-
Question 1
Correct
-
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) = 90 fl, mean corpuscular haemoglobin concentration (MCHC) = 41 g/dl. Further examination of blood sample revealed increased osmotic fragility of the erythrocytes. Which of the following is the most likely cause of this patient’s findings?
Your Answer: Spherocytosis
Explanation:Spherocytes are small rounded RBCs. It is due to an inherited defect of the RBC cytoskeleton membrane tethering proteins. Membrane blebs form that are lost over time and cells become round instead of biconcave. As it is a normochromic anaemia, the MCV is normal. it is diagnosed by osmotic fragility test which reveals increased fragility in a hypotonic solution.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 2
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
-
-
Question 3
Correct
-
A 23 year old woman is Rh -ve and she delivered a baby with a Rh+ blood group. What measure can be performed to prevent Rh incompatibility in the next pregnancy?
Your Answer: Immunoglobulin D
Explanation:Rh disease is also known as erythroblastosis fetalis and is a disease of the new-born. In mild states it can cause anaemia with reticulocytosis and in severe forms causes severe anaemia, morbus hemolytcus new-born and hydrops fetalis. RBCs of the Rh+ baby can cross the placenta and enter into the maternal blood. As she is Rh- her body will form antibodies against the D antigen which will pass through the placenta in subsequent pregnancies.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 4
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: Mitochondria
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
-
-
Question 5
Correct
-
What is the mostly likely cause of prolonged activated partial thromboplastin time (aPPT) ?
Your 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
-
-
Question 6
Correct
-
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: 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
-
-
Question 7
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
-
-
Question 8
Correct
-
The mechanism of action of streptokinase involves:
Your Answer: Direct conversion of plasminogen to plasmin
Explanation:Streptokinase is an enzyme that is produced by group A beta haemolytic streptococcus and is an effective and cost efficient method for the dissolution of a clot used in cases of MI and pulmonary embolism. It works by directly converting plasminogen to plasmin which breaks down the blood components in the clot and fibrin, dissolving the clot. Streptokinase is a bacterial product and thus the body will develop immunity against it.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 9
Correct
-
Which of the following organs is most likely to have dendritic cells?
Your 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
-
-
Question 10
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
-
-
Question 11
Correct
-
Which of the following is a potential cause of a positive D-dimer assay?
Your Answer: Deep venous thrombosis
Explanation:A D-dimer test is performed to detect and diagnose thrombotic conditions and thrombosis. A negative result would rule out thrombosis and a positive result although not diagnostic, is highly suspicious of thrombotic conditions like a deep vein thrombosis, pulmonary embolism as well as DIC.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 12
Correct
-
C5a (a complement component) is a potent?
Your Answer: Anaphylotoxin
Explanation:C5a is a strong chemoattractant as well as an anaphylotoxin and is involved in the recruitment of inflammatory cells such as neutrophils, eosinophils, monocytes, and T lymphocytes. It is also involved in activation of phagocytic cells, release of granule-based enzymes and generation of oxidants. All of which contribute to innate immune functions.
-
This question is part of the following fields:
- General
- Physiology
-
-
Question 13
Correct
-
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: 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
-
-
Question 14
Correct
-
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: 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
-
-
Question 15
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
-
-
Question 16
Incorrect
-
A 65-year old patient with altered bowl movement experienced the worsening of shortness of breath and exertional chest pains over the course of 8 weeks. Examination shows pallor and jugular venous distension. Furthermore, a test of the stool for occult blood is positive. Laboratory studies show:
Haemoglobin 7.4 g/dl
Mean corpuscular volume 70 fl Leukocyte count 5400/mm3
Platelet count 580 000/mm3 Erythrocyte sedimentation 33 mm/h
A blood smear shows hypochromic, microcytic RBCs with moderate poikilocytosis. Which of the following is the most likely diagnosis?Your Answer: Anaemia of chronic disease
Correct Answer: Iron deficiency anaemia
Explanation:Iron deficiency anaemia is the most common type of anaemia. It can occur due to deficiency of iron due to decreased intake or due to faulty absorption. An MCV less than 80 will indicated iron deficiency anaemia. On the smear the RBC will be microcytic hypochromic and will also show piokilocytosis. iron profiles 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
-
-
Question 17
Incorrect
-
The gradual depolarization in-between action potentials in pacemaker tissue is a result of?
Your Answer: An increase in the ‘delayed rectifier’ current due to outward movement of inward K+ (IK)
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
-
-
Question 18
Correct
-
A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance will be raised in the plasma of this patient?
Your 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
-
-
Question 19
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
-
-
Question 20
Correct
-
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: 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
-
-
Question 21
Correct
-
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: 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
-
-
Question 22
Correct
-
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-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
-
-
Question 23
Correct
-
What is the role of factor VII in coagulation?
Your 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
-
-
Question 24
Correct
-
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: 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
-
-
Question 25
Correct
-
A blood sample from a patient with polycythaemia vera will show which of the following abnormalities?
Your 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
-
-
Question 26
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
-
-
Question 27
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
-
-
Question 28
Correct
-
What is the most likely cause of prolonged bleeding time in a 40 year old women admitted for a laparoscopic cholecystectomy?
Your 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
-
-
Question 29
Correct
-
Which of the following cytokines produced by the T cell induce MHC-II proteins?
Your 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
-
-
Question 30
Incorrect
-
Which of the following associations is correctly matched with the body's defence mechanism in fighting infection?
Your Answer: First line of defence → neutrophils
Correct Answer: Specific cellular mechanism → cytotoxic T cells
Explanation:The immune system has certain levels of defence against pathogens. First line includes simple barriers such as skin, mucosa and stomach acid that prevent the pathogen from entering into the body. If this barrier is breached then the innate immune system is activated which includes leukocytes (macrophages, neutrophils, mast cells, eosinophils, basophils, natural killer cells). If the pathogens invade the second layer of defence then the third layer, adaptive immunity is activated, which includes B and T lymphocytes. B cells provide a humoral response whereas cytotoxic T cells have specific cellular mechanisms. They maintain a memory of past infections and are activated faster following a recurrence.
-
This question is part of the following fields:
- General
- Physiology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
