biology

biology

the retina

= The light-sensitive layer 

-2 layers:

pigmented layer

neural layer

-2 cells:

rods 

cones

= The light-sensitive layer of tissue that lines the back of the eye

the retina exists of 2 layers:

pigmented layer

neural layer

   innermost layer of the eyeball

                    contains microscopic structures

                       rods

                       -low-light

                       -non-color vision

                    Cones

                       -Bright-light

                       -Color vision

function retina

-Light processing

-Photons are absorbed in rods and cones:

• cones: fine detail, color
• rods: not detailed, grayscale

function: Light processing starts at the back of the retina.

Photons are absorbed in rods or cone cells, which contain

chemicals called opsins that react when absorbing photons

of light.

the cones detect fine detail and color (very detailed)

rods only register a grayscale of black and white and shape

(not very detailed)

what are the 2 layers of the retina?

1. neural layer & green layer
2. pigmented layer & neural layer
3. pigmented layer & photoreceptor layer
4. photoreceptor layer & optic layer

what are the 2 cells in the innermost layer of the eyeball?

1. fibers & nerves
2. ganglion & bipolar cells
3. rods & nerves
4. rods & cones

long-sighted vision

long-sighted vision:

-medical term= hyperopia

-eyeball is too short

-You see better far away, and it’s blurry when it’s close

-it improves when you get older

- glasses/contact lenses

- symptoms: squinting eyes, tired eyes, headaches,...

It happens when the eyeball is too short

You see better far away, and it’s blurry when it’s close

Most children are born with farsighted vision, when you get older it improves

both are types of refractive errors (vision problem that makes it hard to see clearly)

both are easily corrected with eyeglasses or contact lenses

common signs and symptoms: squinting eyes to see clearly, tired eyes and eye rubbing, eye strain and headaches

near-sighted vision

near-sighted vision:

-medical term: myopia

-eyeball grows too long

-You see better when objects are closer

-gets worse during adolescence, then stabilizes

- glasses/contact lenses

-symptoms: squinting eyes, tired eyes, headaches,...

 (medical term: myopia): You see better when objects are closer

It happens when the eyeball grows too long from front to back

Nearsightedness: it gets worse during adolescence and then stabilizes during early adulthood

40% of Americans are nearsighted

How many procent of Americans are nearsighted?

1. 10%
2. 30%
3. 20%
4. 40%

what is a different word for hyperopia?

ciliary muscle

= muscles that control the movement of the lens/pupil

-iris:

= colored part of the eye

= muscles that control the movement of the lens/pupil

iris = the colored part of the eye

photoreceptors

= the light sensing nerve cells 

located in the retina

the light sensing nerve cells (rods and cones)

located in the retina