Absorption in the small intestine: villi and microvilli

• What is the name of the structure labeled "Villi" in the image?

  Villi
• What are the main components of the intestine shown in the image?

  • Muscle layers
  • Villi
  • Lumen
  • Capillary bed
  • Lacteal
• What is the name of the structure labeled "Epithelium" in the image?

  Epithelium
• How do capillaries and lacteal vessels function in the small intestine?


  They allow absorption of nutrients from food
• What type of microscopic structure is shown in the image?

  • The image shows a microscopic cross-section of intestinal villi
• What is the function of the submucosa in the small intestine?

  It provides supporting tissue with blood vessels
• How do the structures of the intestine, villi, and epithelium work together to facilitate nutrient absorption?

  • Intestine provides the overall structure and lumen for digestion
  • Villi increase surface area for absorption
  • Capillaries and lacteals in villi absorb nutrients from the lumen
  • Epithelial cells and microvilli further facilitate nutrient uptake
• How does the structure of the cell membrane differ from the structure of the cytoplasm?

  The cell membrane is a selectively permeable barrier, while the cytoplasm is the internal fluid-filled region of the cell
• What role do villi and microvilli play in the small intestine?

  • Villi project into the intestinal lumen
  • Increase surface area for absorption
  • Microvilli on epithelial cells further enhance surface area
• What is the purpose of the large surface area created by villi in the small intestine?

  To enhance nutrient absorption
• What is the name of the structure labeled "Terminal web" in the image?

  Terminal web
• What is the name of the structure labeled "Villi" in the image?

  Villi
• What are the three main layers of the small intestine wall?

  Mucosa, submucosa, and outer muscle layers
• What is the name of the structure labeled "Plicae circulares" in the image?

  Plicae circulares
• What is the function of the villi in the small intestine?

  • Increase the surface area for absorption of nutrients
  • Contain capillaries and lymphatic vessels to absorb nutrients
  • Contain microvilli to further increase the surface area
• What is a villus?

  A finger-like projection in the intestinal mucosa
• What is the significance of microvilli on epithelial cells in the small intestine?

  They further increase surface area at microscopic level
• How do microvilli affect surface area?

  They significantly increase surface area for absorption
• What is the function of the plicae circulares in the small intestine?

  • Increase the surface area for absorption of nutrients
  • Create a spiral pattern to slow the movement of food
  • Enhance mixing and absorption of nutrients
• What is absorption in the small intestine?

  Process of moving digested food into bloodstream
• What anatomical features of the intestinal villi can be observed in the image?

  • The image shows the columnar epithelial cells lining the villi
  • The villi have a finger-like projection to increase surface area
  • There are blood vessels and lymphatic vessels within the core of the villi
• By how much does the surface area of the small intestine increase due to villi?

  From 1m² to 500m²
• How do villi enhance nutrient absorption in the small intestine?

  • Increase surface area of the intestine
  • Facilitate mixing of food with digestive juices
  • Allow efficient nutrient collection through blood and lymphatic vessels
• What is the function of the intestinal villi shown in the image?

  • Intestinal villi increase the surface area of the small intestine to facilitate absorption of nutrients from digested food
• How does the structure of the cell membrane differ from the structure of the extracellular space?

  The cell membrane is a selectively permeable barrier, while the extracellular space is the region outside the cell
• What separates each villus from the supporting tissue?

  Basement membrane
• What is the function of microvilli in the intestinal lumen?

  They increase absorption surface area
• If the hepatic portal vein is blocked, how would that affect nutrient absorption in the intestine?

  Nutrients would not be able to be transported to the liver
• What is found in the center of each villus?

  Lacteal (lymphatic vessel)
• What is the title of the image?

  Epithelial transport in disease
• How does the structure of the cell membrane allow it to function as a selectively permeable barrier?

  • Phospholipid bilayer is hydrophobic, allowing only small, uncharged molecules to pass through
  • Membrane proteins act as channels and transporters to regulate what enters and leaves the cell
  • Cholesterol helps maintain membrane fluidity and permeability
• If you wanted to observe the detailed structure of the epithelial cells lining the intestine, which type of microscope would you use?

  Scanning electron microscope
• How do the components of villi contribute to their function?

  They enhance nutrient absorption in the intestine
• Why is the resolution limit of a light microscope 0.2 µm?

  Because it is the wavelength of visible light
• What are the key features of the villi structure shown in the image?

  • Lumen
  • Capillary bed
  • Lacteal
• What are the key features of microvilli?

  • Length: 0.6-1.0 μm
  • Covered in glycocalyx layer
  • Supported by cytoskeleton
• What is the name of the organ that connects the mouth to the stomach?

  Esophagus
• How does the function of a scanning electron microscope (SEM) differ from a transmission electron microscope (TEM) in studying biological samples?

  SEMs produce 3D images of surface structures, while TEMs produce 2D images of internal cellular structures
• How does absorption in the small intestine relate to digestion?

  Absorption follows digestion to utilize nutrients
• What is the name of the space outside the cell membrane?

  Extracellular space