2.1 Part 1 - Basics of the digestive and endocrine systems Flashcards
What is the digestive system? (GI tract)
- digestive and absorptive organ system
- Releases enzymes and hormones to digest food
Amylase is found in the BLANK and digests BLANK into BLANK
Amylase is found in the SALIVA of the mouth it breaks down STARCH into MALTOSE
Proteases (pepsin) and hydrochloric acid are BLANK and digest BLANK into BLANK
Protease and hydrochloric acid are GASTRIC JUICES and digest PROTEINS into PEPTIDES
Proteases (trypsin), Lipases and Amylase are Pancreatic juices that digest BLANKS into BLANKS
Proteases (trypsin), Lipases and Amylases
digest: into
Proteins: peptides and amino acids
Fats emulsified by bile: fatty acids and glycerol
Starch: maltose
Intestinal enzymes: Peptidases Sucrase Lactase Maltase
digest what into what?
Peptidases: Peptides > Amino acids
Sucrase: Sucrose (sugar) > glucose and fructose
Lactase: Lactose (milk sugar) > glucose and fructose
Maltase: Maltose > glucose
What two places specifically produce amylase?
- Pancreas
- Salivary glands in the mouth
Salivary glands produce amylase and a small amount of what?
Lipase!
What is the main function of the mouth and one smaller secondary function?
Digestive - breaking down of foods
Absorption (only a small amount) eg: soluble drugs
What does chewing/mouth trigger?
Stimulates stomach and other organs to begin producing acid, mucus, enzymes and bile
Define satiety:
The state of being full
What does the satiety index refer to?
Foods that tend to produce greater effects of ‘feeling full’ when calories are equated
What effects do the following hormones have on appetite?
CCK (Cholecystokinin)
Ghrelin
Peptide YY
GLP-1 (glucagon like peptide)
CCK = reduce A
Ghrelin = increase A
Peptide YY = reduce A
GLP-1 = reduce A
Stomachs main function?
To digest food
Stretch receptors in the stomach send signals via the BLANK BLANK to tell the brain what?
Via the vagus nerve to tell the brain how full the stomach is
When a more calorie dense meal is consumed what effect does this have on gastric emptying?
It generally will increase the time it takes for gastric emptying to occur
Role of the gallbladder?
To STORE bile (liver secretes it - important note)
It is then released to digest fat in the duodenum of the small intestines (I guess like a reservoir?)
Main function of the small intestine?
2 small notes on structure of the small intestines
Absorb nutrients (most happens here)
via
1) Microvilli
2) A very large surface area to allow more absorption
What are the 3 key sections of the small intestine?
1) duodenum
2) Jejunum
3) Ileum
Enterocytes are what?
The absorptive cells in the intestines
3 key enzymes in the small intestine? (and what group of enzymes are also released into the small intestine via the pancreas?)
Lipase, amylase, protease
Proteolytic enzymes from the pancreas
2 key enzymes released from the pancreas and their functions?
Insulin - reduce blood sugar
Glucagon - increase blood sugar
When are pancreatic juices (digestive enzymes) released?
When it detects macronutrients entering the duodenum
What is the sequence of things that happens when the body detects low blood glucose?
1) pancreas releases glucagon from the alpha cells
2) This stimulates liver to release glucose into the blood
3) blood glucose normalised
(note there are other mechanisms that can contribute to this - this is the basic)
What is the sequence of things that happens when the body detects high blood glucose?
1) Insulin released by beta cells of pancreas
2) Cells take in more glucose from blood
3) blood glucose normalised
** note: glucose oxidation increases when this happens too so our body actively tries to burn more energy!
