Eyes and Ears

Question 1

The fibrous coat of the eye is also called the _____?

Answer 1

Sclera

Question 2

What structure is responsible for the majority of light refraction?

Answer 2

The cornea

Question 3

Where does the cornea draw it’s nutrients from?

Answer 3

The aqueous humor by diffusion

Question 4

What is the external portion of the cornea called?

Answer 4

The conjunctiva

Question 5

What is the purpose of the conjunctiva?

Answer 5

Along with the lacrimal gland, produce a fluid that bathes the anterior surface of the eye and keeps it nourished and moist

Question 6

What is the layer of numerous anastomosing blood vessels called?

Answer 6

The choroid layer

Question 7

What’s the structure that controls the refraction of light from the lens?

Answer 7

The ciliary body

Question 8

What are the two muscles that control pupil size? What are their actions and innervations?

Answer 8

The sphincter pupillae - constricts, parasympathetically innervated
The dilator pupillae - dilates, sympathetically innervated

Question 9

What structure accounts for two thirds of the eye’s optical (refractory) power?

Answer 9

The cornea

Question 10

What nerve innervates the cornea?

Answer 10

CN V

Question 11

What are the three main components of the cornea?

Answer 11

Epithelium, collagen, and endothelium

Question 12

The lens is composed of _____?

Answer 12

Stiff, elongated prismatic cells known as lens fibres

Question 13

The lens has less optical power than the cornea, but is superior how?

Answer 13

It is adjustable by the ciliary muscles

Question 14

What is the condition associated with age and far-sightedness?

Answer 14

Presbyopia

Question 15

What fluid is the anterior chamber filled with, and where is it produced?

Answer 15

It is filled with the aqueous humor and is produced by the ciliary body

Question 16

Where is the aqueous humor of the anterior chamber drained?

Answer 16

The canal of Schlemm

Question 17

What happens in glaucoma?

Answer 17

Increased pressure in the anterior chamber transfers pressure back to the optic nerve and results in damage to the optic nerve and blindness

Question 18

The nervous coat of the eyeball is called the?

Answer 18

Retina

Question 19

What are the two photosensitive cells of the eye and what do they detect?

Answer 19

Rods - more sensitive to light, do not respond to red light

Cones - detect colors (red, blue, green)

Question 20

What is the protein required for rod and cone function and what vitamin is it a metabolite of?

Answer 20

Retinal - Vitamin A

Question 21

Why should the optic nerve be called a tract?

Answer 21

The meninges surround the nerve up to the sclera, the subarachnoid space is filled with CSF, and the ganglion cells of the retina are myelinated by oligodendrocytes and fed by astrocytes

Question 22

Papilledema is a condition of??

Answer 22

Increased CSF limiting venous return from retina and causes edema under optic disc. Visible by blurred disc margins where the optic disc is raised.

Question 23

What is the function and composition of the vitreous body?

Answer 23

It functions to support the retina and applying pressure against the shape of the globe. It is composed of hyaluronic acid and type II collagen fibrils

Question 24

The hyaloid canal is a vestige of what embryonic structure?

Answer 24

The hyaloid artery

Question 25

What is the pathway of nerve impulses from the retina?

Answer 25

The optic nerve to the optic chiasm to the lateral geniculate body of the thalamus to optic radiations to the primary visual cortex

Question 26

What muscle(s) does the abducens nerve (CN VI) innervate and what is/are their action(s)?

Answer 26

Lateral rectus - abducts the eye

Question 27

What muscle(s) does the trochlear nerve (CN IV) innervate and what is/are their action(s)?

Answer 27

Superior oblique - internally rotates, depresses and abducts

Question 28

What muscle(s) does the oculomotor nerve (CN III) innervate and what is/are their action(s)?

Answer 28

Inferior oblique - externally rotates, raises and adducts Medial rectus - internally rotates Inferior rectus - depresses

Question 29

What is the name for the ear canal?

Answer 29

The auditory meatus

Question 30

What is the function of cerumen?

Answer 30

To protect the ear from irritation and infection

Question 31

What is the pathway from the tympanic membrane to the oval window?

Answer 31

Tympanic membrane --> malleus --> incus --> stapes --> oval window

Question 32

What kind of joints are in the middle ear?

Answer 32

Synovial joints

Question 33

What muscles contract to reduce the movement of the ossicles in order to protect the ear from excessive noise?

Answer 33

Tensor tympani - malleus | Stapedius - stapes

Question 34

What are the three parts of the inner ear?

Answer 34

The cochlea, the vestibule, and the semicircular canals

Question 35

Movement of the stapes at the oval window moves the perilymph of?

Answer 35

The scala vestibuli

Question 36

The movement of the perilymph in the scala vestibuli vibrates what?

Answer 36

The endolymph in the scala media, the basilar membrane, and the Organ of Corti

Question 37

What organ translates the movement of hair cells to electrical impulses?

Answer 37

The Organ of Corti

Question 38

Describe the auditory pathway.

Answer 38

The cochlear division transmits nerves to it's nucleus then to the superior olivary nucleus. This information ascends to the inferior colliculus then goes to the thalamus (which allows us to localize sound). From the thalamus, this info is sent to the primary auditory cortex located in the temporal lobe

Question 39

What systems keep us in balance?

Answer 39

The vestibular system, the visual system, and pressure/proprioceptors

Question 40

What are the parts of the vestibule?

Answer 40

The saccule, the utricle, and the 3 semicircular canals

Question 41

What are the hair structures that transmit information on movement?

Answer 41

The otoliths - which are composed of calcium carbonate

Question 42

What structure is at the base of each semicircular canal?

Answer 42

The ampulla, which contains the hair cells responsible for nerve transmission

Question 43

What is BPPV?

Answer 43

Benign Paroxysmal Positional Vertigo - a condition in which the patient is overcome by a sudden sensation of spinning

Question 44

How is BPPV diagnosed and treated?

Answer 44

It is diagnosed with the Dix-Hallpike manuever (the roll test) and treated with the Epley or Semont Manuever