| A | B |
|---|
| enamel | the hardest material in your body that covers a tooth's crown |
| cementum | covers a tooth's root and helps anchor the tooth to the jawbone |
| dentin | a living material that makes up the majority of the tooth |
| pulp | a soft tissue that fills the center of each tooth |
| malocclusion | improper bite; when the upper and lower teeth do not meet properly |
| orthodontist | specialists who correct the position of jaws and teeth |
| halitosis | bad breath |
| plaque | sticky film that bacteria adheres to |
| tartar | plague that has hardened after 48 hours |
| periodontal disease | gum disease |
| epidermis | the outermost layer of skin |
| keratin | protein tha makes the skin tough and waterproof |
| melanin | protein with deep pigment that gives skin some of its color |
| dermis | the tough, elastic layer of skin that lies below the epidermis |
| pore | a tiny opening |
| follicle | structures in the dermis in which hairs grow |
| sebaceous gland | secrete oils into follicles |
| melanoma | the least common form of skin cancer |
| acne | forms when excess oil and dead cells plug hair follicles |
| dermatologist | a doctor who specializes in treating skin problems |
| eczema | a condition in which an area of skin becomes red, swollen, hot, and itchy |
| cornea | the clear tissue that covers the front of the eye |
| pupil | the opening through which light enters the eye |
| iris | a circular structure that surrounds the pupil and regulates its size |
| lens | a flexible structure that focuses light |
| retina | a layer of cells the liens the back of the eye |
| optometrist | a professional who provides eye and vision care |
| eardrum | a thin membrane found at the end of the ear canal; vibrates when sound vibrations strike it |
| cochlea | a hollow, coiled tube filled with fluid |
| semicircular canals | structures that send information to your brain about the movements of your head |
| audiologist | professionals who are trained to evaluate hearing and treat hearing loss |
| insomnia | difficulties falling asleep or staying asleep |
| sleep apnea | a person stops breathing for short periods during sleep and then suddenly resumes breathing |
| narcolepsy | a person experiences severe sleepiness during the day, or falls asleep suddenly |
| circadian rhythm | the body's internal system for regulating behavior patterns during a 24-hour cycle |
