Special Senses

• Touch(General)
• Eyes/seeing(special)
• Ears/hearing(special)-equilibrium(sound/balance)

• Taste/gustatory(special)
• Smell(special)

• Eyelids-shade eyes during sleep, spread eye lubrication over eye ball, protect from excessive light and foreign objects
• Eylashes-protect from border of eyelid and protect eyeballs
• Lacrimal gland-drains lacrimal fluid/tears
• Eyebrows-protect eyeballs from foreign objects and direct sun
• Extrinsic eye muscles-control eye movement

• Lacrimal Gland
• Duct
• Superior or inferior canal
• Lacrimal sac
• Nasolacrimal duct
• Nasal Cavity

1. Fibrous tunic-dense connective tissue, outside of eye; contains cornea and sclera, for protection and transparent for light

• 2. Vascular Tunic-Supply other layers with blood contains melanin, absorbs light
•     Choroid-absorb scattered light waves
•     Iris-Ring of smooth muscle control size of       pupil
•     Cilliary Body- Control change shape of lens (smooth muscle) and (accommodation)

• 3. Nervous Tunic/Retina-(inner tunic) sensory neurons that respond to light
•     -Pigmented layer-Epithelial cells(rods and cones) all store pigments from veggies. Light causes nerve impulses
•     -Bipolar cells
•     -Ganglion cells-group of cell bodies lying outside the CNS

• Optic nerve
• Optic Chiasm
• Optic tract
• Thalamus
• Optic radiations
• Primary Visual area of cortex in occipital lobe

All filled with aqueous humor fluid

• Anterior chamber-
• Posterior Chamber-
• Vitreous Chamber-

Accommodation- increase in the curvature of the lens for near vision

Papillary Constriction-narrowing of hole where light enters eye, iris muscles contract

Convergence-medial movement of two eyeballs, both are directed to object being viewed. Ex: pencil moving towards eye

Optic discs-site where optic nerve exits the eyeball

Fovea centralis-small depression at center of posterior portion of retina at visual axis of eye

External ear-collects sound waves and channels them inward

Middle ear-conveys sound vibrations to oval window

Internal ear-houses receptors for hearing and equilibrium

First order of neurons of the olfactory pathway, bipolar neurons with exposed dendrites and axon; respond to inhaled chemicals

• Olfactory nerves
• Olfactory bulbs
• Olfactory tract
• Olfactory cortex

Impulses go to Limbic system

An oval body consisting of three kinds of epithelial cells: supporting cells, gustatory receptor cells and basal cells. Found on tongue called papillae

Supporting cells-surround the gustatory receptor cells

Gustatory receptor cells-

Basal cells-replace receptor cells

• Tastebud
• Thalamus
• Gustatory Cortex

Smell ties to emotions

Supporting cells-surround olfactory receptors

Olfactory receptor cells-

Basal cells-replace olfactory cells

sound and balance=equilibrium

photopigment in rods

• Outer-Pinna/Oracle(cartilage, help direct sound waves into ear), External auditory canal, tympanic membrane(eardrum, vibrate when soundwaves hit it), exocrine glands(make earwax)
• Middle-Malleous, Incus and stape, nasopharynx(auditory tube)
• Inner-Cochlea(auditory receptors), saccule and uticle make up vestibule

Rods are stimulated by by low light and allow dim vision

Cones are stimulated by right light and produce color vision

• enter external auditory canal
• vibrations of tympanic membrane
• ossicles vibrate, strike oval window
• setup waves in perilymph
• strike vestibular membrane and scala tympani
• setup waves in endolymph
• vibrate vasilar membrane
• stimulate hair cells on spiral organ

vestibule(saccule and utricle)

semicircular ducts