Special Senses (Chapter 17)
How can myopia be corrected?
A concave (diverging lense). Glasses that project light further back.
What does it mean to say that someone has 20/20 vision?
A person can see at 20 feet what a normal person can see at 20ft.
What does it mean to say that someone has 20/60 vision?
A person can see at 20 feet what a normal person can see at 60 feet.
if more aqueous humor is produced than is absorbed in the canal of Schlemm, which condition results?
An increase amount of aqueous humor will eventually push on the lens and ventricels which will damages the retina. It is called Glaucoma.
Why does conjunctivitis lead to red eye?
An inflammation can causes the blood vesses to dilate that makes the white part of they eye appear red.
why does the lens lose its ability to accommodate in older people
As we age, we lose elasticity in our lens and our eyes can't buldge.
How can hyperopia be corrected?
By a convex (converging lens). Glasses that project light closer back.
Name a part of the brain that receives the input from the vestibule and semicircular canals.
Cerebellum
Which is innervated by the oculomotor nerve?
Constrictor pupillae and ciliary muscle
What is the function of the ciliary muscle?
Contracts and relaxes to change the shape of the lens in order to focus on near or far away objects
Name three cranial nerves that carry impulses for taste?
Facial nerve, Glossopharyngeal, Vagus
Why would a patient with chronic dry mouth have difficulty taste food?
In order to taste the food you must break it down thoroughly in your moth saliva aids in the breakdown of food particles. Without saliva, it will be hard to break down food limiting flavors from reaching taste receptors
What is its (auditory tube) significance?
It allows us to equalize our pressure
Why is the crossing of retinal fibers significant?
It allows us to see a coherent image using both eyes.
What is conduction deafness?
It is interference with the passage of sound waves or vibrations. Sound does not get to the cochlea.
What is unique concerning the cornea?
It lacks blood vessels
Which muscle is innervated by the abducens nerve?
Lateral Oblique
Where is the lacrimal gland located?
Lateral Superior surface
What is the role of the lens in the refraction of the light?
Lens help focus incoming light onto the retina.
Name the nerve that innervates the cilliary muscle?
Oculomotor
Which nerve innervates the other four muscles?
Oculomotor
Which cranial nerve carriers olfactory impulses?
Olfactory
Where are taste buds located?
Papillae of the tongue
What is the dilator pupillae innervated by?
Parasympathetic nervous system.
Where are rods and cones primary located?
Periphery
What type of vision might be lost when a person has a tumor of the pituitary gland?
Periphery vision
Where do the pathway for olfaction end in the brain?
Primary Olfactory cortex
What are the two types of photoreceptos and what do they dectect?
Rods and cones
What is the purpose of the tympanic membrane?
Sound waves hit the tympanic membrane causing it to vibrate
Where is the nasal epithelium for smell located?
Superior Nasal conchere
Which muscle is innervated by the trochlear nerve?
Superior Oblique
Name the six extrinisic eye muscles:
Superior Rectus Inferior Rectus Medial rectus Lateral Rectus Superior Oblique Inferior Oblique
Why might a patient with a fractured ethmoid bone have difficulty tasting food?
Taste and smell are integrated in the orbitofrontal cortex together combing the sensory information
What bone does the external auditory canal travel to?
Temporal bone
Where is the hearing center in the brain located?
Temporal lobe
What is accomodation?
The eye ability to adjust the shape of the lens to focus on objects at different distances.
How does astigmatism affect the visual field?
The irregular curve or the cornea cuases the light to focus on multiple points of the retina. This causes distorted blurred and stretched images.
Why is it difficult for a myopic person to see objects clearly that are at a distance?
The light form the lens doesn't hit the retina
What is the link between the hypothalamus and the sense of smell?
The olfactory bulbs also send information to the hypothalamus, it becomes apart of the limbic system.
What is meant by the optic disc or blind spot? Are any photoreceptors located at the optic disc?
The optic disc is a round section of the back of they eye. It is where the retina and optic nerve connect. The only areas on the retina without any photoreceptors. The area in the eye where there are no rods or cones.
What happens to the number of taste buds with age?
They decrease with age.
What type of tissue does the tympanic membrane contain?
This membrane that has stratified squamous on the outside and simple cubdoil on the inside. Also, some elastic fibers below.
How is the lens accomodating for near vision in a myopic person and distance vision in a hyperopic person?
Very well.
Which nerve carries hearing impulses to the brain?
Vestibulocochlear
What is unique about vitreous humor?
We never exchange vitreous humor we are born with what we have.
Are rods and cones evenly distributed in the retina?
You have alot more rods than you do cones in your eye.
Define accomodation
ability of the lens to change its shape.
what is the importance of adaptation?
allows our sensory system to remain responsive to new odors by densensitizing the old ones. The goal is to adapt to unpleasant smells over a period of time
Where is the canal of schlemm located?
anterior chamber
What is the fovea centralis?
area of the retina with only cones
Is the lacrimal gland innervated by the autonomic or somatic nervous system?
autonomic or nervous system
The lens will ___ when looking at an object up close
bulge
An infection of the tarsal glands is called?
chalazion
Taste buds are ____ receptors
chemo
What types of receptors are found in the nasal epithelium?
chemoreceptors ( bipolar neurons), dendritic endings
what makes up the vascular tunic?
choroid, ciliary body, iris
How does the lens change its shape?
ciliary muscles is a smooth muscle that connects the shape of the lens.
What two part make up the ciliary body?
ciliary process and ciliary muscle
what does the external ear do?
collects sound waves and transmit them to the middle ear
pharyngotympanic (auditory) tube
connects the middle ear to the nasopharynx; equalizes pressure in the middle ear cavity with the external air pressure
What is the inner ear?
consists of an equilibrium apparatus and a hearing apparatus
How do the olfactory nerve enter the brain?
cribriform plate through ethmoid bone
The lens is made of protein called?
crystaline
What is sensoneural deafness?
damage in the cochlea, vestibulocochlear nerve and temporal lobe
Name the type of tissue that is found in the sclera?
dense irregular collagen fibers
What are rods?
detect dim light, useful for night
What are the three intrinisic eye muscles?
dilator pupillae constrictor pupillae and ciliary muscle
What two intrinsic eye muscles are located in the iris?
dilator pupillae and constrictor pupillae
What is unique type of tissues does the auricle contain?
elastic cartilage
What is the importance of smell in tasting?
enhances sensory perception help detect harmful spoiled foods
Name the layers of the eyelid from superficial to deep
epidermis (stratified squamous), dermis, hypodermis and skeletal muslce (levator palpebrae) & (orbicularis oculi)
What is the difference between extrinsic eye muscles and intrinsci eye muscles?
extrinsic are voluntary and are located outside the eye. intrinsic are involuntary and are located inside the eye
hyperopia
eyeball is too short
Diagrams where conjucntiva are found in the eye.
eyelashes help keep debris away from inside the eye. They also have sebaceous glands that make oil. Inflammation causes a sty.
Which cranial nerve innervates the lacrimal glands?
facial nerve (#7)
The lens will ____ when looking at an object that is far away?
flatten
will the lens become rounder of flatter when an object is viewed at farther away distance?
flatter
How does the cornea get its nourishment?
from the aqueous humor or come from the tears that flow across the anterior surface of the eye.
What is the middle ear?
function: amplify the sound waves and transmit them to the inner ear.
The axons of ____ cells form the optic nerve.
ganglion
What is the function of the vitreous humor?
gel like ball that holds the shape of the eye.
name two functions of the fibrous sclera?
helps maintain eyeballs shape protects eyeball form injury
what is inside the anterior chamber?
iris and cornea
What is the astigmatism?
irregular curvature of the cornea
What is the function of the lens?
it focuses light on the retina.
What is inside the posterior chamber?
lens and iris
What gives the iris its color?
melanin
What is emmetropia?
normal vision
What are functions of the choroid?
provides nourishment (blood vessels) for the retina absorbs light (contains melanin)
Name the three types of cones:
red, green, blue
will the lens become rounder or flatter when an object is viewed at a close distance?
rounder
What chemicals are in tears?
salt, lysozyme, mucus, ion (to inhibit bacterial growth; detects infections of the eye)
What are the tissues located inside the fibrous tunic?
sclera and cornea
What is the function of the ciliary body?
secretes aqueous humor which flows through the pupil and retina into the canal of Schlemma.
what does it mean to say that there is a low threshold for smell?
sensitive to faint orders
Are the intrinisci eye muscles smooth or skeletal muscles?
smooth muscles
Name six types of taste that can be discriminated:
sweet, sour, bitter, salty, fat, uriami (savory)
what is presbyopia?
the lens loses the ability to change its shape.
What is the function of aqueous humor?
to provide lubrication and protection to the eyeball.
What are cones?
visual acuity (sharpness) and colors
