Red Blood Cells Function and Structure

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What is the composition of blood?

55% plasma, 45% blood cells

How is blood and plasma separated?

By centrifugation or simple gravity

What are the components transported by blood?

Oxygen, nutrients, hormones, heat, antibodies, and cells of the immune system

What is the approximate percentage of body weight made up by blood?

7% Signup and view all the answers

What is the role of erythropoietin (EPO) in the body?

It increases production of proerythroblasts Signup and view all the answers

What is the function of reticulocytes in erythropoiesis?

They increase oxygen-carrying capacity Signup and view all the answers

What causes hypoxia in the body?

Lung disease Signup and view all the answers

What happens to red blood cells after their 120-day lifespan?

They are broken down by macrophages Signup and view all the answers

What determines blood groups in individuals?

Red cell surface proteins (antigens) Signup and view all the answers

Why were blood transfusions historically unsuccessful?

Incompatibility of blood types based on antigens Signup and view all the answers

What is the significance of individuals with AB blood type?

They can receive blood from any group safely Signup and view all the answers

Why are the terms 'universal donor' and 'universal recipient' misleading?

'Universal recipient' can receive blood from any group safely. Signup and view all the answers

Which blood type individuals make neither anti-A nor anti-B antibodies?

Type AB Signup and view all the answers

What is the main role of neutrophils in the body?

Protecting against bacterial invasion Signup and view all the answers

Which type of white blood cell contains granules filled with toxic chemicals for eliminating parasites?

Eosinophils Signup and view all the answers

What is the average lifespan of neutrophils in the bloodstream?

6-9 hours Signup and view all the answers

Which type of white blood cell is closely associated with allergic reactions?

Basophils Signup and view all the answers

What do elevated white cell counts indicate?

Physiological problem Signup and view all the answers

Which blood type individuals make both anti-A and anti-B antibodies?

Type O Signup and view all the answers

What are the two main types of leukocytes discussed in the text?

Granulocytes and agranulocytes Signup and view all the answers

What is the main function of monocytes in the body?

Phagocytosis and immune response Signup and view all the answers

Which white blood cell type is important for adaptive immunity?

Lymphocytes Signup and view all the answers

What are granulocytes attracted to areas of infection by?

Chemotaxins Signup and view all the answers

What do eosinophils release when they bind to infecting organisms?

Toxic chemicals Signup and view all the answers

What is the approximate blood volume in adults?

5000-6000 ml Signup and view all the answers

What is the main function of plasma proteins?

Maintaining normal plasma osmotic pressure and creating viscosity Signup and view all the answers

Which plasma protein makes up around 60% of the total and acts as a carrier molecule?

Albumin Signup and view all the answers

What is the main responsibility of electrolytes like calcium, potassium, and sodium in the blood?

Maintaining muscle contraction, nerve impulse transmission, and acid-base balance Signup and view all the answers

Where does blood cell formation primarily occur in adults?

Bone marrow Signup and view all the answers

Which type of blood cell is responsible for blood clotting?

Platelets Signup and view all the answers

How is oxygen primarily transported in the blood?

Bound to hemoglobin in red blood cells Signup and view all the answers

Where does haemopoiesis occur in adults?

Flat bones, irregular bones, and the ends of long bones Signup and view all the answers

Which waste products are carried in the blood from the liver to the kidneys for excretion?

Urea, creatinine, and uric acid Signup and view all the answers

What is the primary function of hormones in the bloodstream?

Acting as chemical messengers to target tissues and organs Signup and view all the answers

What role do nutrients like glucose, amino acids, vitamins play in the bloodstream?

Providing energy to cells and tissues Signup and view all the answers

What happens to red marrow in bones in adults?

Is replaced by fatty yellow marrow with no haemopoietic function Signup and view all the answers

What is the main function of red blood cells?

Transport of oxygen and some carbon dioxide Signup and view all the answers

What is the average lifespan of a red blood cell?

120 days Signup and view all the answers

What vitamins are required for red blood cell synthesis?

Vitamin B12 and folic acid Signup and view all the answers

What allows red blood cells to carry oxygen?

Hemoglobin Signup and view all the answers

What is the approximate number of hemoglobin molecules carried by an average red blood cell?

280 million Signup and view all the answers

What can cause deficiency of iron, a necessary component of hemoglobin?

Slow absorption from the alimentary canal Signup and view all the answers

Under what conditions does oxyhemoglobin release oxygen readily?

Low pH levels Signup and view all the answers

What causes oxyhemoglobin to release more oxygen to meet the body's needs?

Low oxygen levels Signup and view all the answers

What is the diameter of a red blood cell?

7 Signup and view all the answers

What type of cells are red blood cells?

They are discoid in shape. Signup and view all the answers

What do red blood cells lack?

They lack a nucleus. Signup and view all the answers

How long does it take for red blood cells to develop from stem cells?

7 days Signup and view all the answers

What makes up approximately 55% of the volume of blood?

Plasma Signup and view all the answers

Which type of blood cell is responsible for clot formation?

Platelets Signup and view all the answers

What is the approximate percentage of body weight made up by blood?

7% Signup and view all the answers

Where does blood cell formation primarily occur in adults?

Bone marrow Signup and view all the answers

What is the approximate blood volume in adults?

5000-6000 ml Signup and view all the answers

What is the main responsibility of electrolytes like calcium, potassium, and sodium in the blood?

Maintaining normal plasma osmotic pressure Signup and view all the answers

What are nutrients like glucose, amino acids, vitamins transported in the bloodstream for?

Providing energy and essential building blocks to the tissues Signup and view all the answers

Where does blood cell formation primarily occur in adults?

Flat bones and irregular bones Signup and view all the answers

What is the main function of platelets in the body?

Stopping bleeding by forming blood clots Signup and view all the answers

What is the main role of hormones in the bloodstream?

Functioning as chemical messengers to target tissues and organs Signup and view all the answers

What is the primary function of red blood cells?

Transporting oxygen to the body Signup and view all the answers

How are most blood cells formed before entering the bloodstream?

Originate from pluripotent stem cells in the bone marrow and go through several developmental stages before entering the blood Signup and view all the answers

Which component makes up about 55% of the blood and is mainly water carrying various dissolved and suspended substances?

Plasma Signup and view all the answers

What is the approximate percentage of plasma proteins in plasma?

7% Signup and view all the answers

What is one of the essential roles of electrolytes like calcium, potassium, and sodium in maintaining body function?

Maintain muscle contraction, nerve impulse transmission, and acid-base balance Signup and view all the answers

What is responsible for maintaining normal plasma osmotic pressure and creating its viscosity?

Albumin Signup and view all the answers

Which type of blood cell is important for defending the body against bacterial invasion and removing dead cells and debris?

Neutrophils Signup and view all the answers

What is the main function of eosinophils in the body?

Eliminating parasites Signup and view all the answers

Which type of white blood cell contains granules filled with heparin and histamine?

Basophils Signup and view all the answers

What is the approximate percentage of the blood volume made up by white blood cells?

5% Signup and view all the answers

What is the approximate average lifespan of neutrophils in the bloodstream?

24 hours Signup and view all the answers

What are the two main types of leukocytes discussed in the text?

Neutrophils and basophils Signup and view all the answers

What is the primary role of monocytes in the body?

Phagocytosis and immune response Signup and view all the answers

Which type of blood cell is responsible for the elimination of parasites?

Eosinophils Signup and view all the answers

What is the main function of basophils in the body?

Promoting tissue inflammation Signup and view all the answers

What is the approximate percentage of body weight made up by white blood cells?

5% Signup and view all the answers

What is the main function of lymphocytes in the body?

Phagocytosis and immune response Signup and view all the answers

What is the approximate percentage of blood volume made up by leukocytes?

1% Signup and view all the answers

What is the primary function of erythropoietin (EPO) in the body?

Promoting red blood cell production Signup and view all the answers

What is the primary role of macrophages in the breakdown of red blood cells?

Breaking down red blood cells (haemolysis) Signup and view all the answers

What determines an individual's blood group?

Antigens (ABO and Rh) on red cell surfaces Signup and view all the answers

What is the main reason for the historical lack of success in blood transfusions?

Incompatibility of blood types based on antigens Signup and view all the answers

What is the main function of cross-matching before a blood transfusion?

Ensuring compatibility between donor and recipient bloods Signup and view all the answers

What is the fate of biliverdin produced during red blood cell breakdown?

Converted to bilirubin and excreted in bile Signup and view all the answers

What is the approximate percentage of individuals with O blood type in the UK population?

45% Signup and view all the answers

What is the main function of antigens (ABO and Rh) in blood groups?

Determining blood groups Signup and view all the answers

What is the primary function of reticulocytes in erythropoiesis?

Speeding up maturation to increase oxygen-carrying capacity Signup and view all the answers

What is the main function of red blood cells?

Transport of oxygen and some carbon dioxide Signup and view all the answers

Which vitamins are required for red blood cell synthesis?

Vitamin B12 and folic acid Signup and view all the answers

What is the approximate lifespan of a red blood cell?

120 days Signup and view all the answers

What enables red blood cells to carry oxygen?

Hemoglobin Signup and view all the answers

What is the primary role of erythropoietin (EPO) in the body?

Promoting red blood cell production Signup and view all the answers

What is the function of low pH levels in relation to oxyhemoglobin?

Accelerates oxyhemoglobin breakdown Signup and view all the answers

Which component is necessary for red blood cell development and takes about 7 days?

Stem cells Signup and view all the answers

What is the approximate number of hemoglobin molecules carried by an average red blood cell?

$280 million$ Signup and view all the answers

What is the primary reason for the lack of nucleus in red blood cells?

To maximize surface area for gas exchange Signup and view all the answers

What can cause deficiency of iron, a necessary component of hemoglobin?

Slow absorption from the alimentary canal Signup and view all the answers

What happens to red blood cells after their 120-day lifespan?

They are engulfed and broken down by macrophages in the spleen and liver Signup and view all the answers

Which component makes up about 55% of the blood and is mainly water carrying various dissolved and suspended substances?

Plasma Signup and view all the answers

What is the approximate percentage of body weight made up by blood?

7% Signup and view all the answers

What type of blood cells are heavier than plasma and sink to the bottom of the sample during centrifugation?

Erythrocytes Signup and view all the answers

What is the primary function of erythropoietin (EPO) in the body?

Stimulating red blood cell production Signup and view all the answers

What is the primary role of platelets in the bloodstream?

Stopping bleeding Signup and view all the answers

What is the approximate percentage of body weight made up by plasma proteins?

Around 7% Signup and view all the answers

What is the main function of hemoglobin in red blood cells?

Transporting oxygen Signup and view all the answers

Where does the process of blood cell formation primarily occur in adults?

Bone marrow Signup and view all the answers

What is the main responsibility of electrolytes like calcium, potassium, and sodium in the blood?

Maintaining muscle contraction, nerve impulse transmission, and acid-base balance Signup and view all the answers

What is the main role of hormones in the bloodstream?

Chemical signaling to target tissues and organs Signup and view all the answers

Which vitamin is required for red blood cell synthesis and is found in dairy products, meat, and green vegetables?

Vitamin B12 Signup and view all the answers

What is the approximate lifespan of a red blood cell?

120 days Signup and view all the answers

What is the primary function of hemoglobin in red blood cells?

Carrying oxygen Signup and view all the answers

What is the approximate percentage of body weight made up by red blood cells?

40% Signup and view all the answers

Which component is slow to absorb from the alimentary canal and can cause deficiency if losses exceed intake?

Iron Signup and view all the answers

Under what conditions does oxyhemoglobin release oxygen readily?

Low pH levels Signup and view all the answers

What allows red blood cells to have a fast entry and exit of gases?

Biconcave shape Signup and view all the answers

What causes oxyhemoglobin to break down and release additional oxygen for tissue use?

$CO_2$ levels Signup and view all the answers

What is the primary function of reticulocytes in erythropoiesis?

Synthesizing hemoglobin Signup and view all the answers

What is the significance of individuals with O blood type?

Universal donors, can donate to all blood types Signup and view all the answers

What is the main function of monocytes in the body?

Phagocytosis of pathogens and debris Signup and view all the answers

What do red blood cells lack?

Intracellular organelles Signup and view all the answers

What is the primary function of erythropoietin (EPO) in the body?

Increasing red blood cell production in response to low oxygen supply Signup and view all the answers

What can result in hypoxia, leading to the stimulation of erythropoiesis?

Lung disease Signup and view all the answers

Where does primary blood cell formation occur in adults?

Bone marrow Signup and view all the answers

What is the approximate lifespan of red blood cells?

120 days Signup and view all the answers

What is the main reason for the historical lack of success in blood transfusions?

Incompatibility of blood types based on antigens Signup and view all the answers

What happens to iron from haemoglobin after red blood cells are broken down?

It is reused for red blood cell production Signup and view all the answers

What is the approximate percentage of UK population with O blood type?

45% Signup and view all the answers

What is primarily responsible for maintaining constant red blood cell numbers through production and destruction?

Homeostatic processes Signup and view all the answers

What is the fate of biliverdin produced during red blood cell breakdown?

It is converted to bilirubin Signup and view all the answers

What component makes up about 55% of the blood and is mainly water carrying various dissolved and suspended substances?

Plasma Signup and view all the answers

What is the primary function of basophils in the body?

Playing a role in the immune response to allergens by releasing histamine and other chemicals Signup and view all the answers

What is the primary role of macrophages in the breakdown of red blood cells?

Phagocytosing and breaking down old or damaged red blood cells Signup and view all the answers

What is one of the essential roles of electrolytes like calcium, potassium, and sodium in maintaining body function?

Maintaining normal plasma osmotic pressure and creating its viscosity Signup and view all the answers

What happens to red blood cells after their 120-day lifespan?

They are phagocytosed and broken down by macrophages Signup and view all the answers

What is responsible for maintaining normal plasma osmotic pressure and creating its viscosity?

Plasma proteins Signup and view all the answers

What is the main function of lymphocytes in the body?

Playing a role in adaptive immunity Signup and view all the answers

What is responsible for transporting oxygen in the blood?

Hemoglobin molecules within red blood cells Signup and view all the answers

What is the approximate number of hemoglobin molecules carried by an average red blood cell?

100-150 hemoglobin molecules Signup and view all the answers

What is the approximate percentage of individuals with type O blood who make both anti-A and anti-B antibodies?

15% Signup and view all the answers

What is the approximate percentage of individuals with type AB blood who make neither anti-A nor anti-B antibodies?

40% Signup and view all the answers

What is the approximate percentage of individuals who are Rh-negative and can produce anti-Rh antibodies under certain circumstances?

25% Signup and view all the answers

Which component makes up approximately 55% of the volume of blood?

Plasma Signup and view all the answers

Where does haemopoiesis occur in adults?

Bone marrow Signup and view all the answers

What is the main function of basophils in the body?

Allergic reactions and parasite defense Signup and view all the answers

What is the primary role of neutrophils in the body?

Phagocytosis of pathogens Signup and view all the answers

What is the primary role of eosinophils in the body?

Eliminating parasites through the release of toxic chemicals Signup and view all the answers

What is the function of basophils in the immune response to allergens?

Releasing histamine and other chemicals to contribute to allergic symptoms Signup and view all the answers

Which type of white blood cell contains granules filled with heparin and histamine?

Basophils Signup and view all the answers

What is the main function of monocytes in the body?

Involvement in phagocytosis and the immune response Signup and view all the answers

Which type of white blood cell is attracted to areas of infection by chemotaxins and engulf and kill bacteria by phagocytosis?

Neutrophils Signup and view all the answers

What is the approximate percentage of people who are Rh-positive and do not make anti-Rh antibodies?

85% Signup and view all the answers

What is the approximate percentage of individuals with type O blood type who make both anti-A and anti-B antibodies?

~25% Signup and view all the answers

What is the main function of granulocytes in the bloodstream?

Protecting the body against bacterial invasion and removing dead cells and debris Signup and view all the answers

What do elevated white cell counts typically indicate?

Infection, trauma, or malignancy Signup and view all the answers

Where does blood cell formation primarily occur in adults?

Bone marrow Signup and view all the answers

What is the main role of lymphocytes in the body?

Important for adaptive immunity Signup and view all the answers

What is one of the main functions of leukocytes in the blood?

Defence and immunity Signup and view all the answers

What is the approximate lifespan of a red blood cell?

120 days Signup and view all the answers

Which type of blood cell is primarily responsible for defending the body against bacterial invasion and removing dead cells and debris?

Neutrophils Signup and view all the answers

What type of blood cells are heavier than plasma and sink to the bottom of the sample during centrifugation?

Erythrocytes Signup and view all the answers

What causes oxyhemoglobin to release more oxygen to meet the body's needs?

Low pH (acidic conditions) Signup and view all the answers

What enables red blood cells to carry oxygen?

Hemoglobin Signup and view all the answers

What allows red blood cells to have a fast entry and exit of gases?

Flexible membrane Signup and view all the answers

What is the approximate percentage of individuals with type O blood who make both anti-A and anti-B antibodies?

~45% Signup and view all the answers

What is the primary role of macrophages in the breakdown of red blood cells?

Removal of dead cells Signup and view all the answers

Under what conditions does oxyhemoglobin release oxygen readily?

Low pH (acidic conditions) Signup and view all the answers

What determines blood groups in individuals?

Antigen markers on red blood cells Signup and view all the answers

What is one of the essential roles of electrolytes like calcium, potassium, and sodium in maintaining body function?

Maintenance of blood pH Signup and view all the answers

What is primarily responsible for maintaining constant red blood cell numbers through production and destruction?

Erythropoietin feedback Signup and view all the answers

What is the approximate diameter of a red blood cell?

7μm Signup and view all the answers

What is the main factor responsible for the slow absorption of iron from the alimentary canal?

Low pH levels Signup and view all the answers

What is the primary function of eosinophils in the body?

Participating in allergic reactions Signup and view all the answers

What is the oxygen-carrying capacity of an average red blood cell, in terms of the number of oxygen molecules?

Over 1 billion oxygen molecules Signup and view all the answers

Under what conditions does oxyhemoglobin release oxygen readily?

Low pH levels Signup and view all the answers

What is the approximate lifespan of a red blood cell?

120 days Signup and view all the answers

What is the primary role of macrophages in the breakdown of red blood cells?

Breaking down hemoglobin into heme and globin Signup and view all the answers

What component makes up about 55% of the blood and is mainly water carrying various dissolved and suspended substances?

Plasma Signup and view all the answers

What are two vitamins required for red blood cell synthesis and found in dairy products, meat, and green vegetables?

Vitamin B12 and folic acid Signup and view all the answers

What is the primary stimulus for the production of erythropoietin (EPO)?

Low oxygen levels in the blood Signup and view all the answers

Which organ is primarily responsible for the breakdown (haemolysis) of red blood cells?

Spleen Signup and view all the answers

What happens to iron released from haemoglobin after red blood cells are broken down?

It is reused Signup and view all the answers

What determines an individual's blood group?

Antigen (protein) on red cell surfaces Signup and view all the answers

Why were blood transfusions historically unsuccessful?

Incompatibility of blood types based on antigens Signup and view all the answers

What is the fate of biliverdin produced during the breakdown of red blood cells?

It is excreted in bile Signup and view all the answers

What role does erythropoietin (EPO) play in erythropoiesis?

It stimulates the release of reticulocytes Signup and view all the answers

Which component of the blood determines an individual's blood group?

Antigens on red cell surfaces Signup and view all the answers

What process primarily regulates red blood cell numbers to maintain homeostasis?

Erythropoiesis Signup and view all the answers

Study Notes

Red blood cells (erythrocytes) are the most abundant type of blood cells, making up 99% of the total.
They are biconcave discs with a diameter of about 7μm and no nucleus.
Their main function is the transport of oxygen and some carbon dioxide.
The shape of red blood cells increases their surface area for gas exchange and allows fast entry and exit of gases.
They are flexible and lack intracellular organelles, allowing more room for hemoglobin.
The average human body contains about 30 trillion red blood cells, with a lifespan of around 120 days.
Red blood cell development starts with stem cells and takes about 7 days, during which they lose their nucleus and become incapable of division.
Vitamins B12 and folic acid are required for red blood cell synthesis and are found in dairy products, meat, and green vegetables.
Haemoglobin, a large molecule containing a protein and a pigmented iron-containing complex, allows red blood cells to carry oxygen.
An average red blood cell carries about 280 million haemoglobin molecules, giving it an oxygen-carrying capacity of over a billion oxygen molecules.
Iron, a necessary component of haemoglobin, is slow to absorb from the alimentary canal and can cause deficiency if losses exceed intake.
Oxygen binds reversibly to hemoglobin to form oxyhemoglobin, which releases oxygen readily under certain conditions.
Low pH levels cause oxyhemoglobin to break down and release additional oxygen for tissue use.
Low oxygen levels (hypoxia) cause oxyhemoglobin to release more oxygen to meet the body's needs.
Erythropoiesis is the process of producing red blood cells (erythrocytes).
Oxygen levels play a role in regulating erythropoiesis: when oxygen levels are low, oxygen is released to tissues, increasing demand and production of red blood cells.
Erythropoietin (EPO) is the hormone that stimulates red blood cell production, primarily in response to hypoxia (low oxygen supply).
Hypoxia can result from various conditions including anaemia, low blood volume, poor blood flow, reduced oxygen content of inspired air, or lung disease.
Erythropoietin increases production of proerythroblasts and release of reticulocytes, speeding up their maturation to increase oxygen-carrying capacity.
Erythropoiesis is a homeostatic process, with red blood cell numbers remaining constant due to production and destruction.
Red blood cells have a lifespan of about 120 days and are broken down (haemolysis) by macrophages in the spleen, bone marrow, and liver.
Iron from haemoglobin is reused, while biliverdin is converted to bilirubin and excreted in bile.
Blood transfusions were historically unsuccessful due to incompatibility of blood types based on antigens (proteins) on red cell surfaces.
Antigens (ABO and Rh) determine blood groups, with different antibodies produced in response.
Individuals with AB blood type (approximately 55% of UK population) have neither A nor B antigens on their red cells and can receive blood from any group safely.
Individuals with O blood type (approximately 45% of UK population) have no A or B antigens on their red cells and can donate to any group safely.
The terms 'universal donor' and 'universal recipient' are misleading, as other antigen systems may cause incompatibility and transfusion reactions.
Cross-matching is required before transfusion to ensure compatibility between donor and recipient bloods.
Red blood cells (erythrocytes) are the most abundant type of blood cells, making up 99% of the total.
They are biconcave discs with a diameter of about 7μm and no nucleus.
Their main function is the transport of oxygen and some carbon dioxide.
The shape of red blood cells increases their surface area for gas exchange and allows fast entry and exit of gases.
They are flexible and lack intracellular organelles, allowing more room for hemoglobin.
The average human body contains about 30 trillion red blood cells, with a lifespan of around 120 days.
Red blood cell development starts with stem cells and takes about 7 days, during which they lose their nucleus and become incapable of division.
Vitamins B12 and folic acid are required for red blood cell synthesis and are found in dairy products, meat, and green vegetables.
Haemoglobin, a large molecule containing a protein and a pigmented iron-containing complex, allows red blood cells to carry oxygen.
An average red blood cell carries about 280 million haemoglobin molecules, giving it an oxygen-carrying capacity of over a billion oxygen molecules.
Iron, a necessary component of haemoglobin, is slow to absorb from the alimentary canal and can cause deficiency if losses exceed intake.
Oxygen binds reversibly to hemoglobin to form oxyhemoglobin, which releases oxygen readily under certain conditions.
Low pH levels cause oxyhemoglobin to break down and release additional oxygen for tissue use.
Low oxygen levels (hypoxia) cause oxyhemoglobin to release more oxygen to meet the body's needs.
The text discusses the Rhesus (Rh) antigen, a red blood cell membrane antigen important for blood compatibility. About 85% of people are Rh-positive and do not make anti-Rh antibodies, while the remaining 15% are Rh-negative and can produce them under certain circumstances.
The text also discusses the ABO blood grouping system, which includes the A and B antigens and the corresponding antibodies. Individuals with type A blood make anti-B antibodies, type B individuals make anti-A antibodies, type AB individuals make neither, and type O individuals make both anti-A and anti-B antibodies.
Leukocytes, or white blood cells, are important for defence and immunity. They are the largest blood cells, making up about 1% of the blood volume, and contain nuclei and some have granules. There are two main types: granulocytes (neutrophils, eosinophils, and basophils) and agranulocytes (monocytes and lymphocytes).
Granulocytes, specifically neutrophils, protect the body against bacterial invasion and remove dead cells and debris. They are attracted to areas of infection by chemotaxins, which are released by damaged cells, and engulf and kill bacteria by phagocytosis. Neutrophils have a complex, multilobed nucleus and granules filled with lysosomes containing enzymes for digesting engulfed material. They live an average of 6-9 hours in the bloodstream.
Eosinophils, another type of granulocyte, are less active in phagocytosis but specialize in the elimination of parasites. They contain granules filled with toxic chemicals, which they release when they bind to infecting organisms. Local accumulation of eosinophils may occur in allergic inflammation, where they can promote tissue inflammation and release histaminase to dampen down the inflammatory process.
Basophils, which are closely associated with allergic reactions, contain granules filled with heparin and histamine. They play a role in the immune response to allergens by releasing histamine and other chemicals, which contribute to the symptoms of allergic reactions.
The text includes figures and diagrams, such as Figure 4.8 on the ABO system of blood grouping, Figure 4.9 on the granulocytes, and Figure 4.10 and Figure 4.11 on the diapedesis and phagocytic action of leukocytes.
The text also mentions monocytes and lymphocytes as part of the agranulocytes, but does not discuss their functions in as much detail. Monocytes are involved in phagocytosis and the immune response, while lymphocytes are important for adaptive immunity.
The text mentions that the numbers of white blood cells, specifically granulocytes, can rise in response to infection, trauma, or malignancy. Elevated white cell counts can indicate a physiological problem.
Red blood cells (erythrocytes) are the most abundant type of blood cells, making up 99% of the total.
They are biconcave discs with a diameter of about 7μm and no nucleus.
Their main function is the transport of oxygen and some carbon dioxide.
The shape of red blood cells increases their surface area for gas exchange and allows fast entry and exit of gases.
They are flexible and lack intracellular organelles, allowing more room for hemoglobin.
The average human body contains about 30 trillion red blood cells, with a lifespan of around 120 days.
Red blood cell development starts with stem cells and takes about 7 days, during which they lose their nucleus and become incapable of division.
Vitamins B12 and folic acid are required for red blood cell synthesis and are found in dairy products, meat, and green vegetables.
Haemoglobin, a large molecule containing a protein and a pigmented iron-containing complex, allows red blood cells to carry oxygen.
An average red blood cell carries about 280 million haemoglobin molecules, giving it an oxygen-carrying capacity of over a billion oxygen molecules.
Iron, a necessary component of haemoglobin, is slow to absorb from the alimentary canal and can cause deficiency if losses exceed intake.
Oxygen binds reversibly to hemoglobin to form oxyhemoglobin, which releases oxygen readily under certain conditions.
Low pH levels cause oxyhemoglobin to break down and release additional oxygen for tissue use.
Low oxygen levels (hypoxia) cause oxyhemoglobin to release more oxygen to meet the body's needs.
Erythropoiesis is the process of producing red blood cells (erythrocytes).
Oxygen levels play a role in regulating erythropoiesis: when oxygen levels are low, oxygen is released to tissues, increasing demand and production of red blood cells.
Erythropoietin (EPO) is the hormone that stimulates red blood cell production, primarily in response to hypoxia (low oxygen supply).
Hypoxia can result from various conditions including anaemia, low blood volume, poor blood flow, reduced oxygen content of inspired air, or lung disease.
Erythropoietin increases production of proerythroblasts and release of reticulocytes, speeding up their maturation to increase oxygen-carrying capacity.
Erythropoiesis is a homeostatic process, with red blood cell numbers remaining constant due to production and destruction.
Red blood cells have a lifespan of about 120 days and are broken down (haemolysis) by macrophages in the spleen, bone marrow, and liver.
Iron from haemoglobin is reused, while biliverdin is converted to bilirubin and excreted in bile.
Blood transfusions were historically unsuccessful due to incompatibility of blood types based on antigens (proteins) on red cell surfaces.
Antigens (ABO and Rh) determine blood groups, with different antibodies produced in response.
Individuals with AB blood type (approximately 55% of UK population) have neither A nor B antigens on their red cells and can receive blood from any group safely.
Individuals with O blood type (approximately 45% of UK population) have no A or B antigens on their red cells and can donate to any group safely.
The terms 'universal donor' and 'universal recipient' are misleading, as other antigen systems may cause incompatibility and transfusion reactions.
Cross-matching is required before transfusion to ensure compatibility between donor and recipient bloods.

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