There are also sensory nerves encircling hair follicles that give information on when the hair is displaced. is my hand flat or in a fist? Am I holding a bat or a ball?). Combined, these receptors allow for the sense of touch and discrimination of shapes, textures, and objects, are resonsible for the sensations of heat and pain, and give information on where the hand and fingers are in relation to the body (i.e. Sensory nerve endings in the fingers include Meisnner’s corpuscles (light touch, rapidly adapting), Pacinian corpuscles (large receptive fields, rapidly adapting), free nerve endings (temperature and pain), Merkel discs (light touch discrimination of objects and texture), and Ruffini endings (slowly adapting, finger position information). If the needles are touched to two smaller receptive fields, such that each needle point contacts a separate receptive field, the nervous system can distinguish these as two separate points. If two needles spaced a millimeter apart are touched to a large receptive field, both points will lie within the receptive field and will be encoded as a single point. For example, the receptive field size of sensory nerves on the human back is much larger than on the fingertip. Smaller receptive fields contribute to acuity. The receptors also differ in the size of their receptive fields. Slowly-adapting receptors deliver information regarding prolonged touch, such as occurs when you are grasping a tool for an extended period of time. Rapidly-adapting nerve receptors deliver information on changes that occur at the skin, such as occurs as you move your finger over a gritty surface. There are several sensory nerve endings and receptors in the human hand.
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