the human eye

Question 1

the conjuctiva

Answer 1

a thin mucous membrane covering the front of the eye and the inner surface of the eyelid, that contains pain receptors that are stimulated by dust and foreign particles, resulting in the blink reflex.

Question 2

tear gland

Answer 2

secretes antiseptic tears that protects the conjunctiva from bacteria and dehydration.

Question 3

outer fibrous layer (sclera)

Answer 3

• a layer of connective tissue that forms the outer layer of the eyeball and extends to the transparent cornea at the front
• protects the internal parts of the eye, helps to maintain the spherical shape of the eyeball, and serves for muscle attachment

Question 4

outer fibrous layer (cornea)

Answer 4

• the transparent front part of the sclera, which is more convex than the rest of the eyeball
• allows light rays through to the inner layer of the eye and causes the refraction of incoming light rays

Question 5

middle vascular layer (choroid)

Answer 5

• a thin, darkly pigmented vascular layer
• pigment absorbs excess light rays to prevent internal reflection which may cause blurred images
• blood vessels supply oxygen and nutrients to cells