1. Special Senses

2. General Senses Widely distributed throughout the body Examples Touch
Pain
Proprioception (provides information about the position of the body)

3. Special Senses Produced by highly localized sensory organs Examples
Smell
Taste
Sight
Hearing
Model of the human nose

4. The Inner Ear

5. Structures of the outer and middle ear
Outer ear
Pinna- collects and focuses sound waves
External auditory canal- passage way that leads to the ear drum
Ear drum- also called tympanic membrane. It vibrates with sound waves.
Middle ear
hammer, anvil, and stirrup- bones that transmit vibrations
Oval and round windows- two openings that connect the middle ear to inner ear
Auditory tube- angles air pressure to be equalized

6. How We Hear
Sound waves are collected by the auricle and conducted through external auditory meatus toward the tympanic membrane which causes vibrations
The vibrations of the stirrup produce waves in the perilymph of the cochlea. This makes the perilymph move and this pushes against the membrane of the round window
This causes the vestibular membrane to vibrate. It creates waves in the indolymph and the basilar membrane
Cochlear nerves (located in the cochlar ganglion), send axons to the cochlar nueculas in the brain stream
Neurons project to other areas of the brain stream to inferior collicuculus thalamus auditory cortex of the cererum. rt

7. Olfactory - nose

8. Smell- Olfactory
Molecules in the air enter the nasal cavity and dissolve in the mucus lining of the uppermost shelf of the nose (chemoreceptors – cilia)
The olfactory neurons of the molecules contact the olfactory receptors who send impulses to the axons.
The olfactory bulbs send this to the brain which interprets each scent.

9. Taste - tongue *

10. Taste
Saliva breaks down the food into fluid. The chemicals in the fluid attach to the taste cells.
Nerve fibers send impulses to the facial nerves, which send impulses to taste cortex of parietal lobe for interpretation.

11. Structures of the eye pictures

12. Accessory structures of the eye
Eyebrows-protect eyes by preventing perspiration from running down the forehead.
Eyelids- protect the eyes from foreign objects
Conjunctiva- covers inner surface of the eyelids
Lacrimal Apparatus- produces tears
Extrinsic Eye Muscles- help movement of the eye

13. Eye structures Sclera – outermost, white, hard, layer
Cornea – transparent part of sclera, light in
Choroid – 2nd layer, black, absorbs light
Retina – innermost layer, bipolar cells: rods- night vision and cones- color vision
Ciliary body – holds the lens in place
Iris – colored part of eye, regulates light
Fovea Centralis – area producing sharpest vision

14. Chambers of the eye
Anterior compartment- between the lens and cornea, divided into anterior chamber and posterior chamber
Filled with aqueous humor
Helps maintain pressure in the eye
Bends light
Provides nutrients to inner eye
Circulates around the cornea
Posterior compartment
Filled with a transparent jellylike substance called the vitreous humor
Holds the retina in place
Has many similar functions to the aqueous humor
Unlike aqueous humor, it does not circulate

15. Path of sight input The rods / cones synapse bipolar sensory cells
to the optic nerve
reaches the thalamus of brain
Visual cortex of occipital lobe of cerebrum

16. Eye Disorders
Conjunctivitis- also called pink eye, an infection of the conjunctiva
Chalazion- a small lump in the eyelid caused by obstruction of an oil producing gland
Cataract- clouding of the natural lens
Glaucoma- malformation or malfunction of the eye’s drainage structures
Myopia- nearsightedness
Presbyopia- an eye in which the natural lens can no longer accommodate
Stye- same as chalazion