This power point gives a brief introduction on the classification of sensory receptor based on their location

1. SENSORY ORGANS:
CLASSIFICATION OF
RECEPTORS-2
S.K. SAIKIA
Department of Zoology
Visva-Bharati

2. Types of Receptors(based on location)
 Exteroceptors
 Detect stimuli near outer body
surface
 Interoceptors
 Detect stimuli from inside the body
 Proprioceptors
 Detect stimuli deep within the body

3. Exteroceptors
 Cold
 Warmth
 Touch
 Pressure
 Special senses
 Hearing
 Vision

4. Exteroceptors
 Exteroceptors include a group of sensory
receptors that detect any changes from the
external environment.
 they are well positioned to respond to various
stimuli that come from outside the body.
 Examples are vision, temperature changes,
touch, smell and pain among others

5. Types of exteroceptors
1. Mechanoreceptors 2. Nociceptors 3. Proprioceptors 4. Thermoreceptors
Exteroceptors

7. Mechanoreceptors
 A group of receptors located under the skin.
These receptors respond to such physical
changes as touch, vibration, stretch and
pressure among others.
 Functionally, mechanoreceptors are a type of
somatosensory receptors which relay
extracellular stimulus to intracellular signal
transduction through mechanically gated ion
channels

8. Types of Mechanoreceptors
 Pacinian corpuscles
 Merkel complexes
 Meissner corpuscles
 Ruffini corpuscles

9. Figure from Wikipedia

11. Pacinian corpuscle
Source: Wikipedia
Source: link.springer.com
Source: https://neuromuscular.wustl.edu/

12. Pacinian corpuscle
 The Pacinian corpuscle has an onion-like
capsule in which the inner core of membrane
lamellae is separated from an outer lamella by a
fluid-filled space. One or more rapidly
adapting afferent axons lie at the center of this
structure.

13. Merkel complexes
quora.com
Source: Wikipedia

14. Merkel complexes
 The Merkel cell was discovered by F. S.
Merkel in 1875
 Merkel nerve endings are mechano-
receptors, that are found in the
basal epidermis and hair follicle.
 They are nerve endings and provide
information on mechanical pressure,
position, and deep static touch
features, such as shapes and edges.
 The corpuscle is composed of a specific
epithelial cell and an afferent axon
terminal.
Source: backyardbrains.com

15. Ruffini’s corpuscles
 The Bulbous corpuscle or Ruffini ending or Ruffini
corpuscle is a slowly adapting mechanoreceptor located
in the cutaneous tissue between the dermal papillae
and the hypodermis. It is named after Angelo Ruffini, a
histologist who first described the Bulbous corpuscle.
 This spindle-shaped receptor is sensitive to skin stretch,
and contributes to the kinesthetic sense of and control
of finger position and movement.
 They are at the highest density around the fingernails
where they act in monitoring slippage of objects along
the surface of the skin, allowing modulation of grip on
an object

16. Ruffini’s corpuscles
Source: www.backyardbrains.com

17. Meissner's corpuscles are a type
of mechanoreceptor discovered by
anatomist Georg Meissner
(1829–1905) and Rudolf Wagner.
This corpuscle is a type of nerve
ending in the skin that is
responsible for sensitivity to light
touch
Source:
backyardbrains.com
Source:
UTHealth

18. The term “nociceptor” has been derived from the Latin
“nocere,” which means to harm or to damage.
A nociceptor (sensory neuron) that responds to damaging
or potentially damaging stimuli by sending “possible threat”
signals to the spinal cord and the brain.
NOCICEPTORS
Nociceptors are characterized by two distinctive features:
(i) they are responsive preferentially to tissue threatening
stimuli and encode their intensity,
(ii) they mediate nocifensive motor and vegetative reactions
by their central connections.

19. Source: media.springernature.com
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20. Proprioceptors
Proprioception is the sense of knowing your body's relative
position in space
1) These are the sensory receptors situated on the nerve
endings of the inner, ear, muscles, skin, joints, tendon,
and other tissues.
2) They relay information about our body's spatial
position to the brain, the signals of which are
translated into both large and subtle movements.

21. From Sports-health.com cdn.prod.openfit.com
From Sports-health.com
From: advancedathletics.com

22. From Slideshare

23. Thermoception or thermoreception is the
sense by which an organism perceives
temperatures.
THERMORECEPTORS
A thermoreceptor is a sensory receptor or, more
accurately, the receptive portion of a sensory
neuron that codes absolute and relative changes
in temperature, primarily within the innocuous
range.

24. Krause end bulb receptor which
can detect cold
Ruffini ending receptor which can
detect warmth
Thermoreceptors
Capsule Receptors

25. Thermoreceptors
 Thermoreceptors: free nerve endings
 Thermal sensations: coldness and warmth
 Temperatures between 10 and 40C (50-105F)
 activate cold receptors
 located in the epidermis
 Temperatures between 32 and 48C (90- 118F)
 activate warm receptors
 located in the dermis
 Below 10C and above 48C stimulate
 nociceptors
 produce painful sensations

26. Interoceptors
 Interoceptors are receptors in your muscles
and joints, there are also receptors
inside your organs, including your skin.These
receptors send information about the inside
of your body to your brain.
 Interoception helps you understand and feel
what’s going on inside your body. For
instance, you know if your heart is beating
fast or if you need to breathe more deeply.

27. Interoceptors
 Taste
 Smell
 pH
 Distension
 Spasm
 Flow