Plasma Proteins Flashcards
Plasma constitutes ______ % of blood
55-60
The normal total plasma protein concentration is around
6-8g/dl of blood
Albumin concentration
3.5-5g/dl
Globulins concentration
2-3g/dl
Fibrinogen concentration
0.2-0.4g/dl
What is used as liver function test and why
Estimation of serum albumin. It is used because albumin is only synthesised by liver.
Structure of albumin
- single polypeptide chain
- 585 Amino acids
- 17 disulphide bonds
- M.W 69000
Functions of albumin
- Maintains colloidal osmotic pressure of plasma.
- Transport function for free fatty acids, phospholipids, bilirubin, steroid hormones, thyroxine, metallic ions
- Buffering action
- Nutritional function: contributes to protein synthesis during periods of starvation.
- Pre-albumin transports thyroid hormones.
EP pattern in acute infections
Alpha 1,2 increase
EP pattern in chronic infections
Gamma increase
EP in nephrotic syndrome(proteinuria)
Albumin is diminished and prominent alpha 2 is seen
When albumin excretion is increased to _____ it is called _____ or _____.
30-300mg/dl
Paucialbuminuria
Microalbuminuria
Low albumin levels are seen in
Kwashiorkor
Liver cirrhosis
Nephrotic syndrome
Chronic inflammatory diseases
Normal A/G ratio
1.2:1 to 2:1
A/G ratio is lowered or reversed in
Cirrhosis of liver
Nephrotic syndrome
Multiple myeloma
Concentration of pre-albumin
20-40mg/dl
Functions of a1-antitrypsin
- called a1-antiproteinase
- inhibits trypsin and other serine proteases (proteolytic enzymes with serine in their active sites)
- also inhibits elastase
Types of A1 globulins
A1 antitrypsin A1 lipoprotein A1 fetoprotein Retinol binding protein Thyroxine binding globulin Cortisol binding globulin
List of A2 globulins
A2 Macroglobulin (major) Haptoglobin Prothrombin Ceruloplasmin Transcobalamin
Functions of haptoglobin
- binds with free haemoglobin
- prevents loss of free Hb in urine
- decreased in haemolytic anaemia
Deficiency of prothrombin
- associated with vit K deficiency.
- observed in obstructive jaundice in adults.
Functions of ceruloplasmin
- synthesised by liver
- involved in copper detoxification and storage
- deficiency leads to Wilson’s disease— accumulation of copper in liver and brain
List of B globulins
- B lipoproteins
- Transferrin
- Hemopexin
- Plasminogen
Functions of transferrin
- siderophilin
- iron binding, controls the level of free iron in biological fluids
Functions of hemopexin
- synthesised by liver
- highest heme binding affinity
- helps in maintaining and recycling iron pool
CRP levels rise after
Myocardial infarction
Trauma
Neoplastic proliferations
Cell mediated immunity is involved in
Hypersensitivity reactions
Defence against malignant cells and viruses
Functions of IgG
- 75-80% of
- involved in secondary immune response.
- can cross placental barriers and protect newborn from infections.
- the antibodies transferred are active for 3-4 months after birth.
- play a major role in Rh iso-immunisation.
Functions of IgA
- occur as dimers
- connected by a J chain
- majorly found in colostrum
- seen in seromucous secretions of GIT, nasopharyngeal tract, urinogenital tract, tears, saliva, sweat.
Functions of IgM
- largest
- 5 subunits are joined together.
- it can combine with 5 antigens simultaneously and is therefore very effective for agglutinating bacteria.
- involved in primary immune response.
- natural antibodies.
Functions of IgD
- has a single Y shaped unit
- mostly occurs on surface of B cells
Functions of IgE
- mediate allergy, hypersensitivity, anaphylaxis
- usually bind onto mast cells and basophils.
