05_Cardiovascular System 1 Flashcards
What is the main function of blood in the human body?
Transporting oxygen, carbon dioxide, nutrients, waste products, and hormones
Blood helps regulate pH and temperature, and has immune functions.
What are the three main components of the cardiovascular system?
- Heart
- Blood vessels
- Blood
What percentage of body weight does blood account for?
7%
What is blood primarily composed of?
- Plasma (55%)
- Cells (45%)
What is blood plasma?
The yellow-coloured liquid that remains when cells are removed from blood.
What are the main components of blood plasma?
- Water (91%)
- Proteins (7%)
- Mineral salts (0.9%)
- Nutrients
- Waste materials
- Hormones
- Enzymes
- Gases
What is the function of albumin in blood plasma?
- Carrier of substances (lipids, steroid hormones)
- Maintains osmotic pressure
What is the role of globulins in blood plasma?
- Immunity (immunoglobulins)
- Transport iron, lipids, and vitamins
What is fibrinogen’s function in blood plasma?
Essential for blood clotting
What are the main types of blood cells?
- Erythrocytes (red blood cells)
- Leukocytes (white blood cells)
- Thrombocytes (platelets)
What is haematopoiesis?
The production of all blood cells.
Where do all blood cells originate from?
Pluripotent stem cells in the red bone marrow.
What is the lifespan of erythrocytes?
90–120 days
What is the average haematocrit for females?
Approximately 42%
What is the average haematocrit for males?
Approximately 47%
What is the structure of haemoglobin?
Consists of four polypeptide chains (globin) bound to haem.
What nutrients are required for erythrocyte formation?
- Vitamin B12
- Folate (vitamin B9)
- Iron
What stimulates the secretion of erythropoietin (EPO)?
Hypoxia
What is haemolysis?
The destruction of erythrocytes to release haemoglobin into plasma.
What is bilirubin?
A yellow-coloured pigment formed from the breakdown of haem.
How many recognized blood group systems are there?
Over 40
What are the two most important blood group systems?
- ABO
- Rhesus
What identifies blood group A?
Presence of antigen A
What is the universal donor blood group?
O–
What is the universal recipient blood group?
AB+
What are the five types of leukocytes?
- Neutrophils
- Monocytes
- Eosinophils
- Basophils
- Lymphocytes
What is the primary function of neutrophils?
Phagocytosis: ingest and destroy microbes.
What do eosinophils primarily eliminate?
Parasites
What triggers the production of anti-rhesus antibodies?
Contact with the rhesus antigen
What condition can arise from Rh incompatibility during pregnancy?
Haemolytic disease of the newborn
What are the primary functions of eosinophils?
• Eliminate parasites.
• Modulation of hypersensitivity reactions (e.g., allergies).
• Phagocytosis.
• Releases proteins that exert direct anti-parasitic effects.
• Migrate to allergic site.
What are the primary functions of basophils and mast cells?
• Key cells in inflammation.
• Release histamine and heparin.
• Histamine dilates blood vessels.
• Heparin is an anti-coagulant.
Where are basophils found in the body?
In blood as basophils and in tissue as mast cells.
What are the main types of lymphocytes?
• B-lymphocytes
• T-lymphocytes
• Natural Killer (NK) cells
What is the role of T-lymphocytes and NK cells?
Kill invading pathogens (NK cells do this non-specifically).
What do B-lymphocytes produce?
Antibodies (immunoglobulins).
What are thrombocytes and how are they produced?
Thrombocytes are small non-nucleated discs produced in the red bone marrow from megakaryoblasts that transform into megakaryocytes.
What is the life span of thrombocytes?
10 days.
What is the first stage of blood clotting?
Vasoconstriction.
What occurs during platelet plug formation?
Platelets stick to the damaged wall and become sticky, forming a platelet plug.
What enzyme converts fibrinogen into fibrin during coagulation?
Thrombin.
What is the final stage of blood clotting?
Fibrinolysis.
What is the role of Vitamin K in blood clotting?
Responsible for making four clotting factors.
List two sources of Vitamin K.
• Vitamin K1 is found in dark green vegetables and tomatoes.
• Vitamin K2 is synthesised by intestinal bacteria and found in fermented foods.
What is the function of heparin?
Heparin is a natural anti-coagulant produced by the body.
What is the most common cause of anaemia worldwide?
Iron deficiency.
What characterizes iron-deficiency anaemia?
It is a hypochromic microcytic anaemia due to reduced concentration of haemoglobin.
What are key signs of iron-deficiency anaemia?
• Spoon-shaped nails (koilonychia)
• Angular stomatitis
• Glossitis
• Brittle hair
What is megaloblastic anaemia characterized by?
Large, immature, and dysfunctional red blood cells.
What vitamins are required for DNA synthesis affecting erythrocytes?
Folate (folic acid) and vitamin B12.
What is aplastic anaemia?
A rare and potentially life-threatening failure of haematopoiesis (blood cell production).
What are common causes of aplastic anaemia?
• Congenital (e.g., Fanconi’s anaemia)
• Idiopathic
• Secondary to drugs, chemicals, radiation, cancer.
What is the pathophysiology of sickle cell anaemia?
An abnormal beta-globin chain in haemoglobin distorts the shape of the cell.
What are the signs and symptoms of sickle cell anaemia?
• General signs and symptoms of anaemia
• Splenomegaly
• Jaundice
• Pain and swelling in hands/feet
What is thalassaemia?
A defect in the synthesis of either the alpha or beta haemoglobin chains.
What is the definition of erythropoiesis?
The process of producing red blood cells.
What is the meaning of ‘-blast’ in medical terminology?
Immature cell (only partially differentiated).
What does ‘-cytosis’ refer to?
More than normal cell numbers.
What does ‘-penia’ indicate?
Lack of cells.
What is the definition of A-Thalassaemia?
A-Thalassaemia can be lethal in utero in severe cases. Signs/symptoms include anaemia, jaundice, splenomegaly, and hepatomegaly.
A-Thalassaemia involves defects in the alpha globin genes, leading to reduced production of alpha chains.
What are the signs and symptoms of B-Thalassaemia?
Signs and symptoms include failure to thrive and anaemia. It starts when HbA production begins and gamma chain ceases, usually later in the first year.
B-Thalassaemia results from mutations affecting beta globin production.
What triggers Haemolytic Disease of the Newborn?
Occurs when the mother produces anti-rhesus antibodies that cross the placenta.
This condition may lead to agglutination and haemolysis of fetal red blood cells.
What is polycythaemia?
Polycythaemia describes an excessive production of erythrocytes, resulting in increased blood viscosity, reduced blood flow, and an increased risk of thrombosis.
It is also known as erythrocytosis.
What are the causes of polycythaemia?
Causes include:
* Occurs at high altitude
* Unknown/genetic
Polycythaemia can also occur due to other factors, including certain diseases.
What are the symptoms of mild cases of polycythaemia?
Mild cases may cause no symptoms.
More severe cases can lead to arterial and venous thrombosis.
Define leukopenia.
Leukopenia is a marked reduction in the number of leukocytes.
A common subgroup is neutropenia, defined as a neutrophil count of less than 1.5 x 10^9/L.
What are the causes of leukopenia?
Causes include:
* Viral infections (e.g., glandular fever, hepatitis, HIV)
* Drug toxicity (e.g., chemotherapy)
* Radiation
* Bone marrow diseases
* Nutritional deficiencies (e.g., folate, B12)
Each cause impacts the bone marrow’s ability to produce leukocytes.
What are the common signs and symptoms of leukopenia?
Signs and symptoms include:
* Severe illness
* Nausea
* Fatigue
* Cough
* Shortness of breath
* Fever
* Malaise
Severe leukopenia can lead to fatal infections and sepsis.
What is leukocytosis?
Leukocytosis is a marked increase in the number of all leukocytes.
This condition often indicates a response to infections or physical stress.
What characterizes leukaemia?
Leukaemia is characterized by an abnormal over-production of leukocytes, leading to suppressed erythrocyte and thrombocyte production.
It is a group of bone marrow cancers.
Differentiate between acute and chronic leukaemia.
Acute leukaemias have a rapid onset with immature cells, while chronic leukaemias have an insidious onset with more differentiated cells.
Acute leukaemia is more aggressive than chronic leukaemia.
List the four types of leukaemia.
The four types of leukaemia are:
* Acute myelogenous leukaemia (AML)
* Acute lymphocytic leukaemia (ALL)
* Chronic myeloid leukaemia (CML)
* Chronic lymphocytic leukaemia (CLL)
Each type has distinct characteristics and treatment approaches.
What are the signs and symptoms of leukaemia?
Signs and symptoms include:
* Malaise
* Anaemia (fatigue, pallor)
* Frequent infections
* Easy bleeding/bruising
* Fever
* Weight loss
* Splenomegaly
* Lymph node enlargement
Symptoms vary between acute and chronic forms.
How is leukaemia diagnosed?
Diagnosis involves:
* Full blood count
* Blood film
* Bone marrow biopsy
These tests help identify abnormalities in blood cell counts and morphology.
What is thrombocytopenia?
Thrombocytopenia is a reduction in the thrombocyte count.
It is characterized by excessive bleeding and bruising.
What are the causes of thrombocytopenia?
Causes include:
* Leukaemia
* Congenital disorders (e.g., Fanconi’s anaemia)
* Radiation, drugs, chemotherapy
* Viral infections (EBV, hepatitis, HIV, MMR)
* Autoimmune destruction
Each cause affects the production or destruction of platelets.
What is haemophilia?
Haemophilia is a deficiency of clotting factors, specifically:
* Haemophilia A: Deficiency of clotting factor VIII
* Haemophilia B: Deficiency of clotting factor IX
This condition is often genetic and affects males more than females.
What are the signs and symptoms of severe haemophilia?
Signs and symptoms include:
* Excessive and easy bleeding
* GIT/mucosal haemorrhage
* Haematuria
* Haemarthrosis
The severity can vary based on the level of clotting factor deficiency.
What is the treatment for haemophilia?
Treatment includes:
* Replacement of clotting factors
* Blood transfusion
* Avoiding contact sports
* Use of herbs, homeopathy, and nutrition
Management focuses on preventing bleeding episodes.
What is the average lifespan of a red blood cell?
The average lifespan of a red blood cell is approximately 120 days.
After this period, red blood cells are typically removed by the spleen.
What is megaloblastic anaemia?
Megaloblastic anaemia is characterized by the presence of large, abnormal red blood cells due to impaired DNA synthesis.
This condition is often caused by vitamin B12 or folate deficiency.
