Anatomy P110/J.Wiens
Porterville College
Senses: General and Special
I. Two Divisions
1. General Senses 2. Special Senses –
Stimuli – changes in the
Receptors –
Tonic Receptors –
Phasic Receptors – detect stimuli, then can undergo
II. Classification of Receptors
1. Stimulus Origin
Exteroceptors – detect stimulation from
Interoceptors – detect stimuli from
Proprioceptors – detects
(Located in joints, muscles, and tendons)
2. Modality of Stimulus
Chemoreceptors – sensitive to
Thermoreceptors – sensitive to
Photoreceptors – sensitive to
Mechanoreceptors – mechanical stimuli from
Baroreceptors – sensitive to pressure change within
Nociceptors – sensitive to
Phantom Pain – example:
Referred Pain – example:
Pain from internal organs is interpreted elsewhere as superficial pain.
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Anatomy P110/J.Wiens
Porterville College
III. General Senses
Tactile Receptors
1. Free nerve endings
touch –
root hair plexus –
pain –
temperature – thermoreceptors for heat thermoreceptors for cold -
2. Tactile discs (Merkel)
3. Krause Bulbs (found in mouth, nasal cavity)
4. Pacinian (Lamellated) corpuscle – Located deeper in dermis. Larger structure lamellated with CT.
5. Ruffini Corpuscle –
6. Meissner (Tactile) Corpuscle – Small CT structure in papillary layer of dermis.
Numerous in lips and fingertips.
Special Sense Receptors - Olfactory (smell), Gustatory (taste), Eye (vision), Ear (hearing)
IV. Olfactory Receptors
a) Chemoreceptors stimulated by
b) Located in the
c) Olfactory receptors are neurons with
d) Can be
V. Gustatory Organs
a) Taste buds are on the ________ of papillae. The “onion” has a
b) Five taste sensations:
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Anatomy P110/J.Wiens
Porterville College
c)
VI. The Eye
1. Accessory Structures
(A) Eyelid
(B) Conjunctiva – the thin membrane that covers
(C) Lacrimal Apparatus –
2. Structure of Eyeball
A. Fibrous tunic
Sclera – ____________ of the eye
Protective covering to which
Optic nerve –
Cornea – ____________ of the eye.
______________light rays. Clear, made of C.T. and few cells.
B. Vascular tunic
Choroid – Brownish-black in color.
Ciliary body – ______________ _______ ___ __________ that helps hold lens
Iris –
Brown eyes Blue eyes
-
Radial muscle –
Circular muscle Lens –
Held in place by suspensory ligaments.
Accommodation
For close-up viewing – When ciliary body _____________, the “ring” becomes
______________, the suspensory ligaments ____________, and the lens naturally
____________.
For distance viewing – opposite of above.
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Anatomy P110/J.Wiens
Porterville College
Why we need glasses or bifocals as we get older:
Lens thickens with age and becomes less resilient. It is not able to spring out to the more spherical shape
needed for close-up vision. So our lens is too ___________ to read clearly and we need to thin it
out…How? Hold reading farther away or get reading glasses.
Also see page _____.
Near-sighted means you can only see clearly ___________. This occurs because your eyeball becomes
too __________. Your glasses need to have _____________ lenses to spread the light rays.
Far-sighted means you can only see clearly _______________. This occurs because your eyeball
becomes too __________. Your glasses need to have ____________ lenses to focus light rays.
Aqueous humor- _______________________________ that maintains the shape of the eyeball.
C. Neural tunic
Retina contains rods and cones.
Rods
Cones
Macula lutea – this area has the ________ ____________. (Area of _____________ _________.)
Optic disc – where ________ __________ from rods and cones turns backward and _________ the
eye.
X
O
Vitreous humor – ________, _____________ ________ in the posterior cavity that helps maintain
the shape of eye
VII. The Ear
1. Outer ear
A. Auricle –
B. External auditory canal – guarded by hairs and has _____________ ________ which help keep out
insects and dust.
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Anatomy P110/J.Wiens
Porterville College
C. Tympanic membrane
2. Middle ear
A. Tympanic cavity
B. Ossicles
C. Muscles – attach to ossicles.
Function -
3. Inner ear
The labyrinth includes the
A. Vestibule – organ of ____________ __________________.
Consists of a ______________ and ________________ that each have a _______________
containing ________________ in a _________________ _________________. Tilting of the
head causes membrane to shift on the macula, which causes _________________ of the
stereocilia and kinocilium on the hair cells.
B. Semicircular canals – organ of ___________ _________________.
Three canals – all at right angles to each other.
Each contains an ___________ which contains an elevated _________ ___________ which
contains stereocilia. On top is a gelatinous dome called the ___________. When moving, the
inertia of endolymph causes the cupula to bend, which causes the stereocilia to bend, which
sends ____________ to the brain.
C. Cochlea – organ of __________________
Snail –shaped, fluid-filled structure.
______________ of stapes against the _______ __________ produces pressure waves.
__________________ (also called the Spiral Organ) is the specific organ of ____________.
D. Use the lab and textbook to memorize the anatomy of the cochlea and be able to describe how
sound waves move through the different parts.
E. Look closely at the spiral organ and be able to explain why we hear sound.
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