the other set is called TRP-V1 that will detect decreases.

1- Similarly when the TRP-V1 cells heat up they also send a signal. But this time the nervous message reach the brain to tell it to feel hotness in that specific part o the mouth.

2- When the temperature decreases the TRP-M8 neurons will open sodium gates, allowing positive sodium ions to move into the cell and potassium to flow out, this creates a voltage which sends a nervous signal along the thin tail of the nerve cell towards your brain. This nervous message tells the brain to feel cold in that specific part of the mouth.

Why does Mint cause mouth freshness?It was discovered that Mint contains

Menthol which is a chemical

substance that is able to act on the

cold temperature receptors of the

mouth opening them and initiating a

nervous message to be transmitted to

the brain just like any decrease in the

mouth temperature will do.

REFERENCES http://www.myonlinewellness.com/topic/cidpcauses

http://kidshealth.org/parent/general/body_basics/brain_nervous_system.html#

http://www.abacon.com/psychsite/dict.html

http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/does-a-mint-make-your-mouth-cold/

http://drbenkim.com/health-benefits-mint.htm

http://www.answers.com/topic/taste-bud