4 - Blood Flashcards
Components of blood
- Cellular components (Erythrocytes, leukocytes, platlets)
- Extracellular matrix (plasma)
Blood plasma
- Liquid portion of blood
- Mainly H2O
- Contains proteins
- Contains variety of other molecules
% of components in blood
- Plasma (55%)
- Erythrocytes (45%)
- Leukocytes and platelets (<1%)
Proteins contained in plasma
- Albumin produced by liver (most abundant); transport of solutes, pH buffering
- Antibodies formed by some white blood cells; immune system functions
- Fibrinogen produced by liver; Required for formation of blood clots
Other molecules contained in plasma
- Nitrogenous compounds
- Nutrients
- O2
- CO2
- N
- Electrolytes
Serum
Identical to plasma except for absence of fibrinogen
Erythrocytes
Red blood cells (RBC)
Leukocytes
White blood cells (WBCs)
3 subcategories of Leukocytes
- Granulocytes (contain granules)
- Lymphocytes
- Monocytes
Granulocytes
- Neutrophils
- Eosinophils
- Basophils
Lymphocytes
Small (T cells, B cells) and Large (Natural killer cells)
Thrombocytes
Platelets. Cell fragments from megakaryocytes in bone marrow
Haemopoiesis
Production of blood cells. Dynamic process (continuous turnover, responsive to stimuli)
In the embryo what does the yolk sac produce
stem cells that colonise
foetal liver, bone marrow, spleen, and thymus and multiply to give rise to blood cells during
Which cell differentiates into macrophages and dendritic cells
Monocytes
Which cell differentiates into basophils, nuetrophils, eosinophil and monocytes
Myeloblast
RBC two main functions
- Transfer of O2 from lungs to tissue
- Transfer of CO2 from tissue to lungs
4 covalently linked subunits of haemoglobin
- 2 alpha and 2 beta chains
- Each contain heme which binds oxygen
Anaemia
A reduction in the oxygen-transporting capacity of
blood, resulting from a decrease in the red cell mass to subnormal level
Causes of anaemia
- Increased red cell destruction (haemolysis)
- Decreased red cell production
- Blood loss (haemorrhage)
Clinical manifestations of anaemia
- Acute: shortness of breath, organ failure, shock
- Chronic: pallor, fatigue, lassitude
WBC Function
- Recognise and respond to “foreign”
- Mediate inflammatory & immune responses
- Individuals born with deficiencies in certain WBC have increased risk of infection and death
how are platelets made
- Megakaryocytes live in bone marrow next to capillaries
- Long tendrils of cytoplasm protrude into the capillaries
- Force of the blood flow splits off fragments called platelets
How long to platelets circulate freely for
5-6 days
How do platelets work
- Platelets release serotonin (constricts blood vessel) to prevent blood loss
- Platelets stick to exposed collagen fibres on the broken blood vessel wall and temporarily seal the break
- Platelets become enmeshed in fibrin (a sticky protein), forming a strong, long-lasting clot that allows for healing
Types of bleeding disorders
- Primary (born with): Haemophilia, Platelet dysfunction.
- Secondary (acquired): Anticoagulants, Vit K deficiency, Hepatic and renal failure
Haemophilia A
Inherited X-linked deficiency of factor VIII
Presentation of haemophilia A
- Spontaneous bleed or excessive bleed after trauma
- Haemarthrosis (bleed into joint) or soft tissue
Diagnosis of haemophilia A
- Family History (Males affected, female carriers)
- Factor VIII level <10% (Normal 80-120%)
Treatment of haemophilia A
Treat bleeds with Factor VIII replacement
Thrombocytopenia
Too little platelets
Thrombocytosis
Too many platelets
Primary Thrombocytosis
Essential Thrombocythaemia
Secondary Thrombocytosis
Reactive, medications, stress
Von Willebrand disease
- Type 1: quantitative deficiency (20-50% of normal)
- Type 2: Qualitative deficiency
- Type 3: Quantitative deficiency (severe)
Increased destruction of RBC
autoimmune haemolytic anaemia
Decreased production of RBC
iron deficiency anaemia
anaemia due to blood loss
haemorrhage
