Anatomy & Physiology: Tissue Organization & Integumentary System

Vocabulary flashcards covering tissue types, epithelial, connective, muscle, and nervous tissues, body membranes, tissue modifications, and integumentary system anatomy and repair from Chapters 5A, 5B, 6A, and 6B.

Histology

The study of tissues.

Epithelial Tissue

Tissue composed of one or more layers of closely packed cells with little to no extracellular matrix and no blood vessels, covering body surfaces, lining cavities, and forming the majority of glands.

Apical Surface

The distinctive cell surface of an epithelium exposed to the external environment or an internal body space, which may contain microvilli or cilia.

Basal Surface

The fixed bottom surface of epithelial tissue that attaches to the underlying connective tissue via a basement membrane.

Simple Epithelium

Epithelial tissue consisting of a single cell layer thick, where all cells maintain direct contact with the basement membrane.

Stratified Epithelium

Epithelial tissue consisting of two or more layers of cells, where only the deepest basal layer is in contact with the basement membrane.

Pseudostratified Columnar Epithelium

Epithelial tissue that appears layered due to nuclei scattered at different distances, though all cells remain in direct contact with the basement membrane.

Goblet Cells

Unicellular exocrine glands interspersed in epithelial tissue that secrete glycoprotein mucin, which forms mucus when mixed with water.

Keratinized Stratified Squamous Epithelium

Epithelial tissue whose superficial layers consist of dead, anucleate cells filled with the protective protein keratin, found in the epidermis.

Nonkeratinized Stratified Squamous Epithelium

Epithelial tissue composed of multiple layers of living cells containing nuclei and organelles while lacking keratin, kept moist by secretions in locations like the oral cavity and esophagus.

Transitional Epithelium

Specialized epithelium limited to the urinary tract whose cell shape varies from cuboidal/polyhedral when relaxed to flattened when distended.

Endocrine Glands

Glands that lack ducts and secrete hormones directly into the blood.

Exocrine Glands

Glands formed from invaginated epithelium in connective tissue that connect to an epithelial surface via an epithelium-lined duct.

Acini

Cell clusters in multicellular exocrine glands that produce secretions.

Merocrine Glands

Exocrine glands that package their secretions into vesicles and release them by exocytosis without damaging the gland cell.

Apocrine Glands

Exocrine glands whose secretory production involves the pinching off of the apical cell membrane containing the secretion.

Holocrine Glands

Exocrine glands whose secretions are produced through the total disintegration and rupture of the entire secretory cell.

Fibroblasts

Flat cells with tapered ends that are the most abundant resident cells in connective tissue proper, producing protein fibers and ground substance.

Mesenchymal Cells

Embryonic stem cells residing within connective tissue that divide upon damage to produce a replacement stem cell and a committed cell.

Fixed Macrophages

Large, irregular resident cells derived from monocytes that phagocytize damaged cells or pathogens within connective tissue.

Scurvy

A nutritional deficiency disease caused by a lack of vitamin C, leading to impaired collagen fiber synthesis, weakness, gum ulceration, and hemorrhages.

Marfan Syndrome

A rare genetic disorder of connective tissue caused by an abnormal chromosome 15, resulting in long limbs, weak ligaments, thoracic cage malformations, and cardiovascular defects.

Connective Tissue Proper

A category of connective tissue divided into loose connective tissue and dense connective tissue based on fiber density and ground substance proportion.

Areolar Connective Tissue

A loose connective tissue featuring scattered fibroblasts and unorganized collagen and elastic fibers embedded in abundant viscous ground substance.

Adipose Connective Tissue

A loose connective tissue composed predominantly of adipocytes whose nuclei are pushed to the cell edge by large lipid droplets.

Reticular Connective Tissue

A loose connective tissue containing a meshwork of reticular fibers, fibroblasts, and leukocytes that forms the stroma of lymphatic organs.

Dense Regular Connective Tissue

A connective tissue containing densely packed, parallel arrays of collagen fibers with few blood vessels, found in tendons and ligaments.

Dense Irregular Connective Tissue

A connective tissue containing randomly arranged and clumped collagen fiber bundles that withstand stress applied in multiple directions.

Hyaline Cartilage

The most common type of cartilage, featuring irregularly arranged chondrocytes in lacunae within a glassy-appearing extracellular matrix surrounded by perichondrium.

Fibrocartilage

A weight-bearing, compression-resistant cartilage containing parallel collagen fibers and large chondrocytes in lacunae, lacking a perichondrium.

Elastic Cartilage

A flexible cartilage containing closely packed chondrocytes and abundant elastic fibers forming a web-like mesh, surrounded by a perichondrium.

Osteons

Cylindrical structural units of compact bone composed of concentric lamellae arranged around a central canal containing blood vessels and nerves.

Erythrocytes

Formed elements in blood responsible for transporting respiratory gases including oxygen and carbon dioxide.

Plasma

The liquid ground substance of blood containing dissolved proteins, nutrients, wastes, and hormones.

Skeletal Muscle Tissue

Voluntary, striated muscle tissue consisting of long, cylindrical, unbranched, multinucleated fibers arranged in parallel.

Cardiac Muscle Tissue

Involuntary, striated muscle tissue composed of short, branching cells with one or two central nuclei, joined by intercalated discs in the myocardium.

Intercalated Discs

Specialized intercellular connections between cardiac muscle cells that strengthen structural ties and promote rapid electrical conduction.

Smooth Muscle Tissue

Involuntary, nonstriated muscle tissue composed of short, fusiform cells with a single centrally located nucleus, found in the walls of hollow organs.

Neurons

Nerve cells featuring a cell body, dendrites, and an axon that process, receive, and transmit nerve impulses.

Glial Cells

Nonexcitable helper cells in nervous tissue that support, nourish, and protect neurons.

Mucous Membrane

A body membrane lining compartments open to the external environment, consisting of an epithelium and an underlying connective tissue layer called the lamina propria.

Serous Membrane

A body membrane lining closed internal cavities, composed of simple squamous mesothelium and areolar connective tissue that secretes serous fluid.

Synovial Membrane

A membrane lining joint cavities composed of specialized connective tissue that secretes fluid to lubricate moving bone ends.

Totipotent Stem Cells

Embryonic stem cells formed from the zygote that can differentiate into any cell type in the organism as well as placenta structures.

Pluripotent Stem Cells

Stem cells derived from the embryoblast of a blastocyst that can mature into any tissue cell within the body except the placenta.

Hypertrophy

An increase in the size of pre-existing cells within a tissue.

Hyperplasia

An increase in the total number of cells within a tissue.

Metaplasia

The structural transformation of a mature epithelium into another mature epithelial form in response to environmental stimuli.

Dysplasia

Abnormal, potentially precancerous tissue development characterized by altered cell structure.

Neoplasia

Uncontrolled tissue growth resulting in the formation of an abnormal mass or tumor called a neoplasm.

Necrosis

Irreversible tissue cell death resulting from severe damage and accompanied by an inflammatory response.

Stratum Basale

The deepest epidermal layer consisting of a single layer of cuboidal to low columnar cells including stem keratinocytes, melanocytes, and tactile cells.

Melanocytes

Pigment-producing cells in the stratum basale that synthesize melanin and transfer melanosomes to keratinocytes to protect DNA from UV rays.

Epidermal Dendritic Cells

Immune cells located in the stratum spinosum and granulosum (also called Langerhans cells) that initiate immune responses against pathogens.

Stratum Lucidum

A thin, translucent layer of 2 to 3 dead cell layers filled with eleidin protein, found exclusively in thick skin.

Stratum Corneum

The most superficial epidermal stratum, consisting of 20 to 30 layers of dead, anucleate, interlocking keratinized cells.

Papillary Layer

The superficial region of the dermis composed of areolar connective tissue with dermal papillae that interlock with epidermal ridges.

Reticular Layer

The deeper, thicker region of the dermis composed of dense irregular connective tissue surrounding blood vessels and hair follicles.

Lines of Cleavage

Predominant parallel alignments of collagen and elastic fiber bundles in the skin that resist movement stresses.

Subcutaneous Layer

A layer deep to the dermis (hypodermis) composed of areolar and adipose connective tissues that functions in energy storage, insulation, and cushioning.

Eponychium

The cuticle; a narrow band of epidermis extending from the margin of the nail wall onto the proximal edge of the nail body.

Hyponychium

A region of thickened stratum corneum underlying the free edge of a nail.

Lanugo

Fine, unpigmented, downy hair that appears on the fetus during the third trimester of development.

Vellus

Fine, lightly pigmented primary human hair covering most of the body surface.

Terminal Hair

Coarse, pigmented, longer hair found on the scalp, eyebrows, and eyelashes, which replaces vellus hair in axillary and pubic regions during puberty.

Hair Matrix

An active structure at the base of the hair bulb where epithelial cells divide to produce new hair cells.

Arrector Pili

Ribbons of smooth muscle extending from hair follicles to dermal papillae that contract to pull hair upright, causing goosebumps.

Sebaceous Glands

Holocrine exocrine glands that secrete oily sebum into hair follicles to lubricate skin and hair.

Ceruminous Glands

Modified apocrine sweat glands located in the external ear canal that produce waterproof earwax called cerumen.

Regeneration

The restoration of organ function by replacing damaged or dead cells with the exact same functional cell type.

Fibrosis

The repair process where damaged tissue is replaced by scar tissue composed of collagen produced by fibroblasts, without restoring functional activities.

Granulation Tissue

A vascularized connective tissue that temporarily fills a wound gap during the third stage of skin wound healing as blood vessels regrow.

Rule of Nines

A clinical estimation method used to calculate the proportion of total body surface area affected by burns.

Vernix Caseosa

A protective coating on fetal skin composed of sloughed periderm cells mixed with sebum.