MCB 244 Lecture Exam 2: Tissues and Integumentary System

Vocabulary practice flashcards based on MCB 244 lecture exam notes, focusing on epithelial tissue classes, connective tissue components, membrane varieties, and cellular adaptations.

Epithelial Tissue

A primary tissue class that covers body surfaces, lines organs and body cavities, contains very little extracellular matrix, and is richly innervated, highly regenerative, and avascular.

Polarity (Epithelial Tissue)

The structural cellular organization characteristic of epithelia exhibiting an attached basal border and a free apical border.

Organ

A structure composed of two or more ($2+$) tissue types working collaboratively to execute specific, shared physiological functions.

Simple Squamous Epithelium

A single layer of flattened cells directly attached to a basement membrane; provides minimal protection and is optimally suited for rapid diffusion and filtration, such as in lung alveoli.

Simple Cuboidal Epithelium

A single layer of cube-shaped cells forming the walls of kidney tubules, functioning in the resorption of water, ions, and nutrients filtered from blood plasma.

Stratified Columnar Epithelium

An epithelium composed of multiple cellular layers featuring tall, slender cells situated at the apical layer.

Pseudostratified Ciliated Columnar Epithelium

A seemingly stratified tissue that lines portions of the respiratory system and features cilia along its apical domain.

Transitional Epithelium

A specialized stratified epithelium that lines the urinary bladder and can accommodate stretching; some cells may be binucleated.

Keratinized Stratified Squamous Epithelium

A multi-layered tissue whose surface cells are dead and filled with keratin, forming the outer epidermis contacted when rubbing fingers together.

Nonkeratinized Stratified Squamous Epithelium

A durable lining tissue in which cells in the superficial layers remain alive; lines moist internal cavities including the oral cavity, pharynx, esophagus, and vagina.

Microvilli

Microscopic cytoplasmic folds extending from the apical surface of certain epithelia that increase surface area for absorption and secretion.

Goblet Cells

Unicellular glands found interspersed within epithelial tissues that synthesize and secrete mucin.

Mucus

A viscous protective substance formed when the glycoprotein mucin hydrates and mixes with water.

Exocrine Glands

Glands that discharge their secretory products through a duct onto an epithelial surface; anatomically composed of a duct and a secretory portion.

Endocrine Glands

Ductless glands that release chemical messengers called hormones directly into interstitial fluid or the bloodstream.

Merocrine Glands

Exocrine glands that package secretions into vesicles released via exocytosis without damaging the cell; responsible for saliva and eccrine sweat production.

Holocrine Gland

A type of exocrine gland in which entire cells disintegrate to release accumulated secretory products, exemplified by oily secretions of sebaceous glands.

Connective Tissue (CT)

The most widely distributed primary tissue class in the body, consisting of cells, protein fibers, and ground substance; includes blood, adipose tissue, cartilage, bone, ligaments, and tendons.

Extracellular Matrix (ECM)

The extracellular component of connective tissues consisting of a combination of protein fibers and non-cellular ground substance.

Mesenchyme

The earliest embryonic connective tissue derived from mesoderm, serving as the common precursor to all adult connective tissue varieties.

Mucous Connective Tissue

A specialized gelatinous embryonic connective tissue located exclusively within the umbilical cord.

Macrophage

A resident connective tissue proper cell derived from circulating monocytes that functions to phagocytize pathogens and cellular debris.

Fibroblasts

Abundant resident cells of connective tissue proper responsible for synthesizing and secreting protein fibers and ground substance.

Reticular Fibers

Thin, branched connective tissue protein fibers that form a delicate meshwork framework providing structural support within organs such as the spleen.

Glycosaminoglycans (GAGs)

Large, negatively charged polysaccharide molecules found as constituents of the ground substance in connective tissues.

Collagen

The body's most abundant structural protein, accounting for approximately $25\%$ of all body protein content.

Areolar Connective Tissue

A loose connective tissue located in the papillary layer of the dermis containing all standard cell types of connective tissue proper.

Dense Irregular Connective Tissue

A dense connective tissue with multidirectional collagen bundles that predominates in the deep reticular dermis to provide tensile skin strength.

Hyaline Cartilage

The most common cartilage type in the human body, characterized microscopically by its uniform, glassy appearance.

Fibrocartilage

A tough cartilage rich in collagen fibers that forms intervertebral discs and withstands severe compression forces.

Lacuna

A small anatomical space or cavity housing chondrocytes in cartilage or osteocytes in bone tissue.

Perichondrium

A dense connective tissue sheath covering and supporting the surface of cartilage.

Osteon

The functional cylindrical unit of compact bone comprising concentric rings of calcified matrix surrounding a neurovascular central canal.

Spongy Bone

Bone tissue characterized by an internal latticework structure that imparts strength while minimizing overall skeletal weight.

Hemopoietic Tissue

Specialized red bone marrow tissue situated within bone interiors responsible for producing blood cells.

Plasma

The fluid extracellular ground substance of blood containing suspended cells and dissolved proteins.

Mucous Membrane

A body membrane lining cavities opening directly to the exterior that traps foreign particles, prevents desiccation, and furnishes lubrication.

Cutaneous Membrane

The largest body membrane, commonly known as the skin, covering the exterior surface of the entire body.

Synovial Membrane

A joint-lining membrane consisting of areolar connective tissue capped by squamous epithelial cells that secretes fluid.

Visceral Layer (Serous Membrane)

The inner sheet of a serous membrane sac in immediate physical contact with the exterior surface of an enclosed organ, such as the heart.

Glial Cells

Supportive and protective cells of the nervous system that do not conduct nerve impulses.

Axon

The neuronal cell process dedicated to transmitting outgoing electrical signals away from the cell body.

Metaplasia

A reversible phenotypic conversion wherein one mature epithelial tissue type is substituted by another mature epithelial type.

Hyperplasia

An increase in tissue size resulting directly from an elevated number of constituent cells.

Neoplasia

Uncontrolled, abnormal cellular proliferation culminating in the growth of a tumor mass.

Atrophy

A reduction in tissue mass caused by a decrease in cell size or cell number.

Cardiac Muscle

Striated involuntary muscle characterized by branching cells that contain one or two centrally located nuclei.

Smooth Muscle

Non-striated, involuntary muscle consisting of spindle-shaped (fusiform) cells specialized to push substances through hollow internal organs.

Heterograft

A surgical graft or tissue transplantation performed between different biological species (such as animal-to-human).

Allograft

A tissue transplant procured from a non-genetically identical donor of the same species as the recipient.

Stratum Granulosum

The epidermal layer of stratified squamous epithelium in which the process of cell keratinization initiates.

Apocrine Sweat Glands

Exocrine glands releasing sweat through a mechanism where the apical cellular cytoplasm pinches off alongside the secretion.