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Intestinal structure
 Structure
• Crimpy structure to facilitate the contacts
between nutrients and absorptive cells
 Extends surface area to 300 m2
 Functions
• Lined by a single layer of enterocytes
 Efficient structure for absorption of
nutrients
 Not an effective structure for barrier
function
(Illustration: courtesy of the University of Waikato)
• To effectively block pathogens
 Barrier system
 Gut-associated immune system
Intestinal structure
(photo: courtesy of Southern Illinois University, School of Medicine)
Capillaries leading to portal veins underneath the single layer of enterocytes
Any damage in enterocytes will open up primary barrier function and pigs will be exposed to infections
Intestinal immune system – antigen uptake as a surveillance system
• Antigen sampling through M cell
• Preparing possible open up of
intestinal barrier and pathogen
invasion
• Require energy and protein
• Perform less efficiently in a dirty
environment
Nature Reviews Immunology,
Mowat et al., 2003
Physical barriers in the monolayer of enterocytes
Paracellular permeability is directly related to pathogen
translocation into the body system and TJ plays a key role
Loose tight junction causes “leaky gut”
Groschwitz and Hogan, 2009