Eyes and Ears
Reflexes, Cutaneous receptors, Referred pain
December 5, 2008
Reflex arcs are the pathways from the muscle fiber to the spinal cord. They act as a go-between for your reflexes. The Arcs involve a receptor, an afferent nerve fiber, sometimes one or more interneuron, an efferent nerve fiber, and an effector. Without these pathways we would have no quick “life saving” reflexes. One example would be a situation in which your nerve signals to the spinal cord to withdraw your hand from a stove eye. There are five groups of reflex arcs: ipsilateral, contralateral, monosynaptic, intersegmental, and the polysynaptic. They are explained as follows: Ipsilateral reflex arc in which the sensory input and motor output are on the same sides of the spinal cord such as the acoustic stapedious, the contralateral reflex arc in which input and output on opposite side of the spinal cord, the intersegmental reflex arc in which the input and output occur on different levels of the spinal cord for example when foot pain causes pain higher up in the body such as abdomen or hip muscles, the monosynaptic reflex arc in which the afferent and efferent neurons is only one synapse, for example the knee jerk reflex, and the polysynaptic reflex arc in which signals occur all over the many synapse on their way back to the muscle fiber.
Cutaneous receptors are any of the various types of sense organs located in the dermis or epidermis of the skin, usually a thermoreceptor, nociceptor, or mechanoreceptor. These are used in time of pain. The thermoreceptors are used to detect temperature. The nociceptors are used to detect sharp pains and the mechanoreceptors are used to detect touch, vibration, stretch, and more of the dull pains. Cutaneous receptors are used in the two-point threshold experiment talked about later in this report.
Referred pain is pain felt somewhere in which the problem is not located. For example, when...