Chapter 3

• Central Nervouis System
• .Brain and Spinal Cord
• Peripheral Nervous System
• .Nerve cells that send messages to the central nervous system

• Nerve Cells
• .Communicate with each other to send and receive messages from other parts of the body
• .Muscles and glands
• .We have 100 billion neurons mostly in the brain

Produces energy that fuels activity

Receives information from other neurons and passes messages through cell body

Carries messages away from cell body

White fatty sunstance that insulates and protects axon

Speeds transmission of messages

Small fibers at the end of the axon that branch out

A junction between the axon terminals of one neuron and the dendrites of another neuron

Carry information received by the sense to the central nervous system

Carry information from the central nervous system to the muscles and glands and influnce their functioning

Chemicals stores in sacs in the axon terminals

A neurotransmitter that, among its functions, triggers muscle contractions

• .Means "morphine within"
• .Natural, opiate-like neurotransmitters
• .Linked to pain control and to pleasure

• .Consists of neurons of the spinal cord and the brain
• .Spinal cord extend from the brain down the back
• .Spinal reflex:a simple, automatic response to something
• .Touching something hot on the stove

.Responsible for transmitting messages between the central nervous system and all parts of the body

• .Somatic: transmits sensory messages to the CNS
• .Activated by touch, pain, changes in temperature or body position
• .Autonomic (means involuntary): regulates body's vital functions such as heartbeat, breathing, digestion and blood pressure
• .Sympathetic: Prepares the body for action
• ."fight or flight" response: when the body decides what route to take in an uncertain situation
• .Parasympathetic: restores the body after action