What is the main focus of the presentation on September 7, 2024?
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Types of covering epithelia.
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What is the main focus of the presentation on September 7, 2024?
Types of covering epithelia.
What defines a simple gland?
A simple gland has a duct that does not branch.
What are the characteristics of Loose (areolar) Connective Tissues?
Delicate, flexible, and contains all constituents of connective tissue.
What shape is the top layer of stratified columnar epithelium?
Columnar in shape.
What is the classification of epithelium based on the number of layers?
It can be classified as Simple (one layer of cells) or Stratified (more than one layer of cells).
What are the two types of embryonic connective tissue?
Mesenchyme and Mucous.
What defines Simple epithelium?
It consists of one layer of cells.
What are the general features of fibroblasts?
Elongated cells with long tapering processes, basophilic cytoplasm, and a large oval central nucleus.
Where can simple columnar ciliated epithelium be commonly found?
In the oviducts.
What is a key characteristic of pseudostratified epithelium?
All cells rest on the basement membrane, but not all reach the apical surface.
What does mesenchymal connective tissue give rise to?
All types of connective tissues.
What is a key characteristic of nonkeratinized stratified squamous epithelium?
Surface cells are nucleated.
What are keratinized cells filled with in keratinized stratified squamous epithelium?
Tonofilaments.
What type of epithelium lines the renal calyces, ureters, bladder, and proximal segment of the urethra?
Transitional epithelium (urothelium).
What is the structure of a goblet cell?
It has a narrow base and an oval apical portion expanded with mucin-secreting granules.
What defines Stratified epithelium?
It consists of more than one layer of cells.
Which glands are classified as merocrine?
Pancreas, salivary, and sweat glands.
What is the primary function of unilocular adipocytes?
Storage of fat.
What is the structure of simple cuboidal epithelium?
It consists of one layer of cuboidal cells.
Where are the nuclei located in simple squamous epithelium?
Flattened or ovoid nuclei, located close to the center of the cells.
What role does connective tissue play in defense mechanisms?
It has a role in the defense mechanism of the body.
What is the date of the presentation?
Saturday, September 7, 2024.
What type of tissue is mucous (mucoid) tissue?
A gel-like connective tissue.
What are the two types of secretory portions in multicellular exocrine glands?
Tubular and alveolar (or acinar).
What do the top layers of keratinized stratified squamous epithelium consist of?
Keratinized cells that are flattened, nonnucleated, and dead.
What are the main components of mesenchymal connective tissue?
Mesenchymal cells in a gel-like amorphous ground substance.
What type of cells do plasma cells derive from?
B lymphocytes.
What are the two categories of connective tissue proper?
Loose (Areolar) and Dense (Irregular and Regular).
What are the types of specialized connective tissue?
Adipose (unilocular & multilocular), Reticular, Elastic, Cartilage, Bone, and Blood.
What type of surfaces does nonkeratinized stratified squamous epithelium often cover?
Wet surfaces.
What is the difference between unilocular and multilocular adipose tissue?
Unilocular has one large fat droplet, while multilocular has multiple smaller fat droplets.
How does connective tissue contribute to nutrient transport?
It plays a role in the transport of nutrients to other tissues.
What substances do fibroblasts synthesize and secrete that comprise the ground substance?
Glycosaminoglycans, proteoglycans, and glycoproteins.
What role does histamine play in mast cell activity?
It promotes increased vascular permeability and smooth muscle contraction.
What type of epithelium is found in the duct of sweat glands?
Stratified Cuboidal Epithelium.
What is mesenchymal connective tissue?
A type of connective tissue present in the embryo.
Where is mucous tissue most abundantly found?
Around blood vessels in the umbilical cord.
How do glands develop in the fetus?
From covering epithelia through cell proliferation and growth into the underlying connective tissue, followed by further differentiation.
What distinguishes columnar cells from other cell shapes?
They are taller than they are wide, resembling columns.
Where is nonkeratinized stratified squamous epithelium commonly found?
Lining the oral cavity, esophagus, and vagina.
What is the shape of plasma cells?
Oval cell.
What is a characteristic feature of transitional epithelium?
A superficial layer of large, dome-like cells called umbrella cells.
What are free connective tissue cells?
Cells that originate from hematopoietic stem cells in bone marrow, circulate in the blood, and then move into connective tissue.
What are the general characteristics of epithelium?
Covers exterior surfaces and lines internal cavities and body tubes.
What are examples of free connective tissue cells?
Macrophages, plasma cells, mast cells, and leucocytes.
Where are multilocular adipocytes primarily found?
In embryos and newborns.
What is the primary function of plasma cells?
Synthesis of immunoglobulin antibodies.
Name an example of where simple cuboidal epithelium can be found.
Ducts of glands.
What is the primary function of connective tissue?
To support, bind, and protect other tissues and organs.
What are mixed (seromucous) glands?
Glands that produce both serous and mucous secretions.
What are dust cells?
Resident macrophages in the lung.
What is collagen type III also known as?
Reticular fiber.
Where is elastic connective tissue primarily found?
In the walls of arteries closest to the heart, such as the aorta.
What is the shape of squamous cells?
They are flat and 'scale' like.
Where is Loose (areolar) Connective Tissue commonly found?
Beneath the epithelial lining of many organs and filling spaces between fibers of muscle and nerve.
How do reticular fibers appear under staining?
They are stained black with silver.
What are fixed connective tissue cells?
Cells that originate locally from mesenchymal cells and are permanent residents of connective tissue, e.g., fibroblasts and adipocytes.
What are the main components of connective tissue?
Cells and extracellular matrix.
What is the mode of secretion for merocrine glands?
Secretory granules leave the cell by exocytosis with no loss of other cellular material.
What are unilocular adipocytes?
Adipocytes that contain one large central fat droplet with a flat and eccentric nucleus.
What is one of the primary functions of fibroblasts?
To produce and maintain most of the tissue's extracellular components.
What are the best examples of dense regular connective tissue?
Tendons and ligaments.
What characterizes apocrine glands?
The secretory product is discharged together with parts of apical cytoplasm.
What is the function of heparin released by mast cells?
It acts as an anticoagulant.
How do multilocular adipocytes differ from unilocular adipocytes?
They contain numerous lipid droplets, are polygonal, smaller, and have a spherical central nucleus.
Are epithelia vascular or avascular?
Epithelia are avascular.
Which gland's follicles contain simple cuboidal epithelium?
The thyroid gland.
How do macrophages participate in immune responses?
By presenting antigens to lymphocytes.
What is another location where simple squamous epithelium can be found?
Thin segments of the loop of Henle.
What is the major fiber component of reticular tissue?
Type III collagen.
Where is keratinized stratified squamous epithelium found?
In the skin.
Where are the nuclei of cells in pseudostratified epithelium typically located?
At different levels.
What is a characteristic feature of mucous tissue?
It has few cells.
What is another name for brown adipose tissue?
Multilocular adipose tissue.
What is the structure of reticular fibers?
They are very fine, branch, and reunite to form a network.
What distinguishes endocrine glands from exocrine glands?
Endocrine glands lose their connection to the original epithelium and lack ducts.
What characterizes dense regular connective tissue?
Collagen bundles arranged in a regular pattern with fibroblasts in rows.
What characteristic does the cytoplasm of plasma cells have?
Basophilic cytoplasm.
What is simple squamous epithelium composed of?
A single layer of flattened cells.
What proteins do fibroblasts synthesize and secrete?
Collagen and elastin.
In which direction does dense regular connective tissue resist force?
In one direction.
What do all epithelia rest on?
A basal lamina that separates them from underlying connective tissues.
What is the function of microvilli in simple columnar epithelium?
To increase the apical surface area of the cell to aid in absorption.
Which gland is classified as holocrine?
Sebaceous gland.
In which part of the kidney is simple cuboidal epithelium found?
In the tubules of the kidney.
What are the two main components of connective tissue?
Cells and extracellular matrix.
What is a key characteristic of collagen fibers?
They are unbranched and highly resistant to stretch.
What is the primary function of cilia in simple columnar ciliated epithelium?
Cilia aid in the transport of material across the surface of the epithelium.
What characterizes a compound gland?
A compound gland has a duct that branches.
What structures does reticular tissue help to form the architectural framework for?
Liver, bone marrow, lymph nodes, and spleen.
What is another name for white adipose tissue?
Unilocular adipose tissue.
What is the structure of simple columnar epithelium?
It consists of one layer of columnar cells.
What is an example of a unicellular gland?
Goblet cell.
Can secretory units be branched in multicellular exocrine glands?
Yes, either type of secretory unit may be branched.
What does the extracellular matrix consist of?
Protein fibers and areas of ground substance rich in glycosaminoglycans, proteoglycans, glycoproteins, and water.
Does the branching of secretory units depend on the duct?
No, a secretory unit may be branched even if the duct is not branched.
What is the function of umbrella cells in transitional epithelium?
To protect underlying tissues from the hypertonic and potentially cytotoxic effects of urine.
What do macrophages look like under a transmission electron microscope (TEM)?
They have a characteristic irregular surface with protrusions and indentations.
How are epithelial cells arranged?
They are formed of closely arranged cells with very small amounts of intercellular substance.
Which gland is an example of an apocrine gland?
Mammary gland.
What are Kupffer cells?
Resident macrophages in the liver.
What do serine proteases activate?
Various mediators of inflammation.
In which direction does dense irregular connective tissue resist tension/stress?
From any direction.
Which glands are examples of mixed (seromucous) glands?
Submandibular and sublingual glands.
How are collagen fibers arranged?
In a parallel array forming collagen bundles.
What is the primary function of elastic connective tissue?
Provides distensible support and accommodates pressure changes.
What is the composition of stratified columnar epithelium?
It is composed of two or three layers of cells.
What are reticular fibers primarily composed of?
A special type of collagen (type III) protein.
What is the shape of tubular secretory portions?
They can be either short or long and coiled.
Give two examples of where pseudostratified epithelium can be found.
In the trachea and epididymis.
What characterizes exocrine glands?
They remain connected with the surface epithelium via tubular ducts.
What are examples of fixed connective tissue cells?
Fibroblasts and adipocytes.
How does nonkeratinized stratified squamous epithelium compare to keratinized squamous epithelium?
It is similar except that surface cells are nucleated.
What are the characteristics of macrophages?
Large, irregular cells with oval or kidney-shaped nucleus.
What is the role of connective tissue in the body?
It supports and physically connects other tissues and cells to form the organs of the body.
What type of secretion is produced by serous glands?
Watery secretion.
How does the thickness of transitional epithelium change when the bladder is stretched?
The thickness is much reduced, and surface cells are extremely flattened.
Where are the nuclei located in simple cuboidal epithelium?
The nuclei are centrally placed and spherical in shape.
What type of secretion is produced by mucous glands?
Thick secretion.
Which glands are examples of mucous glands?
Brunner’s glands in the duodenum and pyloric glands in the stomach.
What do eosinophil and neutrophil chemotactic factors do?
They attract eosinophils and neutrophils.
Where else can simple cuboidal epithelium be found?
On the surface of the ovaries.
Where are elastic fibers commonly found?
In large arteries, such as the aorta.
Where is collagen type I found?
In the dermis, bone, tendon, and ligaments.
What are the two types of adipose connective tissue?
Unilocular (white) adipose tissue and multilocular (brown) adipose tissue.
How would you describe cuboidal cells?
They are as wide as they are tall, resembling cubes.
Where can stratified columnar epithelium be found?
In the conjunctiva.
What characterizes alveolar or acinar secretory portions?
They are rounded and saclike.
How does the height of simple columnar epithelial cells compare to their width?
The height is greater than the width.
What is the shape of mast cells?
Oval or irregularly shaped with a rounded central nucleus.
Where are goblet cells commonly found?
In the lining of the small intestine, colon, and respiratory airways.
What fills the cytoplasm of mast cells?
Granules for the release of various substances.
How are multicellular glands classified?
According to morphology of duct, shape of secretory unit, nature of secretion, and mode of secretion.
What organelles are well-developed in macrophages?
Golgi complexes and lysosomes.
What characterizes dense irregular connective tissue?
Collagen bundles are arranged in different directions.
What is the primary function of multilocular adipocytes?
To provide body heat.
What structure do microvilli form when densely packed?
A brush border.
Where can simple columnar epithelium with microvilli be found?
In the duodenum, jejunum, ileum, and proximal convoluted tubule of the kidney.
What type of connective tissue stores fat?
Adipose tissue.
What are elastic fibers composed of?
The proteins elastin and fibrillin.
What gives collagen fibers their great tensile strength?
The protein called collagen.
Where is the nucleus typically located in simple columnar epithelial cells?
In the basal region of the cell.
How do endocrine glands transport their secreted products?
Capillaries adjacent to endocrine cells absorb their secreted hormone products for transport in blood to target cells.
Give an example of where simple columnar epithelium can be found.
Lining of the stomach.
Describe the nucleus of a plasma cell.
Eccentric with a large nucleolus and a clock face appearance due to special chromatin arrangement.
Which glands are examples of serous glands?
Parotid gland and exocrine pancreas.
What is an example of simple squamous epithelium that lines blood and lymphatic vessels?
Endothelium.
What does mesothelium line?
Serous cavities (peritoneal, pleural, and pericardial cavities).
Into how many main groups are epithelia divided?
Two main groups: covering and glandular epithelia.
Which part of the kidney contains simple squamous epithelium?
The parietal layer of Bowman’s capsule.
What is a key characteristic of elastic fibers?
They are soft, flexible, and can recoil when the force is removed.
How many types of collagen exist in vertebrates?
A family of 28 collagens.
What is the mode of secretion for holocrine glands?
The product of secretion is shed with the whole cell.
What is one function of macrophages?
Phagocytosis of foreign objects.
What are the main types of connective tissue?
Loose connective tissue, dense connective tissue, adipose tissue, cartilage, bone, and blood.
What is the primary role of the apical surface area increased by microvilli?
To aid in the absorption of fluid and other materials from a lumen.
How do elastic fibers appear structurally?
They are fine, present singly, and can branch.
Where is dense irregular connective tissue commonly found?
In the dermis of the skin.
Where can simple squamous epithelium be found in the lungs?
In the lung’s alveoli.
What is the role of fibers in connective tissue?
To provide strength, elasticity, and support.
What are the most numerous fibers in connective tissue?
Collagen fibers.
Where is collagen type II found?
In hyaline cartilage.
Where can collagen type III be found?
In lymphoid organs and the liver.
