sensory neuron Neuron that carries nerve impulses from sense organs or internal organs
to the central nervous system.
somatic nervous system Part of the motor division that carries nerve impulses to mus-
cles that control voluntary body movements.
spinal cord Long, tube-shapedbundleofneuronsthatcarrynerveimpulsesbackandforth
between the body and brain.
sympathetic division Division of the autonomic nervous system that prepares the body
for fight or flight in emergencies.
synapse Place where the axon of one neuron meets the dendrite of another neuron.
Points to Consider
- The sensory division of the peripheral nervous system carries messages from sense
organs to the central nervous system. What are some examples of sense organs? - Do you know how sense organs work? For example, do you know how your eyes sense
light?
20.2 Lesson 20.2: Eyes and Vision
Lesson Objectives
- Describe how humans see and explain why vision is important.
- Explain how the eye works to produce images.
- Describe the nature of light.
- Explain how lenses correct vision problems.
Check Your Understanding
- What are some ways that people use their eyes?
- Which part of the nervous system carries messages from the eyes to the central nervous
system? - Which part of the brain interprets messages from the eyes?