CHAPTER 1: THE WORLD THROUGH OUR SENSES
1.6 The Sense of Sight
Structure of the human eye
1 The eye is a sensory organ of sight. It is sensitive to light.
2 The spherical human eyes are held by muscles in the bony sockets of the skull.
3
Three pairs of muscles control the movements of the eyeballs.
4 The tear gland produces tears to clean the eyes and kill microorganisms.
Photo 1.2 Front view of the human eye
5 The wall of the eyeball is made up of three layers:
• the sclera
• the choroid
• the retina6 (a) The sclera is the outer layer of the eyeball. It is white, tough and opaque.
(b) The choroid is the middle layer of the eyeball. It has black pigments and a lot of blood vessels.
(c) The retina is the innermost layer of the eyeball. It has many receptors that are sensitive to light. These are called photorceptors (cones and rods).7 Figure 1.11 shows the internal structure and functions of different parts of the eye.
Figure 1.11 Parts of the eye and their functions
How do we see
ŞİMDİ OKUDUĞUN
Learn Science [Form 2]
RastgeleThis book is not a story. This book is a study book for those who likes to study science. I put this way for those who are so lazy to study in their actual books. So, yeah. Hope this book helps you for your knowledge about science. Actually, the les...