Lab 11 The Special Senses

Question 1

What is the “white of the eye”?

Answer 1

Sclera

Question 2

Is the cornea transparent?

Answer 2

Yes.

Question 3

What fluid is found in the anterior portion of the eye?

Answer 3

Aqueous Humor

Question 4

What is the function of aqueous humor?

Answer 4

To nourish the eye and maintain internal pressures.

Question 5

Describe the 2 muscles involved with the iris.

Answer 5

Inner circular portion and outer radial smooth muscles arranged around the central opening (pupil)

Question 6

What happens to the pupil in bright/dim light?

Answer 6

Bright: the muscles of the iris constrict causing the pupil to constrict allowing less light into the eye

Dim: the muscles of the iris contract dilating the pupil and allowing more light to enter the eye.

Question 7

What controls the shape of the lens?

Answer 7

Cilliary Muscles

Question 8

What is the function of the choroid?

Answer 8

To absorb excess light rays to prevent reflection and the scattering of light within the eyeball.

Question 9

What forms the inner most layer of the eye?

Answer 9

The Retina

Question 10

What fluid fills the posterior portion of the eye?

Answer 10

Vitreous Humor (body)

Question 11

What are the photoreceptors involved in the eye?

Answer 11

Rods and Cones

Question 12

What area contains no photoreceptors?

Answer 12

The optic disc.

Question 13

What structure of the eye allows for sharpness of vision and why?

Answer 13

The forea centralis contains only cones allowing for high sharpness.

Question 14

Describe Rods and Cones?

Answer 14

Rods: are stimulated by dimmer light and allow us to see in shades of black, white and grey.

Cones: are stimulated by bright light ad produce color vision (Red Blue Green)

Question 15

What is glaucoma?

Answer 15

The build up of pressure within the eye which can cause damage to the optic nerve and can result in permanent vision loss.

Question 16

What is a cataract?

Answer 16

Condition in which the lens of the eye becomes opaque.

Question 17

What is Accommodation?

Answer 17

At close range the eye must become more rounded or convex in shape in order to view objects at close range.

Question 18

How do Cilliary muscles and the suspensory ligaments aid in accommodation?

Answer 18

They support and allow for movement of the eye.

Question 19

What portion of the retina contains a large amount of cones but no rods?

Answer 19

Fovea Centralis

Question 20

Regarding the Snellen Test, explain what 20/30 vision means?

Answer 20

This means that the person can see at 20 feet what people with normal vision can see at 30 feet.

Question 21

Describe characteristics of an eye that has Hyperopia?

Answer 21

Eyeball is shorter, lens is flat.

Question 22

What can happen as a result of having a long shaped eye and long/rounded lens?

Answer 22

Myopia

Question 23

Where does the light refract during Myopia and Hyperopia?

Answer 23

Myopia (Near Sighted): focal point of light is in front of the retina, causing sight to be blurry far away

Hyperopia (Far Sighted): Focal point of light is behind the eye, causing sight to be blurry at far ranges

Question 24

What is astigmatism?

Answer 24

The cornea or lens has an irregular shape in surface curvature which can cause objects to appear clear in one axis and blurry in another.

Question 25

What is the function of the pinna?

Answer 25

Acts as a funnel for sound waves to travel into the ear

Question 26

What glands are located in the skin of the ear and what do they secrete?

Answer 26

Ceruminous glands; ear wax.

Question 27

What is the function of ear wax?

Answer 27

To lubricate the ear canal, clean the external auditory canal, keep out bacteria.

Question 28

Which cranial bone is hollowed out for the middle ear?

Answer 28

Temporal Bone

Question 29

What are the 3 ossicles?

Answer 29

Malleus, Incus, Stapes

Question 30

What do the ossicles function as?

Answer 30

Vibrations of the tympanic membrane are transferred and magnified by the ossicles to cause vibrations at the oval window.

Question 31

What is the functions of the pharyngotympanic tube?

Answer 31

Controls pressure within the middle ear; making the air pressure equal within the ear equal to the air pressure outside the body.

Question 32

What 2 divisions are found in the internal ear?

Answer 32

- Bony labyrinth | - membranous labyrinth

Question 33

What fluid is found in the bony labyrinth?

Answer 33

Perilymph fluid

Question 34

What 3 structures make up the bony labyrinth?

Answer 34

Cochlea, Vestibule, Semicircular canals

Question 35

Where are the receptors for hearing are located where?

Answer 35

Cochlear Duct

Question 36

What structure contain the receptors for equilibrium?

Answer 36

Saccule, Utricle, Semicircular ducts

Question 37

What is the receptor organ for hearing?

Answer 37

organ of Corti

Question 38

What is the pathway of sound waves from the auricle to the oval window?

Answer 38

Auricle, External Auditory Canal, Tympanic Membrane, Malleus, Incus, Stapes, Oval Window