Eyes

Question 1

Ciliary Body

Answer 1

-Smooth muscle attached to lens

Question 2

Ciliary Zonule

Answer 2

-suspensory ligament that attaches the lens to the ciliary body in the anterior eye

Question 3

Cornea

Answer 3

• Transparent, central anterior portion
  - Allows for light to pass through
  - Repairs itself easily
  - The only human tissue that can be transplanted without fear of rejection

Question 4

Iris

Answer 4

-regulates amount of light entering eye

Question 5

Pupil

Answer 5

-rounded opening in the iris

Question 6

Aqueous Humor

Answer 6

• Watery fluid found between lens and cornea
• Similar to blood plasma
• Helps maintain intraocular pressure
• Provides nutrients for the lens and cornea
• Reabsorbed into venous blood through the scleral venous sinus, or canal of Schlemm

Question 7

Lens

Answer 7

• Biconvex crystal-like structure

- Held in place by a suspensory ligament attached to the ciliary body

Question 8

Canal of Schlemm

Answer 8

-Aqueous humor fluid is reabsorbed into venous blood

Question 9

Vitreous Humor

Answer 9

• Gel-like substance posterior to the lens
• Prevents the eye from collapsing
• Helps maintain intraocular pressure

Question 10

Sclera

Answer 10

• White connective tissue layer

- Seen anteriorly as the “white of the eye”

Question 11

Choroid

Answer 11

• blood-rich nutritive layer in the posterior of the eye

- Pigment prevents light from scattering

Question 12

Retina

Answer 12

• Outer pigmented layer
  - Inner neural layer
  - Contains receptor cells (photoreceptors)
  - Rods- Images
• Cones-Colors

Question 13

Fovea Centralis

Answer 13

-area of the retina with only cones

Question 14

Optic Nerve

Answer 14

-Receives impulses for interpreting sight

Question 15

Central Artery and Vein of the Retina

Answer 15

-Vascularize the eye

Question 16

Optic Disc (Blind Spot)

Answer 16

• where the optic nerve leaves the eyeball

- Cannot see images focused on the optic disc

Question 17

Accessory Structures of the Eye

Answer 17

• Eyelids and Eyelashes
• Conjunctiva
• Lacrimal Apparatus
• Extrinsic Eye Muscles

Question 18

List of Extrinsic Eye Muscles

Answer 18

• Lateral Rectus: Moves eye laterally
• Medial Rectus: Moves eye medially
• Superior Rectus: Elevates eye and turns it medially
• Inferior Rectus: Depresses eye and turns it medially
• Inferior Oblique: Elevates eye and turns it laterally
• Superior Oblique: Depresses eye and turns it laterally

Question 19

Eyelids and Eyelashes

Answer 19

• Tarsal glands lubricate the eye

- Ciliary glands are located between the eyelashes

Question 20

Conjunctiva

Answer 20

• Membrane that lines the eyelids
• Connects to the surface of the eye
• Secretes mucus to lubricate the eye

Question 21

Lacrimal Apparatus

Answer 21

• Lacrimal gland—produces lacrimal fluid
• Lacrimal canals—drain lacrimal fluid from eyes
• Lacrimal sac—provides passage of lacrimal fluid towards nasal cavity
• Nasolacrimal duct—empties lacrimal fluid into the nasal cavity

Question 22

Properties of Lacrimal Fluid

Answer 22

• Dilute salt solution (tears)

- Contains antibodies and lysozyme (avoid bacterial infections)

Question 23

Functions of the Lacrimal Apparatus

Answer 23

• Protects, moistens, and lubricates the eye

- Empties into the nasal cavity

Question 24

Cones

Answer 24

• Allow for detailed color vision
• Densest in the center of the retina
• Cone Sensitivity:
  
  • Three types of cones
  • Different cones are sensitive to different wavelengths
    
    • Red, Green, Yellow
  • Color blindness is the result of the lack of one cone type

Question 25

Rods

Answer 25

- Most are found towards the edges of the retina - Allow dim light vision and peripheral vision - All perception is in gray tones

Question 26

Night Blindness

Answer 26

-inhibited rod function that hinders the ability to see at night

Question 27

Glaucoma

Answer 27

-can cause blindness due to increasing pressure within the eye

Question 28

Hemianopia

Answer 28

- loss of the same side of the visual field of both eyes | - results from damage to the visual cortex on one side only

Question 29

Cataracts

Answer 29

- when lens becomes hard and opaque | - our vision becomes hazy and distorted

Question 30

Color Blindness

Answer 30

- genetic conditions that result in the inability to see certain colors - Due to the lack of one type of cone (partial color blindness)

Question 31

Emmetropia

Answer 31

-eye focuses images correctly on the retina (normal vision)

Question 32

Astigmatism

Answer 32

- Images are blurry - Results from light focusing as lines, not points, on the retina due to - unequal curvatures of the cornea or lens

Question 33

Hyperopia (Farsighted)

Answer 33

- Near objects are blurry while distant objects are clear - Distant objects are focused behind the retina - Results from an eyeball that is too short or from a “lazy lens”

Question 34

Myopia (Nearsighted)

Answer 34

- Distant objects appear blurry - Light from those objects fails to reach the retina and are focused in front of it - Results from an eyeball that is too long

Question 35

Pathway of Light Through the Eye

Answer 35

- Light must be focused to a point on the retina for optimal vision - The eye is set for distance vision (over 20 feet away) - Accommodation—the lens must change shape to focus on closer objects (less than 20 feet away) - Image formed on the retina is a real image - Real images are - Reversed from left to right - Upside down - Smaller than the object

Question 36

Ophthalmoscope

Answer 36

- Instrument used to illuminate the interior of the eyeball | - Can detect diabetes, arteriosclerosis, degeneration of the optic nerve and retina

Question 37

Layers forming the wall of the eyeball

Answer 37

- Fibrous Layer: Outside layer for protection - Vascular Layer: Middle Layer, blood transports oxygen and nutrients - Sensory Layer: Inside Layer w/ nerves