6.1 Digestion Flashcards
What are the 2 major groups of organs which comprise the human digestive system?
alimentary canal and accessory organs
What does the alimentary canal consist of?
The alimentary canal consists of organs through which food actually passes (oesophagus, stomach, small & large intestine)
What are the accessory organs?
salivary glands, pancreas, liver, gall bladder
What is the difference between alimentary canal an accessory organs?
Food passes through alimentary canal, but accessory organs aid in digestion but do not actually transfer food
What is the structure of the oesophagus?
A hollow tube connecting the oral cavity to the stomach (separated from the trachea by the epiglottis)
What is the role of the oesophagus?
Food is mixed with saliva and then is moved in a bolus via the action of peristalsis
What is the structure of the stomach?
A temporary storage tank where food is mixed by churning and protein digestion begins
What is the stomach lined with?
It is lined by gastric pits that release digestive juices, which create an acidic environment (pH ~2)
What is the structure and role of the small intestine?
A long, highly folded tube where usable food substances (nutrients) are absorbed
What are the 3 sections of the small intestine?
Consists of three sections – the duodenum, jejunum and ileum
What is the structure of the large intestine?
Consists of the ascending / transverse / descending / sigmoidal colon, as well as the rectum
What is the role of the large intestine?
The final section of the alimentary canal, where water and dissolved minerals (i.e. ions) are absorbed
What is the structure of the salivary glands?
Salivary glands include the parotid gland, submandibular gland and sublingual gland
What is the role of the salivary glands?
Release saliva to moisten food and contains enzymes (e.g. amylase) to initiate starch breakdown
What is the role of the pancreas?
Produces a broad spectrum of enzymes that are released into the small intestine via the duodenum
What, apart from enzymes, does the pancreas secrete?
Also secretes certain hormones (insulin, glucagon), which regulate blood sugar concentrations
What is the overall role of the liver?
Takes the raw materials absorbed by the small intestine and uses them to make key chemicals
What are the 5 main functions of the liver?
Its role includes detoxification, storage, metabolism, bile production and haemoglobin breakdown
What is the role of the gall bladder?
The gall bladder stores the bile produced by the liver (bile salts are used to emulsify fats)
Where is bile stored and where is it released into?
Bile stored in the gall bladder is released into the small intestine via the common bile duct
Learn how to draw the digestive system
How is food digested? (methods)
Food can be digested by a combination of two methods – mechanical digestion and chemical digestion
What is mechanical digestion?
In mechanical digestion, food is physically broken down into smaller fragments via the acts of chewing (mouth), churning (stomach) and segmentation (small intestine)
Where is food initially broken down mechanically?
Food is initially broken down in the mouth by the grinding action of teeth (chewing or mastication)