W4 L3 (Vision)

Question 1

What is the retina?

Answer 1

A layer of light-sensitive cells

Question 2

What is the general path of image transduction?

Answer 2

An image is coded on the retina and transmitted through a series of complex steps

Question 3

What is the stimulus in vision?

Answer 3

Light waves between 380 and 760nm

Question 4

Who needs light?

Answer 4

All species need light to see, some can see wavelengths that we can’t

Question 5

What are the 3 properties of light and what do they impact of what we see?

Answer 5

1. Wavelength- Color
2. Intensity- Brightness
   3 Purity-Saturation

Question 6

What determines intensity and purity

Answer 6

Intensity- # of photons

Purity- # of wavelengths

Question 7

What happens at the pupil?

Answer 7

Light is let in

Question 8

What is the iris?

Answer 8

The colorful part of the eye

Question 9

What are the 4 protective mechanisms of the eye?

Answer 9

1. Sheltered in a bony socket
2. Eyelids act like shutters
3. Blinking disperses tears
4. Eyelashes trap debris

Question 10

What produces tears and where is this structure located?

Answer 10

The lacrimal gland in the upper lateral corner under the eyelid

Question 11

Where do tears drain?

Answer 11

The corners of the eye and back into the nasal passageway

Question 12

What are the 3 layers of the eye from peripheral to the interior?

Answer 12

1. Sclera/cornea
2. Choroid/Ciliary body/iris
3. Retina

Question 13

What is the sclera?

Answer 13

The visible white part of the eye

Question 14

What is the cornea?

Answer 14

The clear, anterior most outer layer of the eye through which light rays pass to the interior of the eye

Question 15

What is the choroid?

Answer 15

The layer under the sclera that is highly pigmented and contains blood vessels that nourish the retina

Question 16

What is the retina?

Answer 16

The innermost layer in the posterior region of the eye that contains the eye’s photoreceptors, the rods and cones

Question 17

What is the difference between rods and cones?

Answer 17

Rods- Night vision

Cones- Day vision

Question 18

What do the photoreceptors of the eye do?

Answer 18

Convert light energy to nerve impulses

Question 19

What do the pigment in the choroid and retina do?

Answer 19

Absorb light that scatters after striking the retina

Question 20

What is the lens?

Answer 20

A transparent, biconvex structure of the eye that refracts (bends) light rays and whose strength can be adjusted to accommodate for vision at different distances

Question 21

What is the vitreous humor and what does it do?

Answer 21

A semifluid, jelly-like substance located in the larger posterior (rear) cavity between the lens and retina; is important in maintaining the spherical shape of the eyeball

Question 22

What is the aqueous humor and what does it do?

Answer 22

The clear, watery fluid in the anterior chamber of the eye; provides nourishment for the cornea and lens

Question 23

Why are there no blood vessels in the cornea and lens

Answer 23

Because they would impede the passing of light to photoreceptors

Question 24

What is the ciliary body?

Answer 24

The portion of the eye that produces aqueous humour and contains the ciliary muscle

Question 25

What is refraction?

Answer 25

The convex shape of the cornea and lens that bends light inwards

Question 26

What are the two muscles around the pupil?

Answer 26

1. Circular (constrictor) | 2. Radial (dilator)

Question 27

What happens when the radial muscle (dilator) opens up the pupil, and when does this happen?

Answer 27

It increases the number of photons admitted and this is good for dim light

Question 28

Which of the constrictor or dilator responds to the para and what one responds to the symp?

Answer 28

Para-Constrictor | Symp-Dilator

Question 29

What does creates a clearer image a large or small pupil in clear light?

Answer 29

Small

Question 30

What is a sign of arousal with regards to the eye?

Answer 30

Dilated pupil

Question 31

What structures direct light to the retina?

Answer 31

Cornea and lens

Question 32

What part of the eye is the basis for eye scanning?

Answer 32

The iris

Question 33

What is a light ray?

Answer 33

The forward movement of light in a particular direction

Question 34

What is refraction?

Answer 34

The bending of a light ray

Question 35

Do convex and concave lens' diverge or converge rays and what is found in the eye?

Answer 35

Convex-Converge Concave-Diverge The lens of the eye is convex

Question 36

What is astigmatism?

Answer 36

A defect in the eye or lens caused by a deviation from spherical curvature, resulting in distorted images, as light rays are prevented from meeting at a common focus

Question 37

What is accommodation?

Answer 37

The ability to adjust the strength of the lens in the eye so that both near and far sources can be focused on the retina

Question 38

What is the ciliary muscle?

Answer 38

A circular ring of smooth muscle within the eye whose contraction increases the strength of the lens to accommodate for near vision

Question 39

What are the 2 main components of the ciliary body and what are their functions?

Answer 39

1. Ciliary muscle-Strengthen lens | 2. Capillary network-Produces aqueous humor