The first part of the small intestine is called the duodenum. The duodenum is only 25 cm long, but most of the digestion takes place in this region.

Small intestines

Small intestinesSmall amounts of chyme are ejected approximately every 20 seconds from the stomach into the duodenum. #digestion

Small intestines

#digestion #juices

Also opening into the duodenum are ducts from the pancreas and the gall bladder. These allow enzyme-rich pancreatic juice and bile to be released and mixed with the chyme.

Small intestinesChemical breakdown of carbohydrate, protein and fats into smaller absorbable molecules takes place.

#digestion #absorptionbegins

Peristaltic waves of muscular contraction mix and move the chyme down the duodenum and into the jejunum, measuring about 2.5 m long.

Small intestines

#absorption

Small intestinesPeristaltic waves of muscular contraction move the chyme through the jejunum until it reaches the ileum.

#absorption

Small intestinesThe jejunum has a huge surface area created by finger-like structures called villi. These assist with the absorption of nutrients into the bloodstream.

#absorption #villi

VilliVilli play an important role in absorbing the breakdown products of digestion.The increase in surface area, allows for ready absorption of these products of digestion.

#absorption #villi

VilliWith villiFlat surface

Nutrients to bloodstream

VilliEach villus has a rich blood supply, allowing nutrients to be readily absorbed and transported to the liver. A lacteal is also present; absorbing fat nutrients and carrying them to the circulatory system.

#whatyatalkinboutvillus