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Afferent nerve

 
Afferent Nerve

 
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Afferent nerve
 
 
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In the nervous system
Nervous system

The nervous system is a Neural network of specialized cells that communicate information about an animal's surroundings and itself. It processes this information and causes reactions in other parts of the body....
, afferent neurons (otherwise known as sensory
Sensory neuron

Sensory neurons or also known as afferent neurons are neurons that are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord....
 or receptor neuron
Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s), carry nerve impulses
Action potential

An action potential is a self-regenerating wave of electrochemical activity that allows nerve cells to carry a signal over a distance. It is the primary electrical signal generated by nerve cells, and arises from changes in the permeability of the nerve cell's axonal Cell membranes to specific ions....
 from receptor
Receptor (biochemistry)

In biochemistry, a receptor is a protein molecule, embedded in either the plasma membrane or cytoplasm of a cell, to which a mobile signaling molecule may attach....
s or sense organs toward the central nervous system
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneuron
Interneuron

An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways. Like motor neurons, interneuron cell body are always located in the central nervous system ....
s. The opposite activity of direction or flow is efferent
Efferent nerve

In the nervous system, efferent nerves ? otherwise known as motoneuron or effector neurons ? carry action potential away from the central nervous system to effectors such as muscles or glands ....
.

In the nervous system there is a "closed loop" system of sensation, decision, and reactions.






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Encyclopedia


In the nervous system
Nervous system

The nervous system is a Neural network of specialized cells that communicate information about an animal's surroundings and itself. It processes this information and causes reactions in other parts of the body....
, afferent neurons (otherwise known as sensory
Sensory neuron

Sensory neurons or also known as afferent neurons are neurons that are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord....
 or receptor neuron
Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s), carry nerve impulses
Action potential

An action potential is a self-regenerating wave of electrochemical activity that allows nerve cells to carry a signal over a distance. It is the primary electrical signal generated by nerve cells, and arises from changes in the permeability of the nerve cell's axonal Cell membranes to specific ions....
 from receptor
Receptor (biochemistry)

In biochemistry, a receptor is a protein molecule, embedded in either the plasma membrane or cytoplasm of a cell, to which a mobile signaling molecule may attach....
s or sense organs toward the central nervous system
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneuron
Interneuron

An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways. Like motor neurons, interneuron cell body are always located in the central nervous system ....
s. The opposite activity of direction or flow is efferent
Efferent nerve

In the nervous system, efferent nerves ? otherwise known as motoneuron or effector neurons ? carry action potential away from the central nervous system to effectors such as muscles or glands ....
.

In the nervous system there is a "closed loop" system of sensation, decision, and reactions. This process is carried out through the activity of afferent neurons, interneurons, and efferent neurons.

A touch or pain
Pain

Pain, in the sense of physical pain, is a typical sensory experience that may be described as the unpleasant awareness of a noxious stimulus or bodily harm....
ful stimulus
Stimulus (physiology)

In physiology, a stimulus is a detectable change in the internal or external environment. When a stimulus is applied to a sensory receptor, it elicits or influences a Reflex action via Transduction ....
, for example, creates a sensation
Sensation

Sensation is the Fiction-writing modes for portraying a character's perception of the senses. According to Ron Rozelle, ?. . .the success of your story or novel will depend on many things, but the most crucial is your ability to bring your reader into it....
 in the brain only after information about the stimulus travels there via afferent nerve pathways. Afferent neurons are pseudounipolar neurons, that have a single long dendrite
Dendrite

Dendrites are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or Soma , of the neuron from which the dendrites project....
 and a short axon
Axon

An axon or nerve fiber is a long, slender projectionof a nerve cell, or neuron, that conducts action potentialaway from the neuron's cell body or soma....
, and a smooth and rounded cell body
Soma (biology)

The soma, or cyton or perikaryon, is the bulbous end of a neuron, containing the cell nucleus. The word soma is Greek language, meaning "body"; the soma of a neuron is often called the "Cell body"....
. The dendrite is structurally and functionally similar to an axon, and is myelin
Myelin

Myelin is an electrically-insulating dielectric material that forms a layer, the myelin sheath. Usually, myelin surrounds only the axon of a neuron....
ated; it is these axon-like dendrites that make up the afferent nerves. Just outside the spinal cord
Spinal cord

The spinal cord is a long, thin, tubular bundle of neuron and glia that extends from the brain. The brain and spinal cord together make up the central nervous system....
, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal root
Dorsal root

In anatomy and neurology, the dorsal root is the afferent nervesomatosensory system root of a spinal nerve.At the distal end of the dorsal root is the dorsal root ganglion, which contains the neuron cell bodies of the nerve fibres conveyed by the root....
 known as the dorsal root ganglion
Dorsal root ganglion

In anatomy and neurology, the dorsal root ganglion is a nodule on a dorsal root that contains cell bodies of neurons in afferent nerve spinal nerves....
. (See efferent nerve
Efferent nerve

In the nervous system, efferent nerves ? otherwise known as motoneuron or effector neurons ? carry action potential away from the central nervous system to effectors such as muscles or glands ....
.)

Etymology and mnemonics

Afferent is derived from Latin
Latin

Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
 participle afferentem (af- = ad- : to + ferre : bear, carry), meaning carrying into. Ad and ex give an easy mnemonic device for remembering the relationship between afferent and efferent : afferent connection arrives and an efferent connection exits.

Another mnemonic device is SAME. Sensory Afferent Muscle Efferent.

See also

  • Efferent nerve
    Efferent nerve

    In the nervous system, efferent nerves ? otherwise known as motoneuron or effector neurons ? carry action potential away from the central nervous system to effectors such as muscles or glands ....
  • Motor nerve
    Motor nerve

    Motor nerves allow the brain to stimulate muscle contraction. A motor nerve is an efferent nerve that exclusively contains the axons of somatic and branchial motoneurons, which innervate skeletal muscles and branchial muscles ....
  • Interneuron
    Interneuron

    An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways. Like motor neurons, interneuron cell body are always located in the central nervous system ....