Description

This activity maps to the OpenStax biology textbook, 30.6 Plant Sensory Systems and Responses

Student Introduction: The nervous system depends on neurons working together to transmit signals. Neurons are special cells that have plasma membranes capable of generating and conducting electric impulses. Each neuron is composed of dendrites that collect information from other neurons, a cell body where nerve impulses are initiated, an axon along which impulses are conducted, and axon terminals that synapse with a target cell such as another neuron or muscle tissue.

The electric potential of neurons is responsible for signal transmission. The inside of a neuron generally has an excess of negative charges. When a neuron is unstimulated, the difference in electric charge across the plasma membrane is the resting potential. A neuron is sensitive to physical or chemical changes that cause changes in the resting potential. A sudden and rapid reversal in charge across the membrane is called an action potential. When a neuron is stimulated, the action potential moves along the axon to the axon terminals to the target cell. The post-synaptic membrane of the target cell integrates the information it receives. In order for the target cell to be stimulated, the stimulus must be greater than the target cell's action potential. Neurotransmitters that affect the membrane bring about an excitatory postsynaptic potential (EPSP). When several EPSP's arrive at the cell body simultaneously, the potential is summed over the number of synaptic knobs, and an action potential may be reached.

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