Integumentary System, Tissues, Organs, Membranes, and Glands

Comprehensive vocabulary flashcards covering histology, epithelial and connective tissue classifications, body membranes, gland types, and integumentary physiology based on lecture notes.

Histology

The microscopic study of tissues.

Epithelial Tissue

A primary body tissue that covers body surfaces, lines body cavities and lumens, and forms glands.

Simple Squamous Epithelium

An epithelial tissue consisting of a single layer of flattened cells, located in lung alveoli, blood vessel linings, and serous membranes, that functions in rapid diffusion, filtration, and secretion.

Simple Cuboidal Epithelium

An epithelial tissue composed of a single layer of cube-shaped cells, located in kidney tubules and thyroid follicles, that functions in absorption and secretion.

Non-ciliated Simple Columnar Epithelium

An epithelial tissue lining the stomach, small intestine, and large intestine that functions in absorption and secretion, typically featuring microvilli and goblet cells.

Ciliated Simple Columnar Epithelium

An epithelial tissue found in uterine tubes and smaller airways (bronchioles) that functions in mucin secretion and moving mucus or oocytes.

Ciliated Pseudostratified Columnar Epithelium

An epithelial tissue lining the nasal cavity, trachea, and bronchi that functions in protection, mucin secretion, and moving mucus.

Keratinized Stratified Squamous Epithelium

An epithelial tissue forming the epidermis of the skin, composed of multiple layers including dead surface cells filled with keratin to protect against abrasion.

Nonkeratinized Stratified Squamous Epithelium

An epithelial tissue lining the mouth, throat, esophagus, anus, and vagina that protects underlying tissues from abrasion while remaining moist.

Transitional Epithelium

A specialized epithelial tissue lining the urinary bladder and ureters that changes cell shape to accommodate urine volume changes.

Areolar Connective Tissue

A loose connective tissue containing collagen fibers, elastic fibers, and fibroblasts that protects organs, binds skin to deeper tissues, and provides space for nerves and blood vessels.

Adipose Connective Tissue

A loose connective tissue composed of adipocytes that stores energy, provides thermal insulation, and cushions organs.

Reticular Connective Tissue

A loose connective tissue forming a supportive meshwork stroma for lymphatic organs, including the spleen, lymph nodes, and red bone marrow.

Dense Regular Connective Tissue

A connective tissue densely packed with parallel collagen fibers, found in tendons and ligaments, that resists mechanical stress in a single direction.

Dense Irregular Connective Tissue

A connective tissue containing randomly arranged collagen fiber bundles, located in the dermis and organ coverings, that withstands mechanical stresses in all directions.

Dense Elastic Connective Tissue

A connective tissue rich in elastic fibers, located in vocal cords, the trachea, and walls of elastic arteries like the aorta, allowing for stretch and recoil.

Hyaline Cartilage

The most common cartilage type, found at the tip of the nose, trachea, larynx, articular ends of long bones, and fetal skeleton, providing flexible support.

Fibrocartilage

A durable cartilage type found in intervertebral discs, pubic symphysis, and menisci of the knee that resists compression and acts as a shock absorber.

Elastic Cartilage

A flexible cartilage containing elastic fibers, found in the external ear and epiglottis, that maintains structure while permitting extensive flexibility.

Skeletal Muscle Tissue

A voluntary, striated muscle tissue composed of long, cylindrical, multinucleated fibers attached to bones and skin that moves the skeleton and generates heat.

Cardiac Muscle Tissue

An involuntary, striated muscle tissue found exclusively in the heart wall, consisting of short, branched cells connected by intercalated discs.

Smooth Muscle Tissue

An involuntary, nonstriated muscle tissue composed of spindle-shaped cells with a single nucleus, located in the walls of hollow organs to propel materials.

Neuron

The impulse-conducting cell of nervous tissue, consisting of a soma (cell body), dendrites to receive signals, and an axon to transmit impulses.

Organ

A structure composed of two or more distinct tissue types working together to perform specific, complex functions.

Mucous Membrane

A membrane lining passageways and compartments that open to the external environment, composed of an epithelium and an underlying connective tissue called the lamina propria.

Serous Membrane

A two-layered membrane lining closed body cavities, consisting of simple squamous epithelium that produces friction-reducing serous fluid.

Parietal Layer

The outer portion of a serous membrane that lines the inner surface of a body cavity wall.

Visceral Layer

The inner portion of a serous membrane that directly covers the outer surface of internal organs.

Endocrine Gland

A ductless gland that secretes hormones directly into the bloodstream to regulate target body tissues.

Exocrine Gland

A gland formed by epithelial invagination that secretes products through ducts onto an epithelial surface.

Merocrine Gland

A gland that packages secretions into vesicles and releases them via exocytosis without damaging the cell, such as salivary and lacrimal glands.

Apocrine Gland

A gland that releases secretions when the apical portion of the secretory cell pinches off, such as mammary and ceruminous glands.

Holocrine Gland

A gland whose secretion consists of disintegrated entire dead cells, such as sebaceous glands.

Integumentary System

The body system comprising the skin and its accessory organs, accounting for $7\%-8\%$ of total body weight.

Stratum Basale

The deepest layer of the epidermis containing rapidly dividing keratinocyte stem cells, melanocytes, and tactile (Merkel) cells.

Stratum Spinosum

An epidermal layer composed of nondividing keratinocytes joined by desmosomes and containing epidermal dendritic (Langerhans) cells.

Stratum Granulosum

The epidermal layer where keratinocytes undergo keratinization, filling cells with keratin to grant strength and water resistance.

Stratum Lucidum

A thin, clear layer of the epidermis found only in thick skin, containing cells filled with the protein eleidin.

Stratum Corneum

The most superficial layer of the epidermis, composed of dead, keratin-filled cells that shed approximately one month after formation in the stratum basale.

Melanin

A skin pigment produced by melanocytes in the stratum basale that protects underlying tissue from UV radiation damage.

Lines of Cleavage

Bundles of collagen and elastic fibers in the reticular layer of the dermis aligned parallel to resist directional stress from movement.

Anagen Phase

The active growth stage of the hair cycle, lasting from $18\text{ months}$ to $7\text{ years}$, where hair bulb cells divide rapidly.

Catagen Phase

The brief regression phase of the hair cycle, lasting $3-4\text{ weeks}$, during which cell division in the hair bulb ceases.

Telogen Phase

The resting phase of the hair cycle, lasting $3-4\text{ months}$, after which hair shedding occurs and anagen restarts.

Merocrine Sweat Glands

The most numerous sweat glands ($3-4\text{ million}$) that secrete thermoregulatory sweat composed of $99\%$ water and $1\%$ solutes via exocytosis directly onto the skin.

Apocrine Sweat Glands

Sweat glands activated at puberty, located around nipples, axillary, and pubic regions, that secrete viscous, cloudy sweat into hair follicles via exocytosis.

Sebaceous Glands

Holocrine glands that secrete an oily, waxy substance called sebum into hair follicles to lubricate skin and hair and inhibit bacterial growth.

Calcitriol

The active hormone form of Vitamin D converted by the kidneys, which increases calcium and phosphate absorption in the small intestine.

Regeneration

Tissue repair process replacing damaged or dead cells with the same cell type, fully restoring organ function.

Fibrosis

Tissue repair process filling gaps with fibrous scar tissue when damage is severe, binding parts together without restoring organ function.

Rule of Nines

A clinical estimation tool that divides the body surface into 11 areas of $9\%$ each to determine total burn area.

Basal Cell Carcinoma

The most common and least dangerous skin cancer, originating in the stratum basale layer.

Squamous Cell Carcinoma

A skin cancer originating in the stratum spinosum layer that can metastasize if not caught early.

Melanoma

The most deadly skin cancer, originating from melanocytes, characterized by aggressive growth and metastasis.