Serum Proteins 2

Question 1

what are 3 types of lipid

Answer 1

fatty acids
phospholipids
cholesterol

Question 2

what are the functions of lipids

Answer 2

Major component of cell membranes 
Solubilise fat soluble vitamins 
Biosynthetic precursors (steroid hormones e.g. testosterone) 
Protection and insulation 
Major energy source

Question 3

Lipids are Hydrophobic- how are they transported round the body?

Answer 3

They combine with (are “packed inside”) proteins to form lipoprotein particles.
They have a hydrophilic surface monolayer, and hydrophobic core.

Question 4

what is classification of lipoproteins based on?

Answer 4

Classification is based on their density (NMR spectrum) and electrophoretic mobility.

Question 5

what are the 4 classes of lipoproteins?

Answer 5

Chylomicrons (CM)
Very low density lipoproteins (VLDL)
Low density lipoproteins (LDL)
High density lipoproteins (HDL)

Question 6

what are Apolipoproteins

Answer 6

the proteins associated with lipoproteins

Question 7

describe the exogenous pathway of lipid metabolism

Answer 7

Comes from diet
The liver produces bile acids to emulsify fats, absorbed through small intestine, and either used or recycled

(NOT FULL EXPLANATION OBVS)

Question 8

Describe the endogenous lipid metabolism

Answer 8

Cholesterol is produced by liver, packaged from liver in VLDL, travels around blood, broken down to produce heat energy, free fatty acids stored in adipose tissue, lose fats (IDL), lose more (LDL), HDL can take tryglycerides from IDL.

(NOT FULL EXPLANATION OBVS)

Question 9

who is LDL removed, and what happens if there is too much

Answer 9

LDL is removed from circulation by peripheral cells via LDL receptors which recognise ApoB-100.
If there is an excess of LDL this results in downregulation of receptor and high concentration of circulating LDL.

Question 10

what is atherosclerosis

Answer 10

Chronic inflammatory response to deposition of LDL causing two main problems:

• narrowing of arteries (stenosis)
• thrombus breaks from main plaque causing infarction

Question 11

what are cadiovascular risk factors

Answer 11

male sex, age, smoking, high plasma cholesterol, low plasma HDL, hypertension, obesity, sedentary lifestyle, diabetes

Question 12

describe HDL and reverse cholesterol transport

Answer 12

Nascent HDL removes free cholesterol from macrophage and returns it to the liver (“reverse” cholesterol transport).
50% of cholesterol in HDL is transferred to VLDL, IDL and LDL by CETP for ongoing “forward” transport

Question 13

why do we need hemostais

Answer 13

Blood is the transport system for oxygen, nutrients, hormones, minerals, metabolic products.
Must limit loss via day to day accidents.
Mechanism must stem flow but not occlude vessels at site of origin (thrombosis) or downstream (embolsm).
A careful balance is needed.

Question 14

what are the 4 stages of Haemostasis

Answer 14

1. Vasoconstriction
2. Platelet aggregation and plug formation
3. Blood coagulation (clotting)
4. Permanent repair and clot dissolution (fibrinolysis)

Question 15

describe platelet plugs

Answer 15

Minor vessel injuries can be plugged by platelets alone.
Platelets adhesion to collagen fibers is stabilized by von Willebrand factor, an adhesive glycoprotein.
Healthy cells produce nitric oxide to prevent platelets binding.

Question 16

what are the 3 parts of coagulation

Answer 16

• Intrinsic - Initiated by contact activation (-vely charged surfaces)
• Extrinsic – involves tissue factor which is released when tissues are damaged
• Common pathway – allows amplification of the cascade

Question 17

what can happen if you have deficiencies in any of the 14 factors in the coagulation cascade

Answer 17

Deficiencies in any factor can cause excess bleeding.

Question 18

how does warfarin inhibit coagulation

Answer 18

Vitamin K is a co-factor for the enzyme g-glutamyl carboxylase (cannot function without vitamin K).
Post-translational carboxylation required for activity of factors II VII IX X
The presence of Warfarin leads to accumulation of non-carboxylated and therefore inactive clotting factors

Question 19

why does warfarin need constant monitoring

Answer 19

Warfarin has a narrow therapeutic window therefore constant monitoring is required:
• Dose too low - Ineffective
• Dose too high - Risk of bleeding (esp in brain)

Question 20

how does aspirin work as an anti-coag.?

Answer 20

inhibits the production of Thromboxane-A2 which is produced by activated platelets to signal to other platelets for the initial aggregation

Question 21

how does haemophilia affect clotting

Answer 21

lack of clotting resulting in prolonged bleeding and internal haemorrhage