Blood and Haemostasis Flashcards
State the Components of Blood
55% plasma
45% RBC
less than 1% WBC and platelets
serum = water, salts, glucose
plasma = serum + clotting factors
State the Layers of the Structure of Blood Vessels
Tunica Externa - external elastic membrane
Tunia Media - smooth muscle
Tunica Intima - internal elastic membrane and endothelium
In terms of Structure, what do Larger Arteries Lack?
smooth muscle
What are the 3 Components of Virchow’s Traid
Vessel Wall
Blood Flow
Coagulation Factors
all 3 make clotting more or less likely
Describe what does the Vessel Wall and internal elastic membrane contain, and what do they express
collagen and express’ Von Willebran Factor
Describe what Happens when the Endothelium gets Damaged. (4) Describe the end result (2)
- platelets and collagen in the blood are exposed to Von Willebrand Factors in the vessel wall
- VWF bind to platelets
- platelets are activated
- platelet changes shape from circle to star-shaped (increase SA)
- platelets bind to each other
= platelet plug
leads to
- platelet aggregation
- trapped fibrinogen
What is Von Willebrand’s Disease
a blood disorder in which blood does not clot properly as it lacks VWF
What is a Vascular Spasm?
a broken vessel wall
- smooth muscle contracts
- smaller
- less blood flow
- allows clot to form
What are Coagulation Factors?
proteins in the blood
Which Coagulation Factors are made in the liver?
2
7
9
10
What are the 3 Pathways for Coagulation Factors to Take and Explain.
Extrinsic Pathway
- activtated by factors outside the vessel wall
- F3 is expressed outside the vessel wall
- exposure of F3 to blood activates F7
- F7 catalyses the conversion of FX TO FXa
- allows the conversion of prothrombin to thrombin
Instrinic Pathway
- activated by factors inside the vessel wall if there are foreign particles
- F12 gets activated and cascades the activation of F11, F9
- F8 is also part
- allow to the conversion of prothrombin to thrombin
Final Pathway
- thrombin allows the conversion of fibrinogen into fibre
= cross linking fibre network
- the result of factors:
- F10 into F10a
- prothrombin into thrombin
- fibrinogen into fibrin
What does Irregular or Slow Blood Flow lead to? Which Conditions can it Lead to?
coagulation
- atrial fibrillation
- deep vein thrombosis
What is Arterial Fibrillation?
a heart condition that causes an irregular and abnormal fast heart rate
Describe Steps of Arterial Fibrillation.
- SAN and conduction of cardiac impulse = abnormal
- atrial wall doesn’t contract well and at different times
= turbulent flow
What is the Cause of Pulmonary Embolism?
Deep Vein Thrombosis
What does Deep Vein Thrombosis lead to?
Pulmonary Embolsim
How does Deep Vein Thrombosis come about?
people sat for long time
blood pools beneath lower limbs
clot develop
can end up in pulmonary circuit
= pulmonary embolism
How can you Prevent Blood Clots in the Vessel Wall? (5)
- prevent platelet activation
- metabolise cyclooxygenase
- warfarin and heparin = anticoagulants
- clopirdogel and aspirin = anti-platelet medicine
- artificial heart valve
What type of Medicine is Clopidrogel?
anti-platelet - prevent binding of platelet
similar to aspirin
How long do Warfarin, Aspirin and Clopidrogel last?
the lifetime of the platelet - its irreversible
How long do Warfarin, Aspirin and Clopidrogel last?
the lifetime of the platelet - its irreversible
Which Medicine is Similar to Heparin
Warfarin
How can you Prevent DVT?
- activity
- compression stockings
- Heparin and Warfarin (anticoagulants)
How can you Prevent Atrial Fibrillation?
- correct fibrillation
- heparin and warfarin (anticoagulants)
How does Heparin work? Delivery and Monitoring. How Long Lasting is it and can it be Reversed?
- prevents activation of F10
- prevents cross linking fibrin network forming
- delivered via injection
- monitored via APTT
- short lasting
- reversed by protamine sulphate
How does Warfarin Work? (4) Delivery and Monitoring. How Long Lasting is it and can it be Reversed?
- prevents metabolism of Vitamin K in the liver
- prevents conversion of F9 into F8
- prevent catalytic conversion of F7
= prevent prothrombin into thrombin - delivered via oral tablet
- monitored by checking PT or INR
- long lasting, take a while for effect
- reversed by Vitamin K
List some other Anti-Coagulant Drugs and 3 Features.
apixaban
rivaroxaban
edoxaban
- prevent conversion of F10
dabigratran
- prevent conversion of fibrinogen
- all taken orally
- short acting
- cannot be reversed
What can Blood Clots lead to in the Brain, Lungs, Limbs, Gut, Heart, Veins
Brain - stroke
Lungs - pulmonary embolism
Limbs - ischemia
Gut - gut ischemia
Heart - myocardial ischaemia
Veins - DVT
How can Atherosclerosis lead to Clotting?
- plaque formation under the blood vessel endothelium
- obstructs the vessel
- if rupture can introduce extrinsic and intrinsic pathway to occur
- clotting
- stroke
How can Liver Disease lead to Abnormal Bleeding?
- produces a lot of clotting factors and metabolises vitamin K
What are Questions to ask a Patient in Relation to Abnormal Bleeding?
- personal and family history
- medication
- do they bruise easily, bleed a lot if theres a cut
Describe 5 Tests that Measure Abnormal Bleeding.
Extrinsic Pathway Test = Prothrombin Time (PT)
- sample of plasma
- add F3
- set timer for fibrin clot to form
INR = same test as external but international normalised ratio
Instrinic Pathway Test = Activated Partial Thromboplastin Time (APTT)
- sample of plasma
- add foreign material
- F12 activated and cascade
- set timer to fibrin clot to form
- the rests are in a ratio
- if less than 1 = little time to clot
- if more than 1 = more time to clot
Platelet Count Test
- 150,000-400,000 is normal
concern if less than 100k
action required if less than 80k
Individual Factor Assays
- done by haemotology
How Do You Stop Blood Clotting
breakdown fibrin
Why is Blood Clotting Relevant to Dentistry? What can be Provided?
need to be careful when extracting teeth
- if no healing can given the patient
- tranexamic acid as a mouthwas
- prevents breakdown of fibrin and allows clot
Define Haematopoeisis.
blood cell production
What is the Function of Haemocytoblasts? What are they also known as?
give rise to the formed elements in blood
pluripotential haemopoietic stem cells
What is the Function of Blood? (4)
- deliver oxygen, remove carbon dioxide
- maintain temp, pH and fluid volume
- prevent infection
- transport hormones and nutrients
What are the 3 Types of Haemoglobin?
HbA = most common
HbA2 = small amounts
HbF = foetal haemoglobin
When does Haemoglobin Appear Red and then Purple/Blue?
when its oxygenated then deoxygenated
How are Blood Cells Produced?
haematopoeisis derived from bone marrow stem cells
Which Hormone Enhances Erythopoiesis?
Testosterone
What is the Name for Erythocyte Cell Death?
Eryptosis
What can it mean if Urine/Faeces appear Dark?
more red blood cell death
Provide 5 Types of Red Blood Cell Associated Disease
- Anaemia
- Pernicious Anaemia
- Haemoglobinopathis
- Sickle Cell Anaemia
- Thalassaemia
…. means blood cell production
haematopoiesis
what cells allow elements to form in the blood?
haemocytoblasts AKA pluripotential haemopoietic stem cells
What Regulates Plasma Production?
Thrombopoeitin
Describe the Appearance of Platelets.
purple granules
blue-staining outer region
- bi-concave disc
- 2/3µm
What are the Constituents of Platelets?
serotonin
Ca2+ enzymes
ADP
platelet derived growth factor
What are the Components of Plasma, Percentages, Solutes (6)
water = 90%
solutes = 8%
- proteins
- gas
- electrolytes
- organic nutrients
- hormones
- metabolic waste
What are the Blood Types, their Corresponding Antigens and Antibody’s?
Type A = A antigen, Anti-B
Type B = B antigen, Anti-A
Type AB = A and B antigens, no antibodies
= CODOMINANT
Type O = Neither A or B antigens, Anti-A and Anti-B
= RECESSIVE
What is Rhesus factor?
protein that can be found on the surface of the red blood cell
two types:
positive = 85% dominance
negative = 15% recessive
- the positive or negative sign next to the blood group is the Rhesus factor
What is Haemolytic Disease? How can it be Detected?
When there is a +Rh foetus and -Rh mother
- lead to anti-rhesus antibodies from mother attacking the foetal blood cells
= haemolytic anaemia
- take a RhoGAM test at 28 weeks
What is the Most Common Rh blood type?
+Rh Type O
What is the Least Common Rh Blood Type?
-Rh Type AB
Define Thrombus
A structured solid mass or plug of blood constituents formed within the heart of blood vessels
Define Thrombosis
the process of thrombus formation
What are the 3 Types of Thrombus
- Arterial
- usually at site of endothelial injury
- common sites = corony, cerebral, femoral - Cardia aka Mural Thrombi
- over areas of myocardial injury
- also with arrhythmias and cardiomyopathy - Venous
- sites of vascular stasis
- lower limbs, DVT
What are the Outcomes of Thrombus, Considering the Patient had Survived the Immediate Effect of Obstruction
- propagation
- embolism
- dissolution
- and/or organisation/recanalisation
What are the Primary and Secondary Predisposing Conditions to Thrombus? SASAPMDOWN
Primary - genetic
- protein C or S deficient
- antithrombin deficient
- F5 Mutations
- prothrombin mutations
Secondary - environmental
- Stasis - no movements - coagulation facts are not cleared, platelets clump
- Atherosclerosis - damage to vessel wall and lumen lining
- Smoking - increase prothrombin biomarkers
- Atrial Fibrillation - blood pooling
- Prosthetic Heart Valves - negative change can activate intrinsic pathway
- MI and Vasculitis - damage to vessel wall
- Neoplasia - malignancy induced abnormal coagulation
- Oral Contraceptives - increase in circulating fibrinogen
- Disseminate Intravascular Coagulation
- widespread activation of clotting cascade
How do you Prevent Thrombosis?
Aspirin - for stroke and MI
Heparin - prevent post-op DVT
Warfarin -
newer therapeutics
- anticoagulants = rivaroxaban, apixaban, betrixaban
- antiplatelt = clopidrogel
Describe Thrombolysis
thrombolysis
- streptokinase and tissue type plasminogen actiavtor
- activates the body natural fibrinolytic system to break down thrombus
What is an Embolus?
an abnormal mass of material which is carried in the bloodstream from one part of the circulation to another, impacting in a vessel which calibre is too small to allow it to pass
What is an Emboli?
plural of embolus
Describe the Types of Thromboembolism
Pulmonary
- originate from detached piece of thrombus in the deep vein of the leg
- travel via venous system
- to the heart
- out of the pulmonary artery
- GETS STUCK in pulmonary arterial tree
Systemic
- originate from detached piece of mural thrombus
- travels via aorta into systemic arterial circulation
- GETS STUCK in lower limbs, brain, kidney, gut
Cerebral
- originate from detached piece of thrombus in common carotid artery
- travels via arterial system to brain
- GETS STUCK in cerebral vasculature - stroke
Lower Limb/Renal
- originate from detached piece of thrombus in abdominal aorta
- GETS STUCK in arteries - renal or lower lim
What is a Paradoxical Embolism?
embolism that originates in the systemic veins and enters system arterial circulation
- travel expected from right heart to pulmonary artery
- travels from right heart to aorta
Define Ischemia
an inadequate blood supply to an organ or part of the body
- heart - coronary artery - get angina
- legs - intermittent claudication (femoral, iliac and popliteal arteries)
- gut - mesenteric artery - ischemic bowel
Define Infarction
death of an area of tissue due to ischemia
- heart - MI
- brain - cerebrovascular accident, stroke
- bowl - bowel infarction
What is Shock? Describe the 9 Steps. Shock Hurts Very Lovely and Exciting Peeps And People
a life threatening condition of low blood perfusion to tissues resulting in cellular injury and inadequate tissue function
- failure of pre-capillary sphincters
- cell hypoxia
- vasoconstriction
- lactic acid and fall in pH
- metabolic acidosis
- cell mem dysfunction
- influx of sodium and water, efflux of potassium
- toxic substances enter circulation
- capillary endothelium damage
- cell death - energy deficit
- inadequate perfusion
- anaerobic respiration
- peripheral pooling of blood
What are the 4 Types of Shock?
Cardiogenic Shock
- distended jugular vein due to venous pressure
- weak or absent pulse
- arrhythmia
- reduces blood pressure
- causes: prevention of heart pumping properly
Obstructive Shock
- cardiac tymponade
- pulmonary embolsim
- aortic stenosis
- causes: obstruction of blood flow outside heart
Hypovolaemic Shock
- rapid, weak pulse
- tachycardia
- cool, clammy skin - vasoconstriction
- hypothermia
- thirst and xerostomia
- causes: insufficient fluid circulation
- adults - haemorrhage
- children - vomiting, diarrhoea, burns, excess urine
Distributive Shock
- causes:
- infectious - septic shock - dilation lead to hypotension
- anaphylactic - vasodilation - hypotension and increased capillary permeability
- neurogenic causes
- typically present with systemic inflammatory response syndrome
- high resp rate, high body temp, tachycardia, low or very high WBC count
How is Shock Treated
ABCDE
- oxygen and bolus of fluid
- meds - vasopressors
- prognosis is poor
- with cariogenic - 70-90% mortality
- with septic shock - 30-50% mortality
Define Antiphospholipid Syndrome
= connective tissue disease
- body produces antibodies attacking phospholpids
- can generate blood clots
- linked to rheumatoid arthritis
