1. Our electrochemical controls
The Nervous System
Our electrochemical controls

2. Human Body Systems
The Nervous System controls the function of all of the other systems in the body.
Through this regulation the body can maintain homeostasis.
Movement, digestion, circulation, breathing and many other body functions are all controlled by the responses of the nervous system.

3. Neurons
The cells that transmit the electrical signals of the nervous system are called neurons
Sensory neurons carry information (impulses) from the sense organs to the central nervous system (CNS).
Motor neurons carry information (impulses) from the central nervous system (CNS) to the muscles and glands.
Interneurons, found in the CNS, connect the two.

4. Structure of a neuron The neurons consist of:
A cell body, where the nucleus is contained.
Dendrites, which picks up the impulse and carries it to the cell body
And Axons, which carry the impulse away from the cell body. Axons end in axon terminals.
The impulse is an electrical impulse while it is traveling along the neuron.

5. The Myelin Sheath
Schwann cells create a myelin sheath around each axon.
Exposed regions, called the nodes of Ranvier, plays an important part in the propagation of the nerve impulse.
Myelin increases speed of signal.

6. Action Potential
For a neuron to reach an action potential, it must reverse the electrical charge across the cell membrane.
Once the action potential reaches the end of the axon, neurotransmitters are released into the synapse.

7. The Synapse
The junction of an axon with another cell is called a synapse.
This junction can be with another neuron, muscles or glands. All receiving cells have receptors.
Chemicals, called neurotransmitters, are released into the synapse to transmit the impulse from one neuron to the next, or to the receptor tissue.

8. Central Nervous System (CNS)
The nervous system is divided into two parts.
The first part is the central nervous system (CNS), which is made up of the brain and the spinal cord.
Function is to relay, analyze and process information.

9. The Brain The brain is made up of:
The cerebrum, which is where thinking takes place.
The cerebellum, controls balance, coordination and voluntary actions.
The brain stem, controls breathing, heartbeat and blood pressure. Involuntary actions.

10. The Spinal Cord
The spinal cord carries the nervous impulses to different levels of the body.
An injury to the spinal cord would affect all of the areas serviced below the injury.
If you injured the lumbar region, what would be affected?

11. Peripheral Nervous System (PNS)
The peripheral nervous system (PNS), is made up of all of the nerves that are not part of the brain and spinal cord.
It is made up of the sensory and motor divisions.
The motor division of the PNS is further divided into the somatic and autonomic nervous systems.

12. Motor: Somatic Nervous System
The somatic nervous system is the nervous system that we can control.
After the brain has processed the information, the somatic motor neurons respond.
Some somatic nerves are used in reflex arcs and are not under our conscious control.
Ex: dancing or video games

13. Motor: Autonomic Nervous System
We do not control the ANS, therefore, it is said to be under involuntary control.
The ANS allows for homeostasis to occur.
These nerves have opposite effects on the organs they control, one nerve will speed up the heart and another will slow it down
It is not on and off, it is more like gas and brake.

14. Overview
Nerve video…frogs