Flattened, plate-like cells that allow rapid diffusion; found lining capillaries and blood vessels.
The presence of microvilli, cilia, or the protein keratin.
Endothelium
Increases surface area for absorption
They provide strong attachment between cells, particularly in tissues subject to abrasion and physical stress, such as skin and heart muscle.
An epithelium with two or more layers of cells.
They have a centrally located nucleus and abundant but extremely thin cytoplasm.
Atherosclerosis is an arterial disease caused by the loss of proper endothelial function, common in patients with diabetes, hypertension, or other chronic conditions.
Goblet cells secrete mucus.
Cilia are microscopic projections of the apical cell membrane found lining parts of the respiratory tract and the uterine tubes in females.
Common cold viruses, chemicals in tobacco smoke, barbiturates, old age, and cold air.
Organs combine to function within a particular system.
A brush border is formed by abundant microvilli and is visible under a light microscope.
Epithelia are classified based on the number of cell layers and the shape of the cells on the surface.
Goblet cells secrete mucus to trap particles in inspired air and moisten the surface of the respiratory tract.
Stratified squamous epithelium consists of multiple layers of cells with the top layer being flat, providing protection against abrasion.
An epithelium with a single layer of cells.
Squamous, cuboidal, and columnar.
Cells that are 2-3 times taller than they are wide, often involved in active transport or secretion.
Toxic substances like nicotine open up intercellular junctions, allowing large molecules to pass through the vessel wall, leading to degenerative changes and vascular disease.
The synchronous movement of cilia.
Connective tissue consists of cells, fibers, and extracellular matrix. It is a very diverse group of tissues.
Microvilli increase the surface area for absorption, especially in sites like the small intestine and proximal convoluted tubule of the kidney.
Epithelial tissue is polarized with a free, or apical surface, exposed to the outside, and an attached or basal surface, resting on the underlying basement membrane.
Simple squamous epithelium is a single layer of flat cells that allows for easy diffusion and filtration.
Stratified cuboidal and columnar epithelia consist of multiple layers of cube-shaped or column-shaped cells, respectively, and are involved in protection and secretion.
To increase the surface area.
Pseudostratified columnar epithelium
Small intestine
They prevent the passage of molecules and ions through the space between cells and block the movement of integral cell membrane proteins between the apical and basolateral surfaces.
It is composed of a single layer of flattened, plate-like cells with a central nucleus, often referred to as 'pavemented epithelium' due to its appearance.
Cells are approximately twice as tall as they are wide; functions in secretion and absorption, found in the GI tract.
At sites where rapid diffusion of gas or fluid is necessary, such as alveoli of the lungs, or where a friction-free surface is required, such as walls of blood vessels.
Has two or more layers with the apical layer being cuboidal; changes shape as the epithelium is stretched, found lining the bladder.
The meninges become disrupted and the BBB is breached, allowing antibiotics to penetrate more easily.
Epithelial tissue, connective tissue, nervous tissue, and muscle tissue.
Goblet cells are modified columnar cells that are abundant in the gastrointestinal and respiratory tracts.
It appears to be composed of multiple layers but is actually a single layer with all cells making contact with the basement membrane.
They are mitotically active and replace the cells lost by 'wear and tear'.
To increase the surface area for absorption.
A change from pseudostratified columnar to stratified squamous epithelium.
Microvilli
The number of layers of cells, the shape of the cells lining the apical/luminal surface, and specializations of the cell surface.
Flat, scale-like cells that allow rapid diffusion but are fragile.
Has two or more layers with the apical layer being flattened and plate-like; provides protection, found in the esophagus and epidermis.
Mesothelium provides a friction-free surface by secreting a watery fluid, facilitating movement of organs within a cavity.
Endothelial cells control the passage of substances in and out of the bloodstream, assist in forming the basement membrane, control blood pressure, assist in blood coagulation, secrete factors to break down blood clots, and are involved in angiogenesis.
Pseudostratified columnar epithelium.
Muscle tissue contracts to perform movements such as skeletal muscle movements, propulsion in the GI tract, and pumping blood in the heart.
Epithelial tissue is composed of one or more layers of cells with very little intercellular space.
Epithelial tissues function in protection, absorption, secretion, and sensation.
It is composed of two or more layers of cells.
It is composed of two or more layers of cells with the apical layer being squamous cells.
Protection of underlying tissues from abrasion by the swallowed bolus of food.
Transitional epithelium.
Carcinoma
They have tiny pores that allow the passage of small molecules between adjacent cells, enabling cells to respond to stimuli as a unit.
An epithelium that appears to have several layers of cells but actually has only one layer, with all cells making contact with the basement membrane.
Cells that are approximately as wide as they are tall.
They form an almost impermeable barrier, such as in the blood-brain barrier.
Has two or more layers with the apical layer being columnar; found in the male urethra.
Mesothelioma is a cancer of the mesothelium where cells become abnormal and divide without control, often linked to asbestos exposure.
Increased goblet cells and mucus production occur in cystic fibrosis, asthma, and COPD.
Epithelial tissue covers and lines surfaces and cavities of the body (inside and out).
Up to 3000 microvilli per cell.
Epithelial cells are cells that line the surfaces of the body, including skin, blood vessels, organs, and cavities.
Simple cuboidal epithelium consists of a single layer of cube-shaped cells that function in secretion and absorption.
Flattened form with flattened nuclei.
They completely encircle each cell, providing stability by binding the cells together and linking the cytoskeletons of neighboring cells.
They appear as flattened, plate-like cells with a central nucleus, and their nuclei are sausage-shaped in longitudinal sections and round in transverse sections.
They are activated by cytokines and express cell adhesion molecules for neutrophils.
They lose attachment to each other and retract, allowing fluid and proteins to diffuse out into the local tissues causing tissue swelling termed oedema.
In endocrine glands and the kidney.
Found in salivary glands and sweat glands; has two or more layers with the apical layer being cuboidal.
Endothelium is the simple squamous epithelium that lines the luminal surface of blood vessels, lymphatics, and the heart.
Mucus traps and eliminates microorganisms, dust, and other particles, protects cells from desiccation, and moistens inhaled air.
Extracellular stimuli such as irritants in the intestine, dust, and smoke.
A group of similar cells forms a tissue.
The basement membrane is a thin sheet composed of collagen and glycoprotein, produced partly by epithelial cells and partly by underlying connective tissue cells.
The apical portion is goblet-shaped due to being filled with mucigen granules, while the basal portion contains the nucleus and other organelles.
Simple columnar epithelium is a single layer of tall, column-like cells that function in absorption and secretion.
Pseudostratified columnar ciliated epithelium appears to be stratified but is actually a single layer of cells with cilia, involved in secretion and movement of mucus.
By the type of cells present on the apical surface of the tissue.
Pathology related to the replacement of epithelial tissue involves conditions where the normal epithelial cells are replaced by abnormal cells, leading to diseases.
In the small intestine (high absorption), stomach (high secretion), and gall bladder (high absorption).
Simple columnar epithelium.
A change from oesophageal stratified squamous to gastric or intestinal simple columnar epithelium after repeated acid reflux.
The tumour cells do not cross the basement membrane.
Found in the liver and kidneys; functions in secretion and absorption.
Appears to have two layers due to varying cell heights but is actually a single layer; found in the respiratory epithelium lining the conducting part of the airway.
Mesothelium is the simple squamous epithelium that lines the body cavities and is derived from embryonic mesoderm.
By hypertension, hyperosmolitity, exposure to microwaves, radiation, infectious agents, brain trauma, ischemia, inflammation, increased skull pressure, hypercholesterolaemia, diabetes, or if not fully formed at birth.
Nervous tissue carries information in the form of impulses throughout the body.
Various tissues form an organ.
Epithelial tissue is formed from an uninterrupted layer of cells, covers all external and internal body surfaces, and forms boundaries between body compartments.
Goblet cells secrete mucus to moisten and protect the epithelial surfaces.
Mesothelium lines body cavities, while endothelium lines blood vessels and the heart.
To transport mucus and debris upwards towards the larynx where it can be swallowed.
In areas of the body not subjected to drying out but where abrasion occurs, such as the cornea, oral cavity, oesophagus, rectum, and vagina.
Protect underlying tissues, synthesis and secretion, absorption of nutrients, excretion of waste substances, transport, sensation, and forming a friction-free surface.
Because it has no blood supply; nutrients diffuse through the basement membrane from capillaries in the underlying connective tissue.
Gaps between individual endothelial cells that allow large molecules to move between the blood and surrounding tissues.
The BBB restricts potentially harmful substances but allows essential nutrients, oxygen, CO2, and some drugs like alcohol and general anesthetics.
Cover external surfaces of the body, line closed spaces of the body, form specialized receptors, form secretory portions of exocrine glands and ducts, and act as selective barriers.
By the action of cilia which beat towards the larynx.
Epithelial cells are tightly attached to one another by various types of intercellular junctions.
It is found in the uterine tubes, where cilia help sweep an ovum from the ovary to the uterus.
The blood-brain barrier is a selective permeability barrier that protects the brain from harmful substances in the blood.
Stratified squamous keratinized epithelium has a layer of dead cells filled with keratin on the surface, providing a tough, protective barrier.
Lining tubules and ducts, such as the collecting duct of the kidney, salivary glands, and the pancreas.
The process where the apical layers of stratified squamous epithelial cells are sloughed off and replaced by mitosis in the basal cells.
Microvilli and goblet cells.
A change (usually abnormal) from one distinctive tissue to another at a definite site after normal development is complete, implying a change in cell type (transdifferentiation).
Intra-abdominal adhesions are fibrous adhesions between opposing surfaces caused by insufficient removal of fibrin deposits due to damage to the mesothelium during surgical procedures.
A condition where cilia fail to beat or beat less effectively, leading to mucus buildup and respiratory obstruction.
Polarization is particularly apparent in secretory and absorptive cells, reflecting the directional transport of material.
Basal cells, goblet cells, and columnar ciliated cells.
The respiratory epithelium has cilia and goblet cells that help trap and move particles out of the airways.
Endothelial cells.
The height of a columnar cell is usually 2-3 times its width.
A tumour can form.
They enter the circulation and can metastasize (spread to other parts of the body).
A tumour originating in epithelial cells.
Stratified squamous epithelium.
Simple columnar epithelium.
Transitional epithelium is a type of stratified epithelium that can stretch and is found in the urinary bladder.
Cuboidal or columnar.
Cuboidal cells with a round, centrally located nucleus.
In the outermost layer of the skin.
Mechanical damage (cuts and grazes), penetration (needles, insect bites), bacteria, fungi, and toxic chemicals.
In tissues where brisk mitosis occurs, for example in the gut.
