Chapter 2. Functional Anatomy of the Eye
2.1 Title slide
Demonstration 2.2
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title
Functional Anatomy of the Eye
Interact with a depiction of the human eye.
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The main function of the human eye is to provide the brain with information about “what is where” in the visible world. All the different structures of the eye work in exquisite coordination to accomplish this goal. [Ramón Rivera-Moret]
What Is the Functional Anatomy of the Eye?
The human eye is roughly spherical, with a diameter of about 24 mm (the optic axis is an imaginary diameter line from the front to the
back of the eye).
Three membranes surround the eye:
• The outer membrane is made up of the sclera (a protective covering whose visible portion is the white of your eye) and the transparent cornea at the front of the eye.
• The middle membrane is the choroid; it contains most of the blood vessels that supply the inside of the eye with oxygen and nutrients.
• The inner membrane is the retina, which is made up of neurons, including the receptors that convert the light entering the eye into neural signals.
Light enters the eye by first passing through the cornea, which sharply refracts (bends) the light. The light then passes through the pupil and into the lens, a transparent structure that further refracts the light. The shape of the lens is adjusted to ensure that light focuses properly on the retina.
The pupil is an opening in the middle of the iris, a small donut-shaped muscle. The iris controls the size of the pupil by contracting and relaxing.
The zonule fibers connect the lens to the choroid. The ciliary muscles are also attached to the choroid. When the ciliary muscles relax, the choroid pulls on the zonule fibers, stretching the lens; when the ciliary muscles contract, they oppose the pull by the choroid on the zonule fibers, and the lens isn't stretched as much.
The fovea is the area at the center of the retina, receiving light from objects at the center of gaze. The optic disk is the place where the optic nerve exits the eye and where blood vessels enter and exit the eye.
The anterior chamber is the space between the cornea and the iris; the posterior chamber is the smaller space between the iris and the lens. Both chambers are filled with a fluid called aqueous humor. The large vitreous chamber—the main interior portion of the eye—is filled with a fluid called vitreous humor. The fluids in these chambers exert outward pressure on the eye and keep it from collapsing.
Three membranes surround the eye:
• The outer membrane is made up of the sclera (a protective covering whose visible portion is the white of your eye) and the transparent cornea at the front of the eye.
• The middle membrane is the choroid; it contains most of the blood vessels that supply the inside of the eye with oxygen and nutrients.
• The inner membrane is the retina, which is made up of neurons, including the receptors that convert the light entering the eye into neural signals.
Light enters the eye by first passing through the cornea, which sharply refracts (bends) the light. The light then passes through the pupil and into the lens, a transparent structure that further refracts the light. The shape of the lens is adjusted to ensure that light focuses properly on the retina.
The pupil is an opening in the middle of the iris, a small donut-shaped muscle. The iris controls the size of the pupil by contracting and relaxing.
The zonule fibers connect the lens to the choroid. The ciliary muscles are also attached to the choroid. When the ciliary muscles relax, the choroid pulls on the zonule fibers, stretching the lens; when the ciliary muscles contract, they oppose the pull by the choroid on the zonule fibers, and the lens isn't stretched as much.
The fovea is the area at the center of the retina, receiving light from objects at the center of gaze. The optic disk is the place where the optic nerve exits the eye and where blood vessels enter and exit the eye.
The anterior chamber is the space between the cornea and the iris; the posterior chamber is the smaller space between the iris and the lens. Both chambers are filled with a fluid called aqueous humor. The large vitreous chamber—the main interior portion of the eye—is filled with a fluid called vitreous humor. The fluids in these chambers exert outward pressure on the eye and keep it from collapsing.
2.2 Explain - dnd
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Drag and drop each of the labels into the correct box on this cross-section
of the eye
viewed from above.
2.3 Explain - dnd
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Drag and drop each of the labels into the correct box on this cross-section
of the eye viewed from above.
2.4 Explain - dnd
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Drag each label on the illustration into the box above the matching description.
2.5 Explain
explain_text
What Is the Functional Anatomy of the Eye?
The human eye is roughly spherical, with a diameter of about 24 mm (the optic axis is an imaginary diameter line from the front to the back of the eye).
Three membranes surround the eye:
• The outer membrane is made up of the sclera (a protective covering whose visible portion is the white of your eye) and the transparent cornea at the front of the eye.
• The middle membrane is the choroid; it contains most of the blood vessels that supply the inside of the eye with oxygen and nutrients.
• The inner membrane is the retina, which is made up of neurons, including the receptors that convert the light entering the eye into neural signals.
Light enters the eye by first passing through the cornea, which sharply refracts (bends) the light. The light then passes through the pupil and into the lens, a transparent structure that further refracts the light. The shape of the lens is adjusted to ensure that light focuses properly on the retina.
The pupil is an opening in the middle of the iris, a small donut-shaped muscle. The iris controls the size of the pupil by contracting and relaxing.
The zonule fibers connect the lens to the choroid. The ciliary muscles are also attached to the choroid. When the ciliary muscles relax, the choroid pulls on the zonule fibers, stretching the lens; when the ciliary muscles contract, they oppose the pull by the choroid on the zonule fibers, and the lens isn't stretched as much.
The fovea is the area at the center of the retina, receiving light from objects at the center of gaze. The optic disk is the place where the optic nerve exits the eye and where blood vessels enter and exit the eye.
The anterior chamber is the space between the cornea and the iris; the posterior chamber is the smaller space between the iris and the lens. Both chambers are filled with a fluid called aqueous humor. The large vitreous chamber—the main interior portion of the eye—is filled with a fluid called vitreous humor. The fluids in these chambers exert outward pressure on the eye and keep it from collapsing.
Three membranes surround the eye:
• The outer membrane is made up of the sclera (a protective covering whose visible portion is the white of your eye) and the transparent cornea at the front of the eye.
• The middle membrane is the choroid; it contains most of the blood vessels that supply the inside of the eye with oxygen and nutrients.
• The inner membrane is the retina, which is made up of neurons, including the receptors that convert the light entering the eye into neural signals.
Light enters the eye by first passing through the cornea, which sharply refracts (bends) the light. The light then passes through the pupil and into the lens, a transparent structure that further refracts the light. The shape of the lens is adjusted to ensure that light focuses properly on the retina.
The pupil is an opening in the middle of the iris, a small donut-shaped muscle. The iris controls the size of the pupil by contracting and relaxing.
The zonule fibers connect the lens to the choroid. The ciliary muscles are also attached to the choroid. When the ciliary muscles relax, the choroid pulls on the zonule fibers, stretching the lens; when the ciliary muscles contract, they oppose the pull by the choroid on the zonule fibers, and the lens isn't stretched as much.
The fovea is the area at the center of the retina, receiving light from objects at the center of gaze. The optic disk is the place where the optic nerve exits the eye and where blood vessels enter and exit the eye.
The anterior chamber is the space between the cornea and the iris; the posterior chamber is the smaller space between the iris and the lens. Both chambers are filled with a fluid called aqueous humor. The large vitreous chamber—the main interior portion of the eye—is filled with a fluid called vitreous humor. The fluids in these chambers exert outward pressure on the eye and keep it from collapsing.
2.6 Test - single choice
You must select an answer and then click SUBMIT before you can click proceed
to the next screen.
test_single_choice
Select your answer to the question below. Then click SUBMIT.
Question
Photo © Steve Allen / Getty Images.
Correct! Click EXPLAIN if you want to review this topic.
Incorrect. The correct answer is C. Click EXPLAIN if you want to review this topic.
2.7 Test - dnd
You must complete the question and then click SUBMIT before you can click proceed to the next screen.
test_dnd
Drag the labels into the blank boxes from left to right, in the order in which light encounters these structures on its path into the eye. Then click SUBMIT.
2.8 Test - dnd
You must complete the question and then click SUBMIT before you can click proceed to the next screen.
test_dnd
Drag each description at left to attach to the matching part of the eye. Then click SUBMIT.