Histology of Epithelia and Tissues

A group of cells with a common embryonic origin that work together to perform specialized functions.

Covers body surfaces, lines hollow organs, body cavities, ducts, and forms glands.

Protects, supports, and binds organs. It stores energy as fat, provides immunity, and more.

Generates the physical force needed to move body structures and produce body heat.

Detects changes in the body and responds by generating nerve impulses.

The process during embryonic development where the three primary germ layers (ectoderm, mesoderm, and endoderm) are formed.

A group of cells with a common embryonic origin that work together to perform specialized functions.

The study of tissues.

Web-like strands of transmembrane proteins that fuse cells together, forming a seal and preventing leakage between cells. They are commonly found in epithelial tissues of the stomach, intestines, and urinary bladder.

A dense layer of proteins called plaque that resists cell separation during contraction or stretching.

Specialized cell junctions containing plaque and cadherins, linking adjacent cells and attaching to intermediate filaments.

Resemble half a desmosome, anchoring cells to the basement membrane via transmembrane glycoprotein integrin.

Connections between cells, allowing direct communication through fluid-filled tunnels called connexons. These help exchange ions, nutrients, waste, and signals between cells.

The free surface of epithelial cells, facing the body surface, cavity, or lumen.

The surface of epithelial cells that faces adjacent cells.

The bottom surface of epithelial cells, attaching to the basement membrane.

A thin double layer that supports and anchors epithelial tissue. It has two components: the basal lamina and the reticular lamina.

A single layer of cells that allows for rapid diffusion, osmosis, filtration, secretion, or absorption.

A type of epithelium that appears to have multiple layers due to the arrangement of cell nuclei at different levels, but all cells attach to the basement membrane.

Two or more layers of cells that protect underlying tissues in areas of wear and tear.

A type of epithelium with cells that are thin and arranged like floor tiles, allowing for rapid passage of substances.

A type of epithelium with cells that are as tall as they are wide, resembling cubes or hexagons. They often have microvilli, and their main functions are secretion and absorption.

A type of epithelium with cells that are much taller than they are wide, resembling columns. They may have cilia or microvilli, and their main functions are secretion and absorption.

A type of epithelium with cells that change shape, transitioning from flat to cuboidal, allowing organs such as the urinary bladder to stretch and collapse.

A type of simple squamous epithelium that lines the heart, blood vessels, and lymphatic vessels.

A type of simple squamous epithelium that forms the epithelial layer of serous membranes, such as the pericardium, pleura, and peritoneum.

A type of simple columnar epithelium that contains columnar cells with microvilli at their apical surface and goblet cells, which secrete mucus.

Secretory cells that release products surrounded by a portion of their cytoplasm and plasma membrane.

Cells accumulate secretory products, then undergo apoptosis, releasing both products and cell debris into the gland lumen.

Single secretory cells scattered among other non-secretory cells.

Glands composed of multiple cells that work together to secrete products.

Glands with unbranched ducts.

Glands with branched ducts.

Glands with secretory portions shaped like a tube.

Glands with secretory portions shaped like a flask or sac.

A type of epithelium that appears to have multiple layers due to nuclei at various depths, but all cells are attached to the basement membrane in a single layer. It contains ciliated cells that secrete mucus and bear cilia, and nonciliated cells that lack cilia and include goblet cells.

A type of stratified epithelium where the apical layer cells are flat. New cells are pushed up towards the apical layer, and as they move further from the blood supply they dehydrate, harden, and die. This epithelium can be keratinized (contains keratin, found in skin) or nonkeratinized (no keratin, found in mouth and esophagus).

A relatively rare type of epithelium with cuboidal cells in the apical layer. Functions in protection.

Another uncommon type of epithelium with only columnar cells in the apical layer. Basal layers have short, irregular shaped cells. Functions in protection and secretion.

Glands that release their products onto a body surface directly or through epithelial ducts connected to the surface. They secrete substances, and the ducts may or may not modify the secretion by absorbing or secreting substances.

Glands that lack a duct and secrete their products into the circulation, where they function as hormones.

Cells located in the deep epidermis that contact the tactile disc of sensory neurons, responsible for the sensation of touch.

The deepest layer of the epidermis, composed of cuboidal or columnar cells responsible for regeneration through mitosis. It contains melanocytes and Langerhans cells.

The layer above the stratum basale, characterized by polyhedral keratinocytes that become flattened. It has a spine-like appearance due to the attachment of intermediate filaments to desmosomes.

The middle layer of the epidermis, composed of flattened keratinocytes undergoing apoptosis. Contains keratohyalin granules and lamellar granules that secrete lipids between cell layers.

A thin layer found only in thick skin of palms and soles, located between the stratum corneum and stratum granulosum. It contains dying keratinocytes with a lot of keratin.

The outermost layer of the epidermis composed of dead, flat keratinocytes filled with keratin. These cells are continuously shed and replaced by cells from the deeper layers.

The deeper layer of the dermis, composed of dense, irregular collagen and elastic fibers, fibroblasts, blood vessels, and nerves. It also houses sweat and sebaceous glands.

The most common type of skin cancer, appearing as a shiny pearly nodule. It often develops on sun-exposed areas of the body.