Integumentary System Structure and Glands

Vocabulary flashcards covering the structural layers of the skin, dermal regions, hypodermis, and cutaneous glands based on the lecture transcript.

Stratum lucidum

A layer found only in thick skin (fingertips, palms, and soles) made up of several layers of flat dead keratinocytes that provides extra toughness to thick skin regions.

Stratum corneum

A superficial skin layer made up of an average of up to $30$ layers of flat dead keratinocytes that overlap, resist abrasion, penetration, and water loss, and are continuously shed and replaced.

Dermis

A layer composed of dense irregular connective tissue containing collagen and elastic fibers, supplied with blood vessels, sweat glands, sebaceous glands, and nerve endings, housing hair follicles and nail roots.

Papillary region

A region of the dermis containing dermal papillae that project into the underside of the epidermis, containing a thin zone of areolar tissue that allows for the mobility of leukocytes and other defense cells.

Sebaceous glands

Oil glands, most of which open directly onto the surface of the skin or connect to hair follicles, that secrete an oily substance called sebum to keep skin and hair from becoming dry, brittle, and cracked.

Sebum

An oily substance secreted by sebaceous glands that is composed of triglycerides, cholesterol, proteins, and salts.

Ceruminous glands

Coiled, simple tubular wax glands in the external ear canal that produce a waxy lubricating secretion and are found as far down as the subcutaneous layer.

Cerumen

Earwax produced when secretions of wax and oil glands combine, which keeps the eardrum pliable, waterproofs the canal, kills bacteria, and makes guard hairs sticky to block foreign particles.

Reticular region

A region of the dermis that attaches to the hypodermis, containing blood vessels, nerves, hair follicles, sebaceous glands, sudoriferous glands, and fibers that give skin the ability to stretch and return to its original shape.

Dermal papillae

Upward finger-like extensions of the dermis that form a wavy boundary with the superficial epidermis.

Epidermal ridges

Downward waves of the epidermis, which produce prominent friction ridges on fingertips.

Hypodermis

Subcutaneous tissue containing more areolar and adipose tissue than the dermis that supports the body, binds skin to underlying tissues, and serves as a common site for drug injection.

Exocrine glands

Glands in the skin that secrete their products to an outer surface by a duct.

Sudoriferous glands

Sweat glands that release sweat into hair follicles or onto the skin surface through pores.

Apocrine sweat glands

Coiled tubular glands with larger ducts found in the groin, axillae, and male bearded face regions that open into hair follicles, respond to stress and sexual stimulation, and do not function until after puberty.

Bromhidrosis

Disagreeable body odor produced by bacterial action on sweat from apocrine glands.

Eccrine sweat glands

Coiled, simple tubular glands found throughout the skin of the forehead, palms, and soles that secrete watery perspiration to help cool the body.

Sweat

A fluid originating as a protein-free filtrate of blood plasma produced by the deep secretory portion of sweat glands, containing some $NaCl$ and small solutes, consisting on average of $99|\text{\%}$ water with a pH range of $4$ to $6$.