____ is the process by which inhibitory transmitters cause the inside of the neuron to become more negative
By the end of these activities, students will. 1  understand the hierarchical organization of the brain, neuron, and synapse; 2  understand the sequence of events involved in communication at the synapse; and. 3  understand that synaptic transmission involves neurotransmitters that may be either excitatory or inhibitory. Some axons are over 1 meter long. 1  Display the top half of a transparency of Master 2.2, Neurons Interact with Other Neurons Through Synapses. Point out that the axon terminals of one neuron end near the dendrites of another neuron. 2  Reveal the lower portion of Master 2.2 showing the synapse. (b) Inhibitory transmitters cause hyperpolarization, an increased negative charge inside the axon. The charge inside the axon must reach the dashed line to trigger an action potential. Effect of excitatory (E) and inhibitory (I) input on the firing rate of a neuron. The amount of excitatory and inhibitory input to the neuron is indicated by the size of the arrows at the synapse. Fig. 2-17, p. 43 Recording Neural Signals - continued Electrical signals or action potentials occur when: permeability of the membrane changes Na+ flows into the fiber making the neuron more positive K+ flows out of the fiber making the neuron more negative This process travels down the axon in a propagated response Figure 2.7 (a) When a nerve fiber is at rest, there is a difference in charge of -70 mV between the inside and the outside of the fiber. The resting membrane potential is, by convention, assigned a negative number because the inside of the neuron is more negatively charged than the outside of the neuron. This negative charge results from the unequal distribution of sodium ions (Na +), potassium ions (K +), chloride ions (Cl –), and other organic ions. A stimulus occurring at the cell body starts an electrical change that travels like a wave over the length of the neuron. This electrical change, the action potential, results from a change in the permeability of the neuronal membrane. Sodium ions rush into the neuron, and the inside of the cell becomes more positive. A neuron is a specialized cell that can produce different actions because of its precise connections with other neurons, sensory receptors, and muscle cells. A typical neuron has four morphologically defined regions: the cell body, dendrites, axons, and presynaptic, or axon, terminals. 1,2,3 The resting membrane potential is, by convention, assigned a negative number because the inside of the neuron is more negatively charged than the outside of the neuron. This negative charge results from the unequal distribution of sodium ions (Na+), potassium ions (K+), chloride ions (Cl–), and other organic ions. This positivity is the rising phase of the action potential. (C) As the nerve impulse moves past the electrode, the charge inside the fiber becomes more negative. This is the falling phase of the action potential. (D) Eventually the neuron returns to its resting state. Figure 2.4: (a) Recording of an action potential in an axon following stimulation due to changes in the permeability of the cell membrane to sodium and potassium ions. (b) The cell membrane of a resting neuron is more negative on the inside of the cell than on the outside. When the neuron is stimulated, the permeability of the membrane changes, allowing Na+ to rush into the cell. This causes the inside of the cell to become more positive. This local change starts a similar change in the adjoining segment of the neuron’s membrane. In this manner, the electrical impulse moves along the neuron.
Hyperpolarization is the process by which inhibitory transmitters cause the inside of the neuron to become more negative.