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Goose bumps are created when tiny muscles at the base of each hair, known as arrector pili muscles, contract and pull the hair straight up. The reflex is started by the sympathetic nervous system, which is responsible for many fight-or-flight responses. The muscle cells connected to the hair follicle have been visualized by actin ...
Disparity from planes of different depths. Far cells would respond to disparities on planes 1 and 2. Near cells would respond to disparities on planes -1 and -2. Tuned zero cells would respond to disparities on plane 0, or the plane of fixation. Simple cells have separate regions in their receptive field that respond to light and dark stimuli.
Thus, to Barcroft homeostasis was not only organized by the brain—homeostasis served the brain. [12] Homeostasis is an almost exclusively biological term, referring to the concepts described by Bernard and Cannon, concerning the constancy of the internal environment in which the cells of the body live and survive.
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Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges, blood vessels, and ducts. The two main types of cells in the brain are neurons, also known as nerve cells, and glial cells, also known as neuroglia. [1]
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Many of the cells and vasculature channels within the nervous system make up the neurovascular unit, which regulates cerebral blood flow in order to rapidly satisfy the high energy demands of activated neurons. [2] Nervous systems are found in most multicellular animals, but vary greatly in complexity. [3]
This form of microglial cell is commonly found at specific locations throughout the entire brain and spinal cord in the absence of foreign material or dying cells. This "resting" form of microglia is composed of long branching processes and a small cellular body.