Problem 1
1)
- What is the anatomy and function of the human eye?
- How does vision form?
- Structure and function of retina!
- Structure and function of blind and yellow spot
2)
- How do we process visual information? (not in the brain but the front side of the eye)
- How is light/image projected to the retina?
- Conditions and diseases of the eye?
3)
- What part of the eye is responsible for color vision?
- How do we perceive color?
- How do we differentiate between different shades of colors?
- Why do we see dots? lateral inhibition
- Blake & Sekuler Chapter 2&3
- The visual systems of all vertebrates include 3 components: eyes (capture light and covert
into neural messages), visual pathways (modify and transmit those messages from the eye
to the brain), and visual centers of the brain (interpret the messages in ways useful for
guiding behavior)
- Light is electromagnetic radiation
o It travels rapidly and in straight lines which means it retains the geometrical
characteristics of the objects that are reflected
- Humans lack panoramic vision, we can compensate by turning our heads and eyes
o The extraocular muscles (six in each eye) enable movement of eyes in all directions
o The muscle contracts and pulls on the eyeball and moves it, the amount of
movement depends of the strength of the contraction, the direction depends on
the place where the contraction muscle is attached
Structure of the Human Eye
- The human eye is nearly spherical, with a diameter of 23 millimeters
- Optic axis: imaginary diameter line from the front to the back of the eye, passing through
the center of the lens
- Consists of 3 concentric layers:
o Outermost: fibrous tunic: protects the eyeball
o Middle: vascular tunic: nourishes the eyeball
o Innermost: retina: detects the light and
initiates neural messages for the brain
Fibrous tunic:
- The white part of the eye
- Made of tough, dense material called the sclera (in
Greek means hard)
- The sclera is made of tightly packed fibers running
parallel to the surface
- The sclera is so tough because the pressure in the
eyeball is double than the atmosphere
, - At the front of the eye the white coloring becomes transparent: at the bulge in front of the
eye: cornea
- The transparency of the cornea allows light to enter the eyeball
- The transparency of the cornea also plays a crucial role in the formation of the images in
the back of the eye
- The cornea has extremely high sensitivity to touch for self-protection
Vascular tunic:
- Vascular tunic hugs the wall of the eyeball, towards the front of the eye it pulls away from
the wall
- Most of the middle layer consists of a spongy structure called choroid
- Choroid contains a network of blood vessels, including capillaries: these capillaries
nourishes the photoreceptors in the retina that turn light into neural signals
- The choroid’s heavy pigmentation reduces light scatter, the tendency for light to be
reflected irregularly around inside the eyeball
- The dark pigmentation absorbs light that isn’t captured by the photoreceptors
Anterior chamber:
- Toward the front of the eye the choroidal layer curls away and a long slender structure
called the ciliary body forms
- Ciliary body produces aqueous humor, the watery fluid that fills the smaller, anterior
chamber that is located behind the cornea and in front of the lens
- The aqueous humor:
o transports oxygen and nutrients to several structures
o carries away waste products
o helps maintain the shape of the eyeball
o constant pressure is maintained
o if drainage is blocked is slowed down pressure builds up, if it remains high for a
long-time vision can be impaired permanently (glaucoma)
The Iris, Pupil and Lens
The Iris:
- This section of tissue gives your eye the characteristic color
- It has 2 layers: the outer layer containing the pigment and the inner layer containing blood
vessels
- If the outer layer is heavily pigmented it will be brown, if it’s lightly pigmented the inner
layer becomes visible and iris looks lightly colored
The Pupil:
- At the center of your own pupil is the black region: pupil
- The pupil is an opening within 2 sets of muscles
- Pupillary reflex: The inner set is a circular band and when it contracts the pupil gets
smaller, the outer set of muscles contract and the pupil widens/dilates
- The size of the pupil depends on: light level (size decreases as the level light increases),
events that stimulate autonomic nervous system
The Lens:
- The crystalline lens lies right behind the iris
- The lens has 3 parts:
o An elastic covering called capsule: moderates the flow of aqueous humor into the
lens helping it retain transparency, molds the shape of the lens and thus the lens’
optical power the variation of this optical power is called accommodation
1)
- What is the anatomy and function of the human eye?
- How does vision form?
- Structure and function of retina!
- Structure and function of blind and yellow spot
2)
- How do we process visual information? (not in the brain but the front side of the eye)
- How is light/image projected to the retina?
- Conditions and diseases of the eye?
3)
- What part of the eye is responsible for color vision?
- How do we perceive color?
- How do we differentiate between different shades of colors?
- Why do we see dots? lateral inhibition
- Blake & Sekuler Chapter 2&3
- The visual systems of all vertebrates include 3 components: eyes (capture light and covert
into neural messages), visual pathways (modify and transmit those messages from the eye
to the brain), and visual centers of the brain (interpret the messages in ways useful for
guiding behavior)
- Light is electromagnetic radiation
o It travels rapidly and in straight lines which means it retains the geometrical
characteristics of the objects that are reflected
- Humans lack panoramic vision, we can compensate by turning our heads and eyes
o The extraocular muscles (six in each eye) enable movement of eyes in all directions
o The muscle contracts and pulls on the eyeball and moves it, the amount of
movement depends of the strength of the contraction, the direction depends on
the place where the contraction muscle is attached
Structure of the Human Eye
- The human eye is nearly spherical, with a diameter of 23 millimeters
- Optic axis: imaginary diameter line from the front to the back of the eye, passing through
the center of the lens
- Consists of 3 concentric layers:
o Outermost: fibrous tunic: protects the eyeball
o Middle: vascular tunic: nourishes the eyeball
o Innermost: retina: detects the light and
initiates neural messages for the brain
Fibrous tunic:
- The white part of the eye
- Made of tough, dense material called the sclera (in
Greek means hard)
- The sclera is made of tightly packed fibers running
parallel to the surface
- The sclera is so tough because the pressure in the
eyeball is double than the atmosphere
, - At the front of the eye the white coloring becomes transparent: at the bulge in front of the
eye: cornea
- The transparency of the cornea allows light to enter the eyeball
- The transparency of the cornea also plays a crucial role in the formation of the images in
the back of the eye
- The cornea has extremely high sensitivity to touch for self-protection
Vascular tunic:
- Vascular tunic hugs the wall of the eyeball, towards the front of the eye it pulls away from
the wall
- Most of the middle layer consists of a spongy structure called choroid
- Choroid contains a network of blood vessels, including capillaries: these capillaries
nourishes the photoreceptors in the retina that turn light into neural signals
- The choroid’s heavy pigmentation reduces light scatter, the tendency for light to be
reflected irregularly around inside the eyeball
- The dark pigmentation absorbs light that isn’t captured by the photoreceptors
Anterior chamber:
- Toward the front of the eye the choroidal layer curls away and a long slender structure
called the ciliary body forms
- Ciliary body produces aqueous humor, the watery fluid that fills the smaller, anterior
chamber that is located behind the cornea and in front of the lens
- The aqueous humor:
o transports oxygen and nutrients to several structures
o carries away waste products
o helps maintain the shape of the eyeball
o constant pressure is maintained
o if drainage is blocked is slowed down pressure builds up, if it remains high for a
long-time vision can be impaired permanently (glaucoma)
The Iris, Pupil and Lens
The Iris:
- This section of tissue gives your eye the characteristic color
- It has 2 layers: the outer layer containing the pigment and the inner layer containing blood
vessels
- If the outer layer is heavily pigmented it will be brown, if it’s lightly pigmented the inner
layer becomes visible and iris looks lightly colored
The Pupil:
- At the center of your own pupil is the black region: pupil
- The pupil is an opening within 2 sets of muscles
- Pupillary reflex: The inner set is a circular band and when it contracts the pupil gets
smaller, the outer set of muscles contract and the pupil widens/dilates
- The size of the pupil depends on: light level (size decreases as the level light increases),
events that stimulate autonomic nervous system
The Lens:
- The crystalline lens lies right behind the iris
- The lens has 3 parts:
o An elastic covering called capsule: moderates the flow of aqueous humor into the
lens helping it retain transparency, molds the shape of the lens and thus the lens’
optical power the variation of this optical power is called accommodation
