Describe the process of carbohydrate digestion in human beings.

- In the mouth food is mechanically broken down by the teeth through a process called
mastication or chewed. This helps to reduce food into small particles increasing surface area for enzymatic action and also moisten and mix food withsaliva. Saliva contains
mucus to lubricate food easier swallowing.
-Saliva also contain salivary amylase/ptyalin enzyme act on starch that digest/ breakdown starch and convert it to maltose. Saliva also has water which acts as a solvent and provides an alkaline medium for amylase enzymes.
-Food is pushed to the oesophagus and passes down to the stomach through peristalsis. Food
in the stomach stimulates production of gastrin hormone that stimulates release of gastric juice.
-Starch digestion stops in the stomach due to acidic PH caused by hydrochloric
acid in gastric juice. Walls of the stomach contract and relax causing
churning of food leading to fluid called chyme. Chyme is let out into duodenum through pyloric sphincter. Presence of food in the duodenum stimulates production secretin hormone from duodenal wall.
-Secretin hormone in turn stimulates release of bile juice from the gall bladder
and pancreatic juice from pancreas. Bile neutralizes acid in the chyme,
providing an alkaline medium suitable for action of enzymes in the duodenum. Pancreatic juice contain pancreatic amylase which speeds up the breakdown of remaining starch
and convert it to maltose.
-The chime then moves into ileum. The inner walls of the ileum secretes
mucus and succus entericus/intestinal juice due to presence of chyme in the ileum. The juice
contain enzymes namely:
- Maltase that acts/ breakdown of maltose converting it to glucose.
- Sucrase or invertase that acts on sucrose and speeds up breakdown of
sucrose into glucose and fructose.
- Lactase which acts on lactose and converts it to galactose and glucose.
Complete digestion results in formation of chime with soluble products ready to
be absorbed.