Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Special Senses > Lesson 2: Structures Involved in Vision > Flashcards

Lesson 2: Structures Involved in Vision Flashcards

(111 cards)

Start Studying
1
Q

the act of seeing, is extremely important to human survival. More than half the sensory receptors in the human body are located in the eyes, and a large part of the cerebral cortex is devoted to processing visual information.

A

Vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Accessory Structures of the Eye:

A

Eyelids
Eyelashes
Eyebrows
Lacrimal Apparatus
Extrinsic Eye Muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

These structures are not involved directly on visual functions but are primarily designed for:

A

Protection
Lubrication
Movement of the Eyes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

It protect the eyes from foreign objects, from perspiration and direct rays from the sun.

A

Eyebrows & Eyelashes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

It shades the eyes during sleep. Also, it protect the eyes from excessive light and foreign objects, and spread lubricating secretions over the eyeballs.

A

Upper and Lower Eyelids - Palpebrae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  • special levator muscle in the superior region of the upper eyelid.
A

Levator Palpebrae Superioris Muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The space between the upper and lower eyelids that exposes the eyeball.

A

Palpebral Fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The angle of the palpebral fissure which is broader and nearer to the nasal bone.

A

Medial Commissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The angle of the palpebral fissure which is narrower and closer to the temporal bone.

A

Lateral Commissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

It is the small, reddish elevation, which contains sebaceous (oil) glands and sudoriferous (sweat) glands.

A

Lacrimal Caruncle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

is a thick fold of connective tissue that gives form and support to the eyelids.

A

Tarsal Plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

is a row of elongated modified sebaceous glands that secrete a fluid that helps keep the eyelids from adhering to each other.

A

Tarsal Glands or Meibomian Glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

It is a thin, protective mucous membrane composed of nonkeratinized stratified squamous epithelium with numerous goblet cells that is supported by areolar connective tissue.

A

Conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

lines the inner aspect of the eyelids

A

Palpebral Conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

passes from the eyelids onto the surface of the eyeball, where it covers the sclera (the “white” of the eye) but not the cornea.

A

Bulbar Conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

is a group of structures that produces and drains lacrimal fluid or tears in a process called lacrimation.

A

Lacrimal Apparatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

It is about the shape & size of an almond, secretes lacrimal fluid which drains into 6-12 excretory lacrimal ducts.

A

Lacrimal Gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

These are 2 small openings in each of the papilla of the eyelid at the midline commissure of the eye.

A

Lacrimal Puncta/ Punctum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

These are 2 small ducts connected with to each lacrimal punctum.

A

Lacrimal Canals/ Canaliculi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

It is the expanded portion of the nasolacrimal duct.

A

Lacrimal Sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

It carries the lacrimal fluid into the nasal cavity.

A

Nasolacrimal Duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A composition of lacrimal fluid, described as a protective bactericidal enzyme.

A

Lysozyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Each gland produces about _______ of lacrimal fluid per day.

A

1 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The eyes sit in the bony depressions of the skull called the ______.

A

Orbits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
extend from the walls of the bony orbit to the sclera of the eye and are surrounded in the orbit by a significant quantity of periorbital fat. These muscles are capable of moving the eye in almost any direction.
Extrinsic Eye Muscles
25
Six extrinsic eye muscles move each eye:
Superior Rectus Inferior Rectus Medial Rectus Lateral Rectus Superior Oblique Inferior Oblique
26
turns the eye upward
SR
27
turns the eye downward
IR
28
turns the eye towards the midline
MR
29
turns the eye towards the lateral side
LR
30
these preserves rotational stability of the eyeball
2 Oblique Muscles
31
rotates the eyeball so the cornea turns in a downward & outward direction.
SO
32
rotates the eyeball so the cornea turns in an upward, outward direction.
IO
33
They are spherical in shape. It measures about 2.5 cm (1 inch) in diameter.
Eyeball or Bulbus Oculi
34
The total surface area of the eyeball, only the ___________ is exposed & the remaining portion is protected by the ORBIT.
Anterior 1/6
35
3 LAYERS/TUNICS OF THE EYEBALL:
Fibrous Tunic Vascular Tunic Nervous Tunic
36
is the superficial layer of the eyeball and consists of the anterior cornea and posterior sclera outer layer. It is AVASCULAR.
Fibrous Tunic
37
a transparent coat that covers the colored iris. It is located on the anterior portion and has no capillaries.
Cornea
38
Because it is curved, the __________helps focus light onto the retina.
Cornea
39
consists of nonkeratinized stratified squamous epithelium.
Outer Surface of the Cornea
40
consists of collagen fibers and fibroblasts
Middle Coat of the Cornea
41
is simple squamous epithelium
Inner Surface of the Cornea
42
as one of the media for refraction, it permits light to enter the eye (bends/refracts light)
Cornea
43
is the “white” of the eye, is a layer of dense connective tissue made up mostly of collagen fibers and fibroblasts. It is located on the posterior portion.
Sclera
44
The _________covers the entire eyeball except the cornea.
Sclera
45
a) it gives shape to the eyeball; b) makes it more rigid; c) protects its inner parts; d) serves as a site of attachment for the extrinsic eye muscles.
Sclera
46
is an opening located at the junction of the sclera and cornea. Aqueous humor (a fluid), drains into this sinus.
Canal of Schlemm or Schleral Venous Sinus
47
is the middle layer of the eyeball. It contains lots of blood vessels (the layer containing most of the blood vessel of the eyes). It is composed of three parts: choroid, ciliary body, and iris.
Vascular Tunic
48
the posterior portion of the vascular tunic, lines most of the internal surface of the sclera. Its numerous blood vessels provide nutrients to the posterior surface of the retina.
Choroid
49
_____________ in the choroid absorbs stray light rays, which prevents reflection and scattering of light within the eyeball.
Melanin
50
is the anterior portion of the vascular layer. It is the thickest portion of the vascular tunic which extends from the ORA SERRATA of the retina to the point behind the junction of the sclera & cornea.
Ciliary Body
51
the jagged anterior margin of the retina
Ora Serrata
52
Parts of the Ciliary Body:
Ciliary Process Ciliary Muscle
53
are protrusions or folds on the internal surface of the ciliary body. They contain blood capillaries that secrete aqueous humor.
Ciliary Process
54
Extending from the ciliary process are _________________________ that attach to the lens.
Zonular Fibers or Suspensory Ligaments
55
is a circular band of smooth muscle. Contraction or relaxation of the ciliary muscle changes the tightness of the zonular fibers, which alters the shape of the lens, adapting it for near or far vision.
Ciliary Muscle
56
lens is relatively flat
Distant Vision
57
lens bulges/increases in its curvature
Near Vision
58
It is flexible, biconvex, transparent disc (crystal-clear). It is located just posterior to the pupil and iris.
Lens
59
The lens is made up of _________ & _________.
65% water & 35% CHON
60
Within the cells of the lens are proteins called ___________, arranged like the layers of an onion
Crystallins
61
The ________helps focus images on the retina to facilitate clear vision.
Lens
62
PRINCIPAL REFRACTIVE MEDIUM (fine-tunes light rays onto the retina to facilitate clear vision)
The Lens
63
the space anterior to the lens
Anterior Cavity
64
lies between cornea & iris
Anterior Chamber
65
lies behind the iris and in front of the zonular fibers and lens
Posterior Chamber
66
what fluid fills the anterior cavity?
Aqueous Humor
67
a clear, watery fluid with similar composition as the CSF.
Aqueous Humor
68
composed of 99% water, it is transparent, jelly-like substance. Also, contains phagocytic cells that remove debris, keeping the post cavity clear.
Vitreous Humor
69
a narrow channel that runs thru the vitreous body from the optic disc to the posterior aspect of the lens.
Hyaloid Canal
70
the colored portion of the eyeball, is shaped like a flattened donut. It is suspended between the cornea and the lens and is attached at its outer margin to the ciliary processes.
Iris
71
The amount of ___________in the iris determines the eye color.
Melanin
72
The eyes appear __________ when the iris contains a large amount of melanin.
brown to black
73
The eyes appear __________ when its melanin concentration is very low
blue
74
The eyes appear __________ when its melanin concentration is moderate.
Green
75
The iris is made up of contractile muscles that surround an opening called __________.
Pupil
76
2 Types of muscles of the iris:
Circular Muscle or Sphincter Pupillae Radial Muscle or Dilator Pupillae
77
What happens when the eyes-PUPILS are directed to BRIGHT LIGHT?
Circular muscles contract, the pupils CONSTRICT
78
What happens when the eyes-PUPILS are directed to DIM LIGHT?
Radial muscles contract, the pupils DILATE
79
is the inner coat of the eyeball, lines the posterior three-quarters of the eyeball and is the beginning of the visual pathway.
Retina
80
It contains the photoreceptors.
Retina
81
is the site where the optic (II) nerve exits the eyeball.
Optic Disc
82
Bundled together with the optic nerve are the two blood supply:
Central Retinal Artery Central Retinal Vein
83
The non-visual portion. It is a sheet of melanin-containing epithelial cells located between the choroid and the neural part of the retina.
Pigmented Layer
84
It is a multilayered outgrowth of the brain that processes visual data extensively before sending nerve impulses into axons that form the optic nerve.
Neural Layer
85
Three distinct layers of retinal neurons:
Photoreceptor Layer Bipolar Layer Ganglion Cell Layer
86
Two types of cells present in the bipolar cell layer:
Horizontal cells Amacrine cells
87
are specialized cells in the photoreceptor layer that begin the process by which light rays are ultimately converted to nerve impulses.
Photoreceptors
88
Each retina has about _________ cones and ___________ rods.
6 million cones 120 million rods
89
20x more than cones. They very sensitive to light (have low light threshold). It can function in very dim light but they do not provide color vision (specialized for black & white vision in dim light).
Rods
90
It allow us to see in dim light, such as moonlight.
Rods
91
Rods is most abundant toward the edge of the retina, thus providing _____________.
Peripheral Vision
92
Photopigment found in Rods.
Rhodopsin
93
Composition of the photopigment Rhodopsin:
Scotopsin and Retinal
94
It is responsible for COLOR VISION and function best in bright light.
Cones
95
Loss of cones results to...
Legal Blindness
96
inability to distinguish between certain colors because of the absence or deficiency of 1 or 3 photopigment
Color Blindness
97
inability to see well at dim light.
Night Blindness or Nyctalopia
98
Good vision depends on adequate intake of _____________-rich veg such as: carrots, spinach, broccoli, yellow squash, food that contain vitamin A like liver.
Carotenoid
99
a small yellow spot near the center of the posterior portion of the retina.
Macula Lutea
100
A small pit/depression at the center of the macula lutea. It ontains only CONES, thus, the area of highest visual acuity or resolution.
Central Fovea or Fovea Centralis
101
ability to see images most clearly
Visual Acuity
102
sharpness of vision
Resolution
103
is a white spot just medial to the macula lutea. Where blood vessels, optic nerve enter the eyes. It contains no photoreceptors, thus objects focused on this area cannot be seen.
Optic Disc - Blind Spot
104
is the bending of light as it passes from one medium to another.
Refraction
105
is a process by which the lens of the eye changes in shape/curvature to adjust for vision at various distances; the lens either increase/decrease in its curvature.
Accommodation
106
Four Media of Refraction:
Cornea Aqueous Humor Lens Vitreous Humor
107
is the crossing point of light rays
Focal Point
108
is the process of causing light to converge (bend toward each other).
Focusing
109
3 REQUIREMENTS for ACCOMMODATION:
Change in Shape of the Lens Constriction or Dilation of Pupils Convergence of the Eyes
110
When convergence is not complete, it produces double vision also known as...
Diplopia

Special Senses (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions