C3. P2 Flashcards
What is the first part of the eye that light comes in contact with?
Cornea
How does the cornea protect the eye?
Prevents dust, germs, and other dangerous material from entering the eye
How does the cornea manipulate light?
Light bends off the cornea and is directed to the pupil so that it can reach the inner lens
What is the pupil?
The opening through which light can travel
What happens during pupil dilation?
The iris pulls away from the pupil, causing it grow
What happens during pupil constriction?
The iris pulls toward the center of the eye, causing it to shrink
What does the lens do?
Bends light and directs it to the retina, especially the fovea
Where is the lens in the eye?
Directly behind the iris and pupil
What is accommodation?
The lens adjusting its shape
Why would the lens make itself larger?
To focus of objects farther away
Why would the lens make itself thin?
To focus on objects that are close
How does light get to the brain?
Afferent sensory neurons must translate incoming signals from the eye and carry them to the brain
Where is the retina located?
At the back of the eye
What is the purpose of the retina?
To translate light energy to a neural signal
What are photoreceptors?
Light sensitive cells that detect qualities of light and convert it to a signal
What is located at the rearmost portion of the retina?
Photoreceptors
What is located at the inner layers of the retina?
Bipolar sensory neurons and ganglion neurons
What do bipolar sensory neurons and ganglion neurons do?
Translate information from the photoreceptors into a neural signal, sending it to the brain
What are the two types of photoreceptors?
Rods and cones
What do rods do?
Help us see where light is limited, creating blurry images
What do cones do?
Create clear and defined colored images where there is lots of light
Where are rods located?
Spread throughout the retina outside the fovea
Where are cones located?
Primarily in the fovea
Do we have more cones or rods in our eyes?
Rods
Are cones or rods more sensitive?
Rods are more sensitive
What is the purpose of the fovea?
Cone rich center of the retina where the eye attempts to focus light
Are rods or cones better at detecting motion?
Rods
When are cones most active?
During the day
When are rods most active?
During the night
What kind of wavelengths do rods react to?
Short wavelengths (Darker colors, white)
How do cones communicate with the brain?
Many individual cones are directly connected to a single bipolar sensory neuron
When is a cone neural signal sent to the brain when activated?
Always
How do optic nerves form?
The axons of ganglion neurons in each eye bundle together
What is the optic chiasma?
The place in the brain where some of the optic nerve cross to the other side of the brain
What is the blind spot?
A portion of the retina where there is a lack of photoreceptors because this is where the ganglion cells bundle together to form the optic nerve
