B6.2 - Alimentary canal Flashcards
What are the 5 processes of the alimentary canal
Ingestion Digestion Absorption Assimilation Egestion
What is digestion
breaking down of large food molecules into smaller water-soluble molecules using mechanical and chemical processes
What is ingestion
taking in of substance i.e food and drink into the body through the mouth
What is absorption
movement of small food molecules through the wall of the intestine into the blood
What is assimilation
movement of digested food molecules into cells where they can be used to produce other molecules or in respiration
What is egestion
passing out of food that has not been digested, through the anus, as feces
What is the alimentary canal
it is a continuous tube through the body from the mouth where food is ingested to the anus where the remaining food is egested
What parts of the body pass food down the alimentary canal
mouth, oesophagus, stomach, small intestine, large intestine and anus
function of the mouth
for teeth and tongue to break down food into smaller pieces
What parts of the digestive system are not in the alimentary canal
pancreas, liver, salivary glands and gall bladder
function of the salivary glands
to produce liquid saliva which moistens food to be easily swallowed.
Contains enzymes such as amylase to begin breakdown of starch
function of the oesophagus
to move the food from the mouth to the stomach via waves of muscle contraction called peristalsis
function of the liver
To make bile.
Excess glucose is stored as glycogen in liver cells
Proteins are broken down to form urea passed to the kidneys for excretion
Function of gall bladder
To store bile from liver and to pass it along the bile duct into the small intestine.
Bile neutralizes the stomach acids
Function of pancreas
to secrete digestive enzymes in an alkaline fluid into the small intestine
Function of large intestine (colon)
to absorb the rest of the water from the remaining foot material
Function of the anus
feces are egested through here
Fibre helps keep
food molecules clumped together called bolus to be bulky and soft making peristalsis easier
What is mechanical digestion
breaking down bigger pieces of food into smaller pieces using force. It can be done via mastication (chewing) from the teeth, by stomach contracting and by bile
What is chemical digestion
breaking down larger food molecules into smaller soluble particles to be able to pass through the bile in the bloodstream with the use of digestive enzymes
Where are digestive enzymes located
the salivary glands, stomach, pancreas and small intestine
Absorption of food happens in
the iluem
What are the two parts of the small intestine and their functions
Duodenum: responsible for the rest of digestion with the help of digestive enzymes and bile
Ileum: Where food molecules are absorbed through the blood stream via diffusion with the help of small villi. Most water is absorbed into the blood
Why is it necessary to breakdown large, insoluble food molecules into smaller, soluble molecules?
Large, insoluble food molecules can’t be absorbed into the bloodstream.
Small, soluble molecules can be absorbed into the bloodstream and used to construct new carbohydrates, proteins and lipids in the body.
Some glucose produced by digestion is used for respiration.
Why are feces relatively dry
because water has been removed from food remains and absorbed by the small intestine and large intestine and diffused into the blood stream
