Digestion Flashcards
What is the alimentary canal?
The alimentary canal is the journey your food takes from the mouth to the anus, as one long tube, except the liver and pancreas.
What happens in the mouth?
In the mouth, the food (or bolus) is mechanically chewed by the teeth, mechanically digesting it. Additionally, saliva, containing amylase, is secreted from the salivary glands, partially chemically digesting starch into maltose.
What happens in the oesophagus?
In the oesophagus, the bolus is transported from the mouth to the stomach due to peristalsis, the rhythmic contracting of the antagonistically-working muscle pair in the muscle lining of the oesophagus, squeezing food through it.
What happens in the salivary glands?
The salivary glands produce key enzymes (amylase) required for the chemical digestion of carbohydrates.
What happens in the liver?
The liver produces bile
What is another word for the oesophagus?
The gullet
What happens in the stomach?
The stomach contains hydrochloric acid, with a low acidic pH, to kill bacteria and create an optimum pH for enzyme action, such as the protease pepsin. It produces key enzymes.
What happens in the pancreas?
The pancreas produces the vast majority of digestive enzymes located in the body, such as amylase, lipase, trypsin, maltase and more.
What happens in the gall bladder?
Bile is stored from the liver until needed by the body. It send the needed bile to the small intestine and removes infected bile.
What happens in the small intestine?
In the small intestine, peristalsis takes place, as well as the secretion of bile, the chemical digestion of many large molecules, and the absorption of the small units of molecules.
What happens in the duodenum?
Enzymes, such as protease, lipase and amylase, do a lot of chemical digestion, as lipase breaks down lipids into fatty acids and glycerol. First part of small intestine
What happens in the ileum?
Digested food small molecules are absorbed into the bloodstream. Final part of small intestine
What happens in the large intestine?
Peristalsis
What happens in the colon?
First part of the large intestine. Faeces is formed here
What happens in the rectum?
Final part of the large intestine. Faeces is stored here.
What happens in the anus?
Faeces is egested.
What is the bolus?
It is the ball of food made in the mouth.
Bile description
Bile is a key part of the digestive system, but is NOT an enzyme - the liver does not produce digestive enzymes, the pancreas does. Bile is produced in the liver.
Bile function
Bile breaks down large fat droplets into smaller fat droplets for the enzymes to digest them (chemical digestion). It does not alter the fat droplets chemically, that is the role of the enzymes. The fat molecule STAYS THE SAME, it is the droplet size that CHANGES. This process is known as EMULSIFICATION. It also neutralises the low pH in the small intestine (due to hydrochloric acid) in order to create an environment of optimum pH for enzymes.
Ingestion
The intake of substances (food/drink) into the body through the mouth
Digestion
The breakdown of large, insoluble food molecules into small water-soluble molecules using mechanical or chemical processes
Absorption
Movement of digested food molecules across the wall of the intestine in the blood or lymph
Assimilation
Movement of digested food molecules into the cells where they are used, becoming art of the cells (includes uptake and use of food molecules by cells).
Egestion
Passing out of undigested food as faeces, through the anus. Undigested food is the food that cannot be digested.