The document discusses the central and peripheral nervous systems. It provides definitions for key terms, including that the central nervous system is the brain and spinal cord, while the peripheral nervous system connects it to the rest of the body. It describes how neurons transmit electrical signals through the nervous systems and across synapses, or gaps between neurons, to carry messages throughout the body.

1. CENTRAL and PERIFERAL
NERVOUS SYSTEM
SO THE TWO SHALL BECOME ONE

2. Quick facts
• Central nervous system is the brain and the spinal cord.
• Peripheral nervous system is the nerves that connect the
central nervous system to the rest of the body.
• Reflex action is a response by the body that takes place
without the brain being involved.
• Neuron is a nerve cell.
• Synapse is the gap between neurons that carry messages
throughout the nervous system.

4. A FEW FACTS … THE NERVOUS SYSTEM
• Special nerve endings in your skin called receptors can
detect stimuli from outside or inside your body.
• Electrical impulses travel through the peripheral
nervous system via neurons (also known as nerve
cells) to the central nervous system.
• Neurons group together form a nerve.

5. WHAT MAKES A NERVE

6. Structure and function of Neurons
# STRUCTURE FUNCTION
1 DENDRITE Branches that extend from the cell body. These receive chemical
messages from other NEURONS.
2 SOMA CELL body. Contains the Nucleus
3 AXON A long structure through which nerve signals pass from the cell body.
4 NODE OF RANVIER Are small gaps in the myelin sheath. Allow for the electrical signal to
jump from one node to the next.
5 BOUTON or AXON
TERMINAL
Electrical signals in the axon are converted to chemical signals in the
bouton.
6 SCHWANN CELL Make up Myelin. They help to speed up the transmission of electrical
signals along the axon.
7 MYELIN SHEATH Longer axons are covered with a MYELIN sheath. It acts like insulation
around the wire. Prevents short circuits.
8 NUCLEUS Contains the genetic material of the cell.

8. There are three
types of neurons:
1.Sensory neurons - carry
the impulse generated by
the stimulus to the
central nervous system.
2.Interneurons - carry the
impulse through the
central nervous system.
3.Motor neurons - take the
impulse from the central
nervous system to as
muscles or glands.

9. DIAGRAM OF A SYNAPSE
• The gap between neurons is called the synapse.
• Chemical compounds are produced at the end of the axon that carries the impulse to the next
neuron.
• The message is converted to an electrical impulse which continues down the axon.
•

10. REFLEX ARC

12. LETS RECAP

13. REVIEW
• The nervous system is made up of the central
nervous system (brain and the spinal cord) and
the peripheral nervous system.
• A neuron is a nerve cell.
• The Synapse is the gap between neurons.
• The Reflex arc is the central nervous systems
response to a stimulus.