Chapter 17: The Special Senses Flashcards
Where are the receptors for the sense of smell located?
located in the olfactory epithelium of the nose
The olfactory epithelium consists of three kinds of cells, what are they?
olfactory receptor cells
supporting cells
basal cells
What are olfactory receptor cells?
the first-order neurons of the olfactory pathway
Extending from the dendrite of an olfactory sensory neuron are several ________ _____________ ________
nonmotile olfactory cilia
What is the role of olfactory cilia?
responsible for perception of smell.
Within the plasma membranes of the
olfactory cilia are what kind of receptors?
olfactory receptors
What are olfactory receptors?
Proteins that detect inhaled chemicals
Chemicals that bind to and stimulate the olfactory sensory neurons in the olfactory cilia are called?
Odorants
What are supporting epithelial cells?
columnar epithelial cells of the mucous membrane lining the nose.
What do supporting epithelial cells provide?
They provide physical support, nourishment, and electrical insulation for the olfactory sensory neurons and help detoxify chemicals that come in contact with the olfactory epithelium.
_________ epithelial cells are stem cells located between the bases of the supporting epithelial cells
Basal epithelial cells
Within the connective tissue that supports the olfactory epithelium are ________ glands
olfactory glands
What is the role of olfactory glands?
They produce mucus that is carried to the surface of the epithelium by ducts
What is the role of the mucus produced by the olfactory glands?
The secretion moistens the surface of the olfactory epithelium and dissolves odorants so that transduction can occur
What is olfactory transduction?
A series of events in which cells in the nose bind to scent-bearing molecules and send electrical signals to the brain where they are perceived as smells
What is olfactory adaptation?
Nose blindness or adaptation to the smell in an area
What is gustation?
The sense of taste
TRUE or FALSE
gustation is much simpler than olfaction
TRUE
How many primary tastes are there?
There are 5
What are the 5 primary tastes?
Salty, sour, sweet, bitter, and umam
Where are the receptors for taste located?
On the taste buds
What is a taste bud?
sensory organs that are found on your tongue and allow you to experience tastes
Taste buds consist of three kinds of epithelial cells, what are they?
Supporting epithelial cells
Gustatory epithelial cells
Basal epithelial cells
What are gustatory microvilli
are responsible for sensing taste stimulus
What are the three types of papillae?
Vallate papillae
Fungiform papillae
Foliate papillae
What are the chemicals that stimulate gustatory receptor cells called?
Tastants
What is the muscle called that is in the upper eyelid?
levator palpebrae superioris
The space between the upper and lower eyelids that exposes the eyeball is the ________ fissure
palpebral fissure
The space between the upper and lower eyelids that expose the eyeball is the palpebral fissure. Its angles are known as the _____
lateral commissure
What is the lacrimal caruncle?
The small, pink, globular spot at the inner corner, or the medial canthus, of the eye.
The _______ plate is a thick fold of connective tissue that gives form and support to the eyelids.
tarsal
What are the glands called that secrete a fluid that helps keep the eyelids from adhering to each other?
Tarsal Glands
Infection of the tarsal glands produces a tumor or cyst on the eyelid called a ___________
chalazion
The ________ is a thin, protective mucous membrane composed of nonkeratinized stratified squamous epithelium with numerous goblet cells that is supported by areolar connective tissue.
conjunctiva
The _______ conjunctiva lines the inner aspect of the eyelids
palpebral
the ______ conjunctiva passes from the eyelids onto the surface of the eyeball
bulbar
Dilation and congestion of the blood vessels of the ________conjunctiva due to local irritation or infection are the cause of bloodshot eyes.
bulbar
Sebaceous glands at the base of the hair follicles of the eyelashes called
Sebaceous Ciliary Glands
Sebaceous ciliary glands release a lubricating fluid into the ______
follicles
Infection of ________ glands, usually by bacteria, causes a painful, pus-filled swelling called a sty.
sebaceous ciliary glands
The ________ apparatus is a group of structures that produces and drains what type of fluid?
Lacrimal
Tears
The ______ glands, each about the size and shape of an almond, secrete lacrimal fluid
lacrimal
Tears then pass into two ducts, the superior and inferior _________ _________
lacrimal canaliculi
The lacrimal glands are supplied by parasympathetic fibres of the ______ nerves.
Facial (VII)
What is lysozyme?
a protective bactericidal enzyme within lacrimal glands
what is structural fat/ periorbital?
is the padding of the eye inside the orbit
How many extrinsic eye muscles move each eye?
six
Anatomically, the wall of the eyeball consists of three layers, what are they called?
(1) fibrous layer
(2) vascular layer
(3) inner layer (retina)
What is the fibrous layer of the eyeball?
the superficial layer of the eye- ball and consists of the anterior cornea and posterior sclera
What is the cornea?
A transparent coat that covers the coloured iris
What is the sclera?
the “white” of the eye is a layer of dense connective tissue made up mostly of collagen fibres and fibroblasts
At the junction of the sclera and cornea is an opening
known as the _______ __________ __________
scleral venous sinus
What is the vascular layer of the eye?
is the middle layer of the eyeball
What is a choroid?
A thin layer of tissue that is part of the middle layer of the wall of the eye, between the sclera and the retina
What is the ciliary body of the eye?
A part of the middle layer of the wall of the eye
What is the ora serrata?
the transition site between the single, nonpigmented layer of ciliary epithelium and the multilayered retina
What are the ciliary processes?
protrusions or folds on the internal surface of the ciliary body
What is another name for zonular fibres?
suspensory ligaments
What are zonular fibres?
they are ligaments that attach to the lens of the eye
What are the ciliary muscles, and what do they do?
Circular bands of smooth muscle that contract or relax changing the shape of the lens to switch from seeing far and seeing close
What is the iris?
the coloured portion of the eye ball
What is the purpose of the pupil?
regulate the amount of light entering the eye
what is sphincter pupillae?
a muscle located in the colored part of the eye called the iris
What is the dilator pupillae?
A ring of contractile cells within the iris.
The third and inner layer of the eyeball, the ________?
retina
What is the optic disc or blind spot?
is the site where the optic (II) nerve exits the eyeball
What is the central retinal artery and what does it do?
Is the first branch of the ophthalmic artery, and it supplies nerve fibres in the optic nerve as well as the inner layers of the retina
What is the central retinal vein?
a vein that drains the retina of the eye.
The retina consists of a ______layer and a _____ layer
pigmented
&
neural
What is the pigmented layer of the retina?
a sheet of melanin-containing epithelial cells located between the choroid and the neural part of the retina
What does the melanin in the pigmented layer do?
Helps absorb stray light rays
What is the neural (sensory) layer of the retina?
processes visual data extensively before sending nerve impulses into axons that form the optic nerve.
What are the three layers of retinal neurons?
photoreceptor cell layer
bipolar cell layer
ganglion cell layer
The three layers of retinal neurons are separated by what two zones?
the outer and inner synaptic layers
Light passes through the ____ and ______ cells layers and both synaptic layers before it reaches the photoreceptor layer.
ganglion
bipolar
Two other types of cells present in the bipolar cell layer of the retina are called______cells and ______ cells
horizontal
&
amacrine
Horizontal & amacrine cells form ______ circuits?
Neural
________ are specialized cells in the _______layer that begin the process by which light rays are ultimately converted to nerve impulses
Photoreceptors
What are the two types of photoreceptors?
Rods and Cones
What do rods allow us to see?
rods allow us to see in dim light, such as moonlight.
Are there more rods than cones in the eye?
Yes more rods
What do cones allow us to see?
Brighter lights stimulate cones, which produce color vision.
What are the three types of cones?
Blue
Green
Red
Why is the optic disc called the blind spot?
it contains no rods or cones
What is the macula, and where is it located?
The yellow spot in the exact center of the posterior portion of the retina.
At the visual axis of the eye
What is the fovea centralis?
A small depression in the center of the macula contains only cones
the ______ centralis is the area of highest visual acuity
fovea
Behind the pupil and iris, within the cavity of the eyeball, is the _____
lens
What protein within the cells of the lens are arranged like the layers of an onion?
Crystallins
What is the purpose of the crystallins?
make up the refractive media of the lens
The lens divides the interior of the eyeball into two chambers; what are they?
anterior chamber
posterior chamber
What segment of the eye consists of 2 chambers?
Anterior segment
The ________chamber lies between the cornea and the iris
anterior
The _______ chamber lies behind the iris and in front of the zonular fibers and lens
Posterior
Both chambers of the anterior segment are filled with _____ ______
aqueous humor
What is aqueous humor?
a transparent watery fluid that nourishes the lens and cornea
The larger posterior portion of the eyeball is the ________ ________
posterior segment
Where does the posterior segment lie?
lies between the lens and the retina
the _________ _________- that holds the retina flush against the choroid, giving the retina an even surface for the reception of clear images
vitreous humor
What is the hyaloid canal?
Is a narrow channel that is inconspicuous in adults and runs through the poste- rior segment
What is the pressure in the eye called?
intraocular pressure
Where is the intraocular pressure produced?
mainly by the aqueous humor and partly by the vitreous humor
What structures are part of the fibrous tunic?
Corena
Scleara
What structures are part of the vascular tunic?
Iris
Ciliary body
Choroid
What is the function of the cornea?
Admits and refracts (bends) light.
What is the function of the sclera?
It provides shape and protects inner parts.
What is the function of the iris?
Regulates amount of light that enters eyeball.
What is the function of the ciliary body?
Secretes aqueous humor and alters shape of lens for near or far vision (accommodation)
What is the function of the choroid?
Provides blood supply and absorbs scattered light.
What is the function of the retina?
Receives light and converts it into
receptor potentials and nerve
impulses. Output to brain via axons
of ganglion cells, which form optic
(II) nerve.
What is the function of the lens?
Refracts light.
What is the function of the anterior segment?
Contains aqueous humor that helps maintain shape of eyeball and supplies oxygen and nutrients to lens and cornea.
What is the function of the posterior segment?
Contains vitreous humor that helps maintain shape of eyeball and keeps retina attached to choroid.
To understand how the eye forms clear images of objects on the retina, we must examine three processes:
(1) the refraction or bending of light by the lens and cornea
(2) accommodation, the change in shape of the lens
(3) constriction or narrowing of the pupil.
What is refraction?
the bending of light rays as they pass through one object to another.
Images focused on the retina are ________
inverted (upside down)
Images also undergo right-to-left reversal, what does this mean?
that is, light from the right side of an object strikes the left side of the retina, and vice versa
The increase in the curvature of the lens for near vision is called?
accommodation
What is the near point of vision?
The minimum distance from the eye that an object can be clearly focused with maximum accommodation
The normal eye, known as an ________ ________ can sufficiently refract light rays from an object 6 m (20 ft) away so that a clear image is focused on the retina
emmetropic eye
What is myopia?
nearsightedness
_____ individuals can see close objects clearly, but not distant objects
Myopic
What is hyperopia?
farsightedness
_____ individuals can see distant objects clearly, but not close ones
Hyperopic
What is astigmatism?
in which either the cornea or the lens has an irregular curvature
What is binocular vision?
This feature of our visual system allows the perception of depth and an appreciation of the three-dimensional nature of objects.
What is convergence?
refers to this medial movement of the two eyeballs so that both are directed toward the object being viewed
The first step in visual transduction is absorption of light by a _________
photopigment
What is photopigment?
a colored protein that undergoes structural changes when it absorbs light, in the outer segment of a photoreceptor
The single type of photopigment in rods is ________
rhodopsin
All photopigments associated with vision contain two parts:
a glycoprotein is known as opsin
&
a derivative of vitamin A called retinal
______ is the light-absorbing part of all visual photopigments
Retinal
Photopigments respond to light in the following cyclical process
What are the 4 steps?
Isomerization.
Bleaching.
Conversion.
Regeneration.
When cis-retinal absorbs a photon of light, it straightens out to a shape called ______-_____
Trans-retinal.
When cis-retinal absorbs a photon of light, it straightens out to a shape called trans-retinal. This cis-to-trans conversion is called _______
isomerization
______ is responsible for the color of the photopigment, so the separation of trans-retinal from opsin causes opsin to look colorless
Retinal
An enzyme called ________ _________ converts trans-retinal back to cis-retinal.
retinal isomerase
The cis-retinal then can bind to opsin, reforming a functional photopigment. This part of the cycle— resynthesis of a photopigment—is called?
Regeneration
what is otorhinolaryngology?
is the science that deals with the ears, nose, pharynx (throat), and larynx (voice box) and their disorders
The ear is divided into three main regions:
(1) the external ear, which collects sound waves and channels them inward
(2) the middle ear, which conveys sound vibrations to the vestibular window
(3) the internal ear, which houses the receptors for hearing and equilibrium.
The external (outer) ear consists of what three things?
the auricle,
external acoustic meatus
eardrum
What is the auricle?
is a flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin
The rim of the auricle is the _____
helix
The inferior portion of the outer ear is called?
the lobule
What is the external acoustic meatus?
The ear canal
Where does the external acoustic meatus lie?
lies in the temporal bone and leads to the eardrum
What is the tympanic membrane?
eardrum
What is the eardrum?
is a thin, semitransparent partition between the exter- nal acoustic meatus and middle ear.
The tearing of the tympanic membrane is called a ______ eardrum.
perforated
Near the exterior opening, the external auditory canal contains a few hairs and specialized sweat glands called _________ ________
ceruminous glands
What do the ceruminous glands secrete?
earwax
The ________ ear is a small, air-filled cavity in the
petrous portion of the temporal bone that is lined by epithelium
middle ear
Extending across the middle ear and attached to it by ligaments are the three smallest bones in the body, the ________ ________
auditory ossicles
What type of joints are the auditory ossicles
Synovial joints
What is malleus?
A small bone in the middle ear which transmits vibrations of the eardrum to the incus.
What is the incus?
a small anvil-shaped bone in the middle ear, transmitting vibrations between the malleus and stapes.
What is the stapes?
It is the innermost bone of our auditory ossicles in the middle ear, which are responsible for transmitting sound waves from the air outside to the fluid-filled labyrinth (cochlea).
What is the vestibular window?
Is a membrane-covered opening from the middle ear to the cochlea of the inner ear
What is the cochlear window?
The round window is one of the two openings from the middle ear into the inner ear
What is the secondary tympanic membrane?
a membrane closing the round window and separating the scala tympani from the middle ear.
What is the tensor tympani muscle?
A muscle which is supplied by the mandibular branch of the trigeminal nerve
What is the stapedius muscle?
Muscle, which is supplied by the facial (VII) nerve
What is the auditory tube?
A canal that connected the nasopharynx to the middle ear
What is the internal ear?
the innermost part of the vertebrate ear
What is the bony labyrinth?
is a series of cavities in the petrous portion of the temporal bone
The bony labyrinth is a series of cavities in the petrous portion of the temporal bone divided into what three areas?
(1) the semicircular canals
(2) the vestibule
(3) the cochlea
The bony labyrinth is lined with periosteum and contains ______
perilymph
What are sound waves?
are alternating high- and low-pressure regions traveling in the same direction through some medium
The frequency of a sound vibration is its _____
Pitch
The larger the intensity (size or amplitude) of the _____________, the louder is the sound
vibration
The ear not only detects sound but also detects changes in ________
Equilibrium
Collectively, the receptor organs for equilibrium are called the___________apparatus
vestibular
What are the two otolithic organs?
are the utricle and saccule
Attached to the inner walls of both the utricle and the saccule is a small, thickened region called the __________
macula
The two maculae contain the receptors for linear ____________ or _______ and for detecting the position of the head
acceleration or deceleration
What are the two types of cells in the maculae
Hair cells
Supporting Cells
