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Located internally often within body organs or viscera. Proprioceptors: is a spe-cialized type of viscero-ceptors. Located in the skeletal muscles, joint capsules and tendons . Provide info on body movement, orientation in space and muscle stretch. There are tonic and phasic receptors provide positional infor-mation on body or body parts while at rest or during movement.
Mechanoreceptors: activated when “deformed” to generate receptor potential. Example: Pressure ap-plied to the skin. (1) (478) Chemoreceptors: acti-vated by amount or changing concentration of certain chemicals. Example: taste and smell (1) (478) Thermoreceptors: acti-vated by changes in tem-perature (1) (478) Nociceptors: activated by intense stimuli that may damage tissue sen-sation produced in pain Examples: Light and sound (1) (478)
Photoreceptors: found only in the eye. Respond to light stimuli, if the intensity is great enough to generate a receptor potential. Examples: Eye (1) (478) Exteroceptors: on or near body surface, often called cutaneous recep-tors. Examples: pressure, touch, pain and temp (1) (478) Visceroceptors: Provide the body with infor-mation about internal environment ,pressure, stretch, chemical chang-es, hunger and thirst.
Sensory Receptors: Stimulus Detected
Anatomy and Physiology Times
Does that make Sense?
Table of Contents
Page 1
Sensory Receptors
First Story
Stimulus Detected
Secondary News
Structure
Page 2
Special Sense
Smell
Taste
Hearing
Balance
NOVEMBER 5, 2012 VOLUME 1, ISSUE 1
Structure Muscle Spindle- It is contained
within a capsule lying parallel
to muscle fibers. (1) Intramural
fibers are that inside the cap-
sule where in-between them is
a central region, wrapped
within sensory dendrites of the
muscle spindle afferent. (1)
Then there is an ion channel in
the sensory dendrites for
whenever the muscle length-
ens (is being stretched). Those
ions cause a potential reaction
in the action potentials of
muscle spindle afferents. (1)
Meissner Corpuscles- Upper
portion of corpuscle is in direct
contact with the epidermal
basal cells where axon terminals
and laminar cells are interdigitat-
ed with the basal cells. Each
axon; the terminated and those
in contact with epidermis con-
tain mitochondria, micro vesicles
and myelinated dense bodies. (1)
Pacinian Corpuscles: Within the
corpuscles there is a structure
called the first node of Ranvier.
Myelin Sheath as well commenc-
es in this area, conducting elec-
trical impulses relatively quickly.
Nodes of Ranvier are present
through out the entire area
extending from the sensory
receptor, allowing the nodes to
rapidly transmit changes in elec-
trical potential. Free Nerve Endings: Are Within the Epidermis,
commecning with the hair papilla in the same depth of the pacinian
corpuscle going further up attaching to the erector muscle. Above the
nerve ending is the skin papilla lying on the dermis layer of the skin.
root hair plexuses: the root hair plexuses constists of the lowest papilla,
where the root of the hair lies above, then on the inner root sheath
connective tissue sheath runs over it and muscle arrecteur pili is at the
top. underneath the epidermis is the sebaceous gland and at the visible
sight is the hair shaft. (1)
merkel disks: the structure of the merkel disks would consist of that as
to the fingertips, the epidermis the highest level of the skin to the fact
that the function is touch. (1)
Golgi tendon Organs: Within the central nervous system, the Golgi
tendon is made up of motor neurons, to where the organ monitors
muscular and tendon tension from surrounding tissues. (1)
SMELL:
Olfactory Receptors
Olfactory sense organs consist of
epithelial support cells and
specialized olfactory receptor
neurons
Olfactory Cilia- located on the
olfactory receptor neu-
rons that touch the olfac-
tory epithelium lining the
upper surface of the nasal
cavity.
Olfactory Cells- chemorecep-
tors; gas molecules or
chemicals dissolved in the
mucus covering the nasal
epithelium stimulate the olfactory cell.
Olfactory Epithelium- located in most superior portion of the
nasal cavity
Olfactory Receptors- extremely sensitive and easily fatigued
Olfactory Pathways
When the level of SMELL odor- producing chemicals reaches a
threshold level, the following occurs
Receptor potential, and then action potential, is generated and
passed to the olfactory nerves in the olfactory bulb
The impulse then passes through the olfactory tract and into
the thalamic and olfactory centers of the brain for inter-
pretation, integration, and memory storage
Structure Continued...
What are Special Senses?
EXTRA! EXTRA! READ ALL ABOUT THE SPECIAL SENCES
of Ranvier.
Myelin Sheath well com-
mences in this area, con-
ducting electrical impulses
relatively quickly.
Nodes of Ranvier are present
through out the entire area
extending from the sensory
receptor, allowing the nodes
to rapidly transmit changes in
electrical potential.
Free Nerve Endings: Are
Withing the Epidermis,
commecning with the hair
papilla in the same depth of
the pacinian corpuscle
going further up attaching to
the erector muscle. Above
the nerve ending is the skin
papilla lying on the dermis
layer of the skin.
root hair plexuses: the root
hair plexuses constists of the
lowest papilla, where the
root of the hair lies above,
then on the inner root sheath
connective tissue sheath runs
over it and muscle arrecteur
pili is at the top. underneath
the epidermis is the seba-
ceous gland and at the visible
sight is the hair shaft
merkel disks: the structure of
the merkel disks would con-
sist of that as to the finger-
tips, the epidermis the high-
est level of the skin to the
fact that the function is touch
Page 2 DOES THAT MAKE SENSE?
Special Senses are characterized by receptors grouped closely together or grouped in spe-
cialized organs; sense of smell, taste, hearing, equilibrium, and vision.
Taste Buds- sense organs that
respond to gustatory, or taste,
stimuli; associated with papillae
Chemoreceptors that are
stimulated by chem-
icals dissolved in the
saliva (1)
Gustatory cells special-
ized cells in taste
buds; gustatory
hairs extend from
each other into the
taste pores (1)
Sense of taste depends on the
creation of a receptor po-
tential in gustatory cells
because of taste-producing
(1) chemicals in the saliva
Taste buds are similar in struc-
ture; functionally, each taste
bud responds most effec-
tively to one of four primary
taste sensations: sour, sweet,
bitter, and salty(1)
Adaptation and sensitivity thresh-
olds are different for each of
the primary taste sensations
(1)
Neural
Pathway-
taste
sensation
begins
with a
receptor
potential
in the
gustatory cells of a taste bud;
generation and propagation of an
action potential then transmits
the sensory input to the brain.(1)
related to head posi-
tion and deceleration
Otoliths are located with-
in the matrix of the
macula
Dynamic Equilibrium- needed
to maintain to balance when
the head or body is rotated or
suddenly moved; able to de-
tect changes in direction and
rate at which movement oc-
curs (1)
Sense of balance-
Static equilibrium is the abil-
ity to sense the position
of the head relative to
gravity or to sense accel-
eration or deceleration
Movements of the macu-
la, located in both
the utricle and sac-
cule almost right
angles to each other,
provide information
Taste:
Balance:
External ear is divided into two divi-
sions. Auricle or pinna which is the
visible portion. The external auditory
meatus is the tube leading from the
auricle into the temporal bone and
ending at the tympanic membrane. (1)
Middle Ear has tiny epithelium which
is lined cavity hollowed out of the
temporal lobe. It also contain 3 audito-
ry ossicles the malleolus (hammer),
incus (anvil), and stapes (stirrup). (1)
The inner ear has a variety of struc-
tures that consist of the a bony laby-
rinth, a membrane labyrinth, the vesti-
bule and semicircular canals which are
involved with balance, the cochlea, the
end lymph and the perilymph (1)
Hearing: Neural Pathway of hearing– a move-
ment of hair cells against the tectorial
membrane stimulates the dendrites
that terminate around the base of the
hair cells and initiates impulse conduc-
tion by the cocniear nerve to the brain-
stem. The impulses pass through “relay
stations” in the nuclei in the medulla,
pons, midbrain and thalamus before
reaching the auditory are of the tem-
poral lobe.(1)
Mechanisms of Hearing
Page 3 VOLUME 1, ISSUE 1
Nerve impulses from the
anterior two thirds of the
tongue travel dover the
facial nerve; those from
the posterior one-third of
the tongue travel over
the glossopharyngeal
nerve; vagus nerve plays
a minor role in taste.
Nerve impulses are
carried to the medulla
oblongata, relayed into
the thalamus and then
into the gustatory area of
the cerebral cortex in the
parietal lobe of the brain.
(1)