THE NERVOUS SYSTEM

By: Hugh Nguyen and Waylon Yen

Background

The nervous system controls and coordinates functions throughout the body and responds to internal and external stimuli.

The basic units of the nervous system are neurons.

There are 2 kinds of nervous systems: central nervous system and peripheral nervous system

How It Works

The Nervous System is a network that controls and coordinates all the activities

It transmits messages or signals from the brain to the different regions of the body

It works with the help of nerves or neurons, which conduct the signals or impulses between the two components of the nervous system.

The neurons can be of different types, such as sensory and motor neurons.

The sensory neurons generate and transmit the stimuli received from the sensory organs like the eye, nose or skin, to the central nervous system, the brain and the spinal cord.

(Cont)

The brain in turn processes these stimuli and sends them back to the other parts of the body telling them to react to a particular type of stimulus.

The motor neurons are responsible for receiving signals from the brain and spinal cord and transmitting them to the other organs of the body.

The neurons use electrochemical signals in the transmission of signals or impulses from one neuron to another.

Nerve Impulse Resting Neuron

Outside is positive charge while inside negative

Cell membrane pumps sodium ions out of the cell and potassium ions into the cell by active transport

As a result the inside of the cell has more potassium and fewer sodium than the outside

The electrical charge across the cell membrane of a neuron in its resting state is called resting potential

Moving Impulse Neuron remains resting until it

receives stimulus Impulse cause a movement of ions

across cell membrane Impulse travels rapidly down axon

away from cell body and toward axon terminals

Cell membrane thousands of protein channels that allow ions to pass through depending on the “gates”

If sodium ions flow inside in the membrane it causes the membrane to temporarily become more positive, reversing the resting potential

This reverse is called action potential

Central Nervous System

The central nervous system consists of the brain and spinal cord.

The skull and vertebrae in spinal column protect the brain and spinal cord.

Cerebrospinal Fluid bathes the brain and spinal cord and acts as a shock absorber that protects the central nervous system.

Peripheral Nervous System

Consists of all nerves and cells not associated with the brain and spinal cord

Sensory division Transmits impulses

from sense organs to central nervous system

Motor division Transmits impulses

from central nervous to muscles or glands

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Somatic Nervous System Regulates activities under conscious control,

movement of skeletal muscles Some somatic nerves involved with reflexes Rapid response possible because receptors in skin

stimulate sensory neurons, which carry impulses to spinal cord

Autonomic Nervous System Regulates activities that are automatic or involuntary Control functions of the body that are not under

conscious control

Touch The five sensory organs are

touch, sight, hearing, taste, and smell.

The sense of touch is distributed throughout the body.

Four kinds of touch sensations can be identified: cold, heat, contact, and pain.

Hearing

The ear is the organ of hearing. The outer ear is away from the head and is shaped like a cup to direct sounds toward the tympanic membrane, which transmits vibrations to the inner ear through a series of small bones in the middle ear

The brain combines the input of our two ears to determine the direction and distance of sounds.

Taste

The receptors for taste, called taste buds, are situated chiefly in the tongue, but they are also located in the roof of the mouth and near the pharynx.

They are able to detect four basic tastes: salty, sweet, bitter, and sour.

Generally, the taste buds close to the tip of the tongue are sensitive to sweet tastes, whereas those in the back of the tongue are sensitive to bitter tastes. The taste buds on top and on the side of the tongue are sensitive to salty and sour tastes. At the base of each taste bud there is a nerve that sends the sensations to the brain.

Smell

The nose is the organ responsible for the sense of smell. The cavity of the nose is lined with mucous membranes that have smell receptors connected to the olfactory nerve.

The smells consist of vapors of various substances. The smell receptors interact with the molecules of these vapors and transmit the sensations to the brain.

Sight

Sight or vision is the capability of the eye to focus and detect images of visible light on photoreceptors in the retina of each eye that generates electrical nerve impulses for varying colors, hues, and brightness.

There are two types of photoreceptors: rods and cones. Rods are very sensitive to light, but do not distinguish colors. Cones distinguish colors, but are less sensitive to dim light.

Strengths

Many neurons providing fast information to and out of the brain.

Able to strengthen through mental and physical exercise.

Humans have really complex and capable brains, making us able to make advances through history and differentiates us from other animals.

Weaknesses

The many fragile neurons means the brain is very susceptible to damage from a blow in the head.

If one section of the brain doesn't work, most likely, the rest of the body will suffer since the brain controls body functions.

Humans only use 10% of their brain power. If we could learn to utilize the other 90%, we would be progress a lot faster. Unfortunately, we cannot.

Diseases

Conditions associated with the nervous system

Spinal disease is a common nervous system disease which affects the spinal column and/or the spinal cord and spinal nerves which are contained there in.

Spine disease is a large area of study because of the large number of diseases which can affect the spinal system, from purely skeletal disorders to primary nervous system disorders.

All types of spine disease can present with either or both spinal symptoms or neurological symptoms associated with injury or compression of the spinal cord or spinal nerves.

To treat Spinal Disease people must have surgery.

Continued

Epilepsy is a condition characterized by recurring seizures in an individual.

Seizures are an abnormal over activity of the cells of the brain which can affect variable regions of the central nervous system, primarily in the forebrain.

The effects of seizures depend on their location in the brain and their extent.

The classic appearance of seizure with physical convulsions in a patient is a common manifestation of seizures but not all types of seizures include convulsions.

The only cure so far for Epilepsy is surgery.

Continued

Traumatic spine disease refers to any disease of the spine which occurs as the result of a traumatic injury such as a fall or motor vehicle accident.

It can include spinal fractures, traumatic disc herniation and spinal instability.

This causes a break down of many nerves, causing the body to function inorderly.

Some cures are surgery and stability of the spine.

Maintain a Healthy Nervous System

Vitamin B Complex plays a major role in keepingyour nervous system healthy.

Have foods which are rich in it or take vitamin supplements if needed.

Exercise the system by writing ten minutes a dayto stimulate the sensory and motor neurons.

Various medications may be prescribed to treat these disorders and in more severe cases, neurological surgery may be prescribed.

Do not stress out.

THANK YOU