2. The nervous system gathers and interprets information about the body’s internal and external environments and response to that information

3. The nervous system keeps your organs working properly and allows you to speak, smell, taste, hear, see, move, think, and experience emotions. SHHHH, don’t tell him it smells

4. Your nervous system controls and coordinates many things that happen in your body. It acts as a central command post, collecting and process information and making sure appropriate information gets sent to all parts of the body.

5. The nervous system is divided into two subdivisions: The central nervous system (CNS)  The central nervous system (CNS)  Peripheral nervous system (PNS )

6. The Central Nervous system (CNS) includes your brain and spinal cord. It processes all incoming and outgoing messages It processes all incoming and outgoing messages

7. The peripheral nervous system (PNS) consists of communication pathways, or nerves, that connect all areas of your body to your CNS. A. Central nervous system B. Peripheral nervous system B1. Somatic nervous system B2. Autonomic nervous system

8. Neurons transfer messages throughout your body in the form of fast-moving electrical energy

9. Electrical messages that pass along the neurons are called impulses. Impulses may travel as fast as 150 m/s or as slow as 0.2 m/s Impulses may travel as fast as 150 m/s or as slow as 0.2 m/s

10. The neuron is the functional unit of the nervous system. Humans have about 100 billion neurons in their brain alone! While variable in size and shape, all neurons have three parts. Dendrites receive information from another cell and transmit the message to the cell body. The cell body contains the nucleus. The axon conducts messages away from the cell body.neuronDendritescell bodyaxon

11. Dendrites are short, branched extensions that receive information from other cells. A neuron may have many dendrites, allowing it to receive impulses from thousands of other cells A neuron may have many dendrites, allowing it to receive impulses from thousands of other cells

12. From the cell body, information is transmitted to other cells by a fiber called an axon. Axons can be very short or quite long. You have some really long axons that extend almost 1 meter from your lower back to your toes

13. The end of an axon often has branches that allow information to pass to yet more cells. The tip of each branch is called an axon terminal The tip of each branch is called an axon terminal

14. Sensory neurons typically have a long dendrite and short axon, and carry messages from sensory receptors to the receptors to the CNS CNS Sensory neurons have specialized dendrites called receptors that detect changes inside and outside the body.

15. Examples of Sensory Neurons Receptors in your eyes detect the light around you detect the light around you Receptors in your stomach let your brain know when your stomach is full or empty

16. Motor neuronsMotor neurons have Motor neurons a long axon and a long axon and short dendrites and short dendrites and transmit messages transmit messages from the central nervous from the central nervous system to the muscles system to the muscles (or to glands). (or to glands).

17. Motor neurons cause the muscles around your eyes to move when around your eyes to move when the sensory neurons in your eyes the sensory neurons in your eyes detect bright light. This movement detect bright light. This movement makes you squint, which reduces makes you squint, which reduces the amount of light entering the eye the amount of light entering the eye Motor neurons also send messages to your gland, such as sweat glands. These messages tell the sweat glands to release sweat

18. The CNS is connected to the rest of your body by nerves. The CNS is connected to the rest of your body by nerves. A nerve is a bundle of axons A nerve is a bundle of axons Most nerves contain the axons of both sensory and motor neurons. Most nerves contain the axons of both sensory and motor neurons.