sensory receptor

(noun)

A sensory nerve ending that recognizes a stimulus in the internal or external environment of an organism.

Related Terms

Examples of sensory receptor in the following topics:

  • Classification of Receptors by Stimulus

    • Sensory receptors can be classified by the type of stimulus that generates a response in the receptor.
    • Broadly, sensory receptors respond to one of four primary stimuli:
    • Sensory receptors perform countless functions in our bodies.
    • Cutaneous receptors are sensory receptors found in the dermis or epidermis.[2]
    • A tonic receptor is a sensory receptor that adapts slowly to a stimulus, while a phasic receptor is a sensory receptor that adapts rapidly to a stimulus.

  • Classification of Receptors by Location

    • Some sensory receptors can be classified by the physical location of the receptor.
    • Remarkably, specialized receptors have evolved to transmit sensory inputs from each of these sensory systems.
    • Sensory receptors are found throughout our bodies, and sensory receptors that share a common location often share a common function.
    • For example, sensory receptors in the retina are almost entirely photoreceptors.
    • Force-sensitive mechanoreceptors provide an example of how the placement of a sensory receptor plays a role in how our brains process sensory inputs.

  • Functions of the Nervous System

    • These functions are based on the sensory input,  integration and motor output.
    • Sensory input is based on the many sensory receptors that can monitor changes occurring both inside and outside the body.
    • The total sum of the gathered information by these sensory receptors is called sensory input.
    • It does this by extracting information from the environment using sensory receptors.
    • When this signal reaches a synapse, it provokes release of neurotransmitter molecules, which bind to receptor molecules located in the the target cell.

  • Cutaneous Sensation

    • The somatosensory system is composed of the receptors and processing centers to produce the sensory modalities, such as touch and pain.
    • Spread through all major parts of the body, it consists of sensory receptors and sensory neurons in the periphery (for example, skin, muscle, and organs), along with deeper neurons within the central nervous system.
    • Transmission of information from the receptors passes via sensory nerves through tracts in the spinal cord and into the brain.
    • Upon deviation from the norm ,sensory receptors trigger an action potential that can provide feedback or lead to alterations in behavior in order to maintain homoeostasis.
    • Mechanoreceptors are sensory receptors that respond to pressure and vibration.

  • General Organization of the Somatosensory System

    • It includes both sensory receptor neurons in the periphery (eg., skin, muscle, and organs) and deeper neurons within the central nervous system.
    • 1) In the periphery, the primary neuron is the sensory receptor that detects sensory stimuli like touch or temperature.
    • 3) Tertiary neurons have cell bodies in the thalamus and project to the postcentral gyrus of the parietal lobe, forming a sensory homunculus in the case of touch.
    • At this location there is a map of sensory space referred to as a sensory homunculus. 
    • Periphery: Sensory receptors (i.e., thermoreceptors, mechanoreceptors, etc.) detect the various stimuli.

  • Proprioceptive Sensations

    • The proprioceptive sense is believed to be composed of information from sensory neurons located in the inner ear (motion and orientation) and in the stretch receptors located in the muscles and the joint-supporting ligaments (stance).
    • Muscle spindles are sensory receptors within the belly of a muscle that primarily detect changes in the length of a muscle.
    • The Golgi organ (also called Golgi tendon organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptive sensory receptor organ that is located at the insertion of skeletal muscle fibers onto the tendons of skeletal muscle.
    • It provides the sensory component of the Golgi tendon reflex.
    • The spindle is a stretch receptor with its own motor supply consisting of several intrafusal muscle fibers.

  • Organization of the Nervous System

    • The nervous system has three broad functions: sensory input, information processing, and motor output .
    • In the PNS, sensory receptor neurons respond to physical stimuli in our environment, like touch or temperature, and send signals that inform the CNS of the state of the body and the external environment.
    • This sensory information is then processed by the CNS, predominantly by the brain.
    • Central neurons, which in humans greatly outnumber the sensory and motor neurons, make all of their input and output connections with other neurons.
    • When this signal reaches a synapse, it provokes release of neurotransmitter molecules, which bind to receptor molecules located in the the target cell.

  • Sensory and Motor Tracts

    • The spinothalamic tract is a sensory pathway originating in the spinal cord.
    • Somatosensory organization is divided into the dorsal column–medial lemniscus tract (the touch/proprioception/vibration sensory pathway) and the anterolateral system, or ALS (the pain/temperature sensory pathway).
    • Both sensory pathways use three different neurons to get information from sensory receptors at the periphery to the cerebral cortex.
    • These neurons are designated primary, secondary, and tertiary sensory neurons.
    • The types of sensory information transmitted via the spinothalamic tract are described as affective sensation.

  • Sensory Modalities

    • The sensory modality for vision is light.
    • The sensory modality for audition is sound.
    • It collects and sends these vibrations to receptor cells.
    • These receptors are used to detect the presence of smell.
    • The vestibular nerve conducts information from sensory receptors in three ampulla, each of which sense fluid motion in three semicircular canals caused by a three-dimensional rotation of the head.

  • Vestibulocochlear (VIII) Nerve

    • This is the nerve along which the sensory cells (the hair cells) of the inner ear transmit information to the brain.
    • The vestibular ganglion houses the cell bodies of the bipolar neurons and extends processes to five sensory organs.
    • Hair cells of the cristae activate afferent receptors in response to rotational acceleration.
    • The other two sensory organs supplied by the vestibular neurons are the maculae of the saccule and utricle.
    • Hair cells of the maculae activate afferent receptors in response to linear acceleration.