CH04

Tissue

A group of cells working together to perform a specific bodily function.

Histology

The microscopic study of tissue appearance, organization, and function.

Epithelial Tissue

Tissue that covers exposed surfaces, lines internal passageways, and forms glands.

Connective Tissue

Tissue that fills internal spaces, provides support, and stores energy.

Muscle Tissue

Tissue specialized for contraction and movement.

Nervous Tissue

Tissue that conducts electrical impulses and responds to stimuli.

Totipotent Cells

Embryonic cells capable of differentiating into any cell type.

Ectoderm

Germ layer that forms the epidermis and nervous system.

Mesoderm

Germ layer that forms skeletal, muscular, and circulatory systems.

Endoderm

Germ layer that forms digestive and respiratory tract linings and associated organs.

Mucous Membrane

Membrane lining body cavities that open to the exterior; secretes mucus.

Lamina Propria

Connective tissue layer supporting mucous membranes.

Serous Membrane

Membrane lining ventral body cavities that secretes serous fluid.

Pleura

Serous membrane surrounding the lungs.

Pericardium

Serous membrane surrounding the heart.

Peritoneum

Serous membrane lining the abdominal cavity.

Mesentery

Double sheet of peritoneum that suspends digestive organs.

Cutaneous Membrane

The skin; a dry membrane covering the body's exterior.

Synovial Membrane

Membrane lining movable joint cavities that secretes synovial fluid.

Differentiation

Process by which unspecialized cells become specialized.

Cell Junctions

Specialized connections between epithelial cells.

Tight Junction

Cell junction preventing passage of substances between cells.

Desmosome

Anchoring junction that resists stretching and twisting.

Hemidesmosome

Junction attaching epithelial cells to the basement membrane.

Adhesion Belt

Junction strengthening the apical region of epithelial cells.

Gap Junction

Cell junction allowing communication between adjacent cells.

Basement Membrane

Noncellular layer anchoring epithelial tissue to underlying tissue.

Apical Surface

Free surface of epithelial tissue facing the lumen or exterior.

Basal Surface

Surface attached to the basement membrane.

Avascular

Lacking blood vessels.

Cilia

Hair-like structures that move substances across cell surfaces.

Regeneration

Replacement of damaged cells through cell division.

Simple Epithelium

Epithelium consisting of one layer of cells.

Stratified Epithelium

Epithelium with multiple layers of cells.

Pseudostratified Epithelium

Single layer of cells appearing multilayered.

Squamous Cells

Thin, flat epithelial cells.

Cuboidal Cells

Cube-shaped epithelial cells.

Columnar Cells

Tall, rectangular epithelial cells.

Simple Squamous Epithelium

Single layer of flat cells specialized for diffusion and filtration.

Endothelium

Simple squamous epithelium lining blood vessels and the heart.

Mesothelium

Simple squamous epithelium lining serous membranes.

Stratified Squamous Epithelium

Protective epithelium found in areas subject to abrasion.

Keratinized Stratified Squamous Epithelium

Epithelium forming the epidermis of the skin.

Nonkeratinized Stratified Squamous Epithelium

Epithelium lining the mouth and vagina.

Simple Cuboidal Epithelium

Epithelium specialized for secretion and absorption.

Simple Columnar Epithelium

Epithelium specialized for absorption and secretion.

Goblet Cell

Mucus-secreting unicellular exocrine gland.

Stratified Cuboidal Epithelium

Rare epithelium found in ducts of glands.

Stratified Columnar Epithelium

Protective epithelium found in the urethra and some ducts.

Pseudostratified Ciliated Columnar Epithelium

Respiratory epithelium that moves mucus.

Transitional Epithelium

Stretchable epithelium lining the bladder and urethra.

Endocrine Gland

Gland that secretes hormones into the bloodstream.

Exocrine Gland

Gland that secretes through ducts onto body surfaces.

Merocrine Secretion

Secretion by exocytosis.

Apocrine Secretion

Secretion involving loss of the apical portion of the cell.

Holocrine Secretion

Secretion involving destruction of the entire cell.

Serous Gland

Gland producing watery, enzyme-rich secretions.

Mucous Gland

Gland producing mucin-rich secretions.

Mixed Exocrine Gland

Gland producing both serous and mucous secretions.

Sebaceous Gland

Oil gland producing sebum.

Connective Tissue

Most abundant tissue in the body that supports and protects structures.

Mesenchyme

Embryonic connective tissue derived from mesoderm.

Matrix

Combination of ground substance and protein fibers.

Ground Substance

Material filling spaces between connective tissue cells.

Fibroblast

Cell producing connective tissue fibers and ground substance.

Fibrocyte

Cell maintaining connective tissue fibers.

Adipocyte

Fat-storing connective tissue cell.

Mesenchymal Cell

Multipotent stem cell of connective tissue.

Collagen Fiber

Strong fiber resistant to stretching.

Elastic Fiber

Fiber capable of stretching and recoiling.

Reticular Fiber

Fiber forming supportive networks in tissues.

Areolar Tissue

Loose connective tissue acting as packing material.

Adipose Tissue

Loose connective tissue specialized for fat storage.

Reticular Tissue

Loose connective tissue forming supportive frameworks.

Dense Regular Connective Tissue

Tissue with parallel collagen fibers found in tendons and ligaments.

Dense Irregular Connective Tissue

Tissue with irregular collagen fibers providing multidirectional strength.

Elastic Connective Tissue

Dense tissue rich in elastic fibers.

Blood

Fluid connective tissue transporting gases and nutrients.

Plasma

Liquid matrix of blood.

Erythrocyte

Red blood cell that transports oxygen.

Leukocyte

White blood cell involved in immunity.

Platelet

Blood component involved in clotting.

Lymph

Fluid connective tissue of the lymphatic system.

Cartilage

Supportive connective tissue with chondrocytes in lacunae.

Chondrocyte

Cartilage cell located in lacunae.

Lacuna

Small cavity housing cartilage or bone cells.

Perichondrium

Connective tissue covering surrounding cartilage.

Hyaline Cartilage

Cartilage providing support and reducing friction.

Fibrocartilage

Strong cartilage resisting compression.

Elastic Cartilage

Flexible cartilage found in the ear and epiglottis.