| A | B |
|---|
| Integumentary System | Body system consisting of the skin and accessory structures that acts as a barrier to protect against the environment and helps maintain homeostasis |
| Skin | Largest organ of the body that covers and protects external surfaces |
| Epidermis | Outermost layer of the skin that provides a protective barrier and contains melanocytes |
| Dermis | Middle layer of the skin containing blood vessels, nerves, hair follicles, glands, and connective tissue; provides nutrients to the epidermis |
| Hypodermis | Deep layer of skin composed of fat and connective tissue that insulates and cushions the body |
| Keratin | Tough, protective protein found in skin hair and nails |
| Melanin | Pigment produced by melanocytes that determines skin and hair color and protects against UV radiation |
| Melanocyte | Cell in the epidermis that produces melanin |
| Keratinocyte | Cell that produces keratin and forms the majority of the epidermis |
| Sebaceous Gland | Gland that produces sebum to lubricate and waterproof the skin |
| Sebum | Oily substance produced by sebaceous glands that moisturized skin and hair and prevents bacterial growth |
| Sudoriferous Gland | Gland that produces perspiration to regulate body temperature |
| Eccrine Gland | Sweat gland that opens onto the skin surface through pores; used for evaporative cooling |
| Apocrine Gland | Sweat gland that secretes into hair follicles in the armpits, groin, and nipples; active during puberty and secrete in response to stress and hormonal changes; cause body odor |
| Hair | Column of dead, keratinized cells that protects the body, and helps regulate temperature and provide sensory feedback |
| Hair Follicle | Structure in the skin from which hair originates |
| Bulb | End of the hair embedded in the follicle; site of active hair growth |
| Shaft | Visible portion of the heair that extends above the skin surface |
| Hair Root | Portion of a hair that lies beneath the skin surface |
| Arrector Pili | Muscle attached to hair that contracts in response to cold or emotional stimuli |
| Nail | Sheet of hard keratinized cells that protects the tips of fingers and toes |
| Nail Body | Visible part of the nail that covers the fingertip |
| Matrix | Nail root; responsible for nail growth |
| Lunula | White, half-moon shape at the base of the nail; covers matrix |
| Cuticle (Eponychium) | Thin layer of skin that overlaps the base of the nail, protecting the root from infection |
| Sensory Receptors | Structures in the skin that detect touch temperature and pain |
| Thermoregulation | Process of maintaining body temperature through sweating and blood vessel dilation |
| Perspiration | Release of sweat from sweat glands |
| Dermatologist | Physician who specializes in skin and accessory structures |
