Describe the physiology of depolarization and repolarization. Explain the steps in terms of the ions involved. Include the process of exocytosis in your answer.
Neurons: Neurons are nerve cells; they receive and transmit signals. Sensory neurons detect environmental signals such as visual images, odors, taste, touch, and sounds. Motor neurons signal muscle cells to contract. Other types of neurons relay internal messages throughout the body. The neuronal cell body contains the nucleus and may have multiple dendrites branching from it. The axon conducts signals away from the cell body toward the nerve terminals. Dendrites and the cell body recieve signals from the axons of other neurons. All neurons work by use of ion channels to alter membrane potential.
Electrical signaling and voltage-gated ion channels: Depending on the membrane potential, some ion channels change conformation. Voltage-gated Na+ ion channels can be in open, closed, or inactivated conformations.
Resting cell: membrane potential of -60 mV, Na+ ion channel closed.
Electrical signal; depolarization: opens up Na+ channels temporarily, positive charges rush into the cell, neutralizing the ...