1. Eye and Ear

2. Eye

3. Becomes clear in front of the eyes, called cornea
The eye is covered in a tough layer of connective tissue called the sclera
This is covered by a mucous membrane called the conjunctiva
Becomes clear in front of the eyes, called cornea
Next inner layer is the choroid
Turns into ciliary body, then iris (gives the eye its colour)
Iris can change size, regulate amount of light
The hole it makes is the pupil

4. Innermost layer is retina
Made of neurons and photoreceptors (clustered in the back)
In centre of front is lens
Flexible, focuses light entering eye
Shape controlled by ciliary bodies
Ciliary bodies contract, compressing lens, focus on near objects
When the relax, lens lengthens, focus on distance objects
Light passes through clear fluid called vitreous humour

5. Light strikes two types of photoreceptors, rods or cones
Fluid supplied by ciliary bodies
Light strikes two types of photoreceptors, rods or cones
Rods detect intensity
Cones detect colour (three types)
Rods more around perimeter, cones in center
The cluster of cone cells at centre of vision is called fovea
Information is processed and sent through optic nerve

6. The nerve leaves a sort of “optic bald spot”
This is the optic disc, aka blind spot
Visual cortex (posterior of cerebrum) fills in the blanks, so we normally don’t see it

7. Ear
Broken into three sections: outer, middle, and inner

9. Outer Ear Only two structures Actual “ear” that we see is the pinna
Opens to a tube called auditory cannal
Both are designed to collect logitudinal compression and rarefaction waves

10. Middle Ear Contains three bones (smallest in the body)
All three - malleus, incus, and stapes (hammer, anvil, and stirrup) transmit the vibrational waves to the oval window, a membrane connected to the inner ear
Also in middle is a opening to the pharynx called the Eustachian tube
Regulates pressure affecting tympanic membrane

11. Inner Ear Actual center where sound waves are processed
Has fluid filled chambers called semicircular canals, responsible for spatial orientation
The cochlea is the hearing centre
Connected to auditory nerve, which relays info to auditory complex in cerebrum