Types of Sensory Receptors and the Sensory Stimuli They Detect

Table 46-1 lists and classifies most of the body's sensory receptors. This table shows that there are five basic types of sensory receptors: (1) mechanorecep-tors, which detect mechanical compression or stretching of the receptor or of tissues adjacent to the receptor; (2) thermoreceptors, which detect changes in temperature, some receptors detecting cold and others warmth; (3) nociceptors (pain receptors), which detect damage occurring in the tissues, whether physical damage or chemical damage; (4) electromagnetic receptors, which detect light on the retina of the eye; and (5) chemoreceptors, which detect taste in the mouth, smell in the nose, oxygen level in the arterial blood, osmolality of the body fluids, carbon dioxide concentration, and perhaps other factors that make up the chemistry of the body.

In this chapter, we discuss the function of a few specific types of receptors, primarily peripheral mechanoreceptors, to illustrate some of the principles by which receptors operate. Other receptors are discussed in other chapters in relation to the sensory systems that they subserve. Figure 46-1 shows some of the types of mechanoreceptors found in the skin or in deep tissues of the body.

Differential Sensitivity of Receptors

The first question that must be answered is, how do two types of sensory receptors detect different types of sensory stimuli? The answer is, by "differential sensitivities." That is, each type of receptor is highly sensitive to one type of stimulus for which it is designed and yet is almost nonresponsive to other types of sensory stimuli. Thus, the rods and cones of the eyes are highly responsive to light but are almost completely nonresponsive to normal ranges of heat, cold, pressure on the eyeballs, or chemical changes in the blood. The osmoreceptors of the supraoptic nuclei in the hypothalamus detect minute changes in the osmolality of the body fluids but have never been known to respond to sound. Finally, pain receptors in the skin are almost never stimulated by usual touch or pressure stimuli but do become highly active the moment tactile stimuli become severe enough to damage the tissues.

Modality of Sensation—The "Labeled Line" Principle

Each of the principal types of sensation that we can experience—pain, touch, sight, sound, and so forth—is called a modality of sensation. Yet despite the fact that we experience these different modalities of sensation, nerve fibers

Input to the nervous system is provided by sensory receptors that detect such sensory stimuli as touch, sound, light, pain, cold, and warmth. The purpose of this chapter is to discuss the basic mechanisms by which these receptors change sensory stimuli into nerve signals that are then conveyed to and processed in the central nervous system.

Types Touch Receptors

Table 46-1

Classification of Sensory Receptors

Figure 46-1

Several types of somatic sensory nerve endings.

Table 46-1

Classification of Sensory Receptors

Figure 46-1

Several types of somatic sensory nerve endings.

transmit only impulses. Therefore, how is it that different nerve fibers transmit different modalities of sensation?

The answer is that each nerve tract terminates at a specific point in the central nervous system, and the type of sensation felt when a nerve fiber is stimulated is determined by the point in the nervous system to which the fiber leads. For instance, if a pain fiber is stimulated, the person perceives pain regardless of what type of stimulus excites the fiber. The stimulus can be electricity, overheating of the fiber, crushing of the fiber, or stimulation of the pain nerve ending by damage to the tissue cells. In all these instances, the person perceives pain. Likewise, if a touch fiber is stimulated by electrical excitation of a touch receptor or in any other way, the person perceives touch because touch fibers lead to specific touch areas in the brain. Similarly, fibers from the retina of the eye terminate in the vision areas of the brain, fibers from the ear terminate in the auditory areas of the brain, and temperature fibers terminate in the temperature areas.

This specificity of nerve fibers for transmitting only one modality of sensation is called the labeled line principle.

I. Mechanoreceptors

Skin tactile sensibilities (epidermis and dermis) Free nerve endings Expanded tip endings Merkel's discs Plus several other variants Spray endings Ruffini's endings Encapsulated endings Meissner's corpuscles Krause's corpuscles Hair end-organs Deep tissue sensibilities Free nerve endings Expanded tip endings Spray endings

Ruffini's endings Encapsulated endings Pacinian corpuscles Plus a few other variants Muscle endings Muscle spindles Golgi tendon receptors Hearing

Sound receptors of cochlea Equilibrium

Vestibular receptors Arterial pressure Baroreceptors of carotid sinuses and aorta

II. Thermoreceptors Cold

Cold receptors Warmth Warm receptors

III. Nociceptors Pain

Free nerve endings

IV. Electromagnetic receptors Vision

Rods Cones

V. Chemoreceptors

Taste

Receptors of taste buds Smell

Receptors of olfactory epithelium Arterial oxygen

Receptors of aortic and carotid bodies Osmolality

Neurons in or near supraoptic nuclei Blood CO2

Receptors in or on surface of medulla and in aortic and carotid bodies Blood glucose, amino acids, fatty acids Receptors in hypothalamus

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Responses

  • Tobias
    What type of stimulus is detected by the sensory receptors of the skin?
    3 years ago
  • j
    What are the unctional cartegories of receptors and what do they detect in respiratory physiology?
    3 years ago
  • John
    What types of sensory receptors are located in the skin?
    3 years ago
  • Aziz Yemane
    What are the types of sensory receptors and stimulus?
    1 year ago
  • Lalia Noakes
    Are free nerve enndings principal pain receptors?
    1 year ago
  • pasi
    What system Recognizes sensory stimuli?
    1 year ago
  • jouni mattila
    What type of energy of stimuli do humans have energy receptors for?
    1 year ago
  • phil
    What detects sensory stimuli?
    12 months ago
  • karri
    What are the names of all of the sensory receptors in the dermis called and whatdo they detect?
    12 months ago
  • AMEERA
    How stimuli are clasiffied in stimulus type?
    12 months ago
  • jamie-leigh
    What do skin receptors detect?
    12 months ago
  • BELISARIUS
    What type of physical stimules does each of the sensory systems detect in psychology?
    12 months ago
  • Eddie
    What type of stimuli sensory receptors detect?
    11 months ago
  • tuukka
    What stimulus does mechanoreceptors detect?
    11 months ago
  • luukas
    What are the 5 classifications of sensory receptors by stimulus by stimulus type?
    11 months ago
  • Tim Zweig
    What is the stimulus detected by nose?
    11 months ago
  • Janne
    What are the classifications of receptors according to modality of stimulus?
    11 months ago
  • sanna-leen
    Where does sensory receptor stimuli originate?
    10 months ago
  • Mewael
    Which type of receptors stimulated by pain or damaging stimuli?
    10 months ago
  • Victor
    What ia the stimulus that auditory nerves detect?
    10 months ago
  • gorbulas
    What type of receptor by stimulus classification are taste buds?
    10 months ago
  • aydin
    What are the different types of sensory receptors and what do they detect?
    10 months ago
  • SARAH
    What receptors detect weight?
    9 months ago
  • SESUNA
    What does body stimuli body receptors do?
    9 months ago
  • medhanie
    How each stimuli received by receptors in sight and how these stimuli are converted into sensation?
    9 months ago
  • melissa
    Does the body have receptors for preasure?
    8 months ago
  • semret
    What kind of stimuli do pain receptors respond to?
    8 months ago
  • Manfredo
    What type of receptors are in the body to detect surroundings?
    8 months ago
  • liam
    What two ways do sensory receptors respond to stimuli?
    7 months ago
  • pippin
    What 5 types of sensations can human skin detect through its sensory receptors?
    7 months ago
  • george blanchard
    What is a stimulous of sensory receptor?
    7 months ago
  • Luisella
    What sort of neurons in the skin detect touch stimulation?
    7 months ago
  • fernando
    What kind of stimuli is detected by annelids?
    7 months ago
  • MAY
    Which type of sensory receptor can detect taste and smell?
    7 months ago
  • Christina
    What sensations are detected by sensory receptors in the skin?
    7 months ago
  • Shirley
    What type of stimulus is there in balance?
    7 months ago
  • IMMONEN
    How are the stimuli and receptors related to eachother?
    7 months ago
  • casey
    What kind of sensory stimulus are there?
    6 months ago
  • paladin
    What type of sensory input are eyes?
    6 months ago
  • mirren
    How does the brain command recptors to detect a change in stimuli?
    6 months ago
  • teemu
    What type of stimuli do the vestibule detect?
    6 months ago
  • robert
    What are the receptor cells and what stimulus do they detect?
    6 months ago
  • Jennifer
    What are the two classifications of stimuli drugs?
    6 months ago
  • V
    What do electromagnetic receptors detect?
    5 months ago
  • katariina
    What kind of tissue makes detecting sensory information possible?
    5 months ago
  • saare
    What type of receptor is employed to detect hearing?
    5 months ago
  • maximilian
    What are the receptor mechanisms that enable us to sense tactile stimuli?
    5 months ago
  • veijo
    What stimuli does a compass dectect?
    5 months ago
  • MYLIE
    What type of receptors by stimulus classification are taste buds?
    4 months ago
  • tori
    How does "electricity" stimulate sensory receptors?
    4 months ago
  • asfaha
    What cells connect to the skin to detect stimuli?
    4 months ago
  • MAGNUS
    Which type of sensory receptors are primarily dedicated to external stimuli?
    4 months ago
  • ALYSSA
    How does the body detect heal cold pressure pain?
    4 months ago
  • lloyd
    What receptor does the auditory stimuli stimulate?
    4 months ago
  • Eemil
    What is the five basic types of sensory receptors?
    3 months ago
  • artemisia
    What are types of sensory receptor in vet physiology?
    3 months ago
  • sadie alexander
    How does sensory receptor send info for all stimuli for brain to feel sensation?
    3 months ago
  • karolin
    Where in the athletes body are receptor cells that detect stimulus?
    2 months ago
  • enrico
    What are the receptors that detect tissue damage called?
    2 months ago
  • Beata
    When a reflector detects stimulus?
    24 days ago
  • murrin
    How does skin detect stimulus?
    7 days ago
  • natasha
    What type of sensory receptor detects chemical concentration?
    3 days ago

Post a comment