Parts of the Face

The Eye

Structure: sphere about 1 inch in diameter Function: vision (dah) Protected by: Orbital Socket, Eyebrows, Eyelids, & Eyelashes Continuously bathed in fluid (tears) Tears: secreted by the lacrimal gland Flows across the eye into the lacrimal duct at the corner of your eye which empties into your nasal cavity Conjunctiva – membrane that lines eye and eye lid Secretes mucus to lubricate eye

Sclera – Outer layer (whites) Function: Muscle attachments Extrinsic eye muscles – each controls a different movement) Maintains shape Protects inside of eye

Cornea – Clear coat No blood vessels Has pain and touch receptors Function: Protection

Choroid Coat – Pupil & Iris Middle layer of eye Pupil: the black part of eye Function: permits passage of light Big Pupil (Dilated): allows lots of light in Little Pupil (Contricte): Limits light Iris: Colored part Has 2 muscles (intrinsic eye muscles) – control the pupil;

Lens - directly behind iris and pupil Elastic and Disc shaped Losses its elasticity with age Function: to refract light Retina – innermost layer Sends image to optic nerve

The Ear

Function: Hearing & balance (equilibrium) Consists of 3 parts Outer – collect sounds Middle – collect sounds Inner – analyze sounds waves and maintain balance

Outer Ear Outside and ear canal only Outside is known as the Pinna or auricle Composed of skin and cartilage Canal (Meatus) about 1 inch in adults Closed by the eardrum (tympanic membrane) Skin produces wax (for protection)

Middle Ear – small cavity between eardrum and inner ear Conducts sounds to inner ear by 3 tiny movable bones (ossicle) Not connected to outside (eardrum blocks it) Has a Tube (eustrachian) for ventilation which runs down back of the nasal cavity Normally closed except when swallowing and yawning

Inner Ear Very intricate series of structures deep in the skull

The Nose

Composed of bone, cartilage and skin Function: air passage & sense of smell Warms, moistens and filters air before it travels to the lungs Can detect 10000 different smells Smell accounts for about 90% of what we think of as taste

Structure: Junction of nasal bones forms the bridge Separated in halves by the nasal septum Hard palate – roof of mouth, nasal cavity is right above that

Mouth Composed of soft and hard palate, mucous membranes, tongue, teeth (32), lips and cheeks Jaw is made of maxilla (does not move) and mandible (moves) Mandible and maxilla attach at the skull at the temporomandibular joint (TMJ)