chapter 8 special senses Flashcards
what are the special senses?
1) smell
2) taste
3) sight
4) hearing
5) equilibrium
where are 70% of sensory receptors?
eyes
how many nerve fibers does each eye contain?
over 1 million
what are the accessory structures of the eyes
1) extrinsic eye muscles
2) eyelids
3) eye lashes
4) conjuctiva
5) lacrimal apparatus
what glands are located in the eye lashes?
1) tarsal glands
2) ciliary glands
what do tarsal glands secrete?
oily secretions that lubricate eyes
what is conjuctiva?
what is its function?
1) membrane that lines the eyelids and eyeballs
2) secretes mucus to lubricate eye
what does the lacrimal apparatus consist of?
lacrimal glands and ducts
what is the pathway of lacrimal fluid?
1) fluid secreted by gland
2) drains to lacrimal sac
3) travels through nasolacrimal duct and empties into nasal cavity
what does lacrimal fluid consist of?
1) salt solution
2) mucus
3) antibodies
4) lysozyme
what is lysozyme?
an enzyme that destroys bacteria
what is the function of lacrimal fluid?
1) cleanse
2) protect
3) moisten
4) lubricate
what are the 3 layers of the eye wall?
1) fibrous tunic
2) vascular tunic
3) retina
what does the fibrous tunic of the eye wall consist of?
1) sclera
2) cornea
what does the vascular tunic of the eye wall consist of?
1) iris
2) ciliary body
3) choroid
what are the names of the layers in the retina?
1) pigmented layer
2) neural layer
the cornea is avascular, so where does it get its nutrients and oxygen from?
1) lacrimal fluid
2) aqueous humor
what part of the eye does the majority of the focusing?
the cornea
what makes up the majority of the fibrous tunic of the eye wall? what part of the eye is this?
the sclera (the white part of the eye)
what are the functions of the sclera?
1) provides shape
2) protects internal parts
3) attachment site for muscles
what does the choroid contain?
a vast network of capillaries that supply oxygen and nutrients to the retina
what part of the eye is the iris and what does it control?
the pigmented part of the eye
it controls the amount of light that enters the eye by controlling the size of the pupil
what is the ciliary body composed of?
1) ciliary muscles
2) ciliary processes
what is the function of the ciliary body?
changes the shape of the lense to adjust the focal point
what is the pigmented layer of retina attached to and what does it absorb?
its attached to the choroid and absorbs light that passes through the retina
what type of tissue is the pigmented layer of retina made of?
simple cuboidal epithelial tissue
what does the neural layer of retina house?
1) photoreceptors
2) associated neurons
what happens when the neural layer of retina recieves light?
it converts the energy from the light into nerve impulses
how are the neurons arranged in the neural layer of retina?
in 3 layers of bipolar neurons
what is the center of the eyes sharpest vision and why?
fovea centralis because it has the highest proportion of cones with almost no rods
in the neural layer of retina, what are the 3 cell types in order from superficial to deep?
1) photoreceptor cells (rods and cones)
2) bipolar cells
3) ganglion cells
the ganglion cells in the neural layer of the retina have axons that form what?
the optic nerve (CN2)
the aqueous humor has fluid inside with what type of consistancy?
watery consistancy
the vitreous humor has fluid inside with what type of consistancy?
gel- like consistancy
ophthalmoscope =
an instrument used to illuminate the interior of the eyeball and fundus (posterior wall)
what can an ophthalmoscope detect?
1) diabettes
2) arteriosclerosis
3) optic nerve or retina degeneration
optic nerve =
a bundle of axons that exit the back of the eye. carries impulses from the retina
optic chiasm =
where medial optic nerve fibers cross over to the opposite side of the brain
optic tracts contain which nerve fibers?
contains nerve fibers from the lateral side of the eye on the same side and medial nerve fibers from the eye on the opposite side
optic radiation =
axons from the thalamus that run to occipital lobe and synapse with cortical cells.
pathway of impulses from retina to point of visual interpretation =
impulse is sent from retina and travel through:
1) optic nerve
2) optic chiasm
3) optic tract
4) thalamus
5) optic radiation
6) optic cortex in occipital lobe
cataracts =
abnormal structure and/ or arrangment of protiens in the lens causing blurring
glaucoma =
increased fluid pressure inside eyes causes damage to the optic nerve
what are the 2 senses of the ears?
1) hearing
2) equilibrium
what type of receptors are found in the ears?
mechanoreceptors
what 3 areas are the ears divided into?
1) external ear
2) middle ear
3) internal ear
auricle =
AKA pinna.
the outter ear (the cartilage part)
what is the external acoustic meatus?
it is a narrow chamber in the temporal bone that ends at the tympanic membrane
what is the external acoustic meatus lines with?
skin and ceruminous glands
what are ceruminous glands?
anatomical name for earwax glands
what is the external acoustic meatus AKA?
auditory canal
what is the tympanic membrane?
the anatomical name for the eardrum
what is the function of the external ear?
only to collect sound waves
what is the tympanic cavity AKA?
the middle ear cavity
where is the tympanic cavity located?
in the temporal bones between the tympanic membrane and the oval window and round window
what is the function of the tympanic cavity
only to sense hearing
what is the tympanic cavity filled with?
what is it lined with?
filled with air and lined with mucosa
what is the pharyngotympanic tube?
a tube that links the middle ear cavity with the throat
what is the function of the pharyngotympanic tube?
to equalize pressure in the middle ear cavity so the tympanic membrane can vibrate
what are the names 3 auditory ossicles found in the tympanic cavity in order?
1) malleus (hammer)
2) incus (anvil)
3) stapes (stirrup)
what is the function of the auditory ossicles?
to amplify and transmit vibrations from the tympanic membrane the oval window
how do vibrations travel through the auditory ossicles?
malleus>incus>stapes>oval window of the inner ear
where is the osseous labyrinth located?
in the inner ear
what does the osseous labyrinth consist of?
1) cochlea
2) vestibule
3) semicircular canals
what fluids are found in the osseous labyrinth?
1) perilymph
2) endolymph
what are the equilibrium receptors in the inner ear called?
the vestibular apparatus
what are the 2 functions of the vestibular apparatus?
1) static equilibrium
2) dynamic equilibrium
what are maculae?
receptors in the vestibule that report the position of our head to our brain to help keep out head erect
where do maculae send information?
to the cerebellum via the vestibular nerve
study static and dynamic equilibrium
get a grip on it
what is crista ampullaris?
sensory organs that respond to angular or rotational movements of the head
where are the crista ampullaris organs located?
the ampulla of each semicircular canal
where is the spiral organ located?
within the cochlear duct
what are the receptors in the spiral organ of corti?
hair cells on the basilar membrane
what is the tectorial membrane?
a gel like membrane capable of bending air
how does the spiral organ send impulses to the brain?
what part of the brain are they sent to?
hair cells transmit impulses to the auditory cortex on the temporal lobe via the cochlear nerve
what is a unique structural feature of the tectorial membrane?
theres a hook at the end of one side
what is the pathway of vibrations from sound waves?
1) sound waves move passed the auditory ossicles to the oval window
2) ossicles amplify the sound waves
3) pressure waves cause vibrations in the basilar membrane in the spiral organ of corti
4) hair cells in the tectorial membrane are bent when the basilar membrane vibrates against it
5) hair cells send nerve impulses to temporal lobe via the cochlear nerve
what are the 2 types of hearing loss?
1) conductive (outter or middle ear)
2) sensorineurial (hair cells or nerves)
what are the treatments for sensorineural hearing loss?
1) hearing aid
2) cochlear implant
what type of receptors are involved with smell and taste?
chemoreceptors (chemical receptors)
what are chemoreceptors stimulated by?
chemicals in solution
how many different receptors are involved with taste?
5 types
out of smell and taste, which can differentiate a wider range of chemicals?
smell
2 things smell and taste have in common:
both compliment eachother and respond to the same stimuli
what nerve is associated with smell?
olfactory nerve(CN1)
what are olfactory hairs?
receptor cells with long cilia that detect chemicals that have been dissolved in mucus
what must happen to chemicals before olfactory receptors can detect them?
they must first be dissolved in mucus
where are smells interpreted?
olfactory cortex
where are taste receptors housed?
taste buds
where are taste buds located?
1) most are on the tongue
2) soft palate
3) superior part of pharynx
4) cheeks
what is papillae?
projections on the tongue that contain taste buds
what are gustatory cells?
taste receptors
