Unit 3 : Digestion Flashcards
What is the functions of the mouth?
Mechanical breakdown : mastication
Chemical breakdown: saliva from the salivary glands
Where does amylase come from?
salivary amylase from salivary glands
pancreatic amylase from pancreas
Why does the saliva contains water?
to solubilizes dry food and it is required for tasting
What is lysozyme and where is it found (in GI)?
It is contained in the mouth (saliva) and it inhibits bacterial growth.
What are the three actions food go through in the mouth?
1) Ground by teeth
2) Mixed with saliva
3) Moved/mixed and propelled by tongue
How is call the round shape food is forms into by the mouth?
Bolus
How does the pharynx and esophagus move/propel the bolus to stomach?
Using peristaltic contraction
Name the five tissue layers typical of other GI tract organs?
From proximal to distal : Lumen, Mucosa, Submucosa, Smooth muscles, Adventitia.
What is the role of the lumen?
It is a cavity or space
What is the role of the mucosa?
Like epithelium, makes and secretes mucus
What is the role of submucosa?
It connects epithelium to muscle
What is the role of the smooth muscles?
It moves food through organ
What is the role of adventitia?
It is the connective tissue - outside layer
What are peristaltic waves?
Mechanical breakdown and propulsion used by oesophagus, stomach, small intestine and large intestine
Where does the bolus becomes chyme?
In the stomach and it is slowly added to small intestine
What does the stomach secretes?
Mucus (protects from acid/digestive enzymes)
H+ and Cl- from parietal cells
Pepsins from (chief cells protein-digesting enzymes)
Gastric lipase (break down lipids into polypeptides)
What are the function (3) of hydrochloric acid?
solubilizes food particles
kills microbes
denatures (unfolds proteins)
What substances does the stomach absorb?
Alcohol, aspirin, some drugs
How is called the mechanical digestion mixing chyme with digestive juices in the small intestine
segmentation
Where does the digestive juices use in the small intestin come from?
Pancreas, liver and gall bladder
What are the organ that makes bile and the organ that stores it
Liver makes bile, gall bladder stores it
What is the role of bile
To emulsify fats
What breaks down carbohydrates into monosaccharides
Salivary amylase, pancreatic amylase and dextrinase from small intestine
What does trypsin and chymotrypsin breaks down?
Proteins into smaller peptides
What do pancreatic lipases break down?
lipids into fatty acids
What are the two solutions that neutralizes the stomach acid
Bicarbonate and water
What does the pancreas releases into small intestine
pancreatic amylase, trypsin and chymotrypsin, pancreatic lipases, bicarbonate and water
what does the small intestine releases
peptidases, dextrinases, mucus and water
What is the role of the mucus in the small intestine
lubricates to help things keep flowing
What does peptidases breakdown?
small peptides to amino acids
What does the small intestine absorb?
monosaccharides (glucose, fructose, galactose), amino acids, di-peptides, tri-peptides, fatty acids, nucleic acids, vitamins, electrolytes, water
What does the large intestine propel?
food residue
By what is the digestion made in the large intestine?
resident bacteria
What does the large intestine absorb?
water, electrolytes, vitamin K
What is defecated?
Waste and bacteria
What type of muscle is the tongue?
Skeletal muscle
By what are controlled smooth muscles?
Nervous system
