CH 6: Special Senses Flashcards
General senses of touch
− Temperature
− Pressure
− Pain
Special senses
− Smell
− Taste
− Sight
− Hearing
− Equilibrium
either large, complex sensory organs sensory organs (eyes and ears) or localized clusters or receptors (taste buds and olfactory epithelium)
Special sense receptors
complex sensory organs sensory organs
-example
eyes and ears
localized clusters or receptors
-example
taste buds and
olfactory epithelium
__percent of all sensory receptors are in the eyes
70
70 percent of all sensory receptors are in the ___
eyes
Protection for the eye (2)
-bony orbit
-cushion fat
Accessory structure of the eye (2)
eyelids
eyelash
modified sebaceous sebaceous glands produce an oily secretion to lubricate the eye
Meibomian glands
modified sweat glands between
the eyelashes
Ciliary glands
Membrane that lines the eyelids lines the
eyelids
Conjunctiva
Connects to the surface of the eye
Conjunctiva
Secretes mucus to lubricate the eye
Conjunctiva
produces lacrimal produces
lacrimal fluid
Lacrimal gland
drains lacrimal fluid from eyes
Lacrimal canals
Lacrimal apparatus (2)
-Lacrimal gland
-*Lacrimal canals
provides passage of lacrimal fluid
towards nasal cavity cavity
Lacrimal sac
empties lacrimal fluid into the nasal cavity
Nasolacrimal duct
Function of the lacrimal apparatus
*Dilute salt solution (tears)
*Contains antibodies and lysozyme
*Contains antibodies and lysozyme
* Protects, moistens, and lubricates the eye
* Empties into the nasal cavity
extrinsic (external) eye muscle
Muscles attach to the outer surface of the eye
Produce gross eye movements and make it
possible to follow moving objects
extrinsic (external) eye muscle
-eye wall is composed of
-interior is filled with fluids called
three tunics coats
humors
Structure of the eye (4)
- Fibrous tunic (sclera) outside layer
- Choroid
- Choroid middle layer
- Sensory tunic inside layer
Fibrous tunic (2)
sclera
cornea
*White connective tissue layer
sclera
*Seen anteriorly as the “white of the eye”
sclera
*Transparent, central anterior portion
Cornea
The only human tissue that can be
transplanted without fear of rejection– no
blood vessels
Cornea
Blood-rich nutritive tunic
choroid layer
prevents light from scattering
inside the eye
dark pigment
Dark pigment prevents light from scattering inside the eye
choroid layer
Choroid layer is modified interiorly into two structures
ciliary body
iris
smooth muscle to which the
lends is attached
ciliary body
Pigmented layer that gives eye color
iris
rounded opening in the iris for light
to enter
pupil
Contains receptor cells (photoreceptors)
sensory tunic (retina)
Sensory Tunic contains receptor cells (photoreceptors)
*Rods
*Cones
sensory tunic signal pass from photoreceptors via a two neuron chain
*Bipolar neurons
*Ganglion cells
Signals leave the retina toward the brain
through the
optic nerve
Most are found towards the edges of the
retina
rods retina
Allow dim light vision and peripheral vision
rods retina
Perception is all in gray tones
rods retina
Perception is all in __
gray tones
Allow for detailed color vision in bright light
Cones
Densest in the center of the retina
Cones
area of the retina with only
cones– lateral to each blind spot
Fovea centralis
No photoreceptor cells are at the ____ or ___– where the ____ leaves the
eyeball
optic disk, or blind spot
optic nerve
result of lack of one cone
type
Color blindness
Impulses received at the same time are
interpreted as
intermediate colors
Biconvex crystal-like structure
lens
Held in place by a suspensory ligament attached to the ciliary body
lens
internal eye chamber fluids
Aqueous humor
Vitreous humor
Watery fluid found in chamber between the lens and cornea
Aqueous humor
Similar to blood plasma
Aqueous humor
Aqueous humor helps maintain
intraocular pressure
*Provides nutrients for the lens and cornea
Aqueous humor
Aqueous humor is reabsorbed into venous blood through the canal of
Schlemm
*Gel-like substance behind the lens
Vitreous humor
Keeps the eye from collapsing inward by
reinforcing it internally
Vitreous humor
Lasts a lifetime and is not replaced
Vitreous humor
form when the lens becomes
increasingly hard and opaque over time requiring
a transplant or special glasses
cataracts
results when the drainage of aqueous
humor is blocked and pressure within the eye increases dramatically and compresses the delicate retina and optic nerve causing pain and blindness
Glaucoma
Light must be focused to a point on the ___ for optimal vision done by the ___
retina
lens
The ____ is set for distance vision for
distance vision (over __ ft away)
resting eye
20
The lens must change__ to focus for closer
objects accommodation
shape
formed on the retina
Real image
real image are formed in
retina
Photoreceptors of the retina
visual pathway
Optic nerve crosses at the ____ to the opposite side
optic chiasma
result are the optic tracts
Fiber tracts
Optic tracts contains fibers from the____ of the eye on the ___ and the ___ of the ___
lateral side
same side
medial side
opposite eye
Internal muscles are controlled by the
autonomic nervous system
eye reflexes
causes pupils to constrict through
action of radial and ciliary muscles
photopupillary reflex
bright light
*Bright light causes pupils to constrict through action of (2)
radial and ciliary muscles
Viewing close objects causes
accommodation– accommodation pupillary
reflex
photopupillary reflex
control eye movement to follow objects
External muscles
Viewing close objects causes
convergence
the ear houses two senses
*Hearing
*Equilibrium (balance)
respond to physical forces
mechanoreceptors
Although *Hearing and *Equilibrium (balance) organs are housed together in the ear, their receptors respond to ___ and are ____
different stimuli
activated independently
The ear is divided into three areas
*Outer (external) ear
*Middle ear
*Inner (internal)
ear structures involved in hearing only
outer and middle
functions in both equilibrium and hearing
inner ear
Structures of the external ear
Pinna (auricle) the ear
*External auditory canal
Narrow chamber in the temporal bone
external auditory canal
external auditory canal is lined with
skin
secrete earwax– cerumen
Ceruminous (wax) glands
the external auditory canal ends at the ____
where sound waves hit and cause vibrations
tympanic membrane (eardrum)
Air-filled cavity within the temporal bone
middle ear, tympanic cavity
Two tubes are associated with the inner ear
oval window and the inferior, membrane covered round window
*The opening from the auditory canal is
covered by the
tympanic membrane
*The auditory tube connecting the middle ear with the
throat
*Allows for equalizing pressure during
yawning or swallowing
auditory tube
Three bones span the tympanic cavity– the ossicles
*Malleus (hammer)
*Incus (anvil)
*Stapes (stirrup)
Vibrations from eardrum move the
malleus
Amazeof bony chambers within the temporal bone called the
osseous or bony labyrinth
Inner ear or bony labyrinth parts
*Cochlea
*Vestibule
*Vestibule
*Semicircular canals
Bony labyrinth is filled with a plasma-like fluid called
perilymph
Inside of perilymph is a membranous labyrinth that contains a thicker fluid called
endolymph
corni is Located within the
cochlea
hair cells on the basilar
membrane– hearing receptors membrane–
hearing receptors
receptors
Receptors, hair cells on the ____– hearing receptors membrane
basilar
membrane
___ membrane is capable of
bending hair cells
Gel-like tectorial
__nerve attached to hair cells
transmits nerve impulses to____ on temporal lobe
Cochlear
auditory cortex
Vibrations from sound waves move
tectorial membrane
Hair cells are bent by the
membrane
An action potential starts in the
cochlear nerve
can lead to adaptation– stop responding to those sound
Continued stimulation
Receptor cells are in two structures
*Vestibule
*Semicircular canals
- Equilibrium has two functional parts
*Static equilibrium
*Dynamic equilibriu
receptors in the vestibule
Maculae
Report on the position of the head with
respect to gravity– help determine up
from down
Maculae
Send information via the vestibular
nerve
Maculae
Maculae send information via the
vestibular nerve
Hair cells are embedded in the
otolithic membrane
float in a gel around the hair cells
otolithics
(tiny stones)
Otoliths
Movements cause otoliths to bend the
hair cells which send impulses along the
__ to __
vestibular nerve to the cerebellum
receptors in the semicircular canals
Crista ampullaris
Crista ampullaris (2)
*Tuft of hair cells
*Cupula (gelatinous cap) covers the hair cells
stimulates the hair cells– gelatinous cap
cupula
An impulse is sent via the ___ to the ___
vestibular nerve
cerebellum
Senses that uses chemoreceptors
taste and smell
Taste has ___ types of receptors
four
Taste and smell senses complement each other and respond to many of the __
same stimuli
are in the roof of the nasal cavity
Olfactory receptors
sense of smell
olfaction
Neurons with long cilia–
olfactory hairs
Impulses in olfaction are transmitted via the ___ which makes up the ___
olfactory filaments
olfactory nerve
Interpretation of smells is made in the
olfactory cortex
house the receptor organs
taste buds
- Location of taste buds (3)
*Most are on the tongue
*Soft palate
*Inner cheeks
The dorsal tongue is covered with projections called
papillae
– sharp with no taste buds
Filiform papillae
– rounded with taste buds
*Fungiform papillae
– large papillae with taste buds
Circumvallate papillae
Taste buds are found on the s
ides of papillae
he specific cells that respond to chemical
dissolved in saliva are
epithelial cells
Surrounded by supporting cells in the taste
bud
Gustatory cells
Structure of taste buds
*Surrounded by supporting cells in the taste bud
*Have gustatory hairs (long microvilli)
*Hairs are stimulated by chemicals dissolved in saliva
Impulses are carried to the gustatory complex by several____ because taste buds are found in different areas
cranial nerves
(long microvilli)
gustatory hairs
anterior tongue specifically
facial nerve
structure of taste buds
*Facial nerve
*Glossopharyngeal nerve
*Vagus nerve
Taste sensation
- Sweet receptors
- Sour receptors
- Bitter receptors
- Salty receptors
Taste sensation
- Sweet receptors
- Sour receptors
- Bitter receptors
- Salty receptors
- Sweet receptors
*Sugars
*Saccharine
*May respond to the OH
*Some amino acids - Sour receptors
*Acids
*May respond to the H+ - Bitter receptors
*Alkaloids - Salty receptors
*Metal ions in solution
are outgrowths of the brain
Eyes