Blood, Clotting and Haemoglobin Flashcards
Name the main components of blood.
Proteins
Anions - Cl-, HCO3- and PO4 3-
Cations - Na+, K+, Mg2+
Small molecules - glucose, amino acids, lactate, glycerol, urea, ketones
Define serum.
Plasma without fibrin clot
Name and state the functions of serum proteins.
Transferrin - transports iron Caeruloplasmin - transports copper Haptoglobin - transports haemoglobin Apoproteins - transports lipids Thyroid/cortisol/sex hormone binding globulin - transport hormones
What is the importance of serum protein electrophoresis?
Decreased albumin = prolonged malnutrition
Increased albumin = increases in dehydration
Increased alpha globulins = acute inflammatory diseases
Decreased alpha globulins = indicative of liver disease
Decreased gamma globulins = immune suppression or deficiency conditions
Increased gamma globulins = overall increase indicative of polyclonal immune response to chronic infection or sharp distinct increase in one band indicative of myeloma.
Which serum enzymes are analysed for diagnosis and why?
Can provide info on which tissue has been damaged.
- ALT (alanine aminotransferase) = liver damage
- ALP (alkaline phosphatase) = bone deposition, liver damage, hyperthyroidism, biliary disease, increased steroid levels
- GDH (glutamate dehydrogenase) = liver damage
- Gamma GT (gamma glutamyl transferase) = muscle damage
- AST (asparate aminotransferase) = liver and muscle damage
State the 3 stages of haemostasis/blood clotting.
- Formation of the unstable clot in primary haemostasis
- Formation of fibrin clot in secondary haemostasis
- Clot degradation in fibrinolysis
Define haemostasis, thrombus and thrombosis.
Haemostasis - the balance between blood clotting and blood clot dissolution.
Thrombus - clot
Thrombosis - clotting
What is Virchow’s Triad?
Factors which precipitate clotting:
- Hypercoagulability
- Vascular wall injury
- Circulatory stasis
Describe how thrombin is produced and its role in clotting.
Factor Xa produced from factor X via intrinsic or extrinsic pathway of clotting cascade. Intrinsic amplifies and extrinsic initiates, allowing for rapid clotting.
Factor Xa produced is used to activate inactive/uncleaved thrombin called zymogen/factor II. This produces thrombin/factor IIa.
Thrombin cleaves fibrinogen and allows for clotting to occur.
Describe the process of clot dissolution.
Fibrin is degraded in fibrinolysis, which is catalysed by plasmin. Plasmin activity is tightly regulated by a number of other proteins.
State 8 clotting disorders and how they are caused by increased clotting time.
- Hageman deficiency - factor XII deficiency
- Haemophilia A - factor VIII deficiency
- Haemophilia B - factor IX deficiency
- Von Willebrand’s disease - lock of Von Willebrand’s factor, decreasing platelet aggregation
- Thrombocytopenia - decreased platelet count
- Vitamin K deficiency - decreased carboxylation of clotting factors
- Severe liver disease - decreased clotting factor production
- Rodenticide poisoning - warfarin ingestion
How might clotting disorders present?
Nasal, oral or anal bleeding
Describe the role of haemoglobin in oxygen transport.
Tetramer of 2 alpha and 2 beta subunit polypeptides. Binds oxygen cooperatively - binding of oxygen to 1 subunit increases ease of oxygen binding to other subunits. Oxygen dissociation curve is sigmoidal. High affinity at lungs where oxygen saturation is high and low affinity at respiring tissues where oxygen saturation is low.
Describe the role of haemoglobin in carbon dioxide transport.
CO2 and so H+ concentration at respiring tissues are responsible for lowered oxygen affinity. H+ binds and stabilises T/deoxygenated state and CO2 binds to N-termini of subunits to generate negatively charged carbamate tp stabilise T state. Haemoglobin transports CO2 back to the lungs, where the reverse occurs to release CO2 and H+.
Explain how haemoglobin structure relates to its function.
On oxygen binding, alpha and beta subunits rotate in respect to each other. The haem group is domed, as the proximal histidine pulls ferrous iron from the ring plane slightly. Oxygen binding pulls iron back down, moving proximal histidine.
This movement is transmitted to all subunits and males subsequent oxygen binding easier.
