Untitled Deck

Question 1

What is electromagnetic radiation?

Answer 1

Electromagnetic radiation includes gamma rays, X-rays, UV light, visible light, infrared, and radio waves, categorized by their wavelengths.

Wavelengths: gamma rays (short), X-rays (medium), visible light (380-750 nm), infrared (long), radio waves (longer).

Question 2

What is wave-photon duality?

Answer 2

Light travels in a wave-like fashion with ‘single packets’ of energy called photons.

Question 3

What is the visible spectrum?

Answer 3

different colors of light, each with distinct wavelengths.

Wavelengths: Violet (380 nm), Blue (480 nm), Green (550 nm), Yellow (630 nm), Orange (680 nm), Red (730 nm).

Question 4

How is the color of an object determined?

Answer 4

determined by which wavelengths are reflected back to the retina

White reflects all wavelengths; black absorbs all wavelengths.

Question 5

What is light refraction?

Answer 5

Light will bend when it passes from one medium into another

Question 6

What is a convex lens?

Answer 6

A convex lens is thicker at the center and tapered at the edges, causing light to bend and converge at a focal point.

A real image formed by a convex lens is inverted and reversed.

Question 7

What is the role of the cornea in focusing light?

Answer 7

The cornea provides constant (unchanging) refraction.

Question 8

What is the function of the lens in the eye?

Answer 8

The lens can change its refraction and focal length, with ciliary muscles adjusting its convexity.

Question 9

What is the far point of vision?

Answer 9

The far point of vision is the distance beyond which the lens will not change its shape, approximately 20 feet.

Question 10

What is emmetropic eye?

Answer 10

An emmetropic eye is a normal, healthy eye.

Question 11

What adjustments are made for close vision?

Answer 11

(less than 6 feet) accommodation of the lens, pupils, and convergence of the eyes.

Question 12

What is myopia?

Answer 12

Myopia, or nearsightedness, occurs when distant objects are blurred because they are focused in front of the retina.

Causes include an eyeball that is too long or a lens that is too strong.

Question 13

What is hyperopia?

Answer 13

Hyperopia, or farsightedness, occurs when close objects are blurred because they are focused beyond the retina.

Causes include an eyeball that is too short or poor refraction of a lens.

Question 14

What is astigmatism?

Answer 14

Astigmatism is a condition causing blurry images at all distances due to unequal curves on the lens and/or cornea.

Question 15

What is the general structure of rods and cones?

Answer 15

Rods and cones have a pigmented base, outer segment with pigmented discs, inner segment, and synaptic ending. as well as neural layer

Rods are sensitive to dim light, while cones require bright light.

Question 16

What is opsin?

Answer 16

Opsin is a transmembrane protein found in the membrane of pigmented discs of rods and cones.

Question 17

What is retinal?

Answer 17

Retinal is a light-absorbing molecule that changes shape when struck by a photon of light.

Vitamin A is a precursor to retinal.

Question 18

What happens during the bleaching of rhodopsin?

Answer 18

after the absorption of light, leading to the breakdown of 11-cis retinal into all-trans retinal.

Question 19

What is rhodopsin?

Answer 19

Rhodopsin is the visual pigment in rods, located in the membranes of pigmented discs of the outer segment.

Question 20

What is light adaptation?

Answer 20

transitioning from very dark to very bright conditions, causing rods to be bleached and cones to take over.

Question 21

What is dark adaptation?

Answer 21

transitioning from very bright to very dark conditions, allowing rods to gradually take over in dim light.

Question 22

What is nyctalopia?

Answer 22

Nyctalopia, or night blindness, is a deficiency in the function of rods during dim-light situations.

Vitamin A deficiency is a common cause.

Question 23

What is the visual pathway from photoreceptors to the occipital cortex?

Answer 23

The visual pathway includes photoreceptors (rods & cones) to bipolar cells to ganglion cells (optic nerve) to the thalamus and finally to the occipital lobe.

Other areas receiving visual information include superior colliculi and pretectal nuclei.

Question 24

What is binocular vision?

Answer 24

Binocular vision occurs when two eyes have overlapping regions of the visual field, allowing perception of depth based on slightly different angles.

Question 25

What are photopsins?

Answer 25

Photopsins are 3 distinct pigments in cones that are sensitive to 3 different parts of the visible spectrum.

Question 26

What is the maximum sensitivity of blue cones?

Answer 26

Blue cones have maximum sensitivity at 455 nm.

Question 27

What is the maximum sensitivity of green cones?

Answer 27

Green cones have maximum sensitivity at 530 nm.

Question 28

What is the maximum sensitivity of red cones?

Answer 28

Red cones have maximum sensitivity at 625 nm.

Question 29

How do different colors arise in vision?

Answer 29

Different colors arise from the differential activation of each of the three different cones.

Question 30

What causes color blindness?

Answer 30

Color blindness is caused by an inherited gene for one of the photon proteins that is deficient, mainly affecting males.

Question 31

What are the most common types of color blindness?

Answer 31

The most common types of color blindness are red and green mutations.

Question 32

What is light adaptation?

Answer 32

Light adaptation is the process where the eyes adjust from very dark to very bright conditions.

Question 33

What happens to rhodopsin during light adaptation?

Answer 33

Rhodopsin in rods is quickly bleached out during light adaptation.

Question 34

What is the consensual pupil reflex?

Answer 34

The consensual pupil reflex is the constriction of pupils in response to light.

Question 35

What is dark adaptation?

Answer 35

Dark adaptation is the process where the eyes adjust from very bright to very dark conditions.

Question 36

What happens to cones during dark adaptation?

Answer 36

Cones gradually cease to be stimulated during dark adaptation.

Question 37

What is nyctalopia?

Answer 37

Nyctalopia, or night blindness, is a deficiency in the function of rods during dim-light situations.

Question 38

What is a common cause of nyctalopia?

Answer 38

A common cause of nyctalopia is vitamin A deficiency.

Question 39

What is the visual pathway from photoreceptors to the occipital cortex?

Answer 39

The visual pathway is: photoreceptors (rods & cones) -> bipolar cells -> ganglion cells (optic nerve) -> optic nerves -> optic chiasma -> optic tracts -> lateral geniculate body of thalamus -> optic radiation -> occipital lobe (primary visual cortex).

Question 40

What is the role of the superior colliculi?

Answer 40

The superior colliculi control extrinsic eye muscles.

Question 41

What do the pretectal nuclei mediate?

Answer 41

The pretectal nuclei mediate pupillary light reflexes.

Question 42

What is the function of the suprachiasmatic nucleus?

Answer 42

The suprachiasmatic nucleus of the hypothalamus regulates circadian rhythms.

Question 43

What is binocular vision?

Answer 43

Binocular vision occurs when two eyes have overlapping regions of the visual field, allowing the same point to be seen from slightly different angles.

Question 44

What is depth perception?

Answer 44

Depth perception is the ability to perceive relative distances based on information gathered from binocular vision.