1. Nervous System
Week of February 18th

2. Functions of the Nervous System
The nervous system gathers and interprets information from inside your body and from the world outside your body.
The nervous system responds to that information as needed.

3. Central Nervous System (CNS)
Consists of your brain and spinal cord.
Processes and responds to all messages coming from the peripheral nervous system.

4. Peripheral Nervous System
All other parts of the nervous system except the brain and spinal cord.
Uses nerves to carry information between your body and your CNS.

5. Neuron
A nerve cell that is specialized to transfer electrical messages, or impulses, throughout the body.
Sensory neurons: gather information about what is happening in and around your body.
Motor neurons: send impulses from the brain and spinal cord to other systems.

6. Somatic vs. Autonomic Nervous System
Both part of the peripheral nervous system PNS.
The somatic nervous system is under your conscious control.
The autonomic nervous system does not need your conscious control.

7. Autonomic Nervous System
Works to keep your internal environment stable (homeostasis).
Controls body functions such as heart rate, digestion, pupil dilation.

8. The Brain
Involuntary actions are processes that the brain controls that happen automatically.
Voluntary actions are processes that the brain controls that must be processed.

9. The Spinal Cord
The nerve fibers in your spinal cord allow your brain to communicate with your peripheral nervous system.

10. Responding to the Environment

11. Reflex
An involuntary and almost immediate movement in response to a stimulus.
Your brain does not tell your foot to move. Your body reacts.
Sensory neuron, motor neuron, brain

12. Feedback Mechanism
A cycle of events in which information from one step controls or affects a previous step.
Example: temperature- regulating

13. The Eye
Cornea: clear membrane on the front of the eye that protects the eye but allows light to enter.
Iris: a ring of muscle the controls the dilation of the pupil.
Pupil: the opening in the front of the eye that allows light through.

14. The Eye cont.
Lens: located in the back of the eye that light travels through after the pupil.
Retina: the light-sensitive inner layer of the eye that receives images formed by the lens and transmits them through the optic nerve to the brain.

15. The Eye cont.
Light travels in a straight line until it passes through the cornea and the lens and is focused on the retina.