PSB-2000 Chapter Notes - Chapter Ch. 2 + Ch. 3: Neuron Doctrine, Axon Terminal, Cell Nucleus
Document Summary
One end is the input zone with branches like dendrites while the other is the output zone. Neurons transmit touch information from the body into the spinal cord: dendrites comprise the input zone in all neurons. In multipolar and bipolar neurons, the cell body receives synaptic inputs, so it is also part of the input zone. Because they continue to divide into adulthood (unlike neurons), these cells can give rise to deadly brain tumors: some of these cells, especially astrocytes, respond to brain injury by changing size (swelling). This edema, the swelling of tissue in response to injury, can damage neurons and is responsible for many symptoms of brain injuries. But unlike other cells, neurons routine undergo a brief but radical change in polarization, sending an electrical signal from one end of the neuron to the other. Ionic mechanisms underlie the action potential: action potential is created by the sudden movement of na+ ions into the axon.
