MCAT BIO CH. 8 PART 2 Flashcards
How does light enter the eye? What happens to light when it passes through the cornea?
Passing through the cornea
What happens to light when it passes through the cornea?
Refracted; refractive index of the cornea is higher than that of air
What is the sclera? (Based on vision)?
The white of the eye
Where is the choroid located? What does it contain? What’s it purpose? (Based on vision)?
Beneath the sclera; contains darkly pigmented cells; absorbs excess light within the eye
Where is the retina located? What is its purpose? (Based on vision)
Beneath the choroid; the surface upon which light focuses
What is just inside the cornea? What does it contain? (Based on vision)
The anterior chamber; fluid called aqueous humor
What does the iris do? (Based on vision)
Muscles in the iris regulate the diameter of the pupil
What is located just behind the iris? What does it contain? (Based on vision)
Posterior chamber; aqueous humor
What is located at the back of the posterior chamber?(Based on vision)
Lens
What is the purpose of the lens? (Based on vision)
Fine-tune the angle of incoming light so beams are perfectly focused on the retina
How is the curvatures of the lens varied (the refractive power)? (Based on vision)
By the ciliary muscle
As light passed through the lens, where does it go through to reach where? (Based on vision)
Goes through the vitreous chamber en route to the retina
What does the vitreous chamber contain? (Based on vision)
A thick jelly-like fluid called the vitreous humor
What does the retina contain? (Based on vision)
Photoreceptors known as rods and cones
What type of cells do the rods and cones of the retina synapse with? (Based on vision)
Bipolar cells
What are bipolar cells type of nerve cells? (Based on vision)
Only have one axon and one dendrite
What type of cells do bipolar cells from the rod and cones synapse, synapse with? (Based on vision)
Ganglion cells
Which nerve does the ganglion cells stimulate? (Based on vision)
The optic nerve which travels from each eye towards the occipital lobe of the brain
What is the optic disk of the retina? (Based on vision)
The point where many axons from ganglion cells converge to form the optic nerve
What is the blind spot (optic disk)? (Based on vision)
Contains no photoreceptors
What is the macula? (Based on vision)
Portion at the center of the retina that makes vision focused
What is in the center of the macula? (Based on vision)
Fovea centralis (focal point)
What does the fovea centralis only contain and what is it important for?
Contains only cones and responsible for extreme visual acuity
What are special about opsin that are located in rods and cones?
Special pigment proteins that change their tertiary structure upon absorbing light