Shared Flashcard Set

Details

Digestion + Absorption
Digestion + absorption of CHO, proteins, lipids by Joanna Woodnutt
27
Veterinary Medicine
Undergraduate 2
06/02/2012

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
What is a micelle?
Definition
An aggregate of bile salts in aqueous solution- they stick together with a +ve inside (hydrophobic) and -ve outside (hydrophilic) and thus can transport lipids to the brush border
Term
What is the function of a micelle?
Definition
To transport lipids to the brush border, and away from the site of degradation
Term
What is a chylomicron?
Definition
A triacyclglycerol and esterified cholesterol surrounded by protein, cholesterol and phospholipids, making a lipoprotein for lipid transport
Term
What is the function of bile constituents?
Definition
To emulsify fats
Term
What is lingual lipase?
Definition
Lipase that is found in the mouth and begins lipid breakdown during mastication.
Term
True or false: Glycerol forms triacylglycerol in a hydrolysis reaction with three fatty acid chains
Definition
False. Glycerol forms triacylglycerol in a CONDENSATION reaction with three fatty acids!
Term
What is the function of co-lipase?
Definition
To anchor pancreatic lipase at the fat-water interface and allow it to work
Term
True or false? Pancreatic lipase catalyses the hydrolysis of the triacylglycerol, forming glycerol and 3 fatty acids.
Definition
FALSE: Pancreatic lipase catalyses the hydrolysis of triacylglycerol, forming 2-monoacylglycerol and 2 free fatty acids.
Term
Describe the appearance of the pancreas.
Definition
Lobulated structure attached to flexure of duodenum.
Pale pink to yellow
Likely to be self-digesting in necroscopy unless very soon after death.
Term
True or false? The islets of langerhans in the pancreas produce endocrines.
Definition
True
Term
True or false, the exocrine pancreas consists of alpha, beta, and delta cells.
Definition
False- the endocrine pancreas consists of alpha, beta and delta cells, the exocrine pancreas consists of acini cells.
Term
True or false: Carboxypeptidase is an exopeptidase?
Definition
True
Term
What is the action of carboxypeptidase on a protein chain?
Definition
Attacks the carboxyterminal at the end of the amino acid
Term
True or false: Trypsinogen cleaves bonds in the middle of a peptide molecule, after a positively charged amino acid.
Definition
False. Trypsinogen is a zymogen and has no action on peptides.
Term
What is a zymogen?
Definition
An inactive pro-enzyme
Term
How is trypsin activated?
Definition
Trypsinogen is squeezed from the pancreas into the pancreatic ducts, when it reaches SI, enterokinase in the SI activates it. Trypsin further cleaves trypsinogen and other zymogens so speeds up the process, resulting in an 'explosion' of enzymes.
Term
Describe the structure of starch?
Definition
A spiral shaped, unbranched amylose chain with a 1-4 linkages and a branched amylopectin chain with a 1-4 and a 1-6 linkages.
Term
What is the percentage of average liver mass is glycogen?
Definition
8%
Term
True or false: Only D-isomers of monosaccharides can be metabolised
Definition
True.
Term
What are the functions of glucosidases in the brush border?
Definition
To digest disaccharides to monosaccharides.
Term
How are glucose and galactose transported across the mucosa?
Definition
Na+k+ATPase causes a conc gradient, when Na+ then moves into cell it releases energy and glucose gets a 'free ride'. The high intracellular level of glucose then means that it can move through basolateral membrane by facilitated diffusion.
Term
How is fructose absorbed?
Definition
By facilitated diffustion independant of Na+
Term
True or false: Absorption of monovalent ions (Na+, K+, CL- etc) is independant of the needs of the body.
Definition
TRUE! They are all absorbed easily through the paracellular route, but excretion is tightly regulated.
Term
True or false? Vitamin C increases the absorption of iron?
Definition
True, because it reduces Fe3+ to Fe2+ which is absorbed more easily.
Term
What is tranferrin?
Definition
The transport molecule for iron
Term
How is iron uptake regulated?
Definition
If there is too much iron and tranferrin is saturated, the iron taken up all binds to ferritin within the epithelial cells, which inhibits further uptake of iron. If it is low, tranferrin has all it's binding sites free and more iron can be absorbed.
Term
How is calcium uptake regulated?
Definition
When Ca2+ is low, calcitriol is formed, which increases the Ca2+ channels on both apical and basal membrane and increases the sythesis of the protein that Ca2+ binds to to transport it across the cell between these two channels. When there is too much calcium, there are fewer transport proteins and channels and so uptake is slow.
Supporting users have an ad free experience!