Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the...
-
Upload
kenneth-reeves -
Category
Documents
-
view
218 -
download
1
Transcript of Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the...
![Page 1: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/1.jpg)
Lesson 1
![Page 2: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/2.jpg)
IRIS colored part
of the eye
controls the amount of light entering, which changes the size of the pupil
![Page 3: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/3.jpg)
The white part of the eyeball is called the sclera. The sclera is made of a tough material and has the important job of covering most of the eyeball. Think of the sclera as your eyeball's outer coat.
![Page 4: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/4.jpg)
The natural adjustment in the size of the pupils is called the iris reflex, which is extremely rapid.
This iris reflex action the pupil when you automatically adjusts go from a darkened area to a well-lit area, or, from a well-lit area to a darkened one.
![Page 5: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/5.jpg)
Look very closely at the white of the eye, and you'll see lines that look like tiny pink threads. These are blood vessels, the tiny tubes that deliver blood, to the sclera.
![Page 6: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/6.jpg)
The part of the sclera in front of the colored part of the eye is called the cornea. The curved and transparent layer of the sclera at the front of the eye.
![Page 7: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/7.jpg)
Pupil Hole that
light enters
![Page 8: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/8.jpg)
Retina Photorecept
or cells in the retina detect light (rods are highly sensitive to light and cones detect color)
.
![Page 9: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/9.jpg)
![Page 10: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/10.jpg)
Ciliary Muscles
Contract to lengthen the lens and relax to shorten the lens
![Page 11: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/11.jpg)
Vitreous Humour
The eyeball contains fluids, called humours, which prevent the eyeball from collapsing and refract the light that enters the eye.
![Page 12: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/12.jpg)
Rods see in black, white, and shades of gray and tell us the form or shape that something has.
![Page 13: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/13.jpg)
Cones sense color and they need more light than rods to work well. Cones are most helpful in normal or bright light.
![Page 14: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/14.jpg)
![Page 15: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/15.jpg)
The lens in the human eye is a convex lens, which focuses the light rays entering your eye to a point on your retina .
Some people however have eyes that are too long or too short.
![Page 16: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/16.jpg)
If the eye is too long, the image forms in front of the retina
trouble seeing distant objects
![Page 17: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/17.jpg)
If the eye is too short, the image forms behind the retina
Objects that are close to them are difficult to see
![Page 18: Lesson 1. IRIS colored part of the eye controls the amount of light entering, which changes the size of the pupil](https://reader035.fdocuments.us/reader035/viewer/2022062409/5697bff61a28abf838cbe35e/html5/thumbnails/18.jpg)
The shortest distance at which an object is in focus is called the near point of the eye.
The longest distance is called the far point of the eye.
On average, an adult has a near point of about 25 cm, whereas babies have a near point of only 7 cm.
The far point is infinite.