Overview   Lab & Research     Rane Lab     My Research       -Neurons       -Ion Channels       -Patch Clamp       -Growth Factors       -PC12 Cells       -Summary   Pseudoscience   Evolution &   Creationism	Neurons The basic units of human structure and function are cells, microscopic organisms that construct the different tissues and organs of your body. Since I'm an ex-neurobiologist, I tend to believe that the most important cells are neurons. Neurons are specialized cells that serve as the functional and structural units of your nervous system. The nervous system itself can be divided into two separate components: The central nervous system, which consists of the brain and spinal chord, and the peripheral nervous system, which connects the central nervous system with the rest of the body. In turn, the peripheral nervous can be broken down into different divisions, one of which is the symapthetic nervous system. Sympathetic neurons generally act without any conscious control and they participate in many of our physiological responses to stress, the most important of which is the "fight or flight" response that saved many of our primitive ancestors. Thus, the increase in heart rate, sweaty palms, and churning stomach that you might experience during a frightening movie--or any of the Batman sequels--are the result of your sympathetic neurons. Like all cells, neurons come in a myriad of shapes and sizes. Despite this variety, they have been kind to scientists in the sense that they all possess several common physical attributes. These are diagrammed in the figure to your right. The cell body contains the nucleus of the cell, a warehouse for manufacturing cell machinery. The dendrites radiate outward from the cell body and, in general, receive stimuli from external sources, including other neurons. Once the neuron is stimulated, an electrical impulse travels from the dendrites to the cell body and finally into the axon. In turn, the axon propagates the impulse to the synaptic terminal and stimulates the release of chemicals called neurotransmitters. These chemicals can stimulate the dendrites of surrounding neurons, and if they do so, the cycle is renewed in the neuron's neighbors. This rapid, efficient propagation of electrical and chemical impulses is the hallmark of neurons and the nervous system in general. It generates your memories, emotions, and imagination. It underlies all of your actions, your five senses and, if you believe in parapsychology, that elusive sixth sense as well. But how are these impulses generated? Certainly some type of cellular machinery must be responsible. Indeed, it is, and hence our focus shifts to ion channels.
Mind 'Scapes, its pages and contents are © 1998 by Michael D. Hilborn, President of the Biggles 2000 Time-Dimensional Corporation. You are free to copy and use the original artwork on these pages, although I would appreciate it if you ask me first.