Liver Biochemistry Flashcards
State some of the major roles of the liver?
- Bile production
- first destination of most absorbed nutrients and xenobiotics.
- elimination of unwanted molecules.
- secretion of plasma proteins.
- storage of important molecules (vitamins, iron, fuels).
- regulation of metabolism.
In terms of metabolism regulation, how does the liver deal with carbohydrates, lipids and amino acids?
- carbohydrates and lipids are metabolised and stored as fuel.
- amino acids are metabolised via the urea cycle.
What is electrophoresis?
a means of separating out proteins by size. Examples: albumin, alpha-, gamma-globulins, immunoglobulins.
What are some functions of plasma proteins?
- pH buffering
- Maintenance of oncotic/ colloid osmotic pressure (prevents stuff leaking out into the interstitial space).
- transport of hydrophobic substances.
- immunity.
- enzymatic activity.
State the function and give an example of an alpha globulin.
they transport lipoproteins, lipids, hormones and bilirubin e.g. ceruloplasmin.
State the function and give an example of a beta globulin.
- transferrin: transports Fe3+ (indicator of iron deficiency).
- Fibrinogen: inactive form of fibrin (involved in the clotting of blood).
State the function of Albumin.
is the most abundant plasma protein. It is a small, negatively charged, water-soluble molecule and is the main determinant of oncotic pressure. (regulates oncotic pressure)
The liver synthesises about 14g/ day. Insulin stimulates its production and low levels indicate liver disease.
Describe the transport functions of Albumin.
- multiple binding sites for hydrophobic molecules.
- hydrophobic clefts in globular domains.
- endogenous transport: fatty acids, bilirubin, thyroid hormones.
- exogenous transport: aspirin.
How is iron transported?
As Ferric iron (Fe3+), bound to transferrin.
How is iron stored?
As Ferritin.
How is copper transported in the body?
in the blood bound to ceruloplasmin.
State some functions of copper in the human body?
it is essential for regulation of redox reactions and in the transport and use of iron.
What is the disease name for copper deficiency?
Wilson’s Disease
How are hormones transported?
in the circulation bound to specific transport molecules: E.g.
- thyroxine: bound to thyroid-binding globulin.
- cortisol: bound to cortisol-binding globulin.
State some functions of hormones?
- extend biological half-life and increase plasma concentration.
