Chapter 5: Tissues Lecture Notes

Flashcards covering the classification, characteristics, and locations of epithelial, connective, muscle, and nervous tissues based on the Chapter 5 anatomy lecture.

Tissue

A composition of similar cells that are specialized to perform a common function or functions.

Histology

The study of tissues.

Tight junctions

Zipper-like junctions that prevent extracellular leakage; found in the lining cells of the small intestine, kidney tubules, and the blood-brain barrier.

Desmosomes

Junctions that hold adjacent cells, and therefore the layer of cells, together; found in cells of the outer skin layer.

Gap junctions

Channels between cells for the passage of substances and impulses; found in cardiac muscle cells and digestive smooth muscle cells.

Epithelial tissues

One of the four primary tissue types characterized by covering and lining body surfaces and organs.

Apical surface

The free surface of epithelial tissues which opens to the outside or to an internal space called a lumen.

Basement membrane

A distinct membrane that anchors the basal surface of epithelial tissues to underlying connective tissue.

Avascularity

A general characteristic of epithelial tissues meaning they contain no blood vessels.

Basal surface

The surface of epithelial tissues anchored to the basement membrane.

Simple epithelium

An epithelial tissue composed of a single layer of cells.

Stratified epithelium

An epithelial tissue composed of many layers of cells.

Squamous cells

Epithelial cells characterized by a flattened shape.

Cuboidal cells

Epithelial cells characterized by a square shape.

Columnar cells

Epithelial cells characterized as being elongated and taller than they are wide.

Simple Squamous Epithelium

A single layer of flattened cells used for diffusion and cushioning; located in the lining of air sacs, capillaries, and body cavities.

Simple Cuboidal Epithelium

A single layer of square-shaped cells with large centrally located nuclei used for secretion and absorption; located in kidney tubules and gland ducts.

Simple Columnar Epithelium

A single layer of elongated cells with basally located nuclei used for protection, absorption, and secretion; located in the small intestine and uterus.

Goblet cells

Specialized cells that secrete protective mucus, found in simple columnar and pseudostratified columnar epithelia.

Pseudostratified Columnar Epithelium

A single layer of elongated cells with scattered nuclei that appears stratified; often possesses cilia and goblet cells to trap debris in the trachea.

Stratified Squamous Epithelium

Many layers of flattened cells used for protection; found in the epidermis (keratinized) and linings of the mouth, throat, vagina, and anus (non-keratinized).

Transitional Epithelium

Several layers of cells that change shape in response to tension to allow distensibility; found lining the urinary bladder and ureters.

Exocrine glands

Glands that secrete products into a duct which opens onto an external surface (e.g., sweat glands) or an internal space (e.g., gastric glands).

Endocrine glands

Ductless glands that secrete hormones directly into the blood.

Merocrine glands

Exocrine glands that secrete fluid through cell membranes with no loss of glandular cells, such as salivary glands.

Apocrine glands

Exocrine glands that lose a small portion of their cell bodies during secretion, such as mammary glands.

Holocrine glands

Exocrine glands that release entire cells into the secretion, such as sebaceous glands in the skin.

Carcinoma

A tumor or cancer originating from epithelial tissue.

Mesenchyme

The common embryonic origin for all connective tissues, derived from the middle germ layer called mesoderm.

Ground substance

An amorphous matrix filling the space between cells and fibers that functions as a molecular sieve for nutrient and gas diffusion.

Fibroblasts

Fixed, undifferentiated blast cells in connective tissue proper that secrete the matrix.

Mast cells

Cells that secrete heparin to prevent blood clotting and histamine to promote inflammation.

Collagen fibers

Fibers composed of collagen protein providing high tensile strength; they stain pink and are abundant in tendons and ligaments.

Elastic fibers

Fibers composed of elastin protein providing rubbery resiliency; they stain purple and are found in the skin, lungs, and blood vessels.

Reticular fibers

Fine collagenous fibers that form delicate networks in basement membranes and lymphatic tissues.

Areolar CT

A connective tissue proper with a gel-like matrix used for nourishment, cushioning organs, and lubrication; located beneath epithelia.

Adipose Tissue

A connective tissue consisting of specialized adipocytes used for energy storage, insulation, and protection; located beneath the skin and around organs.

Dense Regular CT

A connective tissue composed primarily of collagen fibers providing attachment and high tensile strength; located in tendons and ligaments.

Hyaline cartilage

The most common type of cartilage containing chondrocytes in lacunae within an amorphous matrix; located in the embryonic skeleton and the tip of the nose.

Fibrocartilage

A tough cartilage containing collagen fibers used for tensile strength and shock absorption; located in intervertebral discs and the pubic symphysis.

Bone

A specialized connective tissue with a hard, calcified matrix composed of hydroxyapatite crystals, or $[Ca_3(PO_4)_2 \cdot (OH)_2]$, and osteocytes.

Hematopoiesis

The process of blood cell formation, which is a function of bone tissue.

Lamellae

Concentric circles of compact bone tissue.

Serous membranes

Epithelial membranes lining closed ventral body cavities that secrete thin watery fluid for lubrication; includes the pleura, pericardium, and peritoneum.

Mucous membranes

Epithelial membranes lining body cavities that open to the outside, such as the digestive and respiratory tracts.

Cutaneous membrane

The skin, consisting of keratinized stratified squamous ET attached to a thick layer of dense irregular CT.

Skeletal Muscle Tissue

Voluntary muscle tissue characterized by long, thin fibers with many nuclei and striations; attached to bones.

Smooth Muscle Tissue

Involuntary muscle tissue characterized by spindle-shaped cells with one central nucleus and no striations; located in the walls of hollow organs.

Cardiac Muscle Tissue

Involuntary muscle tissue characterized by a network of branching striated cells with intercalated discs and one central nucleus; located in the heart.

Neurons

The primary cells of nervous tissue that respond to stimuli and transmit signals; they cannot reproduce.

Neuroglia

Supporting cells in nervous tissue that surround neurons and are capable of cell division.