HISTOLOGY-DVMP 735-Lecture 2

The lamina lucida is composed of laminin anchoring filaments.

The basal surface of epithelial tissue is adjacent to connective tissue.

Simple columnar epithelium consists of a single layer of tall, column-like cells. This type of epithelium is often found lining the digestive tract, where it functions in absorption and secretion.

Epithelial tissues regulate and facilitate the exchange of molecules between underlying tissues and other compartments.

Glands are secretory structures formed by certain epithelial cells.

The function of the epithelium is based on the specific role the epithelium plays in the body.

Simple epithelium is a single layer of cells.

Simple cuboidal epithelium consists of cubed cells that line excretory ducts.

Simple cuboidal epithelium is composed of a single layer of cube-shaped cells. This type of epithelium is typically found in glandular tissues and in the lining of the kidney tubules.

Epithelial tissue lacks blood supply, meaning blood vessels are absent in the layer.

Endothelium is a specialized epithelium that lines blood vessels.

Simple squamous epithelium consists of flat cells found in areas where passive diffusion of gases occurs, such as capillaries and alveoli. Mesothelium lines body cavities, and endothelium lines the cardiovascular system.

Simple squamous epithelium consists of a single layer of flat, scale-like cells that are tightly packed. This type of epithelium is found in areas where rapid diffusion or filtration is required, such as the alveoli of the lungs and the lining of blood vessels.

The four basic tissues found in all organs of the body are epithelial, connective, muscular, and nervous tissues.

Epithelial tissues secrete hormones into the bloodstream and produce sweat, mucus, enzymes, and other substances delivered through ducts.

The free surface of epithelial cells is adjacent to the space.

Simple squamous, columnar, or pseudostratified epithelium line surfaces that separate body cavities within the body.

Pseudostratified epithelium appears to be multilayered but is actually a single layer of cells with varying heights, giving the illusion of multiple layers.

Hepatocytes are epithelial cells that form solid tissues and make up the majority of the liver.

Stratified epithelium consists of multiple layers of cells.

Stratified keratinized squamous epithelium is a type of stratified squamous epithelium where the outermost layers of cells are dead and filled with keratin, a tough, protective protein. This type of epithelium is found in the skin, providing a barrier against environmental damage and water loss.

Glandular tissue is formed from glandular epithelium that forms structures from the infolding of epithelium and subsequent growth in the underlying connective tissue.

Exocrine glands secrete their products into a duct that then delivers the product to the lumen of an organ. Examples include the pancreas and salivary glands.

Cell junctions are the contact points between plasma membrane and tissue cells. They are especially abundant in epithelial tissues and are protein complexes that induce connectivity between adjacent epithelial cells, or between a cell and the extracellular matrix. They contribute to the barrier function of epithelia and control paracellular transport.

Membrane projections on a cell that serve to increase its surface area.

A cell modification that facilitates strong cell-to-cell adhesion.

Resident or migratory in connective tissue. Develops from monocyte and has an indented nucleus, lysosomes, and vacuoles. Phagocytic and synthesizes diverse factors.

A fibroblast has a spindle shape and produces the fibers and ground substance of connective tissue.

The two types of adipose tissue are white and brown fat.

The basement membrane serves as a substrate for the attachment, growth, and regeneration of epithelium after injuries.

The lamina fibrorectocularis is composed of fibrils and collagen.

Squamous cells are flattened cells.

Stratified epithelium is classified by the shape of the cells at the uppermost layer.

Mouth, esophagus, and rectum.

The surface of a cell that faces toward a lumen or an external environment.

Fibers and ground substance predominate over cells in connective tissue.

Connective tissue provides support and structural framework for the animal's body.

Fibers of connective tissue proper are collagen, reticular fibers, elastic fibers, and adhesive proteins.

The lamina densa contains Type IV collagen.

Sheets of epithelial cells may be modified into tubes forming glands.

Epithelium covers both the external surface (skin) and internal cavities of the body.

Pseudostratified epithelium appears to be stratified because the nuclei are at different levels, but it is actually a single layer of cells. This type of epithelium is commonly found in the respiratory tract, where it helps trap and move particles out of the airways.

The three principal shapes associated with epithelial cells are squamous, cuboidal, and columnar.

Lining epithelium covers the free surfaces of the body and cavities, regulating the composition of the body by controlling the movement of materials in and out.

Mesothelium.

Seromucous (mixed) secretions are produced by glands that have both serous and mucus-producing cells.

Cilia are projections and a type of organelle seen on the apical surface of epithelial cells. They are motile and beat in a coordinated fashion, assisting in the movement of materials over the epithelial surface.

They are attached to the microfilaments of cytoskeleton made up of keratin protein.

A cellular organelle and modification characterized by membrane projections that can move.

A mesenchymal cell is an undifferentiated precursor cell capable of developing into one of several different cells. It is smaller than a fibroblast and has a euchromatic nucleus.

White adipose cells are specialized in the storage of triglycerides.

Ground substance which fills in between the fibers includes glycosaminoglycans and proteoglycans.

All epithelial tissue is supported by a basement membrane.

Simple columnar epithelium consists of tall and narrow cells that line the intestine, stomach, and other organs.

Stratified cuboidal epithelium is limited to two cell (cuboidal) layers and found in large excretory ducts.

Cuboidal epithelium is composed of cells whose height and width are approximately the same (cube shaped).

Unicellular glands are single cells that secrete their product directly from the cell. Their product may affect adjacent cells (paracrine signaling) or transport away from the secretory cell. An example is the Goblet cell, which is scattered between other epithelial cells.

Simple squamous, columnar, and pseudostratified epithelial cells.

Collagen fibers are inelastic but have great tensile strength, allowing them to be bent without breaking.

Unilocular adipose cells have one large lipid droplet and the nucleus is at the periphery of the cell.

Type V collagen is found in placental basal laminae, tendon, and muscle sheaths.

Elastic fibers are stretchable because they are normally disorganized.

Reticular fibers are coated with proteoglycans and glycoproteins.

Nonkeratinized stratified squamous epithelium lines areas like the oral cavity, esophagus, and rectum.

Surface modifications in epithelial tissue include cilia and microvilli, which are present depending on the tissue’s functional requirements.

Pseudostratified epithelium appears multilayered due to varying nuclear positions, but all cells contact the basement membrane.

Cuboidal cells are cube-shaped cells.

Columnar cells are tall, column-like cells.

Pseudostratified epithelium resembles columnar epithelium but has nuclei at different levels within the cells. It is largely located in the respiratory airways of the nasal cavity, trachea, and bronchi.

Merocrine secretion is the exocytosis of secretory vesicles to the lumen of the gland.

Alveolar secretory units have larger lumens.

They are transmembrane proteins fused on outer plasma membrane.

A specialized type of stratified epithelium that can stretch, lining most of the urinary tract.

Protecting the underlying tissues from injury, including desiccation, pathogen invasion, and physical trauma.

The three layers of the basement membrane are: Lamina lucida (laminin anchoring filaments), Lamina densa (Type IV collagen), and Lamina fibrorectocularis (Fibrils/collagen).

Epithelial tissues are innervated but lack a blood supply.

The cells in epithelial tissue are apposed to each other very closely.

Keratinized stratified squamous epithelium protects against abrasion and water loss.

Mesothelium is a specialized epithelium that covers the pericardium, pleura, and peritoneum.

Simple epithelium is a single layer of cells, each directly in contact with the basement membrane. It is involved in absorption, filtration, and protection.

Stratified epithelium consists of two or more cell layers (multilayered). It is found where body linings have to withstand mechanical or chemical insult.

It is described as keratinized, commonly found in the skin.

Stratified epithelium has multiple cell layers, with only the basal layer of the cell in contact with the underlying basement membrane.

Urothelium, formerly called transitional epithelium, is a unique type of epithelium in which cells can change from squamous to cuboidal, depending on the amount of tension on the epithelium.

Epithelium that forms glands through the process of invagination.

Endocrine glands secrete their product into the extracellular space where it is rapidly taken up by the blood vascular system and transported to target cells. They have no duct system (e.g., Thyroid gland).

They connect the cytoplasm of two cells and allow for the passage of molecules freely between cells.

They attach the epithelial cell to the basement membrane rather than to an adjacent cell.

Connective tissue is a type of tissue that provides support, binds together, and protects tissues and organs of the body.

A layer of dead cells filled with keratin, forming a protective barrier over living cells, typically seen in stratified squamous epithelium.

Produces and store granules of heparin, histamine, and other factors. Granules often obscure the nucleus, and they are metachromatic when stained with toluidine blue.

Type II collagen is found in hyaline and elastic cartilage and in the vitreous body of the eye.

Ground substance is an aqueous gel of glycoproteins and proteoglycans that occupies the space between cellular and fiber elements of the connective tissue. It has a gel-like consistency and determines the permeability of the connective tissue to proteins and solutes.

Columnar epithelium is composed of cells taller than they are wide (columns).

Multicellular glands have multiple secretory cells. They contain functional cells called Parenchyma and supporting connective tissue called Stroma. Examples include small sweat glands and large pancreas.

Holocrine secretion involves the death of an entire cell within a gland, which subsequently sloughs off and releases its content into the lumen of the gland.

An arrangement of epithelial cells in a single layer.

A cell modification that anchors a cell to the extracellular matrix.

Collagen fibers impart both strength and flexibility to tissue.

Cells include fibroblasts, fibrocytes, mesenchymal cells, mast cells, plasma cells, macrophages, adipose cells, pigment cells, reticular cells, and pericytes.

Pigment cells contain various pigments like melanin.

Reticular fibers are composed of type III collagen.

Stratified cuboidal epithelium is a type of epithelial tissue consisting of multiple layers of cube-shaped cells. It is typically found in the ducts of sweat glands, mammary glands, and salivary glands, providing protection and secretion.

1. They line the internal and external body surfaces (lining epithelia). 2. They form secretory structures (glandular epithelium).

Endothelium.

Mucous secretions are viscous and rich in carbohydrates. Glands that produce mucous secretions have light staining cytoplasm due to the accumulation of mucus.

The major types of cell junctions are tight junctions, gap junctions, desmosomes, and hemidesmosomes.

A form of columnar epithelium where the nuclei are positioned at various levels within the cell layer.

When not active, a fibroblast is referred to as a fibrocyte.

Collagen fibers are the predominant fiber of the connective tissue matrix.

Collagen fibers stain pink under H&E stain.

Dense, regular, elastic tissue is an important component in many ligaments and tendons.

Hyaline cartilage has a matrix composed of type II collagen and chondromucoprotein, a copolymer of chondroitin sulfates A and C with protein. Its high concentration of negatively charged sulfate groups makes it appear intensely basophilic under H&E staining. This type of cartilage makes up the articular surface in joints.

Dense irregular connective tissue is composed of haphazardly arranged densely packed collagen bundles.

In organs such as the mammary gland, lung, stomach, colon, pancreas, prostate, and uterus.

Apocrine secretion is the release of budding vesicles off the epithelial cells into the lumen of the gland.

The exocrine duct system is lined with epithelium that ranges in height from low simple cuboidal (secretory cells) to stratified columnar epithelia (large ducts).

Pericytes surround blood vessels and regulate their diameter.

Reticular fibers are produced by fibroblast and reticular cells.

Reticular fibers attract silver stains.

Stratified columnar epithelium is confined to large ducts and regions of the urethra (columnar cells).

Stratified squamous epithelium is a type of epithelial tissue composed of multiple layers of cells, with the outermost layer being flat and scale-like. It provides protection against abrasion, pathogens, and chemical attack.

Serous secretions have a watery consistency and are rich in proteins. Glands that produce serous secretions have basophilic cytoplasm due to high numbers of glandular endoplasmic reticulum.

The exocrine duct system is divided into simple (unbranched) and compound (branched) ducts.

A structural protein and intermediate filament that imparts toughness and protection to certain epithelial cells, notably in cornified or keratinized epithelium.

An arrangement of epithelial cells in multiple layers.

A type of simple squamous epithelium that lines the interior surfaces of vascular structures.

Spherical with eccentric heterochromatic nucleus. Has well-developed granular reticulum in the cytoplasm. Highly differentiated B lymphocytes which produce immunoglobulins.

Connective tissue provides support and structure for the body, and it participates in thermal regulation, defense and repair processes.

Collagen molecules are assembled into fibrils outside the fibroblast where they are produced.

Brown adipose cells are involved in temperature regulation.

Connective tissue can be classified as loose, dense irregular, and dense regular connective tissue.

Elastic fibers are often organized into lamellar (parallel) sheets in the walls of arteries.

Elastic fibers stain orange under H & E stain.

Fibronectin mediates the connection between the cytoskeleton and the extracellular matrix.

Cartilage is a specialized form of connective tissue produced by differentiated fibroblast-like cells called chondrocytes. It is characterized by a prominent extracellular matrix consisting of various proportions of connective tissue fibers embedded in a gel-like matrix.

Squamous epithelium is composed of cells that are flat and wide.

Tubular secretory units have epithelium arranged in a cylindrical form with a narrow central lumen.

The surfaces of a cell that are oriented away from a lumen or external environment.

A cell modification responsible for strong cell-to-cell adhesion, providing resistance to shearing forces within the epithelial layer.

Reticular cells form the supportive framework in lymphoid organs and bone marrow.

Type III collagen is found in reticular fibers, healing wounds, smooth muscle, and fetal skin.

Fibrocartilage is distinguished by its high content and orderly arrangement of type I collagen fibers. It is typically located in regions where tendons attach to bones, the intervertebral discs, and the symphysis between certain bones.

Stratified columnar epithelium is a type of epithelial tissue made up of multiple layers of cells, with the topmost layer being columnar in shape. It is found in parts of the pharynx, male urethra, and some glandular ducts, and it functions in protection and secretion.

Glandular epithelium is an invagination of epithelium that forms a solid tissue structure.

Microvilli are structures found in organs where epithelium plays a primary role in absorption. They increase the surface area without increasing the size of the cell and are often supported by an actin microfilament network. Individual microvilli are very difficult to resolve with a light microscope.

Acinar secretory units have epithelium that forms a sac-like structure with a small lumen.

A fundamental tissue type that generally lines surfaces, such as cavities, lumens, or external surfaces, or forms glands. The plural form is epithelia, and the adjective form is epithelial.

Multilocular adipose cells contain several lipid droplets.

Type I collagen is the most common type, found in every connective tissue.

Chondrocytes are differentiated fibroblast-like cells that produce cartilage.

Loose irregular connective tissue is composed of haphazardly arranged loosely compacted collagen bundles.

Type IV collagen is found in the basal laminae of epithelia.

Elastic fibers are composed primarily of the protein elastin.

Reticular fibers form supporting frameworks in the liver, lymphoid organs, capillary endothelia, and muscle fibers.

Elastic cartilage is characterized by the presence of abundant elastic fibers and is quite cellular. It is made up of type II collagen and is located in the pinna of the ear, the turbinates of the nose, and the epiglottis.

Reticular fibers form a thin reticular network.

Dense regular connective tissue is composed of tightly bundled collagen fibers running in one direction.

Embryonic connective tissue is a very fragile connective tissue composed of thin strands of collagen fibers that contains a large amount of interstitial water content.