The task of the esophagus is very straightforward; transport the food from the mouth cavity into the stomach.
This is the ‘swallowing’ act that we are all familiar with. The food is transported as a sequence of boluses down the tube.
The esophagus is a long tube that passes from the skull, through the thorax, adjacent to the lungs and the heart, runs through a hole in the diaphragm, and finally ends in the stomach.
The swallowing is actually an active process whereby the muscles inside the wall of the esophagus relax and contract in order to ‘push’ the food bolus into the stomach. This is called ‘peristalsis’.
The small intestine is not small at all! It is actually a very long tube, about 3-5 meters in a human adult. The small intestine is not that small! It is actually a very long tube, about 3-5 meters in a human adult.
This is the organ where most of the foodstuff gets absorbed into the body. In a sense, this is the center, or the ‘heart’ of the GI-system.
The chyme is pushed along this long tube by the walls of the tube that contract in a peristaltic manner; pushing the chyme in front of the contractions.
The small intestine is divided into three segments:
a. the duodenum
b. the jejunum
c. the ileum
The duodenum is relatively short, about 20-30 cm long, receives the chyme from the stomach and mixes it with digestive juices that come from the liver and the pancreas.
The jejunum is longer, about 2 meters, and this is were a lot of the nutrients (amino acids, sugar and fatty acids) gets absorbed into the blood stream.
The ileum is the last and longest part of the small intestine, approx. 3 meters long and absorbs mainly vitamin B12 and bile acids.
The liver is the major biochemical factory in the body!
It produces many compounds such as proteins and hormones, regulates glycogen storage etc., etc.
The liver also detoxifies various metabolites and produces bile. This bile, stored in the gallbladder and released into the duodenum, helps in the breakdown and the emulsification (= blending in water) of fats in the food.