Two opposing ideas about the nervous system * Reticular theory ( the nervous system consisted of a large network of fused nerve cells) * Neuron theory ( the nervous system consisted of distinct elements or cells * Discovery of staining led to the acceptance of neuron theory. Staining is a chemical technique that caused nerve cells to become colored so they stood out from surrounding tissue * A way of electricity is transmitted in groups of neurons, such as the optic nerve.
Basic Structure of the brain * Cerebral cortex- A 2mm thick layer that covers the surface of the brain and contains the machinery for creating perception, as well as language, memory, and thinking. * A basic principle of cortical function is modular organization – specific functions are served by specific areas of the cortex * Primary receiving areas- the first areas in the cerebral cortex to receive the signals initiated by each sense’s receptors.- occipital love( vision),, temporal lobe (hearing), parietal lobe (skin senses, eg: touch, temperature, and pain. * The frontal lobe receives signals from all of the sense, and plays an important role in perceptions that involve the coordination of information received through two or more senses.
Structure of neurons * The cell body- it contains mechanisms to keep the cell alive * Dendrites branch out from the cell body to receive electrical signals from other neurons * Axon/nerve fiber is filled with fluid that conducts electrical signals * Some neurons have long axons; others have short axons or none at all * Receptors- which are specialized to respond to environmental stimuli such as pressure for touch, all receptors look different but they all have something in common. Part of each receptors, indicated by the star, reacts to environmental stimuli and triggers the generation of electrical signals, which eventually are transmitted to neurons with axons.
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