Flashcards in this deck (130)

• Epithelium lines internal and external body surfaces and cavities.
  anatomy epithelium
• The functions of epithelium include protection, secretion, and absorption.
  anatomy epithelium function
• Histologically, epithelium has one or more layers of cells that are contiguous with one another.
  histology epithelium
• Epithelial cells are tightly packed and devoid of interstitial space.
  histology epithelium
• Each epithelial cell has a single nucleus.
  histology epithelium
• The properties of epithelium include being avascular and regenerative.
  anatomy epithelium
• The basement membrane consists of two layers: - Basal Lamina - Reticular Lamina.
  biology epithelial tissue
• The basement membrane serves to anchor epithelial cells and provides support.
  biology epithelial tissue
• The apical side of epithelial cells faces the free surface.
  biology epithelial_cells
• The basal side of epithelial cells contacts the basement membrane.
  biology epithelial_cells
• The lateral side of epithelial cells is adjacent to other epithelial cells.
  biology epithelial_cells
• In the apical domain, epithelial cells have junctions such as zonula occludens and zonula adherens.
  epithelial junctions apical
• The lateral domain of epithelial cells contains gap junctions and maculae adherentes (desmosomes).
  epithelial junctions lateral
• The basal domain of epithelial cells includes junctions with the basal lamina, such as hemidesmosomes and focal adhesions.
  epithelial junctions basal
• Most epithelial junctions depend on transmembrane proteins and cytoskeletal elements.
  epithelial junctions composition
• Tight Junctions, also known as Occluding Junctions, are located on the lateral border of epithelial cells and seal off lateral spaces to create a barrier.
  biology cell_biology epithelial_cells
• The main proteins involved in tight junctions are occludin and claudin, which connect to the cytoskeleton via actin filaments.
  cell_biology tight_junctions proteins
• Adherens Junctions, also known as Zonula Adherens, are located on the lateral border of cells and function as a type of anchoring junction.
  cell_biology junctions
• The main function of Adherens Junctions is to reinforce bonding to deal with mechanical stress.
  cell_biology junctions
• Histological identifiers for Adherens Junctions include SEM and a clear space between cells, as well as increased density in the cytoplasm.
  histology cell_biology
• Key junction proteins in Adherens Junctions include cadherin, catenins, and vinculin.
  cell_biology junctions
• Adherens Junctions connect to the cytoskeleton via actin filaments.
  cell_biology junctions
• Desmosomes, also known as Macula Adherens, are located on the lateral border of cells and function as a type of anchoring junction.
  cell_biology junctions
• The primary function of desmosomes is to reinforce bonding between cells, similar to spot welds.
  cell_biology junctions
• Histologically, desmosomes can be identified by a sandwich of two dark plates and fibers extending from these plates, known as intermediate filaments.
  histology desmosomes
• Desmosomes contain junction proteins such as cadherin which connect to the cytoskeleton.
  cell_biology junctions
• Gap junctions are located on the lateral border of adjacent cells and are a type of communicating junction.
  cell_biology gap_junctions
• Gap junctions allow direct passage of signaling molecules between cells.
  cell_biology gap_junctions
• Histological identifiers for gap junctions include SEM and the narrowing of the gap between membranes.
  histology gap_junctions
• Gap junctions are formed by connexons which are composed of connexin proteins.
  cell_biology gap_junctions
• Gap junctions allow small molecules to pass between cells but do not connect the cytoskeleton.
  cell_biology gap_junctions
• The hemidesmosome is a type of anchoring junction located on the basal border of cells, connecting them to the basal lamina.
  cell_biology junctions
• Hemidesmosomes reinforce bonding similar to desmosomes and are composed of junction proteins which are integrins
  cell_biology junctions
• The hemidesmosome anchors to the basal border via intermediate filaments.
  cell_biology junctions
• Focal adhesions are located on the basal border and serve as a type of anchoring junction between the cell and the basal lamina.
  cell_biology focal_adhesions
• Focal adhesions reinforce bonding and are similar to desmosomes or spot welds.
  cell_biology junctions
• The key junction proteins involved in focal adhesions are integrins
  cell_biology focal_adhesions proteins
• Focal adhesions anchor to the basal border via actin.
  cell_biology focal_adhesions actin
• The types of junctions include: - Tight Junctions: Seals adjacent epithelial cells together; prevents leakage. - Adherens Junctions: Joins actin bundles between cells. - Desmosomes: Anchors intermediate filaments between cells. - Gap Junctions: Allows passage of small water-soluble molecules. - Hemidesmosomes: Anchors intermediate filaments to basal lamina.
  cell_biology junctions
• The junction that binds cells to adjacent cells through actin filaments is called Adherens/Zonula Adherens.
  cell_biology junctions
• The junction that anchors cells to basal lamina through intermediate filaments is called Hemidesmosomes.
  cell_biology junctions
• The junction between lateral epithelium cells that forms a barrier is called Tight/Occluding.
  cell_biology junctions
• The junction that allows the passage of small molecules between adjacent cells is called Gap.
  cell_biology junctions
• The junction that binds cells to adjacent cells through intermediate filaments is called Desmosomes/Macula Adherens.
  cell_biology junctions
• The junction that anchors cells to basal lamina through actin filaments is called Focal Adhesions.
  cell_biology junctions
• Apical modifications are present on the apical cell surface and are usually found on columnar shaped cells.
  biology epithelial_cells
• Microvilli are the shortest extension of membrane, while cilia are of medium length and stereocilia are the longest.
  biology epithelial_cells
• Microvilli function to increase surface area for absorption and are found on many epithelial cells.
  biology microvilli function
• The microvilli region can be referred to as striated or brush borders.
  biology microvilli terminology
• Histological identifiers for microvilli include a pinkish haze at the apical surface and a dark line at the base of microvilli called the terminal web.
  biology histology identifiers
• Microvilli contain a core of actin filaments and are anchored by a terminal web.
  biology microvilli structure
• The properties of microvilli include limited movement and cytoplasmic processes containing a core of actin.
  biology microvilli properties
• The micrograph shows the apical surfaces of epithelial cells with numerous microvilli.
  biology microvilli images
• The micrograph of intestinal villi lined by absorptive epithelial cells shows a brush border.
  biology microvilli images
• Cilia can be classified into two types: Motile and Non-Motile.
  biology cilia classification
• The function of motile cilia includes propulsion of surrounding fluid and is commonly found in the respiratory tract.
  biology cilia function
• Non-motile cilia serve as sensory receptors, acting as chemical and mechanical sensors on most cells.
  biology cilia function
• Cilia appear as small hairs under a light microscope and show a dark line at the base called basal bodies.
  biology cilia histology
• The core of cilia is made up of microtubules and is anchored to the cell by basal bodies.
  biology cilia properties
• Cilia are important for the propulsion of fluid and sensory functions in various tissues.
  biology cilia function
• Stereocilia function as a mechanoreceptor in the ear and increase absorption in the male reproductive system.
  biology function stereocilia
• Stereocilia appear as very long hairs under a light microscope and have a tiered appearance in scanning electron microscopy (SEM).
  biology histology stereocilia
• The core of stereocilia is made of actin and is anchored by a terminal web.
  biology properties stereocilia
• Stereocilia are similar to microvilli but not to cilia.
  biology comparison stereocilia
• The terminal web appears as a dark line at the base of microvilli.
  biology histology microvilli
• The treadmilling mechanism in actin involves polymerization and crosslinking.
  biology actin treadmilling
• Stereocilia have limited movement.
  biology properties stereocilia
• Glands are categorized by how products are released, mechanism of secretion, and type of secretion. The two main types are exocrine and endocrine.
  glands secretion biology
• Exocrine glands secrete a product onto a surface directly or through ducts or tubes.
  glands exocrine secretion
• Endocrine glands secrete a product into connective tissue to enter the bloodstream.
  glands endocrine secretion
• Endocrine glands are sometimes called 'epitheloid tissues' because of their haphazard layering pattern and lack of basal lamina.
  glands endocrine tissues
• The three types of exocrine gland secretion are merocrine, apocrine, and holocrine.
  glands exocrine secretion
• Exocrine glands are characterized by their duct structure and have a layered organization around ducts.
  histology glands exocrine
• Endocrine glands are distinguished by being vascular and lacking layering.
  histology glands endocrine
• The three types of exocrine secretion mechanisms are merocrine, apocrine, and holocrine.
  anatomy physiology glands
• In merocrine secretion, the product is secreted via membrane bound vesicles.
  anatomy physiology merocrine
• Apocrine secretion involves the product being secreted with a thin layer of cytoplasm and plasma membrane surrounding it.
  anatomy physiology apocrine
• An example of apocrine secretion is mammary glands.
  anatomy physiology apocrine
• Holocrine secretion involves product accumulation within the cell, leading to cell lysis to release it.
  anatomy physiology holocrine
• An example of holocrine secretion is sebaceous glands.
  anatomy physiology holocrine
• Endocrine secretion is characterized by products being secreted through the basal lamina directly into the blood stream.
  anatomy physiology endocrine
• Types of exocrine secretion include: - Mucous - Serous - Sebaceous - Others like milk and pancreatic enzymes.
  biology histology secretion
• Mucous secretion is characterized by being viscous and slimy with heavily glycosylated proteins.
  biology histology mucous
• Serous secretion is typically watery and contains proteins that are not glycosylated.
  biology histology serous
• Sebaceous secretion consists of lipid products.
  biology histology sebaceous
• Endocrine glands secrete hormones.
  biology endocrine hormones
• Simple glands have a unbranched duct, while compound glands have a branched duct.
  anatomy glands
• The shape of glands can be classified as tubular, alveolar (acinar), or tubuloalveolar.
  anatomy glands
• An example of a simple branched alveolar gland is sebaceous (oil) glands.
  anatomy glands
• Examples of compound glands include mammary glands and salivary glands.
  anatomy glands
• The term coiled describes a tubular shape where the tube is coiled rather than straight.
  anatomy glands
• The intestinal glands are an example of a simple tubular gland that is not found in adults, being a stage in development.
  anatomy glands
• Mucous glands in the mouth and bulbourethral glands in the male reproductive system are examples of compound glands.
  anatomy glands
• A gland that combines tubular and alveolar shapes is referred to as tubuloalveolar.
  anatomy glands
• Goblet cells are unicellular glands that are specialized for mucus secretion in the gastrointestinal and respiratory systems.
  anatomy histology glands
• The structure of a goblet cell includes microvilli, secretory vesicles containing mucin, rough ER, Golgi apparatus, and a nucleus.
  anatomy histology glands
• In histological staining, mucin does not stain well in H&E, giving the goblet cell a goblet appearance.
  anatomy histology glands
• Epithelial tissue can be classified by the number of layers into: - simple (1 cell layer) - stratified (≥ 2 cell layers).
  epithelium classification anatomy
• The unique classifications of epithelial tissue include: - transitional - pseudostratified.
  anatomy epithelium classification
• Simple squamous epithelium consists of one layer of flat cells.
  anatomy epithelium
• Simple squamous epithelium is found in the vascular system, body cavities, and alveoli.
  anatomy locations epithelium
• The main functions of simple squamous epithelium include secretion/lubrication and gas exchange/diffusion.
  anatomy functions epithelium
• In the vascular system, simple squamous epithelium is referred to as endothelium.
  anatomy vascular epithelium
• In body cavities, simple squamous epithelium is known as mesothelium.
  anatomy body_cavities epithelium
• Simple cuboidal epithelium consists of one layer of cube shaped cells.
  biology histology epithelium
• Examples of locations where simple cuboidal epithelium can be found include: - small ducts - surface of ovaries - kidney tubules.
  biology locations epithelium
• The main functions of simple cuboidal epithelium are absorption and secretion.
  biology functions epithelium
• Simple Columnar Epithelium consists of one layer of columnar shaped cells.
  biology epithelium
• Simple Columnar Epithelium is primarily located in the digestive tract and the gallbladder.
  biology epithelium location
• The main function of Simple Columnar Epithelium is absorption and secretion.
  biology epithelium function
• Pseudostratified Columnar Epithelium appears stratified but is actually simple columnar epithelium.
  histology epithelium
• In Pseudostratified Columnar Epithelium, all cells rest on the basement membrane, but not all reach the apical surface.
  histology epithelium
• Pseudostratified Columnar Epithelium can be ciliated or non-ciliated.
  histology epithelium
• Location examples of Pseudostratified Columnar Epithelium include the trachea and bronchial tree.
  histology epithelium location
• The main functions of Pseudostratified Columnar Epithelium are secretion and absorption as well as propulsion (cilia).
  histology epithelium function
• Stratified Squamous Epithelium has an apical layer of squamous shaped cells and multiple layers underneath of varying shapes.
  anatomy epithelium
• Stratified Squamous Epithelium is found in the epidermis, oral cavity, esophagus, and vagina.
  anatomy location epithelium
• The main function of Stratified Squamous Epithelium is barrier/protection.
  anatomy function epithelium
• Stratified cuboidal epithelium has an apical layer of cuboidal shaped cells and is often two layers thick.
  histology epithelium
• Stratified cuboidal epithelium is considered a rare tissue.
  histology epithelium
• Examples of locations where stratified cuboidal epithelium is found include sweat gland ducts and large ducts of exocrine glands.
  histology locations epithelium
• The main functions of stratified cuboidal epithelium are barrier/protection and conduit.
  histology function epithelium
• Stratified Columnar Epithelium has an apical layer of columnar shaped cells and is considered a rare tissue.
  anatomy epithelium
• The main functions of Stratified Columnar Epithelium include barrier/protection and conduit.
  anatomy epithelium function
• Stratified Columnar Epithelium is found in the male urethra and large ducts of exocrine glands.
  anatomy location
• Transitional epithelium is characterized by multiple layers of cells with varying shapes, including dome-shaped cells. It is primarily located in the ureters, bladder, and urethra.
  anatomy histology epithelium
• The main functions of transitional epithelium include acting as a barrier and being distensible.
  anatomy histology epithelium
• The top layer of transitional epithelium is referred to as umbrella cells or dome-shaped cells when not distended.
  anatomy histology epithelium
• Transitional epithelium is found in the urinary tract, specifically in the ureters, bladder, and urethra.
  anatomy urinary epithelium
• Transitional epithelium consists of multiple layers of cells, including the top layer known as umbrella cells.
  anatomy histology epithelium