Blood and lymph Flashcards
How is blood transported
Via vessels and pressure
What is a blood clot
Simply a combination of platelets and fibrin meshed together
What is haemostasis
Process to prevent and stop bleeding
What are the 5 steps to haemostasis?
- Vascular spasm
- Platelet plug formation
- Coagulation
- Clot retraction and repair
- Fibrinolysis
What is vascular spasm?
Injury to endothelium
Release of endothelium
Vasoconstriction, smooth muscle contraction
Stimulation of pain receptors
Explain the coagulation cascade
This results in the accumulation of platelets at the wound site and form a fibrin clot which stems blood flow in order to limit the amount of blood loss
Explain the platelet plug formation
- Von Willebrand factor - initial platelet binding
- Secretion of ADP, TXA2 and serotonin - stimulates and attracts platelets
- Platelets bind together with fibrinogen
- TXA2 and serotonin enhance vascular spasm
Explain clot retraction and repair
- Once body starts healing up, clotting starts to occur
- Platelet contraction - Actin and myosin contract pulling damaged cells together
- Platelet derived growth factor - proliferation of mitosis - repair of muscle/tissue
Vascular endothelial growth factor - renew endothelium - builds tissue backup from damaged vascular tissue repair
Explain fibrinolysis
- Plasminogen - eats fibrin mesh and breaks down clot
- Tissue plasminogen activator - releases plasmon
- Breaks down fibrin - breaks down the clot
- D-Dimer release - diagnostic significance (test)
What are a group of drugs that keep blood flowing
Anti- coagulants
Anti- platelets
Name and explain anti-coagulant drugs
Warfarin inhibits vitamin K and this is needed for clotting factor activation - stops clotting
Rivaroxaban inhibits clotting factor Xa and blocks fibrin
Heparin increase antithrombin III and insist thrombin and factor X
Name and explain anti-platelet drugs
Clopidogrel, ticagrelor inhibits ADP pathway - stops platelets coming together rather than stopping the formation of the clot
Aspirin inhibits the TXA2 pathway
What is TXA
Medication used to treat or prevent excessive blood loss form major trauma - either taken orally or by injection
How does TXA work?
Inhibits fibrinolysis by stopping plasminogen binding to fibrin - this allows clot formation to carry on inhibited - stops clot breaking down stopping the plasminogen binding to fibrin - to maintain the clot for as long as possible
What is blood dyscrasia
This is a non-specific term that refers to a disease or disorder of the blood
State examples of blood dyscrasias
Anaemia
Clotting disorders
Disseminated intravascular coagulation (DIC)
Neoplastic blood disorders
What is anaemia?
Group of diseases which result in decreased haemoglobin content therefore reduced o2 transport
Cellular metabolism is reduced
List the 3 types of anaemia
- Iron deficiency
- Pernicious anaemia
- Sickle cell anaemia
List some general signs and symptoms of anaemia
Fatigue
Pallor
Tachycardia
Dyspnoea
What is iron deficiency anaemia
Reduced iron impairs haemoglobin synthesis
Reduced haemoglobin = reduced o2 transport
Common condition
List signs and symptoms of iron deficiency anaemia
Pallor
Lethargy, fatigue
Delayed healing
Degenerative changes to hair and nails
Menstrual irregularities
Tachycardia, syncope, palpitations
What is pernicious anaemia
Immature nucleated erythrocytes (megaloblastic)
Deficiency B9 folic acid and or B12
Malabsorption of B12 in gastric mucosa
B12 deficiency leads to erythrocytes and impaired maturation
Signs and symptoms of pernicious anaemia
Tongue may be red, sore and shiny
Diarrhoea and nausea
Tingling and burning sensations
Loss of muscle control
What is sickle cell anaemia
Abnormal haemoglobin production
When deoxygenated the haemoglobin crystallised and alters the shape of the erythrocyte - from a disc to a sickle
Short cell lifespan (20 days) - haemolysis - (destruction of red blood cells prior to the end of their normal 120 day lifespan)
Sickle cell causes obstruction in small blood vessels - thrombus formation, infarction, necrosis
