Digestion Flashcards
Why do we need food (3)
To supply us with “fuel” for energy
To provide materials for growth and to repair tissues
To help fight disease and keep our bodies healthy
What are the 7 types of nutrients in all food
Carbohydrates Lipids Proteins Water Fibre Minerals Vitamins
What does too much sugar cause (2)
Sugar gets stored as fat which leads to obesity
Causes tooth decay as the bacteria in the mouth feeds on the sugar and breaks it down releasing acid which dissolves the enamel
Why do we need carbohydrates
Used to release energy during respiration
What are lipids used for
To make cell membranes, insulation, protection of organs, energy store
What can too much fat lead to
Heart disease
What do all cells contain
Protein
Why do we need proteins (5)
For growth and repair of tissues Hormones Enzymes Antibodies Transport
If we are deficient in proteins what do we develop
A disease called kwashiorkor
What is the purpose of digestion
To break food into molecules that are small enough to be absorbed into the blood stream
What is mechanical digestion and examples
Digestion by physically breaking down food into smaller pieces without enzymes
Mouth and teeth chewing food
Stomach churning food
What is chemical digestion
Digestion using enzymes
Which enzyme is excreted from the salivary glands and what is it used to break down into what
Amylase is used to break down starch into maltose
Which enzyme is found in the stomach and what does it break down into what
Protease is used to break down proteins into amino acids
Which enzyme is found in the small intestine that was made in the pancreas and what does it break down into what
Amylase breaks down starch into maltose
Protease breaks down proteins into amino acids
Lipase breaks down fat into glycerol and fatty acids
What is digestion
The chemical and mechanical break down of food
What does digestion do
Converts large insoluble molecules into small soluble molecules which can be absorbed into the blood
What is ingestion
The consumption of a substance
What is absorption
Taking molecules into the bloodstream
What happens in the mouth (4)
Food is ingested
Mechanical digestion- teeth are chewing (increases surface area)
Chemical digestion- amylase in saliva breaks down starch into maltose
Food is rolled by the tongue into a bolus and swallowed
What happens in the oesophagus and wth is it
It is the food pipe connecting the mouth and the stomach
Food is moved down here by muscular contractions know as peristalsis
What is the stomach what types of digestion occur there
What else?
Large muscular bag
Mechanical digestion- churns food
Chemical digestion- gastric juice is excreted
Gastric juice contains pepsin which is activated by HCl as it provides optimum pH 2. Also contains HCl which kills bacteria
Goblet cells produce mucus as a lining to prevent damage from HCl
What is the duodenum what type of digestion occurs there
First section of small intestine where digestion is completed
Chemical digestion - pancreatic juice contains maltase, pancreatic amylase, protease and lipase
And bile
What is bile
Made in the liver, stored in the gall bladder
Function is to emulsify large lipids into small fat droplets, increasing the surface area for the enzymes to work
What pH are bile and pancreatic juice and why
Alkali to neutralise the good covered in stomach acid
What is the ileum and what occurs there
Part of the small intestine
Most of absorption takes place here
How does absorption take place
Passively or by active transport
How is the ileum adapted to it’s function
Highly folded finger like projections called villi
- increases surface area
- thin walls decrease diffusion pathway
- micro villi on the surface
- rich blood supply
What is assimilation
A process which uses products of digestion to build new molecules
What happens after food has been digested and absorbed
Assimilated into the body
What type of stuff is left to go into the colon and what is the colon, what is the main role
Part of the large intestines
Undigested food, mucus, dead cells, bacteria
Reabsorbtion of water and mineral ions
What is the rectum and what is its role
In the large intestines
Where faeces are stored until it is egested from the body via the anus
What is egestion
The discharge of Undigested material from the digestive system
