Mucosa and Integument Lecture Flashcards

Vocabulary flashcards covering epithelial tissue structures, cellular morphology, intercellular junctions, integument layers, and species-specific cutaneous glands based on lecture notes.

Cutaneous Membrane

A dry and waterproof epithelial membrane that covers the external surfaces of the body, commonly known as skin.

Mucosal Membranes

Wet, lubricated, and permeable membranes covering internal body surfaces, such as the gastrointestinal, respiratory, genital, and urinary tracts.

Squamous Epithelial Cells

Thin, flat plate- or scale-like cells.

Cuboidal Epithelial Cells

Box-like epithelial cells shaped like cubes.

Columnar Epithelial Cells

Tall and narrow epithelial cells shaped like columns.

Basement Membrane

A thin, flexible, non-cellular barrier that acts like double-sided tape to anchor epithelial cells to connective tissue.

Basal Lamina

A component of the basement membrane composed of Type IV Collagen.

Reticular Lamina

A layer of the basement membrane composed of Type III Collagen.

Apical Surface

The surface direction of a polarized epithelial cell that faces the outside world or lumen.

Basal Surface

The surface direction of a polarized epithelial cell that faces the inside of the body.

Lateral Surface

The surface direction of a polarized epithelial cell that faces neighboring cells.

Tight Junctions

Intercellular junctions (such as Occludins and Claudins) that form a waterproof seal barrier between cells.

Anchoring Junctions

Intercellular junctions (such as Desmosomes and Adherens) that act like rivets, mechanically linking cells together.

Gap Junctions

Intercellular channels (formed by Connexins) that allow direct cell-to-cell communication.

Simple Epithelia

Epithelial tissue in which every cell is in direct contact with the basement membrane.

Stratified Epithelium

Epithelial tissue where cells are stacked in multiple layers, and only the most basal layer touches the basement membrane.

Keratinized Epithelium

Epithelium where apical cells undergo terminal differentiation, accumulate strong insoluble $\text{α-keratin}$ protein, lose nuclei and mitochondria, and undergo cornification.

Transitional Epithelium

Specialized epithelium optimized for stretch and recoil, characterized by rounded apical umbrella cells.

Pseudostratified Epithelium

Epithelium featuring disorganized nuclei and varying cell heights, where all cells contact the basement membrane.

Integument

The external covering of an organism—including skin, fur, hair, scales, and feathers—functioning in protection, thermoregulation, resource retention, sensation, and interaction.

Epidermis

The thin, epithelial surface layer of skin that contains melanin.

Dermis

A thick connective tissue layer of collagen and elastin that provides strength and flexibility while housing blood vessels, nerve endings, hair follicles, sweat glands, and oil glands.

Subcutaneous Layer (Hypodermis)

A skin layer composed of fat and connective tissue that anchors the skin to underlying muscle or bone, provides insulation, and cushions.

Stratum Basale

The deepest epidermal layer, consisting of a single layer of cuboidal or columnar proliferating stem cells.

Stratum Spinosum

An epidermal layer characterized by a spiny appearance caused by desmosome attachments.

Stratum Granulosum

An epidermal layer consisting of cells in various stages of keratinization.

Stratum Lucidum

A clear epidermal layer found exclusively in areas exposed to high mechanical stress and friction.

Stratum Corneum

The outermost layer of the epidermis, composed of fully cornified cells.

Sebaceous Glands

Glands that open into hair follicles and secrete sebum, an oily/waxy mixture of triglycerides, cholesterol, and cell debris.

Apocrine Glands

Glands opening into hair follicles that secrete a thicker, milky fluid containing water, lipids, and proteins.

Eccrine Glands

Sweat glands that open directly onto the surface of the skin.

Latherin

A surfactant protein present in horse apocrine sweat secretion.

Anhidrosis

Inability to sweat caused by excessive stimulation of $\text{β-adrenergic}$ receptors in horses.

Lanolin

A heavy, complex wax ester secreted by abundant sebaceous glands in sheep for waterproofing, anti-felting, antimicrobial protection, and pheromonal communication.

Uropygial Gland

A single bilobed gland located dorsally, medially, and caudal to the terminal vertebra in birds, used to secrete oil for preening.