Podcast
Questions and Answers
Which characteristic best describes the nuclear orientation in epithelial cells?
Which characteristic best describes the nuclear orientation in epithelial cells?
- Nuclear shape is always spherical.
- Nuclear shape is independent of cell shape.
- Nuclear shape always aligns with the basal surface.
- Nuclear shape corresponds roughly to cell shape. (correct)
In squamous epithelial cells, how does the height (H) compare to the width (W)?
In squamous epithelial cells, how does the height (H) compare to the width (W)?
- H < W (correct)
- H = W
- H ≥ W
- H > W
Which of the following is a characteristic feature of cuboidal epithelial cells?
Which of the following is a characteristic feature of cuboidal epithelial cells?
- Height is negligible.
- Height is greater than width.
- Height is equal to width. (correct)
- Height is less than width.
What is the defining characteristic of columnar epithelial cells in terms of dimensions?
What is the defining characteristic of columnar epithelial cells in terms of dimensions?
What are the three main domains that describe the polarity of epithelial cells?
What are the three main domains that describe the polarity of epithelial cells?
Which of the following best describes the basal lamina?
Which of the following best describes the basal lamina?
What is the primary function of collagen III fibers in the reticular lamina?
What is the primary function of collagen III fibers in the reticular lamina?
What is the main function of tight junctions (zonula occludens) in epithelial tissue?
What is the main function of tight junctions (zonula occludens) in epithelial tissue?
Enterotoxins secreted by Clostridium perfringens prevent maintenance of tight junctions by inhibiting the insertion of which molecules?
Enterotoxins secreted by Clostridium perfringens prevent maintenance of tight junctions by inhibiting the insertion of which molecules?
What is the primary function of gap junctions (nexus) found on the lateral surface of epithelial cells?
What is the primary function of gap junctions (nexus) found on the lateral surface of epithelial cells?
What are the finger-like cytoplasmic projections on the apical surface of epithelial cells specialized for absorption called?
What are the finger-like cytoplasmic projections on the apical surface of epithelial cells specialized for absorption called?
What is the approximate size of microvilli found on the apical surface of absorptive epithelial cells?
What is the approximate size of microvilli found on the apical surface of absorptive epithelial cells?
What is the internal structural component of microvilli that provides support and shape?
What is the internal structural component of microvilli that provides support and shape?
Which disease is characterized by the loss of microvilli brush border in the small intestine's absorptive cells, leading to malabsorption?
Which disease is characterized by the loss of microvilli brush border in the small intestine's absorptive cells, leading to malabsorption?
Where are stereocilia typically found?
Where are stereocilia typically found?
Compared to microvilli, how would you describe stereocilia?
Compared to microvilli, how would you describe stereocilia?
Which of the following is a characteristic feature of cilia?
Which of the following is a characteristic feature of cilia?
What is the primary function of primary cilia?
What is the primary function of primary cilia?
What is the term for a group of similar specialized cells that work together to perform a specific function?
What is the term for a group of similar specialized cells that work together to perform a specific function?
According to the content provided, what are the four basic types of tissues?
According to the content provided, what are the four basic types of tissues?
Which characteristic is associated with epithelial tissue?
Which characteristic is associated with epithelial tissue?
What feature classifies covering or lining epithelia?
What feature classifies covering or lining epithelia?
Which of the following is NOT a characteristic of epithelial tissue?
Which of the following is NOT a characteristic of epithelial tissue?
What is the role of specialized contacts in epithelial tissue?
What is the role of specialized contacts in epithelial tissue?
Where do epithelial tissues derive their nutrients, metabolites, and oxygen?
Where do epithelial tissues derive their nutrients, metabolites, and oxygen?
What is meant by the term 'polarity' in the context of epithelial cells?
What is meant by the term 'polarity' in the context of epithelial cells?
The basement membrane in epithelial tissue primarily functions as:
The basement membrane in epithelial tissue primarily functions as:
A key feature of the reticular lamina is that it:
A key feature of the reticular lamina is that it:
A key function of tight junctions (zonula occludens) is to:
A key function of tight junctions (zonula occludens) is to:
Which junction type facilitates intercellular exchange of small molecules in epithelial layers?
Which junction type facilitates intercellular exchange of small molecules in epithelial layers?
Which of the following is a function associated with microvilli?
Which of the following is a function associated with microvilli?
What is the approximate length and width of microvilli?
What is the approximate length and width of microvilli?
Celiac disease primarily results in damage to which feature of the epithelial cells in the small intestine?
Celiac disease primarily results in damage to which feature of the epithelial cells in the small intestine?
Collagen III fibers are mostly found in the?
Collagen III fibers are mostly found in the?
Which apical modification can move materials in one direction?
Which apical modification can move materials in one direction?
Which structure is considered as not motile and detects light, odor motion, and flow of liquid?
Which structure is considered as not motile and detects light, odor motion, and flow of liquid?
Epithelial cells are charaterized according to?
Epithelial cells are charaterized according to?
Which type of cell is best described by dimensions matching with the cells height and the cells width.
Which type of cell is best described by dimensions matching with the cells height and the cells width.
In epithelial cells, the shape of the nucleus is most indicative of:
In epithelial cells, the shape of the nucleus is most indicative of:
How do the structural components of stereocilia differ from those of motile cilia in epithelial cells?
How do the structural components of stereocilia differ from those of motile cilia in epithelial cells?
What characteristic of epithelial tissue contributes most significantly to its ability to act as a protective barrier?
What characteristic of epithelial tissue contributes most significantly to its ability to act as a protective barrier?
What is the functional significance of the close proximity of epithelial cells in the tissue?
What is the functional significance of the close proximity of epithelial cells in the tissue?
How do anchoring junctions contribute to tissue integrity in epithelial cells?
How do anchoring junctions contribute to tissue integrity in epithelial cells?
What is the role of collagen I fibers in the reticular lamina?
What is the role of collagen I fibers in the reticular lamina?
How does the arrangement of connexons in gap junctions facilitate intercellular communication in epithelial cells?
How does the arrangement of connexons in gap junctions facilitate intercellular communication in epithelial cells?
What is the relationship between Celiac disease and microvilli?
What is the relationship between Celiac disease and microvilli?
How does the length and motility of stereocilia compare to those of microvilli?
How does the length and motility of stereocilia compare to those of microvilli?
What is the primary mechanism by which motile cilia facilitate the movement of substances across epithelial surfaces?
What is the primary mechanism by which motile cilia facilitate the movement of substances across epithelial surfaces?
How are epithelial cells supplied with metabolites and oxygen, given they are avascular?
How are epithelial cells supplied with metabolites and oxygen, given they are avascular?
How might a mutation affecting the production of collagen III impact the function of the reticular lamina?
How might a mutation affecting the production of collagen III impact the function of the reticular lamina?
How does the structural arrangement of tight junctions contribute to their function as barriers in epithelial tissues?
How does the structural arrangement of tight junctions contribute to their function as barriers in epithelial tissues?
How does the internal structure of microvilli differ functionally from that of cilia?
How does the internal structure of microvilli differ functionally from that of cilia?
What characteristic of epithelial tissue allows for quick repair and replacement of damaged cells?
What characteristic of epithelial tissue allows for quick repair and replacement of damaged cells?
Epithelial tissues are classified based on what characteristics?
Epithelial tissues are classified based on what characteristics?
What function does the basal lamina provide?
What function does the basal lamina provide?
What type of intercellular junction prevents passive flow materials between cells?
What type of intercellular junction prevents passive flow materials between cells?
What apical modification is longer and less motile than microvilli and often has distal branching?
What apical modification is longer and less motile than microvilli and often has distal branching?
What apical modification exhibits beating patterns that move materials in one direction?
What apical modification exhibits beating patterns that move materials in one direction?
Flashcards
Cellularity
Cellularity
Cells are closely packed and linked via junctions.
Epithelial Polarity
Epithelial Polarity
Epithelial cells have distinct apical, basal and lateral surfaces.
Basement Membrane Functions
Basement Membrane Functions
These provide structural support and act as a selective filter.
Tight/Occluding Junctions
Tight/Occluding Junctions
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Microvilli
Microvilli
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Stereocilia
Stereocilia
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Cilia
Cilia
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Tissue
Tissue
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Epithelial Tissue
Epithelial Tissue
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Epithelial Characteristics
Epithelial Characteristics
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Epithelial Domains
Epithelial Domains
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Basal surface
Basal surface
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Classification of Covering/Lining epithelia
Classification of Covering/Lining epithelia
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Squamous
Squamous
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Cubodial
Cubodial
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Columnar
Columnar
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Study Notes
- This lecture covers Unit 2: Epithelial Tissue from Human Histology (Lecture) MT120225 for the second semester of A.Y. 2024-2025 at UST General Santos, School of Health Sciences, Department of Medical Technology.
- The unit aims to enable students identify and describe various epithelial tissue types.
- Topics include Epithelial Cells, Epithelial Domains, Covering or Lining Epithelia, Secretory Epithelia and Glands, Transport Across Epithelia, and Renewal of Epithelial Cells.
Characteristic Features of Epithelial Cells
- Epithelial cells are characterized according to shape and dimensions, with nuclear shape corresponding roughly to cell shape.
Epithelial Cell Shapes
- Squamous cells have a height less than their width (H < W).
- Cuboidal cells have a height equal to their width (H = W).
- Columnar cells have a height greater than their width (H > W).
Epithelial Cell Polarity
- Epithelial cells exhibit distinct polarity and have three domains: apical, basal, and lateral.
Basal Surface
- The basal surface rests on the basement membrane, which includes basal lamina (BL) and reticular lamina (RL).
Basal Lamina
- The basal lamina is 20-100 nm thick and composed of glycoproteins, collagen, and proteoglycans. It is produced by epithelial cells.
- The basal lamina's functions: provide structural support to the overlying epithelium, act as semipermeable barriers, and offer interaction site for many cell adhesion molecules.
Reticular Lamina
- The reticular lamina contains collagen III fibers and is produced by fibroblasts in connective tissue.
Lateral Surface
- Intercellular adhesion and other junctions are present on the lateral surface.
- Tight/Occluding Junctions (Zonula Occludens) seal between adjacent cells to prevent passive flow of materials.
- Anchoring Junctions are sites of strong cell adhesion.
- Gap Junctions (Nexus) are patches of many connexons, permitting intercellular exchange of small molecules.
Medical Application: Clostridium perfringens
- Clostridium perfringens secretes enterotoxin that causes food poisoning.
- Enterotoxins prevent maintenance of tight junctions.
- The enterotoxins inhibit insertion of claudin molecules in intestinal cells, causing loss of tissue fluid into the intestinal lumen via paracellular pathway.
Apical Surface Features
- Microvilli: Finger-like cytoplasmic projections of epithelial tissue specialized for absorption, 1 um long and 0.1 um wide and increase surface area by 20-30 fold.
- Microvilli's internal core contains actin filaments and actin binding proteins.
- Stereocilia: Seen on absorptive epithelial cells lining male reproductive system and sensory cells of the inner ear and contains a core of actin filaments and actin binding proteins. They are longer and less motile than microvilli and often have distal branching.
- Cilia: Long, larger than microvilli, abundant on cuboidal or columnar cells, 5-10 um long and 0.2 um.
- Cilia's internal structure contains microtubules.
- Cillia exhibit beating patterns that move materials in one direction.
- Primary cilium: not motile, detects light, odor, motion, and flow of liquid.
Medical Application: Celiac Disease
- Celiac disease is the loss of microvilli brush border of the absorptive cells of the small intestine.
- It is caused by an immune reaction against wheat protein gluten during digestion, resulting in diffuse enteritis.
- Changes in epithelial cells from Celiac disease lead to malabsorption.
Covering or Lining Epithelia
- Covering or lining epithelia are classified according to cell layers and cell shape.
- Epithelial tissue consist of closely aggregated polyhedral cells adhering strongly to one another and to ECM.
- Epithelial tissue covers external surfaces of the body, line the internal cavities and the organs, form various organs and glands, and line their ducts
Characteristics of Epithelial Tissue
- Cellularity: Cells are in close contact with each other.
- Specialized contacts: Have junctions for attachment and communication.
- Polarity: Have apical, basal and lateral surface.
- Supported by connective tissue: Serve as a source of nutrients, metabolites and oxygen.
- Avascular but innervated.
- Regeneration: High mitotic rate.
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Description
Lecture on Unit 2: Epithelial Tissue from Human Histology (MT120225). Covers epithelial cell characteristics, shapes (squamous, cuboidal, columnar), and cell polarity relating to apical, basal, and lateral domains.
