chapter 15 special senses
smell, taste, sight,hearing and equilibrium
What are the special senses
Vision - 70 % of all the sensory receptors in the body are in the eyes and nearly 1/2 of the cerebral cortex is in involved in some aspect of visual processing
What is the dominant sense
A) the sclera. This opaque outer layer appears white due to the presence of collagen fibers.
What part of the eye is called "the white of the eye"? Is it A) the sclera or B) the choroid?
B) the neural layer. The retina contains the neural cells whereas the uvea contains the iris.
In which layer is the retina found? Is it the A) uvea or B) neural layer?
A) green. Color variation is due to concentration and distribution of melanocytes. Blue has the least amount of
Which iris color has more melanin? Is it A) green or B) blue?
The answer is B) crystallins. Collagen is important in the connective tissues and cornea. Crystallins appear in a precisely packed pattern in the lens.
What are the protein fibers called that make up the lens? Are they A) collagens or B) crystallins?
The answer is B) the vitreous body. The aqueous humor is the fluid in the anterior chamber.
What do we call the gel-like substance in the posterior chamber of the eyeball? Is it A) the aqueous humor or B) the vitreous body?
The answer is B) the cones. The cones are stimulated by color and intense light.
Which photoreceptor cells are responsible for sharp vision? Is it A) the rods or B) the cones?
The answer is B) the bipolar cells. They regulate action potentials of the ganglion cells based on stimulation of the rods and cones.
Which neural cells regulate action potential generation in the eye? Is it A) the ganglion cells or B) the bipolar cells?
The answer is B) the fovea. The fovea contains the highest concentrations of cones, resulting in the sharpest vision.
What is the area called where your vision is the sharpest? Is it A) the optic disc or B) the fovea?
the process of increasing the refractive power of the lens of the eye - focusing
accomidation
1. any change in structure or respone to suit a new environment 2. decline in the transmission of a sensory nerve when a receptor is stimulated continuously and without change in stimulus strength
adaptation
a localized dialation of a canal or duct
ampulla
watery fluid in the anterior segment of the eye
aqueous humor
a condition in which unequal curvatures in different parts of the cornea or lense of the eye lead to blurred vision
astigmatism
the trhee tiny bones serving as transmitters of vibrations and located within the middle ear, the malleus, incus, and stapes
auditory ossicles
tube that connects the middle ear and the pharynx - also called the eustachian tube
auditory tube
an indentation of the surface ectoderm in the embryo; the external acoustic meatus developes from it
branchial groove
the vascular middle layer of the eye
choroid
snail shaped chamber of the bony labyrinth that houses the receptor for hearing [the spinal organ (of corti)]
cochlea
one of the two types of photoreceptor cells in the retina of the eye: provide for color vision
cones
thin protective mucus membrane lining the eyelids and covering the anterior surface of the eye itself
conjunctiva
transparent anterior portion of the eyeball: part of the fibrous layer
cornea
sensory receptor organ within the ampulla of each semicircular canal or the inner ear, dynamic equilibrium receptor
crista ampullaris
double vision
diplopia
sense that reports on angular (rotatory) acceleration or deceleration of the head in space
dynamic equilibrium
emitted photons (wave packets) of energy ex. light, x ray, infared
electromagnetic radiation
the six skeletal muscles which attach to and move each eye
extrinsic eye muscles
a pit
fovea
base of an organ part farthest from the opening of the organ for example the posterior wall of the eye
fundus
condition in which intraocular pressure increases to levels that cause the compression of the retina and optic nerve; results in blindness unless detected early
glaucoma
taste
gustation
a condition in which visual images are routinely focused behind rather than on the retina - commonly known as farsightedness
hypertopia
body cavities and membranes of the inner ear
labyrinth
pertaining to the tears
lacrimal
a condition in which visual images are focused in front of rather than on the retina - nearsightedness
myopia
smell
olfaction
pertaining to the eye
opthalmic
pertaining to the eye or vision
optic
the partial crossover of fibers of the optic nerves
optic chiasma
same as auditory ossicles
ossicles
tube that connects the middle ear and the pharynx - also called the auditory tube eustachian tube
pharyngotympanic tube
specialized receptor calls that respond to light energy- roda and cones
photoreceptor
condition that results in the loss of near focussing ability - typical onset is around age 40
presbyopia
opening in the center of the iris through which light enters the eye
pupil
the bending of a light ray when it meets a different surface at an oblique rather than a right angle
refraction
neural layer of the eyeball contains photo receptors (rods - cones)
retina
one of the two types of photosensitive cells in the retina
rods
white opaque portion of the fibrous layer of the eyeball
sclera
taste, smell, vision, hearing and equilibrium
special senses
sense of head position in space with respect to gravity
static equilibrium
sensory receptor oragans that house gustatory cells which respond to dissolved food chemicals
taste buds
eardrum
tympanic membrane
an enlarged area at the begining of a canal - inner ear, nose, larynx
vestibule
the field of view seen when the head is still
visual field
chemoreceptors. Both receptors respond to the chemical content
The receptors for taste and smell are classified as:
zinc .About a third of cases of anosmia are said to be caused by zinc deficiency.
Anosmia, an olfactory disorder, may be caused by a deficiency of:
cornea. The cornea of the eye is part of the eyeball structure and NOT an accessory organ.
The accessory structures of the eye do NOT include:
both the inner surface of the eyelids and the visible portion of the sclera. ith the exception of the cornea, the conjunctival membrane covers the visible portion of the sclera and the palpebral conjunctiva.
The conjunctival mucous membrane covers:
lacrimal gland secretions wash the eyeball and drain into the lacrimal duct, which empties into the nasal cavity.The drainage system for tears goes through the lacrimal duct into the nasal cavity.
When a person cries, he or she tends to keep on wiping their dripping nose. The nose drips because:
medial rectus. he medial rectus inserts into the medial side of the eyeball and moves the eyeball medially.
The horizontal rotation of the eyeball towards the nose is the function of the:
semicircular canals.The ampulla of the semicircular canals houses the receptors that monitor angular movements of the head
Rotational movement of the head is monitored by receptors located in the:
Retina, choroid, sclera Surrounding the cavity of the eyeball, the wall of the eyeball is formed by the sensory tunic, followed by the vascular tunic, and then the fibrous tunic.
Arrange the tunics of the wall of the eyeball in their correct sequence from inside out.
Cornea, anterior segment, pupil, lens, posterior segment The anterior segment and the pupil are in front of the lens, and the posterior segment is behind the lens.
Which sequence follows the correct passage of light entering the cornea?
cochlea. The receptor organs for hearing are housed in the cochlear duct.
The organ of Corti is found in the:
Sympathetic nerves The contraction of radial muscles in the iris causes the pupil to dilate.
Which of the following types of stimulation results in an increase in the diameter of the pupil?
in children. The near point of vision recedes with age and is the shortest in young children.
The near point of vision is the shortest:
protect the hearing receptors from loud sounds. he stapedius and the tensor tympani muscles minimize the excessive vibration of the ossicles caused by loud noise.
The tiny skeletal muscles associated with the ossicles of the middle ear function to:
inner ear cavity. These receptors are found within the bony labyrinth.
The receptors for sound reception and equilibrium are located in the
where the optic nerve leaves the eye. Because of the numerous axons where the optic nerve leaves the eye, there is no room for photoreceptors, causing a blind spot.
The blind spot on the retina is:
allows equilibration of air pressure between the middle ear and outside air.The pharyngotympanic tube connects the pharynx and middle ear and allows equilibration of air pressure.
The pharyngotympanic tube
more flattened.A flat lens bends distance light less, allowing it to focus on the retina.
When focusing on a distant object, the lens is:
sight. Seventy percent of the sensory receptors in the body are located in the eye and are involved with sight.
Seventy percent of the sensory receptors in the body involved with:
sweat glands. Ciliary glands are modified sweat glands
Ciliary glands are modified:
conjunctiva PInk eye is caused by an inflammation of the conjunctiva.
Pink eye is caused by an inflammation of the ______.
congenital weakness of the extrinsic muscles of the eye. Congenital weakness of the extrinsic muscles of the eye would lead to strabismus.
Strabismus is caused by:
distant vision.Our eyes are best adapted for distant vision
Our eyes are best adapted for:
length of the eyeball. Ninety-nine percent of refractive problems in the eye are related to the length of the eyeball.
Ninety-nine percent of refractive problems in the eye are related to the
rods Retinitis pigmentosa is a disease of the rods that occurs when the pigment epithelial cells are unable to recycle the tips of rods as they are sloughed off.
Retinitis pigmentosa is a disease of the _____.
Olfactory receptors Cones cannot replace themselves in adult life. Olfactory receptors are one of the few types of neurons that can replace themselves in adult life.
_______ are one of the few types of neurons that can replace themselves in adult life
process of breaking down the retinal-opsin combinations that form the rhodopsin found in the rods and cones.The oxidation of vitamin A leads to the formation of rhodopsin, not its breakdown, which occurs durning the the bleaching of the pigment.
The bleaching of the pigment refers to the:
The retina becomes less sensitive When one moves from a well-lit room to a dark room, the retina becomes more sensitive, not less sensitive.
Which adaptation does NOT take place when one moves from a well-lit room to a dark room?
Ceruminous glands are modified sweat glands found in the outer ear.
Which of the following would NOT be found in the outer ear?
vision Vision is the only special sense that is not fully functional at birth
The only special sense not fully functional at birth is _______
Glutamate Norepinephrine is not involved with hearing in the inner ear.
Which of the following neurotransmitters is involved with hearing in the inner ear?
true -Taste is about 80% smell.
true or False Taste sensation is heavily dependent on olfactory receptors.
False
When exposed to an odorant for a longer time, olfactory receptors become less sensitive and stop sending action potentials to the sensory cortex.
true or False Olfactory adaptation means that the olfactory receptors become more sensitive to the presence of an odor.
False This muscle is inserted to the inferior surface of the eyeball. It rotates the eye up and laterally
true or False When the eyeballs rotate down, the inferior oblique muscle contracts.
True The circular and radial muscles of the iris reflexively contract and control the diameter of the pupil.
true or False The size of the pupil is dependent on the contraction of the muscles of the iris.
False The rods are adapted for dim light and peripheral vision.
true or False The rods of the retina operate in bright light and provide high-acuity vision.
False Fovea centralis has high cone density and is the focus of acute vision.
true or False The area of the retina with the highest vision is called the optic disc.
False The clear transparent gel filling the posterior segment is called vitreous humor.
true or False The posterior segment of the eyeball is filled with clear gel, called the aqueous humor.
False The malleus is attached to the tympanic membrane and to the incus.
true or False The malleus in the middle ear is attached to the tympanic membrane on one end and to the oval window on the other end.
False High-frequency waves stimulate receptors closer to the oval window, and low-frequency waves stimulate the receptors in the organ of Corti, further away from the oval window.
true or False Sounds of low frequency cause the vibration of the basilar membrane closer to the oval window. Sounds of higher frequencies vibrate the oval window further away from the oval window.
false The cornea is the clear portion of the fibrous tunic.
true or False The cornea is part of the vascular tunic.
False Cranial nerve I is the olfactory nerve.
true or False Impulses from the olfactory epithelium are sent to the brain via cranial nerve II.
False The cranial nerves that carry taste sensations are VII, IX, and X.
true or False Cranial nerve V is one of the nerves that carry the sensation of taste.
True The auditory tube connects to the nasopharynx and allows for pressure equalization.
true or False The auditory tube allows pressure equalization between the middle ear and the external environment.
True The three semicircular canals are oriented in the three planes of movement and evaluate head movements in each of those planes.
true or False The semicircular canals respond to rotational movements.