Chapter 6 Integumentary System - Part 2 (Accessory Structures, Glands, Temperature Regulation, Wounds, Burns)

Vocabulary-style flashcards covering accessory skin structures, skin glands, skin functions, thermoregulation, wound healing, burns, and common hair/nail conditions from the lecture notes.

Accessory structures of the skin

Originate from the epidermis and extend into the dermis or hypodermis; include hair follicles, nails, and skin glands (sweat and sebaceous).

Hair follicles

Tube-like depression of epidermal cells from which hair develops; extends into the dermis or subcutaneous layer.

Hair root

Part of a hair that extends from the skin surface to the dermis or hypodermis.

Hair bulb

Deepest part of the hair root; contains dividing cells of the hair matrix.

Hair shaft

Part of the hair that extends beyond the skin surface; made of dead epidermal cells.

Hair papilla

Contains blood vessels that nourish the hair.

Hair color

Determined by the type and amount of melanin produced in the hair.

Arrector pili muscle

Muscle attached to the hair follicle; contracts in response to cold or fear, causing goosebumps.

Lunula

Pale half-moon region over the nail matrix; the nail matrix conceals deeper blood vessels.

Nail plate (body)

Visible portion of the nail composed of keratinized cells that overlie the nail bed.

Nail bed

Surface of skin under the nail plate.

Nail matrix

Active growth region at the proximal end of the nail bed; not visible.

Cuticle

Fold at the proximal end of the nail; part of the stratum corneum that extends over the nail.

Nails

Protective coverings on the ends of fingers and toes.

Sebaceous glands

Holocrine glands usually associated with hair follicles; secrete sebum to keep hair and skin soft and waterproof; excess sebum can cause acne; absent on palms and soles.

Sebum

Fatty secretion with cellular debris produced by sebaceous glands; keeps hair/skin soft and waterproof.

Acne vulgaris

Disorder of sebaceous glands common at puberty; glands overreact to androgens; clogged glands with sebum and epithelial cells; infection and inflammation; treated with Vitamin A derivatives, systemic antibiotics, salicylic acid, benzoyl peroxide.

Eccrine (merocrine) sweat glands

Most numerous; secretion mainly water, salts, and wastes; regulate body temperature; open to the skin surface through pores.

Apocrine sweat glands

Less numerous; open into hair follicles in axillary and groin areas; secrete by exocytosis; respond to emotions and pain.

Ceruminous glands

Modified sweat glands that secrete ear wax; located in the external acoustic meatus.

Mammary glands

Modified sweat glands that secrete milk; located in the breasts.

Skin functions

Protective barrier; sensation; excretion; production of Vitamin D; regulation of body temperature.

Vitamin D production

Starts in the skin and, when activated, helps with calcium absorption.

Regulation of body temperature

Skin contributes to cooling via sweating and adjusting blood flow.

Heat production

Heat is produced by cellular metabolism, mainly in active cells of the liver and skeletal/cardiac muscle.

Heat loss mechanisms

Radiation (primary), conduction, convection, and evaporation.

Set point

Target body temperature monitored by the hypothalamus (about 37 C / 98.6 F).

Hypothalamus

Brain region that monitors temperature and initiates responses to regulate it.

Thermoreceptors

Receptors that signal the hypothalamus about temperature changes.

Vasodilation

Dilation of dermal blood vessels to release heat.

Vasoconstriction

Contraction of dermal blood vessels to conserve heat.

Hyperthermia

Abnormally high body temperature; can occur when heat loss is overwhelmed by heat input; skin may become dry and the person weak or dizzy.

Fever

Elevated body temperature due to immune response; hypothalamic set point raised by pyrogens to help combat pathogens.

Pyrogens

Substances that raise the hypothalamic set point during fever.

Hypothermia

Abnormally low body temperature from cold exposure or illness; shivering; can progress to confusion and loss of reflexes.

Inflammation

Normal response to injury; blood vessels dilate and become more permeable; redness, swelling, warmth, and pain may occur.

Clot

A fibrin-based network with blood cells and platelets that seals a deep cut.

Scab

Dried clot and tissue fluid that forms over a wound to protect it while healing proceeds.

Fibroblasts

Cells that secrete collagen to bind wound tissue and aid healing.

Growth factors

Signals that stimulate new tissue formation during healing.

Phagocytic cells

Cells that remove dead cells and debris during wound healing.

Scar

Elevated mass of collagen fibers formed during healing; may result from excess scar tissue.

Burns

Injuries classified by depth: superficial/first-degree; deep partial-thickness/second-degree; full-thickness/third-degree.

First-degree burn

Superficial burn affecting only the epidermis; redness and inflammation; heals in days to weeks; no scarring.

Second-degree burn

Deep partial-thickness burn destroying epidermis and part of dermis; may blister; regeneration depends on stem cell survival; hair follicles and glands can aid regeneration; usually no scarring.

Third-degree burn

Full-thickness burn destroying epidermis, dermis, and accessory structures; often requires grafting; limited healing from margins.

Rule of Nines

Estimate burn extent by dividing the body into regions near 9% each to guide treatment.

Androgenic alopecia

Pattern baldness; hair loss at the top of the head linked to androgens and testosterone/estrogen balance.

Alopecia areata

Autoimmune hair loss where antibodies attack hair follicles.