| A | B |
|---|
| Central Nervous System (CNS) | consists of your brain and spinal cord |
| Peripheral Nervous System (PNS) | all the parts of the nervous system except for the brain and spinal cord |
| nerves | specialized structures which carry information between your body and your CNS |
| neuron | a nerve cell that is specialized to transfer messages in the form of fast-moving electrical energy |
| impulses | electrical messages |
| cell body | large region in the center of a neuron; has a nucleus and organelles |
| dendrites | short, branched extensions of the cell |
| axon terminal | the tip of each branch of the axon |
| axon | elongated extensions of a neuron |
| motor neurons | neurons that send impulses from the brain and spinal cord to other systems |
| nerve | a collection of axons bundled together with blood vessels and connective tissue |
| somatic nervous system | consists of neurons that are under your conscious control |
| autonomic nervous system | controls body functions that you don't think about (ex: heart rate, digestion) |
| sympathetic nervous system | one of the two divisions of the autonomic nervous system |
| parasympathetic nervous system | one of the two divisions of the autonomic nervous system; works to maintain homeostasis |
| brain | the main organ of the nervous system |
| involuntary | actions which are NOT under your control (ex: blinking, digestion) |
| voluntary | actions which are under your control |
| cerebrum | the largest part of your brain; the "mushroom cap"; controls voluntary movements, allows you to think |
| hemispheres | one of the two halves of the cerebrum |
| cerebellum | the second-largest part of the brain; lies beneath the back of the cerebrum; processes sensory information |
| medulla | part of the brain which connects to your spinal cord; controls involuntary processes |
| left hemisphere | controls actitvities such as speaking, writing, reading and solving problems |
| right hemisphere | controls actitivies such as spatial thinking, processing music and interpreting emotions |
| verterbrae | protective bones which surround and protect the spinal cord; make up the backbone |
| reflex | an involuntary and almost immediate movement in response to a stimulus |
| feedback mechanism | a cycle of events in which information from one step controls or affects a previous step |
| pupil | opening that allows light to enter the eye |
| iris | ring of muscle controls the amount of light which enters the eye |
| retina | a layer of light-sensitive cells |
| cochlea | the fluid-filled organ of the inner ear; vibrations inside of it make sound waves |
| olfactory cells | receptors for smell |
