| A | B |
|---|
| Regulation | control and coordination |
| Receptors | sensitive to changes in the external and internal environment |
| Neurons | basic unit of structure and function in the nervous system |
| Effectors | Are muscles or glands in which neurons are attached to |
| Impulses | electrochemical message |
| Stimulus | is a change in the external or internal environment which initiates an impulse |
| Dendrites | Fibers that detect stimuli and generate an impulse toward the cyton |
| Cyton | Known as the cell body, Contains the nucleus of the neuron |
| Axon | A fiber that transmits the impulse away from the cyton and towards the terminal branches |
| Synapse | The gap between the terminal branches |
| Neurotransmitters | Chemicals secreted by the terminal branches that aid in the transmission of an impulse across the synapse |
| Hydra | Contains no brain or control center, so impulses travel in all directions across a nerve net |
| Sensory neuron | Carry impulses from the receptors toward the spinal cord and brain |
| Interneuron | Relay Impulses from one neuron to another |
| Motor neuron | Carry impulses from brain and spinal cord toward the effectors |
