Flashcards in Blood & Blood Groups Deck (73):
What are the functions of blood?
Delivery of nutrients.
Transport of gases for gas exchange.
Transport of metabolic waste.
Carriage of hormones, enzymes, drugs and their metabolites.
Where in the body would you find the most blood at anytime?
Small veins & venules
Where in the body would you find the least amount of blood at anytime?
What type of tissue is blood?
Specialised connective tissue
What are bloods 2 components that make it a connective tissue?
Plasma (non-cellular matrix)
Blood cells (formed element)
The fraction of the total blood volume that is occupied by the red cells.
How would you calculate a haematocrit?
Centrifuged blood sample
What is a normal haematocrit value?
35% - 50% (males upper end/ females lower end)
What effect would anaemia have on haematocrit values?
Lower than normal
What effect would polycythaemia have on haematocrit values?
Higher than normal
What does plasma contain?
90-95% water, 5-10% solutes
What is the pH of plasma?
What does plasmas solutes contain?
Salts (electrolytes) - sodium, potassium, calcium, chloride & bicarbonate
What products ate found in plasma?
Salts (electrolytes), glucose, amino acids, urea & other small molecules, hormones, plasma proteins (albumins, globulins, fibrinogen)
Name all 3 plasma proteins?
Albumins, globulins, fibrinogen
What are the functions of plasma proteins?
Own individual functions. Binding, clotting, antibodies.
Maintain fluid balance between plasma & interstial fluid.
Healthy correct level of plasma proteins in the capillary blood.
What is fluid removed from interstial space by?
Lymphatic drainage vessels
What happens if plasma protein levels low?
More fluid than normal leaves the blood the lymphatics are unable to carry all of this fluid away.
What is oedema?
The accumulation of excessive fluid in the tissues.
What are the clinical names for red & white blood cells & platelets?
Red cells- erythrocytes
White cells- leukocytes
What is the name of the stem cells in bone marrow that blood derives from?
How many red blood cells per litre are there in a healthy person?
4.5-6.5 million million per litre
What are the properties of red blood cells?
Biconcave disc, non-nucleated in adult form, no mitochondria, contain haemoglobin (Hb)
What are the properties of Hb?
Iron containing protein.
Binds avidly to oxygen to form oxyhaemoglobin.
Each Hb molecule can combine with 4 oxygen molecules.
What would oxygen saturation be if all 4 Hb molecules combined with 4 oxygen molecules?
What is a normal Hb concentration?
11-18g/100ml (dL) or 110-180g/ litre (may be less in pregnancy
What is the process of red blood cell formation called?
What stimulates erythropoiesis?
Hormone called erythropoietin thats made in the kidneys.
Where is erythropoietin made?
What stimulates the secretion of erythropoietin?
Response to a fall in oxygen levels in arterial blood.
When might oxygen levels fall naturally in arterial blood?
Why can red blood cells not divide?
Have no nucleus
How long do red blood cells live in the circulation?
Around 120 days
Where are red blood cells destroyed?
Spleen ( lesser extent in the liver or lymph nodes)
How many white blood cells are found in a healthy person?
4-10 thousand million per litre
How is white blood cell count reported?
Differential count ( different types if white blood cells are counted seperately)
How do white blood cells differ from red blood cells?
Involved in defending against pathogens.
What type of whit blood cell is a phagocyte?
Neutrophils, Monocytes, Macrophages
What do basophils secrete?
What other than being a phogocyte do macrophages secrete?
What white blood cell is anti-parasitic & play a role in allergic reactions?
What do natural killer cells secrete?
What are platelets?
Cell fragments derived from large cells (megakaryocytes) in the bone marrow.
How many platelets are found in the blood?
1.5 - 4.0 hundred thousand million per litre
How big is a platelet?
Around 2um in diameter - Irregular in shape.
What are platelets involved in?
Haemostasis (blood clotting)
What do platelets play a continuous role in maintaining?
What is haemostasis?
What are the stepsof haemostasis?
Platelets adhere to site of damage in blood vessel wall
Secrete chemicals that promote further platelet adhesion
Platelet plug is formed to stem the flow of blood
The clotting cascade is initiated
Once repaired- clot dissolved (fibrinolysis)
What is the process of a clot dissolving caused?
What does an incompatible blood transfusion result in?
Agglutination, haemolysis, fever & jaundice
What are the antigens & antibodies in blood made from?
Where are antigens in blood found?
Red blood cells
Where are antibodies in blood found?
How many major blood group systems are there?
What is agglutination?
Clumping together of red blood cells that occurs as a result of an antigen -antibody reaction.
What causes agglutination?
Anti-a antibody binds to a -antigens (same with b)
What antigens and antibodies does blood group a contain?
A-antigen anti-b antibody
What antigens and antibodies does blood group b contain?
B-antigen & anti-a antobody
What antigen & antibody does blood group ab contain?
A & b antigen neither antibody
What antigen & antibody does blood group o contain?
Neither antigen & anti-a & anti-b antibodies
What process is used to ensure compatability of blood?
What canincompatible blood transfusions result in?
Agglutination, haemolysis & possibly death
What is the golden rule for blood transfusion in an emergency?
The recipients antibodies must not be able to agglutinate the donors red cells
What blood group is the universal donor?
What blood group is the universal recipient?
What is rhesus status determined by?
Presence of Rh- or D- antigens on the persons red blood cells
What percentage of the population are Rh +?
What do Rh- blood types not have?
Where are anti-rhesus antibodies found?
Arise naturally in plasma
When can Rh- people develop a rhesus antigen?
If they come into contact with cells that posses the rhesus antigen
What is haemolytic disease of newborn?
Anti rhesus antibodies cross the placenta from mother to fetus & cause severe agglutination reaction