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8/11/2019 receptors Types of Receptors
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nerveous tissue
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NERVEOUS TISSUE
Presentation
Made ByAnam ahmad
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Sensory nerve endings
The sensory nerve endings respond to stimuli
in the periphery and send nerve impulses to
the central nervous system(hence they may be
called beginnings)
Nerves come on these ending
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types of receptors
MORPHOLOGICAL CLASSIFICATION OF NERVE
ENDINGS
1) Nonencapsulated (free) nerve endings
2) Encapsulated nerve ending
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NONENCAPSULATED NERVE ENDING
constitute the most common variety of
sensory nerve endings in the body
these may be unmyelinated or fine myelinated
found in connective tissue fibres and cells and
around muscle fibre
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free nerve fibers
are functionally specialized to respond tosensation of pain,temperature and fine touch
in epidermis,
a no. of free nerve terminals form expended, disc likeendings which are associated with modified epithelialcells located in the stratum basale called merkel cells
collectively called as merkel corpuscle
functions specialized mechanoreceptors thatperceive discrimnatory touch found in finger tipsand lips
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CLASSIFICATION OF ENCAPSULATED
NERVE ENDINGS
meissner's corpuscles
pacinian corpuscles
ruffini's corpuscles krause's end bulbs
muscle spindles
golgi tendon organs
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MEISSNER'S CORPUSCLES
these are oval bodies measuring about 150 micro metre inlength and 75 micro metre in diameter found in, finger tips, palms and soles
eyelids, lips and nipples
They are covered by connective tissue capsule,continueswith epineurium
multilayered stacks of transversely disposed flattenedcells,which are supposed to be specialized Schwann cells found with in the capsule
They are concerned with the perception of touch sensationonly also known as tactile corpuscles of Meissner
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PACINIAN CORPUSCLES
large
ovoid structures
diameter, about 1-2 mm in length and 0.5-1 mm in diameter
contains one unmyelinated nerve fibre, which
becomes myelinated as it leaves the corpuscle
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Paccinian corpuscle
INNER CORE
surrounds axon along entire length and consist of
many layers of tightly packed,flatened Schwann
cells
OUTER CORE
bulk of capsule consist of approximately 60
concentric layers found in deep dermis andhypodermis
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Pacinian corpuscle
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RUFFINI'S CORPUSCLES
fusiform structures
about 1-2mm in length and 0.2 mm in diameter
consist of thin connective tissue capsule
enclosing a fluid filled space this space is transversed by bundle of collagen
fibre that pass through capsule are joined toother collagen
ruffin's corpuscles are found indermis,subcutaneous tissue, joint capsule
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KRAUSE'S END BULBS
spherical bodies consisting of thin connective
tissue that surrounds a central cavity
a myelinated fibre enters the cavity loses its
myelin sheath, and divides into a number of
branches which terminate in club like endings
found in papillary layer of dermis of skin, in
peritoneum ,conjunctiva ,joints and external
genitalia
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MUSCLE SPINDLES
also called as neuromuscular spindles
a muscle spindle is generally less than a mmwide upto 5 mm long
each muscle consist of 6 to 14 modefiedstriated muscle fibres called intrafusal musclefibres
smaller in both diameter and length thanordinary muscle spindle called extra fusalmuscle fibre
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GOLGI TENDON ORGANS
found in
tendons and are located near the muscletendon
junction
are cylinderical structures
about 0.1 mm in diameter and 1 mm in length
consist of fiberous capsule which contains a
bundle of loosely arranged, wavy collagen
fibres called intrafusal collagen fibres
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nerve impulses from the golgi tendon organs
reach the interneurons in the spinal cord,
which in turn exert an inhibtory influence on
alpha motor neuron
located in anterior grey horns of spinal cord,
causing relaxation of muscles to which the
particular tendon is attached
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