NociceptionIn physiology, nociception/ˌnəʊsɪˈsɛpʃ(ə)n/, also nocioception (from Latin nocere'to harm/hurt'), is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular signal, and recognize and characterize the signal to trigger an appropriate defensive response.
Afferent nerve fiberAfferent nerve fibers are axons (nerve fibers) of sensory neurons that carry sensory information from sensory receptors to the central nervous system. Many afferent projections arrive at a particular brain region. In the peripheral nervous system, afferent nerve fibers are part of the sensory nervous system and arise from outside of the central nervous system. Sensory and mixed nerves contain afferent fibers.Withdrawal reflexThe withdrawal reflex (nociceptive flexion reflex or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli. The reflex rapidly coordinates the contractions of all the flexor muscles and the relaxations of the extensors in that limb causing sudden withdrawal from the potentially damaging stimulus. Spinal reflexes are often monosynaptic and are mediated by a simple reflex arc.
PainPain is a distressing bodily feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotionalexperience associated with, or resembling that associated with, actual or potential tissue damage." Pain motivates animals to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future.
Receptive fieldThe receptive field, or sensory space, has been defined by Alonso and Chen as: a portion of sensory space that can elicit neuronal responses when stimulated. The sensory space can be defined in a single dimension (e.g. carbon chain length of an odorant), two dimensions (e.g. skin surface), or multiple dimensions (e.g. space, time[,] and tuning properties of a visual receptive field).
Sensory neuronSensory neurons, also known as afferent neurons, are in the nervous system which convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal root ganglia of the spinal cord. The sensory information travels on the afferent nerve fibers in a sensory nerve, to the brain via the spinal cord.
Autonomic nervous systemThe autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its force of contraction, digestion, respiratory rate, pupillary response, urination, and sexual arousal.
SkinSkin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis 'skin').
Charles Scott SherringtonSir Charles Scott Sherrington (27 November 1857 – 4 March 1952) was a British neurophysiologist and academic. His experimental research established many aspects of contemporary neuroscience, including the concept of the spinal reflex as a system involving connected neurons (the "neuron doctrine"), and how signal transmission between neurons can be potentiated or depotentiated. Sherrington himself coined the word "synapse" to define the connection between two neurons.
Threshold of painThe threshold of pain or pain threshold is the point along a curve of increasing perception of a stimulus at which pain begins to be felt. It is an entirely subjective phenomenon. A distinction must be maintained between the stimulus (an external thing that can be directly measured, such as with a thermometer) and the person's or animal's resulting pain perception (an internal, subjective thing that can sometimes be measured indirectly, such as with a visual analog scale).
Action potentialAn action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific cell rapidly rises and falls. This "depolarization" (physically, a reversal of the polarization of the membrane) then causes adjacent locations to similarly depolarize.
Animal disease modelAn animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of harming a human. Although biological activity in an animal model does not ensure an effect in humans, many drugs, treatments and cures for human diseases are developed in part with the guidance of animal models.*As an Amazon Associate I earn from qualifying purchases.