The Digestive System Flashcards
What is mechanical digestion?
The breaking down of food by physical means
What is an example of mechanical digestion?
Chewing
What is chemical digestion?
The breaking down of food using chemical agents
What is an example of chemical digestion?
Enzymes and bile
What are enzymes?
Biological catalysts that speed up the rate of chemical reactions
What is absorption?
The process by which nutrients pass through the walls of the digestive system into the blood
Which occurs in the mouth: chemical digestion, mechanical digestion or both
Both
What enzyme is found in saliva?
Amylase
Where is amylase found?
Saliva (mouth) and pancreas
What does amylase do?
Breaks down starch
What does the swallowed food from the mouth become?
Bolus
What digestion occurs in the oesophagus?
No digestion
What is the function of the oesophagus?
To move bolus from the mouth to stomach
Which occurs in the stomach: chemical digestion, mechanical digestion or both
Both
How does mechanical digestion occur in the stomach?
The muscles in the stomach walls churn the bolus.
How does chemical digestion occur in the stomach?
Digestive enzymes (pepsin) and gastric acids mix with the bolus
What is the form of the food created in the stomach?
Chyme, which is a liquid
Where is pepsin found?
Stomach
What enzyme is found in the stomach?
Pepsin
What does pepsin do?
Breaks down proteins
Where is bile made?
Liver
Where is bile released?
Gall bladder
What does bile do?
Helps digest fats
Where does bile get released to?
The small intestine
What is combined with chyme to start the final part of digestion?
Enzymes from the pancreas and intestinal walls
How is nutrients absorbed in the small intestine?
Through its walls
What is left after chyme exits the small intestine?
Water and undigestible substances
What happens in the large intestine?
Water is reabsorbed and faeces is formed
What are the 4 accessory organs?
Salivary glands, liver, gall bladder, pancreas
What do the salivary glands do?
Moisten the food and and begin the chemical digestion of starches (amylase)
What does the liver do?
Creates bile for fat digestion, processes absorbed vitamins
What does the gall bladder do?
Stores and realeased the bile formed in the liver
What does the pancreas do?
Secretes digestive enzymes into the duodenum. Also makes insulin
What are the 3 parts of the small intestine in order?
Duodenum, jejunum annd ileum
What are some of the enzymes released by the pancreas?
Amylase, Trypsin and Lipase
What does hydrochloric acid do in the stomach?
Denatures proteins and converts pepsinogen into pepsin
What does pepsin do?
Breaks down proteins
What does lipase do?
Breaks down lipids
What does trypsin do?
Breaks down proteins
Where is trypsin in the body?
Small intestine
Where is lipase in the body?
Stomach
Explain the role of hydrochloric acid on the function of pepsin
It creates a pH environment required for pepsinogen to convert it into pepsin. It is also the optimum pH for it to work efficiently
What does the involvement of hydrochloric acid tell you about the optimum pH of pepsin?
The optimum pH of pepsin is low (acidic)
What happens to an enzyme when it is denatured?
It changes shape, so the active site is not longer able to bind with a substrate.
