The Nervous System

http://www.brainpop.com/health/nervoussystem/nervoussystem/

The basic component of the nervous system is a neuron.

Neuron-conducting cells that constitute the brain, spinal column, and nerves, consisting of a nucleated cell body with one or more dendrites and a single axon. Also called nerve cell.

Neurons have 3 basic parts to themCell Body [soma]AxonDendrites

http://www.brainpop.com/health/nervoussystem/neurons/

The nervous system has two basic functions.

It gathers information It interprets information

This information comes from inside the body and from the world outside the body. The nervous system responds to this information as needed.

The way your body interacts with the world is through :

Stimulus Response

Stimulus-something that excites or causes a physical response in an organism.

Response-A reaction to a specific stimulus.

The Brain

http://www.brainpop.com/health/nervoussystem/brain/

The Brain

The nervous system has two parts.

Central nervous systemPeripheral nervous system

The Central Nervous System

Central or CNS- Consists of the brain and spinal cord

SpinalCord

Brain

Peripheral- nerves connecting CNS to muscles and organs

Central Nervous System

Peripheral Nervous System

The CNS processes and responds to all of the messages coming form the peripheral nervous system. Normally, information is transferred from the PNS to the CNS and Back. However, in some cases the PNS causes a response without involving the CNS.

PNS

The PNS has two types of nerves: Somatic and Autonomic nerves.

Somatic-control conscious movement.

Autonomic-control involuntary movements.

Autonomic System

Two divisions: sympathetic Parasympatheitic

Control involuntary functions heartbeat blood pressure respiration perspiration digestion

Can be influenced by thought and emotion

The brain can be divided into 3 regions

medullaCerebellumCerebrum

Cerebrum -is the thinking part of the brain and it controls your voluntary muscles.

Cerebellum -It controls balance, movement, and coordination (how your muscles work together).

Medulla -is to control your involuntary muscles the ones that work automatically, without you even thinking about it, also sorts through the millions of messages that the brain and the rest of the body send back and forth.

Peripheral Nervous System

2 kinds of neurons connect CNS to the body sensory motor

SpinalCord

Brain

Nerves

Motor - CNS to muscles and organs: a nerve cell neuron that sends nerve impulses from the spinal cord or brainstem away from the central nervous system toward a muscle or gland

Sensory - sends nerve impulses from the sense organs (sensory receptors) to the CNS.

Muscle

MotorNeuron

Interneuron

Skin receptors

SensoryNeuron

Brain

The senses provide information about the outside environment to the nervous system.

There are five senses:

SightTouchHearingTasteSmell

5 senses

The senses of sight, touch and hearing involve processing physical information from the environment.

The senses of smell and taste involve processing chemical information.

5 senses

Let’s look each one and explore the nerve responsible for helping navigate our world.

Optic nerve

Optic nerve- the second pair of cranial nerves whose nerve fibers transmit visual light signals from the eye to the brain.

http://www.doereport.com/enlargeexhibit.php?ID=2504

http://www.brainpop.com/health/senses/eyes/

Auditory nerve

Auditory nerve-nerve connecting inner ear to brain: a nerve that conveys impulses relating to hearing and balance from the inner ear to the brain

Olfactory nerve

Olfactory nerve- nerves consisting of sensory fibers that conduct to the brain the impulses from the mucous membranes of the nose.

taste

Taste buds-Oval-shaped clusters of cells located on the tongue and lining of the mouth that contain special nerve endings that help give rise to the sense of taste.

http://www.brainpop.com/health/senses/taste/

skin

Is made up of different layers. Let’s look at 2 of them.

DermisEpidermis

Dermis

Dermis -the dense inner layer of skin beneath the epidermis, composed of connective tissue, blood and lymph vessels, sweat glands, hair follicles, and an elaborate sensory nerve network.

Epidermis

Epidermis-the outer layer of the skin covering the exterior body surface of vertebrates. 

Light to Dark

There are many different skin tones. From the very light to the very dark. Let’s look at what causes us to have different skin color.

Melanin

Melanin-Insoluble naturally occurring dark pigments found in skin, hair, fur, and feathers. Responsible for the color of your skin.

Melanin protects the body by absorbing ultraviolet radiation from the sun.

The End