Cellularity and specialized contacts

• What are the key features of epithelial tissue?

  • Covers body surfaces and lines internal organs
  • Provides protection, secretion, and absorption functions
  • Cells are tightly packed with little extracellular matrix
  • Can be classified into different types (e.g. simple, stratified, columnar, cuboidal)
• What is the function of actin-linked cell matrix junctions?

  They connect the actin cytoskeleton of a cell to the extracellular matrix, anchoring the cell
• How do cell-cell junctions and cell-matrix junctions differ in their functions?

  Cell-cell junctions connect adjacent cells, while cell-matrix junctions connect cells to the extracellular matrix
• How does the appearance of the tissue in the image suggest it is epithelial?

  The tightly packed, organized cells with minimal extracellular matrix is characteristic of epithelial tissue
• What is the function of adherens junctions?

  Adherens junctions connect the actin cytoskeletons of adjacent cells, helping to maintain tissue integrity and organization.
• What is the function of desmosomes?

  Desmosomes are spot-like attachments that connect the intermediate filaments of adjacent cells, providing strong cell-cell adhesion.
• What microscope technique would be best to further study the detailed structure of this epithelial tissue sample?

  • Scanning electron microscope (SEM) to visualize the 3D surface structure in high detail
  • Transmission electron microscope (TEM) to examine the internal ultrastructure of the cells
• What is the function of gap junctions?

  They allow direct communication between adjacent cells by forming channels that permit the passage of small molecules and ions
• What are the different types of cell junctions shown in the image?

  • Tight junctions
  • Adherens junctions
  • Desmosomes
  • Gap junctions
  • Hemidesmosomes
  • Extracellular matrix junctions
  • Cell-cell junctions
  • Cell-matrix junctions
• What is the composition of the reticular lamina?

  Collagen and connective tissue fibers
• What is the composition of the basal lamina?

  Extracellular matrix secreted by epithelial cells
• What visual representation is provided in the study material?

  An image showing junction types
• What do hemidesmosomes do in epithelial tissue?

  Anchor cells to the basement membrane
• What are the key cell junctions found in epithelial cells?

  • Tight junction
  • Adhesive belt
  • Desmosome
  • Gap junction
• What is the function of the cilia-propel structure in the epithelial cells?

  To move substances across the epithelial surface
• What are the three distinct domains of epithelial cells?

  • Apical domain: faces outside or a cavity
  • Basal domain: attaches to basement membrane
  • Lateral domain: connects to neighboring cells via junctions
• Why is the apical domain of the tight junction important?

  It is the site of the barrier function
• How would the structure and components of a blood vessel differ between an artery and a vein?

  • Arteries have thicker muscular walls to withstand higher pressure
  • Veins have thinner walls and larger lumen to accommodate lower pressure
  • Arteries have more elastic fibers, veins have more collagen
  • Arteries have a more prominent endothelium and basal lamina
• How do the structural differences between the blood vessels in the top and bottom images relate to their function and location in the body?

  • Top image likely shows a capillary or small blood vessel with more detailed cellular components
  • Bottom image shows a larger blood vessel, potentially an artery or vein, with a wider lumen and thicker walls
  • Structural differences relate to the varying functions and pressures experienced by blood vessels at different locations in the circulatory system
• What are the key differences between the cross-sections of the blood vessel shown in the top and bottom images?

  • Top image shows a more detailed cross-section with additional labeled structures like vesicles and channel
  • Bottom image provides a more zoomed out view showing the overall vessel structure and lumen
  • Bottom image also labels additional structures like the fenestrae, diaphragm, and knob
• If you wanted to study the detailed surface features of an epithelial cell, which microscope technique would you use?

  Scanning electron microscope (SEM)
• What type of blood vessels are involved in supplying nutrients to epithelial tissue?

  Capillaries
• What are the types of specialized junctions in epithelial tissue and their functions?

  • Tight junctions: Seal space between cells
  • Desmosomes: Provide strong adhesion
  • Gap junctions: Allow direct communication
  • Hemidesmosomes: Anchor to basement membrane
• What is the primary function of desmosomes in epithelial tissue?

  Strong adhesion between cells
• What is the name of the structure labeled as "collagen" in the image?

  Collagen
• What type of junction seals the space between epithelial cells?

  Tight junctions
• What is the purpose of the tight junction in the vertebrate epithelium?

  To create a barrier function and control paracellular transport
• What is the function of the basement membrane?

  It connects epithelium to underlying connective tissue
• How do the structural features of epithelial cells allow them to perform their functions effectively?

  • Cilia-propel moves substances across the surface
  • Microvilli-absorb increases surface area for absorption
  • Cell junctions provide structural integrity and selective permeability
  • Basal region anchors the epithelial cells to the underlying connective tissue
• What are the main components of the adherens junction in the vertebrate epithelium?

  • Cadherin
  • Nectin
• What is the nature of epithelial tissue?

  Avascular
• How do the junction types in epithelial tissue relate to their location?

  Each junction type has a specific layer location
• What are the main structural components of the basal region of an epithelial cell?

  • Basal lamina
  • Reticular fibers
  • Basement membrane
• What does the apical domain of epithelial cells face?

  Outside or a cavity
• How do the basal and reticular laminae work together?

  They provide a firm attachment for the epithelium
• What is the name of the narrow extracellular space between the epithelial cells?

  Narrow extracellular space
• How does the arrangement of cells in epithelial tissue differ from other tissues?

  It has minimal extracellular space
• How are the domains of epithelial cells arranged in vertebrate and insect tissues?

  • Apical domain faces outside or cavity
  • Basal domain attaches to basement membrane
  • Lateral domain connects to neighboring cells
• What does the image in the study material illustrate about epithelial tissue?

  It shows blood vessels in connective tissue below
• How do the tight junctions in vertebrate and insect epithelium differ in their structure and function?

  Vertebrate tight junctions create a barrier, while insect sepate junctions facilitate paracellular transport