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  • Question 1 - A blood sample of a 58 year old male patient, who underwent an...

    Incorrect

    • A blood sample of a 58 year old male patient, who underwent an abdominal aortic aneurysm repair, was sent to the laboratory. The laboratory technician said that the patient’s blood agglutinates with antisera anti-A and anti-D, while the patient’s serum agglutinates cells of blood group B. What is the blood group of this patient?

      Your Answer: AB positive

      Correct Answer: A positive

      Explanation:

      Group A – has only the A antigen on red cells (and B antibody in the plasma)

      Group B – has only the B antigen on red cells (and A antibody in the plasma)

      Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)

      Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma). Many people also have a so-called Rh factor on the red blood cell’s surface. This is also an antigen and those who have it are called Rh+. A person with Rh– blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance) but they can develop Rh antibodies in the blood plasma if they receive blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh– blood without any problems. In this scenario the person has blood group A+ as he has A antigen, anti B antibody and Rh antigen

    • This question is part of the following fields:

      • General
      • Physiology
      66.6
      Seconds

  • Question 2 - A 50 year old man on warfarin therapy following insertion of a pacemaker...

    Incorrect

    • A 50 year old man on warfarin therapy following insertion of a pacemaker presented with epistaxis. Which of the following is true regarding blood coagulation?

      Your Answer: Disseminated intravascular coagulation (DIC) results in depletion of fibrin split products

      Correct Answer: Patients with haemophilia A usually have a normal bleeding time

      Explanation:

      A prolonged bleeding time is seen in platelet disorders like thrombocytopenia. Patients with haemophilia A or B have a prolonged PTT but not a prolonged bleeding time.

      Ca2+ is necessary for coagulation.

      von Willebrand factor is an important part of the factor VIII complex and promotes platelet adhesion and aggregation.

      DIC results in depleted coagulation factors and accumulation of fibrin.

    • This question is part of the following fields:

      • General
      • Physiology
      38
      Seconds

  • Question 3 - The transmembrane proteins responsible for resting membrane potential of vascular smooth muscle cells...

    Incorrect

    • The transmembrane proteins responsible for resting membrane potential of vascular smooth muscle cells was blocked by a drug. Which of the following transmembrane proteins were blocked by this drug?

      Your Answer: Na+/K+ pump

      Correct Answer: K+ channels

      Explanation:

      The resting membrane potential is due to selective permeability of the membrane to potassium ions. The Na/K pump is responsible for the generation of a gradient across the membrane and it is due to the inherent ability of the K channels to allow diffusion back into the nerve at rest which charges the cells. In reality, the resting membrane potential is more positive because of small contributions by Na+ channels, Cl− channels and non-selective cation channels.

    • This question is part of the following fields:

      • General
      • Physiology
      23.1
      Seconds

  • Question 4 - A syndrome responsible for failure to absorb vitamin B12 from the GIT is...

    Correct

    • A syndrome responsible for failure to absorb vitamin B12 from the GIT is called?

      Your Answer: Pernicious anaemia

      Explanation:

      Pernicious anaemia is a type of autoimmune disease in which antibodies form against the parietal cells or intrinsic factor. Intrinsic factor is required for the absorption of vitamin B12. Blood testing typically shows a macrocytic, normochromic anaemia and low levels of serum vitamin B12. A Schilling test can then be used to distinguish between pernicious anaemia, vitamin B12 malabsorption and vitamin B12 deficiency. Symptoms include shortness of breath, pallor and diarrhoea etc.

    • This question is part of the following fields:

      • General
      • Physiology
      14.6
      Seconds

  • Question 5 - An 18 year-old with an iron deficient diet was prescribed an iron supplement...

    Correct

    • An 18 year-old with an iron deficient diet was prescribed an iron supplement by her GP. Lack of iron often results in:

      Your Answer: Hypochromic anaemia

      Explanation:

      Iron deficiency anaemia is the most common type of anaemia. It can occur due to deficiency of iron from decreased intake, increased loss or inadequate absorption. An MCV less than 80 will indicated iron deficiency anaemia. On the smear the RBCs will be microcytic hypochromic and will also show poikilocytosis. Iron profile tests are important to make a diagnosis. Clinically the patient will be pale and lethargic.

    • This question is part of the following fields:

      • General
      • Physiology
      17.8
      Seconds

  • Question 6 - A 47 year-old woman was admitted for elective cholecystectomy, with a past...

    Incorrect

    • A 47 year-old woman was admitted for elective cholecystectomy, with a past history of easy bruising and heavy menstrual periods. The patient was also diagnosed with Willebrand's disease. Willebrand's disease is:

      Your Answer: Characterised by decreased factor VII

      Correct Answer: Autosomal dominant

      Explanation:

      von Willebrand disease is an autosomal dominant disorder marked by the deficiency of vWF, a large protein synthesized by the endothelial cells and megakaryocytes. It mediates adhesion of platelets to the subendothelium at site of vascular injury. Disease characteristics include impaired platelet adhesion, prolonged bleeding time and a functional deficiency of factor VIII (vWF is its carrier protein).

    • This question is part of the following fields:

      • General
      • Physiology
      31.9
      Seconds

  • Question 7 - A 50 year old woman presented with excessive bleeding after an inguinal hernia...

    Incorrect

    • A 50 year old woman presented with excessive bleeding after an inguinal hernia repair. Labs are suggestive of a primary haemostasis defect. Deficiency of which of the following is most likely to cause it?

      Your Answer: Protein C

      Correct Answer: Platelets

      Explanation:

      Primary haemostatic control means the first line of defence against immediate bleeding. This is carried out by the platelets. They immediately form a haemostatic plug at the site of injury. Coagulation starts within 20s after an injury to the blood vessel which damage the endothelial cells. Secondary haemostasis follows which includes activation of the coagulation factors to form fibrin strands which mesh together forming the platelet plug. Platelets interact with platelet collagen receptor, glycoprotein Ia/IIa and to collagen fibres in the vascular endothelium. This adhesion is mediated by von Willebrand factor (vWF), which forms links between the platelet glycoprotein Ib/IX/V and collagen fibrils. The platelets are then activated and release the contents of their granules into the plasma, in turn activating other platelets and white blood cells.

    • This question is part of the following fields:

      • General
      • Physiology
      44
      Seconds

  • Question 8 - What is the mostly likely cause of prolonged activated partial thromboplastin time (aPPT)...

    Incorrect

    • What is the mostly likely cause of prolonged activated partial thromboplastin time (aPPT) ?

      Your Answer: Warfarin therapy

      Correct Answer: Heparin therapy

      Explanation:

      The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is an indicator for measuring the efficacy of both the intrinsic and common coagulation pathway. Prolonged aPTT may indicate: use of heparin, antiphospholipid antibody and coagulation factor deficiency (e.g., haemophilia). Deficiencies of factors VIII, IX, XI and XII and rarely von Willebrand factor (if causing a low factor VIII level) may lead to a prolonged aPTT correcting on mixing studies.

    • This question is part of the following fields:

      • General
      • Physiology
      18.2
      Seconds

  • Question 9 - Signals pass through neuromuscular junctions via the neurotransmitter acetylcholine. After release from the...

    Correct

    • Signals pass through neuromuscular junctions via the neurotransmitter acetylcholine. After release from the skeletal neuromuscular junction, acetylcholine:

      Your Answer: Causes postsynaptic depolarisation

      Explanation:

      Acetylcholine is released from the presynaptic membrane into the cleft where it binds to the ion gated channels on the post synaptic membrane, causing them to open. This results in sodium entering into the fibre and further depolarizing it, creating an action potential.

    • This question is part of the following fields:

      • General
      • Physiology
      28.8
      Seconds

  • Question 10 - After having donated a unit of blood. The blood bank will prefer to...

    Incorrect

    • After having donated a unit of blood. The blood bank will prefer to use which of the following anticoagulants to store the blood?

      Your Answer: Heparin

      Correct Answer: Citrate

      Explanation:

      Calcium is necessary for coagulation to occur. Citrate being a chelator and combining with calcium ions to form un-ionised compound will prevent coagulation. Following transfusion the citrate is removed by the liver with in a few minutes. Oxalate also works on the same principle but it is toxic to the body.

    • This question is part of the following fields:

      • General
      • Physiology
      21.8
      Seconds

  • Question 11 - During pregnancy the uterus enlarges however after delivery it regresses to its original...

    Incorrect

    • During pregnancy the uterus enlarges however after delivery it regresses to its original size. Which of the following organelles is responsible for this regression?

      Your Answer: Endoplasmic reticulum

      Correct Answer: Lysosomes

      Explanation:

      Lysosomes are formed by budding of the Golgi apparatus and contain enzymes which digest macromolecules. They are found in both plants and animals and are active in autophagic cell death, digestion after phagocytosis and for the cells own recycling process. They fuse with the molecules and release their content resulting in digestion.

    • This question is part of the following fields:

      • General
      • Physiology
      39
      Seconds

  • Question 12 - A 26-year-old female patient had the following blood report: RBC count = 4....

    Incorrect

    • A 26-year-old female patient had the following blood report: RBC count = 4. 0 × 106/μl, haematocrit = 27% and haemoglobin = 11 g/dl, mean corpuscular volume (MCV) = 80–100 fl, mean corpuscular haemoglobin concentration (MCHC) = 31–37 g/dl. Which of the following is correct regarding this patient’s erythrocytes:

      Your Answer: Increased cell diameter

      Correct Answer: Normal MCV

      Explanation:

      MCV is the mean corpuscular volume and it is calculated from the haematocrit and the RBC count. It is normally 90 fl. Mean corpuscular haemoglobin concentration (MCHC) [g/dl] = haemoglobin [g/dl]/haematocrit = 11/0.27 = 41 g/dl and is higher than normal range (32 to 36 g/dL).

    • This question is part of the following fields:

      • General
      • Physiology
      52
      Seconds

  • Question 13 - A patient came into the emergency in a state of shock. His blood...

    Correct

    • A patient came into the emergency in a state of shock. His blood group is not known, but on testing it clotted when mixed with Type A antibodies. Which blood should be transfused?

      Your Answer: B +ve

      Explanation:

      There are two stages to determine the blood group, known as ABO typing. The first stage is called forward typing. In this method, RBCs are mixed with two separate solutions of type A or type B antibodies to see if they agglutinate. If this blood clumps, this indicates the presence of antigens within the blood sample. For example, a sample of type B blood will clump when tested with type A antibodies as it contains type B antigens. Group B – has only the B antigen on red cells (and A antibody in the plasma)

      Group B – has only the B antigen on red cells (and A antibody in the plasma)

      Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)

      Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma). Many people also have a Rh factor on the red blood cell’s surface. This is also an antigen and those who have it are called Rh+. Those who have not are called Rh–. A person with Rh– blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance) but they can develop Rh antibodies in the blood plasma if they receive blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh– blood without any problems. The patient’s blood group is B positive as he has antigen B, antibody A and Rh antigens.

    • This question is part of the following fields:

      • General
      • Physiology
      42.7
      Seconds

  • Question 14 - Which of the following proteins prevents red blood cells (RBCs) from bursting when...

    Incorrect

    • Which of the following proteins prevents red blood cells (RBCs) from bursting when they pass through capillaries?

      Your Answer: Integrin

      Correct Answer: Spectrin

      Explanation:

      Spectrin is a structural protein found in the cytoskeleton that lines the intercellular side of the membrane of cells which include RBCs. They maintain the integrity and structure of the cell. It is arranged into a hexagonal arrangement formed from tetramers of spectrin and associated with short actin filaments that form junctions allowing the RBC to distort its shape.

    • This question is part of the following fields:

      • General
      • Physiology
      19
      Seconds

  • Question 15 - Which of the following substances will enhance the activity of antithrombin III? ...

    Incorrect

    • Which of the following substances will enhance the activity of antithrombin III?

      Your Answer: Aspirin

      Correct Answer: Heparin

      Explanation:

      Antithrombin III is a glycoprotein that inactivates multiple enzymes involved in the coagulation system. It inactivates factor X, factor IX, factor II, factor VII, factor XI and factor XII. Its activity is greatly increased by the action of heparin.

    • This question is part of the following fields:

      • General
      • Physiology
      12.3
      Seconds

  • Question 16 - Skeletal muscle fibres are divided into two basic types, type I (slow-twitch fibres)...

    Incorrect

    • Skeletal muscle fibres are divided into two basic types, type I (slow-twitch fibres) and type II (fast-twitch fibres). Fast muscle fibres do which of the following:

      Your Answer: Have numerous mitochondria

      Correct Answer: Use anaerobic metabolism

      Explanation:

      Skeletal muscles are divided into two types:

      1) type I also known as the slow twitch fibres. They use oxygen for their metabolism and as a result they have a high endurance potential. To support this they have abundant mitochondria and myoglobin, so they appear red/dark.

      2) type II fibres also called fast twitch fibres, are low endurance fibres used during anaerobic metabolism. They are required for short bursts of strength and cannot sustain contractions for long periods of time.

    • This question is part of the following fields:

      • General
      • Physiology
      38.2
      Seconds

  • Question 17 - Atractyloside is an inhibitor of electron transport chain. It is expected to have...

    Incorrect

    • Atractyloside is an inhibitor of electron transport chain. It is expected to have little or no effect on the functioning of which of the following cell types?

      Your Answer: Intestinal luminal cells

      Correct Answer: Red blood cells

      Explanation:

      Electron transport chain is a series of electron carriers that are embedded in the mitochondrial membrane. It is the place where ATP is made. Inhibiting the electron transport chain will stop production of ATP. Red blood cells are the only cell in the given option which do not contain ATP.

    • This question is part of the following fields:

      • General
      • Physiology
      208.5
      Seconds

  • Question 18 - Which of the following can lead to haemolytic anaemia? ...

    Incorrect

    • Which of the following can lead to haemolytic anaemia?

      Your Answer: Living at high altitude

      Correct Answer: Presence of haemoglobin S

      Explanation:

      Haemoglobin S is an abnormal type of haemoglobin seen in sickle cell anaemia. This allows for the haemoglobin to crystalize within the RBC upon exposure to low partial pressures of oxygen. This results in rupture of the RBCs as they pass through microcirculation, especially in the spleen. This can cause blockage of the vessel down stream and ischaemic death of tissues, accompanied by severe pain.

    • This question is part of the following fields:

      • General
      • Physiology
      24.2
      Seconds

  • Question 19 - A blood sample from a patient with polycythaemia vera will show which of...

    Incorrect

    • A blood sample from a patient with polycythaemia vera will show which of the following abnormalities?

      Your Answer: Low haematocrit

      Correct Answer: High platelet count

      Explanation:

      Polycythaemia is a condition that results in an increase in the total number of red blood cells (RBCs) in the blood. It can be due to a myeloproliferative syndrome, chronically low oxygen levels or rarely malignancy. In primary polycythaemia/ polycythaemia vera the increase is due to an abnormality in the bone marrow, resulting in increased RBCs, white blood cells (WBCs) and platelets. In secondary polycythaemia the increase occurs due to high levels of erythropoietin either artificially or naturally. The increase is about 6-8 million/cm3 of blood. A type of secondary polycythaemia is physiological polycythaemia where people living in high altitudes who are exposed to hypoxic conditions produce more erythropoietin as a compensatory mechanism for thin oxygen and low oxygen partial pressure.

    • This question is part of the following fields:

      • General
      • Physiology
      28.9
      Seconds

  • Question 20 - Multiple cells were labelled using a fluorescent dye that doesn’t cross the cell...

    Incorrect

    • Multiple cells were labelled using a fluorescent dye that doesn’t cross the cell membrane. One cell in the middle was bleached with a light that destroys the dye, but the cell soon recovers its stain. The presence of which structures best explains this?

      Your Answer: Glycosaminoglycans

      Correct Answer: Gap junctions

      Explanation:

      Gap junctions are attachments between cells that permit intercellular communication e.g. they permit current flow and electrical coupling between myocardial cells. They allow direct electrical transmission among cells and also permit certain substance to pass through as well. They are either homotypic, formed by two identical hemichannels or heterotypic, formed by different hemichannels.

    • This question is part of the following fields:

      • General
      • Physiology
      31.8
      Seconds

  • Question 21 - A 60 year old patient with a history of carcinoma of the head...

    Incorrect

    • A 60 year old patient with a history of carcinoma of the head of the pancreas, and obstructive jaundice presents with a spontaneous nose bleed and easy bruising. What is the most likely reason for this?

      Your Answer: Vitamin B12 deficiency

      Correct Answer: Vitamin-K-dependent clotting factors deficiency

      Explanation:

      Vitamin K is a fat soluble vitamin requiring fat metabolism to function properly to allow for its absorption. People with obstructive jaundice develop vitamin k deficiency as fat digestion is impaired. Vit K causes carboxylation of glutamate residue and hence regulates blood coagulation including: prothrombin (factor II), factors VII, IX, X, protein C, protein S and protein Z.

    • This question is part of the following fields:

      • General
      • Physiology
      50.4
      Seconds

  • Question 22 - A 38-year-old woman with end-stage renal disease, is undergoing haemodialysis. She has normocytic...

    Incorrect

    • A 38-year-old woman with end-stage renal disease, is undergoing haemodialysis. She has normocytic normochromic anaemia. What is the best treatment for her?

      Your Answer: Ferrous sulphate

      Correct Answer: Erythropoietin

      Explanation:

      E erythropoietin (EPO) is a hormone that is released by the kidney. It is responsible for the regulation of red blood cell production in the body. It can be made using recombinant technology and is used in the treatment of anaemia of chronic renal failure and in patients under going chemotherapy

    • This question is part of the following fields:

      • General
      • Physiology
      13.3
      Seconds

  • Question 23 - Which of the following organelles have the capacity to regenerate and spontaneously replicate?...

    Correct

    • Which of the following organelles have the capacity to regenerate and spontaneously replicate?

      Your Answer: Mitochondrion

      Explanation:

      A mitochondria is a membrane bound organelle found in eukaryotic cells. They are called the powerhouse of the cell and are the place where ATP is formed from energy generated through metabolism. They are capable of replication as well as repair and regeneration.

    • This question is part of the following fields:

      • General
      • Physiology
      20.4
      Seconds

  • Question 24 - Electrophoresis is used to detect antibodies (immunoglobulins) in a blood sample from the...

    Incorrect

    • Electrophoresis is used to detect antibodies (immunoglobulins) in a blood sample from the umbilical artery of a new born. Which antibodies have the highest percentage in a new-born?

      Your Answer: IgD

      Correct Answer: IgG

      Explanation:

      IgG is a monomeric immunoglobulin. It is formed by two heavy chains and two light chains and has two binding sites. Its is the most abundant antibody that is equally distributed in the blood and the tissues. It is the only antibody that can pass through the placenta and thus the only antibody present in the baby after it is born. There are four subclasses: IgG1 (66%), IgG2 (23%), IgG3 (7%) and IgG4 (4%). IgG1, IgG3 and IgG4 cross the placenta easily

    • This question is part of the following fields:

      • General
      • Physiology
      24.8
      Seconds

  • Question 25 - What will the destruction of endoplasmic reticulum stop? ...

    Incorrect

    • What will the destruction of endoplasmic reticulum stop?

      Your Answer: Autolysis of proteins

      Correct Answer: Synthesis of proteins

      Explanation:

      The rough endoplasmic reticulum is the factory for the manufacturing of proteins. It contains ribosomes attached to it and transports proteins that are destined for membranes and secretions. The rough ER is connected to the nuclear envelope and to the cisternae of the Golgi apparatus by vesicles that shuttle between the two compartments.

    • This question is part of the following fields:

      • General
      • Physiology
      35.2
      Seconds

  • Question 26 - A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance...

    Incorrect

    • A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance will be raised in the plasma of this patient?

      Your Answer: Ferritin

      Correct Answer: Bilirubin

      Explanation:

      Bilirubin is a yellow pigment that is formed due to the break down of RBCs. Haemolysis results in haemoglobin that is broken down into a haem portion and globin which is converted into amino acids and used again. Haem is converted into unconjugated bilirubin in the macrophages and shunted to the liver. In the liver it is conjugated with glucuronic acid making it water soluble and thus excreted in the urine. Its normal levels are from 0.2-1 mg/dl. Increased bilirubin causes jaundice and yellowish discoloration of the skin.

    • This question is part of the following fields:

      • General
      • Physiology
      7.2
      Seconds

  • Question 27 - What is the reason for a deranged thrombin clotting time? ...

    Incorrect

    • What is the reason for a deranged thrombin clotting time?

      Your Answer: Aspirin therapy

      Correct Answer: Heparin therapy

      Explanation:

      Thrombic clotting time is also known as thrombin time. It is clinically performed to determine the therapeutic levels of heparin. After plasma is isolated from the blood, bovine thrombin is added to it and the time it takes from the addition to clot is recorded. The reference interval is usually <21s. deranged results are indicative of heparin therapy, hypofibrinogenemia, hyperfibrinogenaemia or lupus anticoagulant.

    • This question is part of the following fields:

      • General
      • Physiology
      14.4
      Seconds

  • Question 28 - Which of the following cytokines produced by the T cell induce MHC-II proteins?...

    Incorrect

    • Which of the following cytokines produced by the T cell induce MHC-II proteins?

      Your Answer: β-Interferon

      Correct Answer: γ-Interferon

      Explanation:

      Interferons elicit a non-specific antiviral activity by inducing specific RNA synthesis and expression of proteins in neighbouring cells. Common interferon inducers are viruses, double-stranded RNA and micro-organisms. INF-γ is produced mainly by CD4+, CD8+ T cells and less commonly by B cells and natural killer cells. INF-γ has antiviral and antiparasitic activity but its main biological activity appears to be immunomodulatory. Among its many functions are activation of macrophages and enhanced expression of MHC-II proteins or macrophages.

    • This question is part of the following fields:

      • General
      • Physiology
      35.3
      Seconds

  • Question 29 - Selective destruction of which of the following cells will affect antibody synthesis? ...

    Incorrect

    • Selective destruction of which of the following cells will affect antibody synthesis?

      Your Answer: T lymphocytes

      Correct Answer: Plasma cells

      Explanation:

      Plasma cell are memory cells. After the antigen Is engulfed by the B cells it is presented to the CD4+ helper cells via the MCH II receptor and this leads to their activation which in turn stimulates the B cells to form antibodies against that specific antigen. Some B cells differentiate into plasma cells also called memory cells that get activated after subsequent infection.

    • This question is part of the following fields:

      • General
      • Physiology
      9.2
      Seconds

  • Question 30 - Which of the following organs is most likely to have dendritic cells? ...

    Incorrect

    • Which of the following organs is most likely to have dendritic cells?

      Your Answer: Muscle

      Correct Answer: Skin

      Explanation:

      Dendritic cells are part of the immune system and they function mainly as antigen presenting cells. They are present in small quantities in tissues which are in contact in the external environment. Mainly in the skin and to a lesser extent in the lining of the nose, lungs, stomach and intestines. In the skin they are known as Langerhans cells.

    • This question is part of the following fields:

      • General
      • Physiology
      17.3
      Seconds

  • Question 31 - Regarding the coagulation cascade, Factor VII: ...

    Correct

    • Regarding the coagulation cascade, Factor VII:

      Your Answer: Is a serine protease

      Explanation:

      Factor VII (FVII) is a zymogen for a vitamin K-dependent serine protease essential for the initiation of blood coagulation. It is synthesized primarily in the liver and circulates in plasma. Within the liver, hepatocytes are involved in the synthesis of most blood coagulation factors, such as fibrinogen, prothrombin, factor V, VII, IX, X, XI, XII, as well as protein C and S, and antithrombin, whereas liver sinusoidal endothelial cells produce factor VIII and von Willebrand factor.

    • This question is part of the following fields:

      • General
      • Physiology
      10.9
      Seconds

  • Question 32 - What is the role of factor VII in coagulation? ...

    Incorrect

    • What is the role of factor VII in coagulation?

      Your Answer: Is a co-factor in the coagulation cascade

      Correct Answer: Initiates the process of coagulation in conjunction with tissue factor

      Explanation:

      The main role of factor VII is to initiate the process of coagulation along with tissue factor (TF). TF is found in the blood vessels and is not normally exposed to the bloodstream. When a vessel is injured tissue factor is exposed to blood and circulating factor VII. Factor VII is converted to VIIa by TF.

    • This question is part of the following fields:

      • General
      • Physiology
      14.7
      Seconds

  • Question 33 - Where is factor VIII predominantly synthesised? ...

    Incorrect

    • Where is factor VIII predominantly synthesised?

      Your Answer: Platelets

      Correct Answer: Vascular endothelium

      Explanation:

      Factor VIII is an important part of the coagulation cascade. Deficiency causes haemophilia A. It is synthesised predominantly by the vascular endothelium and is not affected by liver disease. In the circulation it is bound to von Willebrand factor and it forms a stable complex with it. It is activated by thrombin or factor Xa and acts as a co factor to factor IXa to activate factor X which is a co factor to factor Va. Thrombin cleaves fibrinogen in fibrin and forms a meshwork to trap RBC and platelets to form a clot.

    • This question is part of the following fields:

      • General
      • Physiology
      20.8
      Seconds

  • Question 34 - A teenage Somalian boy presents with a complaint of an enlarged lower jaw....

    Incorrect

    • A teenage Somalian boy presents with a complaint of an enlarged lower jaw. His blood film shows blast cells and macrophages. Which virus is responsible for this?

      Your Answer: Cytomegalovirus

      Correct Answer: Epstein–Barr virus

      Explanation:

      Burkitt’s lymphoma is a type of non-Hodgkin’s lymphoma. Histologically it is characterised by a starry sky appearance due to numerous neoplastic macrophages which are required to clear the rapidly dividing tumour cells/blast cells. Burkitt’s lymphoma commonly affects the jaw bone, forming a huge tumour mass. It is associated with translocation of c-myc gene and has three types: 1) endemic/African type, 2)sporadic and 3)immunodeficiency-associated. The first type is strongly associated with EBV.

    • This question is part of the following fields:

      • General
      • Physiology
      24.7
      Seconds

  • Question 35 - An experiment was conducted in which the skeletal muscle protein (not smooth muscle)...

    Correct

    • An experiment was conducted in which the skeletal muscle protein (not smooth muscle) involved in contraction was selectively inhibited. Which protein was inhibited?

      Your Answer: Troponin

      Explanation:

      The mechanism of contraction of smooth muscles is different from that of skeletal muscles in which the contractile protein is troponin whilst in smooth muscle contraction is a protein called calmodulin. Calmodulin reacts with calcium ions and stimulates the formation of myosin crossbridges.

    • This question is part of the following fields:

      • General
      • Physiology
      16.8
      Seconds

  • Question 36 - Depression of the normal coagulation system and excessive bleeding after surgery can occur...

    Correct

    • Depression of the normal coagulation system and excessive bleeding after surgery can occur in which of the following medical conditions?

      Your Answer: Liver disease

      Explanation:

      As most of the coagulation factors are synthesized in the liver, liver diseases like hepatitis or cirrhosis will depress the coagulation system. Vitamin K deficiency can also decrease the production of vitamin K dependent coagulation factors VII, XI, X and prothrombin.

    • This question is part of the following fields:

      • General
      • Physiology
      63.5
      Seconds

  • Question 37 - What is the most likely cause of prolonged bleeding time in a 40...

    Incorrect

    • What is the most likely cause of prolonged bleeding time in a 40 year old women admitted for a laparoscopic cholecystectomy?

      Your Answer: Factor VII deficiency

      Correct Answer: Thrombocytopaenia

      Explanation:

      Bleeding time is related to platelet function, thus a decrease in platelet function, as seen in thrombocytopenia, DIC and von Willebrand disease in which platelet aggregation is defective, leads to an increase in bleeding time. It is not affected by a decrease or deficiency of any other clotting factors. Aspirin and other COX inhibitors prolong bleeding time along with warfarin and heparin.

    • This question is part of the following fields:

      • General
      • Physiology
      32.5
      Seconds

  • Question 38 - A patient admitted for esophagectomy showed low levels of the lightest plasma protein...

    Correct

    • A patient admitted for esophagectomy showed low levels of the lightest plasma protein in terms of weight. Which of the following is the lightest plasma protein:

      Your Answer: Albumin

      Explanation:

      Albumin is the most abundant and the lightest of all the plasma proteins. It maintains osmotic pressure, transports unconjugated bilirubin, thyroid hormones, fatty acids, drugs and acts as a buffer for pH.

    • This question is part of the following fields:

      • General
      • Physiology
      37.2
      Seconds

  • Question 39 - Which of the following is true regarding factor XI? ...

    Correct

    • Which of the following is true regarding factor XI?

      Your Answer: Deficiency causes haemophilia C

      Explanation:

      Factor XI is also known as plasma thromboplastin and is one of the enzymes of the coagulation cascade. It is produced in the liver and is a serine protease. It is activated by factor XIIa, thrombin and by itself. Deficiency of factor XI causes the rare type of haemophilia C. Low levels of factor XI also occur in other disease states, including Noonan syndrome. High levels of factor XI have been seen in thrombosis.

    • This question is part of the following fields:

      • General
      • Physiology
      48.2
      Seconds

  • Question 40 - The gradual depolarization in-between action potentials in pacemaker tissue is a result of?...

    Incorrect

    • The gradual depolarization in-between action potentials in pacemaker tissue is a result of?

      Your Answer: A gradual change in the ratio of extracellular to intracellular ion concentration across the cell membrane

      Correct Answer: A combination of gradual inactivation outward IK along with the presence of an inward ‘funny’ current (If) due to opening of channels permeable to both Na+ and K+ ions

      Explanation:

      One of the characteristic features of the pacemaker cell is the generation of a gradual diastolic depolarization also called the pacemaker potential. In phase 0, the upstroke of the action potential caused by an increase in the Ca2+ conductance, an influx of calcium occurs and a positive membrane potential is generated. The next is phase 3 which is repolarization caused by increased K+ conductance as a result of outwards K+ current. Phase 4 is a slow depolarization which accounts for the pacemaker activity, caused by increased conductance of Na+, inwards Na+ current called IF. it is turned on by repolarization.

    • This question is part of the following fields:

      • General
      • Physiology
      15.9
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

General (15/40) 38%
Physiology (15/40) 38%
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