The Eyes Flashcards
(17 cards)
Whats the function of the eyes
To detect light and convert it into visual information
Describe the cornea
Covers the entire front part of the eye, convex shape so it bends light/refracts incoming light into the lens
Describe the lens
A transparent bi-convex flexible structure that focuses light into the retina
What happens when we want to see something far away
The lens become thinner
What happens when we want to see something close by
The lens become thicker
What does the ciliary muscles do
Changes the thickness and curvature of the lens.[it is connected to the lens by suspensory ligaments]
What is the iris
The colored part of the eye, the muscular structure that regulates the size of the pupil
What is the function of the pupil
Controls the amount of light that enters the eye
Describe what happens when there is alot of light
The iris expands so the pupil becomes smaller which limits the amount of light entering the eye
Describe what happens when there is dim or little light
The iris contracts and the pupil becomes larger so more light can enter
Describe how we see
Light enters the eye through the cornea, passes through the pupil and onto the lens which refract light through the vitreous humour and focuses an image onto the retina. Light-sensitive cones and rods react to wavelengths of light and trigger nerve impulses . These impulses are carried through the optic nerve to the visual centers in the brain where it is interpreted to give us sight.
What are the cells in the retina called
Photoreceptor cells[Rod cells and the Cone cells]
Rod cells
Sensitive to light intensity. Allow us to see black, white and sometimes grey, enable us to determine the shapes of objects. Provides night vision.
Cone cells
Allow us to see color
What is the blind spot of the eye
Area on the retina where the optic nerve connects, lacking light-sensitive cells
What is the optic nerve
A bundle of nerve fibers that transmits visual information from the eye to the brain.
What is the retina
The light-sensitive layer that receives images, converts them into electrical signals, and sends them to the brain for visual perception
