Cardiovascular System - Blood
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20 flashcards - 10 imaging tasks - 15 multiple questions
83 Terms
What is haematology?
The branch of medicine concerned with the study, diagnosis, treatment and prevention of blood-related diseases.
What are the four main functions of blood?
Transport, regulation of pH, osmosis and body temperature, protection, and maintenance of homeostasis.
What is blood?
A specialised connective tissue in which blood cells are suspended in a yellowish fluid called plasma.
What are the three main components of blood after centrifugation?
Plasma, the buffy coat (leykocytes and platelets), and erythrocytes
What percentage of whole blood is plasma?
Approximately 55%
What is the buffy coat?
The thin layer containing leukocytes and platelets, making up less than 1% of whole blood.
What is haematocrit?
The ratio or percentage of the total blood volume occupied by red blood cells.
What is normal pH range of blood?
Approximately 7.35-7.45
Which organs help restore normal blood pH when it becomes too acidic or too alkaline?
The respiratory system and the kidneys.
What is the difference between plasma and serum?
Plasma is the liquid portion of blood. Serum is the remaining fluid after blood has clotted and the solid components have been removed; it lacks fibrinogen and other clotting factors.
What are the three major categories of plasma proteins?
Albumins, globulins and fibrinogen
What the main functions of albumins?
They contribute to blood viscosity and osmolarity, influence blood pressure and help maintain fluid balance
What is haemopoiesis?
The process of blood cell production, mainly in red bone marrow in adults
What are erythocytes?
Red blood cells that transport oxygen using haemoglobin.
Which substances are transported by red blood cells?
Oxygen and carbon dioxide
What is the typical lifespan of an erythrocyte?
Approximately 120 days
What is the structure of an erythrocyte?
A non-nucleated, biconcave disc containing haemoglobin. It lacks mitochondria and generates ATP anaerobically.
How many red blood cells are normally found per mm³ of blood in a healthy adult male?
Approximately 4.5–6.5 million/mm³.
What is haemoglobin made of?
Four protein chains (globins) and four haem groups. Adult haemoglobin usually has two alpha and two beta chains.
How many million haemoglobin molecules does one red blood cell carry?
Approximately 280 million.
What is the function of erythropoietin?
It stimulates red bone marrow to increase red blood cell production
What happens during the erythropoietin feedback mechanism?
Decreased oxygen availability stimulates the kidneys.
Kidneys release erythropoietin into the blood.
Erythropoietin stimulates red bone marrow.
Bone marrow increases erythropoiesis.
Red blood cell numbers increase.
Oxygen-carrying capacity increases and tissue hypoxia is reversed.
Which factors stimulate erythropoiesis?
Haemorrhage, living at high altitude and aerobic exercise.
What are the five types of leukocytes?
Neutrophils, eosinophils, basophils, lymphocytes and monocytes.
What are platelets, and what is their function?
Small, colourless cell fragments without a nucleus. They help form platelet plugs and promote blood clotting.
What are the three main stages of haemostasis?
Vascular spasm, formation of a platelet plug and blood coagulation.
What is the difference between an antigen and an antibody?
An antigen is a substance that can induce an immune response. An antibody is a protein that recognises and binds to an antigen.
Identify the three layers of centrifuged blood and state what each contains.
Top — Plasma: liquid portion, approximately 55%.
Middle — Buffy coat: leukocytes and platelets, less than 1%.
Bottom — Erythrocytes: red blood cells, approximately 45%.
Name the three major plasma proteins and give one function of each.
Albumins: maintain osmotic pressure and fluid balance.
Globulins: provide immune system functions.
Fibrinogen: precursor of fibrin threads that help form blood clots.
What are the sources, normal plasma levels and main functions of the four important plasma proteins?
Albumin — liver; 3.4–5.4 g/dL (54–60%); maintains plasma osmotic pressure and transports various substances.
Globulin — lymphocytes; 1.0–1.5 g/dL (35–38%); fights infection and contributes to osmotic pressure.
Fibrinogen — liver; 0.2–0.5 g/L (4–7%); blood clotting.
Prothrombin — liver; less than 1%; blood clotting.
Describe the shape and two structural characteristics of an erythrocyte.
It is a non-nucleated, biconcave disc. It contains haemoglobin, lacks mitochondria and is highly deformable, allowing it to pass through small capillaries.
Identify the globin chains and haem groups. Where does oxygen bind?
Haemoglobin consists of four globin chains and four haem groups. Oxygen binds to the ferrous iron (Fe²⁺) in each haem group.
Identify the five leukocytes and state which are granulocytes and which are agranulocytes.
Granulocytes: neutrophils, eosinophils and basophils.
Agranulocytes: lymphocytes and monocytes.
Which leukocyte is the most numerous and which is the least numerous?
Most numerous — neutrophils.
Least numerous — basophils.
Which leukocytes are actively phagocytic?
Neutrophils and monocytes.
Rank the five types of leukocytes from most abundant to least abundant in normal blood.
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Which leukocytes increase during allergy attacks?
Eosinophils
Which leukocyte increases during prolonged infections and can develop into a macrophage in tissues?
Monocytes
What is the difference between diapedesis and chemotaxis?
Diapedesis — movement of white blood cells through blood vessel walls.
Chemotaxis — movement of white blood cells in response to chemical signals.
What are leukopenia and leukocytosis?
Leukopenia — an abnormal decrease in white blood cell count.
Leukocytosis — an abnormal increase in white blood cell count.
Which type of stem cell gives rise to lymphocytes?
Lymphoid stem cells.
Identify the antigens on the red blood cells and the antibodies in plasma for each ABO blood group.
Blood group - RBC antigens - Plasma antibodies
A - A - Anti-B
B - B - Anti-A
AB - A and B - Neither anti-A nor anti-B
O - Neither - Anti-A and anti-B
Which ABO blood group can donate red blood cells to all other ABO groups, and why?
Group O, because its red blood cells have neither A nor B antigens.
Which ABO blood group can receive red blood cells from all other ABO groups, and why?
Group AB, because its plasma contains neither anti-A nor anti-B antibodies.
What is a transfusion reaction?
An antigen–antibody reaction that leads to the destruction of red blood cells when incompatible blood is transfused.
What are platelets, and what are two of their functions?
Platelets are small cell fragments without a nucleus. They stick together to form platelet plugs and release substances that promote blood clotting.
Name the three main stages of haemostasis.
Vascular spasm.
Formation of a platelet plug.
Blood coagulation.
What does haemostasis mean?
The stoppage of blood flow (stopping bleeding).
How long does blood normally take to clot?
Approximately 3–6 minutes.
What initiates the intrinsic and extrinsic pathways, and what do they ultimately help produce?
Intrinsic pathway: initiated by factors found in the blood, including factor XII.
Extrinsic pathway: initiated by tissue thromboplastin (factor III) released from damaged tissues.
Both pathways lead towards factor X activation and the formation of fibrin, which helps create a clot.
Describe the sequence of events in blood coagulation.
A break occurs in the blood vessel wall.
Platelets adhere to the damaged vessel wall.
Platelets release serotonin, helping constrict the vessel.
Tissue factor interacts with PF3 on platelet surfaces and other clotting factors.
Prothrombin activator is formed.
Prothrombin is converted into thrombin.
Thrombin acts on fibrinogen.
Fibrinogen forms long strands of fibrin.
Fibrin traps blood cells, forming a clot.
Name the four key features of acute inflammation.
Redness — rubor.
Heat — calor.
Swelling — tumour.
Pain — dolor.
Identify the organs involved in red blood cell breakdown and describe what happens to haemoglobin.
The liver and spleen break down old erythrocytes.
Globin is broken down into amino acids.
Iron is stored or reused.
Heme is converted into biliverdin and then bilirubin.
Match the following types of anaemia with their causes:
Iron deficiency anaemia
Pernicious anaemia
Haemorrhagic anaemia
Haemolytic anaemia
Iron deficiency — insufficient iron.
Pernicious — reduced vitamin B12 absorption due to autoimmune damage to stomach tissue.
Haemorrhagic — blood loss.
Haemolytic — destruction of red blood cells.
Identify four cell types involved in cell-mediated immunity.
Natural killer cells, cytotoxic T cells, helper T cells and macrophages.
What is the average blood volume in a 70 kg man?
5.6 L
Which component makes up approximately 55% of whole blood?
Plasma
Serum contains fibrinogen and all the clotting factors found in plasma.
False. Serum lacks fibrinogen and other blood clotting factors.
Which plasma protein is the smallest and most abundant?
Albunim
Where does blood cell production mainly occur in adults?
In the red bone marrow
What is the average lifespan of an erythrocyte?
120 days
Which hormone stimulates red blood cell production?
Erythropoietin
Why are erythrocytes biconcave and highly deformable?
Their biconcave shape and flexibility help them pass through small capillaries and support their role in gas transport.
Which leukocyte releases histamine and heparin?
Basophil
Which leukocyte is the largest type of white blood cell?
Monocyte
Which blood group has both A and B antigens on red blood cells?
AB
What can happen when incompatible blood groups are mixed?
Agglutination (clumping) or haemolysis (rupture) of red blood cells can occur.
Explain the difference between iron deficiency anaemia and pernicious anaemia.
Iron deficiency anaemia results from insufficient iron. Pernicious anaemia results from reduced vitamin B12 absorption due to autoimmune damage to stomach tissue.
What are the possible effects of anaemia on the body?
Tissue hypoxia, shortness of breath, lethargy, oedema, reduced blood viscosity, increased heart rate and reduced blood pressure.
What is the role of heparin and antithrombin in preventing blood clotting?
Heparin interferes with prothrombin activator, while antithrombin deactivates thrombin.
Which mineral is essential for blood coagulation?
Calcium
Name the interleukins and interferon mentioned in the lecture in relation to immunity.
Interleukins 2–6 and interferon gamma.
Which substance converts fibrinogen into fibrin during coagulation?
Thrombin
What is the difference between procoagulants and anticoagulants?
Procoagulants promote blood coagulation, while anticoagulants inhibit coagulation.
What is fibrinolysis?
The dissolution of a blood clot. Plasmin breaks down fibrin.
How are old erythrocytes recycled?
They are broken down in the liver and spleen. Haemoglobin is separated into globin and heme.
What happens to iron released from haemoglobin?
Iron is stored or reused for the production of new haemoglobin.
How is bilirubin produced and removed from the body?
Heme is converted into biliverdin and then bilirubin. Bilirubin is excreted in bile and leaves the body in faeces.
What is pernicious anaemia?
An autoimmune condition affecting stomach tissue, resulting in reduced vitamin B12 absorption.
What is haemorrhagic anaemia?
Anaemia caused by blood loss.
What is haemolytic anaemia?
Anaemia caused by the destruction of red blood cells.
What is antithrombin?
A natural anticoagulant produced by the liver that deactivates thrombin.
Which cells are involved in cell-mediated immunity according to the lecture?
Natural killer (NK) cells, lymphocytes, cytotoxic T cells, helper T cells, suppressor T cells, macrophages and dendritic cells.