Your nervous system is broken down into two separate parts Your (CNS) or Central Nervous System And your (PNS) Peripheral Nervous System Your Spinal.

Your nervous system is broken down into two separate parts

Your (CNS) or Central Nervous System

And your (PNS) Peripheral Nervous System

Your Spinal Cord and BrainThe cordinator and decision maker

All of the nerves and wiring (sendsmessages from your brain to the rest of

your body)Sending sensory input and causing motor output

There is an Automatic Nervous System (ANS) shares nerves withBoth PNS and CNS ( Automatic responses such as blood pressure)

Neurons - Specialized cells that make up the nervoussystem. They carry information around the body in the form of an electrical or chemical signal

Your nervous system regulates and coordinates the actions and activities of your body in response to internal and externalenvironment changes

These changes are called stimuli

Stimuli initiate impulses in sensory receptors…eyes, ears, nose, tongue, skin, internal sensors

Neurons differ from other cells in the body, because they are ableTo transmit signals from one cell to another in chemical and Electrical form

Brain and Spinal Cord

The brain has 100 billion neurons, controls actions, thoughts,and memory

The brain weights about 3 pounds and is protected by the Cranium

The Spinal Cord is a bundle of nerves that extend from the baseof the brain to the bottom of the backbone

The Spinal Cord is about 3 foot long and about an inch wide, protectedby your vertebra

SC controls both voluntary and involuntary actions

Cerebrospinal fluid fills the openSpace in the brain and spinal

Chord (Shock Absorber)

The PNS has 31 pairs of spinal nerves and 12 pairs of cranial nervesIn the body

Carries nerve impulses to and from the CNS

The PNS has two parts… the Somatic and Autonomic systems

Somatic = Actions you control (Voluntary) (Skeletal Muscle)

Autonomic = Actions you cannot control (Involuntary) (Smooth Muscle)

Spinal nerves connect with the spinal cord and innervate most areas Of the body, the cranial nerves connect vital organs directly to the brain

The autonomic nervous system is in connection with our internal organs such as heart, lungs, stomach, and reproductiveorgans. These organs processes stand above our awareness andare automatically controlled by the nervous system

The somatic side of things handles muscles in our extremities andjoints. These processes are very much controlled by our own will.

The PNS consists of two types of neurons

Sensory - runs from stimulus receptor that inform the CNS of thestimuli

Motor - runs from the CNS to muscles and glands

There are many different types of NeuronsWe will discuss two of them

Sensory Neurons- Send signals from the sense organ to the spinal cord and brain

Motor Neurons- send signals from the brain to the body’s muscles(These are the fastest neurons found in the body)

Neurotransmitters- Chemicals that are released at the synapse ofa nerve impulse to the target cell or neuron… carry out Communication in the body(Made within the neuron)Some examples of neurotransmittersAre ….EndorphinsAcetylcholine Dopamine

Soma - another word for the cell body

Nucleus - the brain of the neuron

Dendrite - this section of the neuron receives neurotransmitters

Axon - the axon terminals send neurotransmitters

Synapse - a gap between the axon and dendrite.. Neurotransmitterspass over this. A typical neuron will synapse around 1,000 to 10,000times during a communication

Schwann cells - make myelin, this substance is a fatty insulatorthat speeds nerve transmission

Neurons cannot regrow After damages, exceptIn the Hippocampus…Most neurons stop Reproducing after birth!

Receive message

Sends the message

Soma

Glial cells –Take 3 dif.Forms in thebody. Their Main purposeIs to protect andNourish theNeuron.

BBB (Blood Brain Barrier) - prevents most harmful substancesfrom passing through the blood into the nervous system. TheBBB is permeable to Alcohol!

There is a special carrier system that allows water, O2, CO2,glucose, and Nutrients to pass through the barrier

Drugs and your Neurons or Nervous System

It is now proven that abuse drugs affect the limbic system of thebrain (regulates feelings of pleasure)

Drugs of abuse produce feelings of pleasure by altering neurotransmission by neurons in the reward system that release the neurotransmitter dopamine

Dopamine like other neurotransmitters transfers from one neuron to Another and is then sent back to its source to be used again(reuptake system)

When drugs such as crack are used the drug “Clogs” these receptor Sites and creates a dopamine flood creating an uneven and Unhealthy balance of dopamine in your system

Body adjusts to functioning with the chemical, requiresthe drug to function normally