Onwards towards the metabolic capital (Absorption of nutrients) Flashcards
Pancreatic enzymes cannot digest all nutrients. TRUE OR FALSE?
TRUE
Where does final digestion take place?
On the lumenal surface
Where does intracelluar digestion occur?
In enterocytes
How are digestive enzymes secreted?
As proenzymes
What is secretion regulated by and list a few of these?
-By many secretagogues e.g Acteylcholine, Histamine, Gastrin, Secretin
What are carbohydrates and proteins made up of?
Carbohydrates are made up of monosaccharides
Proteins are made up of amino acids
Pancreatic enzyme breakdown proteins and carbohydrates into their constituent monosaccharides. TRUE OR FALSE?
TRUE
What transport system is used to absorb the constituents into the epithelial cells (enterocytes)?
-Active transport
How are lipids (emulsions) stabilised and how is this used to break them down into free fatty acids?
By combiding with bile salts
-This provides a large surface area to volume ration which allows the lipase enzyme to attck the triglycerides and break them down into free fatty acids
Where are micelles packaged back into triglycerides?
-Enterocytes
How are chylomicrons formed?
-When triglycerides are coated in protein
Where are chylomicrons then secreted?
Into the lacteal system
Why are chylomicrons not secreted into the blood?
-This would lead to the creation of seperate layers of fat in the blood which could lead to complications
From which organ are amylase and lysozyme psecreted?
-Salivary glands
From which organ are Pepsin A and gastric lipase secreted?
Stomach
From which organ are Trypsin, chymotripsin, elastase, carboxypeptidase A and B and pancreatic lipase?
-Pancrease
Lysozymes removes soe of the polysaccharide chains from the surface of the bacteria which renders them unable to interact with each other and multiply. TRUE OR FALSE?
TRUE
How is pepsin secreted as?
Pepsinogen (an inactive pro-enzyme)
What does gastric lipase do?
-Breaks down triglycerides into monoglycerides
What does pancreatic enzyme do?
-Breaks down triglycerides into monoglycerides
Trypsin, chymotripsin, elastase, carboxypeptidase A and B are all proteolytic enzymes that break down proteins. TRUE OR FALSE?
TRUE
Give some examples brush border proteins and what their substrates are?
- Maltase - Maltose
- Sucrase - Sucrose
- Glucoamylase - Amylose
- Lactase - Lactose
- Endopeptides - Proteins
- Leucine aminopeptidase - Peptides
- Enteropeptidase - Trypsinogen
What enzyme is used as the driving force for absorption of all of the digested micro-nutrients (for endothelial transport)?
NA+/K+ ATPase
How many NA and K ions are pumped in and out by the NA/K ATPase?
- 3Na+ are pumped out of the cell
- 2K+ are pumped into the cell