Anatomy- Sense organs

The sense organs include the eyes, ears, nose and tongue. All of these organs send signals to the central nervous system (CNS).

The eyes:
- Made up of 3 layers
     - Sclera & Cornea: white of eye, covers everything except anterior, covered by conjunctive
     - Choroids: absorb light rays
     - Retina: Only place where blood vessels can be observed to view pathological changes. The retina
     includes the pigmented layer (visual data) and the neural layer (contains photoreceptors, bipolar,
     ganglion)
- Lens: refracts (bends) light
- The eye has two cavities: Anterior (filled with aqueous humour) and Posterior (filled with vitreous humour). Both of these help maintain the shape of the eyes.


The ears:
Outer ear 
Pinna: What we see. This conducts sound waves to the middle ear
Ear canal: Leads to middle ear
Ear wax: Cerumen
Eardrum: Tympanic membrane (separates middle and external ear)
Middle ear- Amplifies sound waves
Contains 3 bones:
Malleus (hammer), incus (anvil), stapes (stirrup)
- All of these amplify vibrations
*air pressure equalized by eustachian tube- connects middle ear and throat*
Inner ear
- Contains mechanoreceptors (converts sound waves to nerve impulses)
- Perilymph & endolymph (carry vibrations within the ear)
- Cochlea: contains "organ of corti" which responds to sound waves by stimulating the cochlear nerves