The Digestive System Flashcards
How many organs are in the digestive system?
10 organs.
What do enzymes, hormones, nerves and blood do?
Break down food, modulate digestive process and deliver the final products.
What is the function of the teeth in the digestive process?
They mechanically break down food.
What is the function of saliva in the digestive system?
Saliva carries enzymes.
What do the enzymes in saliva break down?
Starch.
Do enzymes complete chemical or mechanical digestion?
Chemical.
Why are the walls of the stomach muscular?
To churn up food.
What are the functions of stomach acid?
It kills bacteria, and lowers the Ph for enzymes to survive.
What happens in the small intestine?
Small, soluble molecules are absorbed into the bloodstream.
What happens in the large intestine?
Water is reabsorbed.
What is the liver’s function?
It produces bile to digest lipids.
What is the function of the pancreas?
It produces several enzymes.
What are enzymes?
Catalysts.
What do enzymes do?
They speed up chemical reactions.
True or false: enzymes are not altered by the reactions they speed up.
True
What are proteins broken down into (by pepsin)?
Amino acids.
What does pepsin break down?
Proteins.
What are lipids broken down by?
Lipase
What does lipase break down lipids into?
Fatty acids
What does amylase break down?
Carbohydrates
What are carbohydrates broken down into (by amylase)?
Small sugars
What is the purpose of villi?
To absorb soluble substances to be passed into the bloodstream.
What is the process of soluble substances being passed into the bloodstream called?
Diffusion
Name 3 adaptations of villi:
Thin walls, large surface area, good blood supply.
Why do villi have thin walls?
So that substances don’t have to travel far to get to blood.
Why do villi have a large surface area?
To make absorption faster - more molecules can be absorbed at one time.
Why do villi have good blood supply?
So that substances can be immediately transported to body cells.
What is the first step of the digestive process?
The brain anticipates food, and sends an electrical impulse to make the salivary glands start to produce saliva.
What happens after the salivary glands start to produce saliva?
Chewing combines saliva and food.
What does chewing the saliva and food create?
A bolus.
What is the name of the tube which the bolus is passed down?
The oesophagus.
What is the name of the muscle contractions that moves food down the oesophagus?
Peristalsis.
After the bolus is in the stomach, what happens next?
The stomach walls break it into chunks.
What do the cells in the lining of the stomach secrete?
Hormones.
What do the hormones (which the cells in the lining of the stomach secrete) trigger?
Acid and enzyme-rich juices are released from the stomach wall. They also alert the pancreas, liver and gallbladder to produce digestive juices and transfer bile.
How long does it take for the bolus to become chyme?
3 hours
What does the bolus become?
Chyme
After the bolus becomes chyme, where does it go?
The small intestine
The liver sends bile to the gallbladder, where is this secreted?
The first portion of the small intestine - the duodenum.
What does bile dissolve (in chyme)?
fat.
What is fat in chyme broken down into?
fatty acids and glycerol.
What are the names of the lower regions of the small intestine?
The jejunum and ileum.
What is another name for the large intestine?
The colon.
What happens in the colon?
leftover fibre, water and dead cells are reabsorbed.
Where does stool go after being in the large intestine?
the rectum.
Where is stool egested from?
the anus.
What is egestion?
The expulsion of undigested food via the anus.
What do gut bacteria live off, in a diet?
Fibre
What do gut bacteria do?
Assist in breaking down food molecules, produce some vitamins, break down harmful toxins.
Give some examples of vitamins that gut bacteria produce.
Vitamin K and B12
What can increase gut bacteria?
Probiotics
