60 Questions
Which type of epithelial tissue is specialized for stretching and distensibility, commonly found in the urinary bladder?
Transitional epithelium
Which cell junction forms a barrier to the diffusion of solutes through the intercellular space and prevents the mixing of proteins in the apical and basolateral cell membranes?
Tight junctions
Which stain is commonly used to highlight mucin, a glycoprotein found in mucus secretions?
Periodic acid-Schiff stain (PAS)
What is the primary function of motile cilia in the respiratory tract?
Propulsion of mucus
What is the component of gluten that individuals with celiac disease mount an immune response to?
Gliadin
What is the effect of the inflammatory response on the villus in individuals with celiac disease?
Flattening and damage to enterocytes
How does gliadin enter the lamina propria in individuals with celiac disease?
Through the paracellular route after causing disassembly of tight junction proteins
What is the role of zonulin in the process of gliadin entering the lamina propria?
Causing phosphorylation of ZO proteins
What is the impact of the inflammatory response in celiac disease on nutrient absorption?
Reduction of surface area for absorption
Which protein is involved in the disassembly of tight junction proteins in the context of gliadin entering the lamina propria?
Zonulin
What is the percentage of the population affected by celiac disease?
Up to 1%
Which grains contain gluten, the component to which individuals with celiac disease mount an immune response?
Wheat, barley, rye
What is the minimum size of structures that light microscopy can visualize?
0.2 microns
Which microscopy technique involves loading a cell with a fluorescent probe?
Fluorescence microscopy
What is the purpose of staining in histology?
Improving visualization of cells
Which staining procedure highlights different molecules or organelles?
Periodic acid-Schiff stain
What is the main benefit of histology at the junction of anatomy and physiology?
Deducing a cell or tissue's function by its microscopic structure
What is the primary use of electron microscopy?
Visualizing organelles and large molecules
What is the first step in preparing tissues for examination?
Fixation
In the context of tissue dysfunction, what can histology help identify?
Diseased cells or tissues
What is the main focus of histology in the text?
Tissue preparations and microscopy images
What type of microscopy allows for viewing a cell or tissue in a particular plane?
Confocal microscopy
What is the size limit for structures visualized by electron microscopy?
3 nm
Which staining procedure highlights DNA and cytosolic proteins?
Hematoxylin and eosin
Which type of junction is found at the apical aspect of most epithelial cells and acts as a barrier, regulating the movement of molecules between cells and helping establish polarity?
Tight junctions
Which type of epithelial cells determines their nomenclature based on their shape?
Flattened, square, or tall
Which junction is located below tight junctions, strengthens and stabilizes them, and participates in cell-cell signaling that regulates cell division and proliferation?
Adherens junctions
What is the primary function of epithelial cells in mucous membranes and the skin?
Providing protection and distensibility
Which cytoskeletal component contributes to the shape, strength, polarity, and motility of epithelial cells?
Microtubules
What determines the nomenclature of epithelial cells?
Their shape
Which type of epithelial cells is involved in the absorption of water, nutrients, and electrolytes, and the removal of wastes from the body?
Columnar
What is the function of desmosomes in connecting epithelial cells?
Connect to intracellular intermediate filaments
Which type of junction provides strong adhesion between cells and connects to the actin cytoskeleton?
Adherens junctions
What is the role of tight junctions in epithelial cells?
Regulate movement of molecules between cells
Which component of the cytoskeleton contributes to the strength and stability of epithelial cells?
Intermediate filaments
What is the primary function of epithelial cells in the bladder?
Protecting from urine and stretching for storage
Which type of cell junction is responsible for the paracellular transport of substances and acts as a barrier that restricts movement of substances across the epithelium?
Tight junctions
Which type of connective tissue contains a lot of ground substance, many cells, and relatively little collagen?
Loose connective tissue
What is the primary function of motile cilia in the respiratory tract?
Propelling fluids in a single direction
Which type of collagen is oriented in one particular direction and resists stresses along one line or plane?
Type I collagen
Which type of cell junction contributes to the strength of the epithelial lining and determines the polarity of the epithelial cell?
Adherens junctions
What is the structure of motile cilia found in columnar epithelial cells of the uterine tubes and larger airways?
9 + 2
Which type of connective tissue has collagen arranged in bundles in different directions and resists stresses from multiple directions?
Dense irregular connective tissue
What is the primary function of non-motile primary cilia?
Sensing and signaling
Which type of cell junction is involved in signaling and regulation of the activity of the epithelial cell?
Desmosomes
Which type of collagen forms the basement membrane?
Type IV collagen
Where are non-motile primary cilia longer than microvilli typically found?
Kidney tubules
Which type of connective tissue contains fewer cells and less ground substance than loose connective tissue?
Dense regular connective tissue
Which molecule binds to type IV collagen and integrins of hemidesmosomes?
Laminin
What is the primary function of proteoglycans in the extracellular matrix (ECM)?
Provide structural integrity
Which skin condition is associated with impaired skin barrier and specific type 2 inflammation?
Atopic dermatitis
What type of epithelium is found in the intestinal mucosa, specialized for absorption and glandular functions?
Simple columnar
What type of connective tissue forms the dermal layer under the epidermis, providing structural support and housing dermal vasculature?
Dense irregular connective tissue
What is a common source of pathology at epithelial and connective tissue interfaces?
Disrupted barrier function
Which molecule binds to collagen, glycosaminoglycans (GAGs) on proteoglycans, and some integrins?
Fibronectin
What is the primary function of the lamina propria in the intestinal mucosa?
Immune defense
Which type of tissue is the skin's stratified squamous epithelium specialized to protect against?
Abrasion
What is a characteristic symptom of atopic dermatitis?
Itchy papules
What is the main function of the intestinal mucosa's simple columnar epithelium?
Nutrient absorption
Which component of the extracellular matrix (ECM) is highly hydrated and contributes to the storage of growth factors?
Proteoglycans
Study Notes
Introduction to Histology and Microscopy Techniques
- Histology is the study of tissues under a microscope, with light microscopy being able to visualize structures as small as 0.2 microns.
- Confocal microscopy allows for viewing a cell or tissue in a particular plane, while fluorescence microscopy involves loading a cell with a fluorescent probe.
- Electron microscopy can visualize structures as small as 3 nm and is used to visualize organelles and large molecules.
- Tissues are prepared for examination through fixation, dehydration & clearing, infiltration and embedding, and trimming.
- Staining involves exposing cells to dyes or molecules that improve visualization, such as hematoxylin and eosin, which highlight DNA and cytosolic proteins.
- Other staining procedures include periodic acid-Schiff stain, masson’s trichrome, methylene blue, and acid fuchsin, each highlighting different molecules or organelles.
- Histology is useful at the junction of anatomy and physiology, allowing deduction of a cell or tissue's function by its microscopic structure.
- It is also helpful in identifying diseased cells or tissues, as they often appear abnormal under the microscope.
- The text provides examples of histological tissue preparations and microscopy images, such as a small intestine stained with H&E and mouse skin stained with Masson's trichrome.
- The structure and composition of various tissues, including connective tissues, skin, and intestinal mucosa, are described in detail.
- Common sources of pathology, such as atopic dermatitis and celiac disease, are briefly explained in the context of tissue dysfunction.
- The text also introduces exotic microscopy techniques like confocal microscopy and electron microscopy, providing examples from the University of Saskatchewan.
Cellular Junctions and the Epithelium
- Desmosomes provide structural stability to the cell by linking adjacent cells through transmembrane proteins called integrins that bind to laminin in the basement membrane.
- Hemidesmosomes, different from desmosomes, link epithelial cells to the basement membrane through integrins and do not have important intracellular signaling functions.
- Tight junctions are responsible for the paracellular transport of substances and act as a barrier that restricts movement of substances across the epithelium.
- Adherens and desmosomes contribute to the strength of the epithelial lining, while tight junctions determine the polarity of the epithelial cell.
- Desmosomes are involved in signaling and regulation of the activity of the epithelial cell, while hemidesmosomes anchor the epithelial cell to the underlying connective tissue.
- Motile cilia, with a 9 + 2 structure of microtubules, are found in columnar epithelial cells of the uterine tubes and larger airways, propelling fluids in a single direction.
- Non-motile primary cilia, with a ring of 9 microtubular structures, are longer than microvilli and have a range of receptors and intracellular signaling mechanisms.
- Loose connective tissue, found beneath the epithelial lining of many tissues, contains a lot of ground substance, many cells, and relatively little collagen.
- Dense irregular connective tissue, with fewer cells and less ground substance than loose connective tissue, has collagen arranged in bundles in different directions and resists stresses from multiple directions.
- Dense regular connective tissue, containing a lot of type I collagen, is oriented in one particular direction and resists stresses along one line or plane.
- Different types of collagen, including type I, II, III, and IV, have various functions in connective tissue, such as resisting tension, pressure, and forming the basement membrane.
- The basement membrane is formed from an organized meshwork of type IV collagen, proteoglycans, and laminin, to which integrins (hemidesmosomes) bind.
Microscopic Anatomy of Epithelial and Connective Tissue Interfaces
- Laminin binds to type IV collagen and integrins of hemidesmosomes
- Fibronectin binds to collagen, glycosaminoglycans (GAGs) on proteoglycans, and some integrins
- Proteoglycans have a 3-part structure: hyaluronic acid, linking proteins, and shorter GAG chains
- Proteoglycans are highly hydrated, bring structural integrity to the ECM, and store growth factors
- Epithelial and connective tissue interfaces are involved in various conditions relevant to naturopathic medicine
- Common sources of pathology include disrupted barrier function, disrupted transport, and inflammation
- The skin has a stratified squamous epithelium with protective functions against abrasion
- The dermal layer under the epidermis is dense irregular connective tissue with dermal vasculature
- Atopic dermatitis is a common heritable skin condition with symptoms like itchy papules and plaques
- Atopic dermatitis is highly heritable and is associated with impaired skin barrier and specific type 2 inflammation
- The intestinal mucosa has a simple columnar epithelium specialized for absorption and glandular functions
- The intestinal mucosa sits on a bed of highly vascularized loose connective tissue known as the lamina propria
Test your knowledge of histology and microscopy techniques with this quiz. Explore topics like tissue preparation, staining procedures, and the structure of various tissues. Learn about cellular junctions, epithelial and connective tissue interfaces, and their relevance to conditions in naturopathic medicine.
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