the villi are located in the lumen of the small intestine.
the villi are located in the lumen of the small intestine.
where is the villi located in the small intestine?
the lumen
eggs are deposited in feces of dogs, becoming infectious after 2–4 weeks. dogs ingest infectious eggs, allowing the eggs to hatch and the larval form of the parasite to penetrate through the gut wall. in dogs under 3 months of age, the larvae hatch in the small intestine, get into the bloodstream, migrate through the liver, and enter the lungs. once in the lungs, the larvae crawl up the trachea. the larvae are then coughed up and swallowed, leading back down to the small intestine, where they mature to adulthood. this process is called tracheal migration. in dogs older than 3 months of age, the larvae hatch in the small intestine and enter the bloodstream, where they are carried to somatic sites throughout the body (muscles, kidney, mammary glands, etc.) where they become encysted second stage larvae. this process is called somatic migration. at the height of pregnancy, the encysted eggs in an infected female dog will migrate from the mother to the developing fetus, where they will reside in the liver. after parturition, the larvae migrate from the pup's liver to the lungs to undergo tracheal migration. alternatively, the migrating larvae in the mother may encyst within the mammary glands, becoming active during lactation and passing directly to the nursing puppy via the milk. larvae transmitted in this manner do not migrate once they are within the small intestine of the puppy; they will develop directly into the adult stage in the small intestine. once infected, a female dog will usually harbor sufficient larvae to subsequently infect all of her litters, even if she never again encounters an infection. a certain amount of the female dog's dormant larvae penetrate into the intestinal lumen, where molting into adulthood takes place again, thus leading to a new release of eggs containing l larvae.
toxocara canis
after this, the digesta is moved to the true stomach, the abomasum. this is the gastric compartment of the ruminant stomach. the abomasum is the direct equivalent of the monogastric stomach, and digesta is digested here in much the same way. this compartment releases acids and enzymes that further digest the material passing through. this is also where the ruminant digests the microbes produced in the rumen. digesta is finally moved into the small intestine, where the digestion and absorption of nutrients occurs. the small intestine is the main site of nutrient absorption. the surface area of the digesta is greatly increased here because of the villi that are in the small intestine. this increased surface area allows for greater nutrient absorption. microbes produced in the reticulorumen are also digested in the small intestine. after the small intestine is the large intestine. the major roles here are breaking down mainly fiber by fermentation with microbes, absorption of water (ions and minerals) and other fermented products, and also expelling waste. fermentation continues in the large intestine in the same way as in the reticulorumen.
ruminant