Blood Circulatory System MCQ for RRB & SSC and other Competitive exams
91
Which of the following correctly describes the role of erythropoietin (EPO)?
✓ Answer:
B
It stimulates RBC production in bone marrow
Erythropoietin (EPO) is a hormone produced mainly by the kidneys (and partly the liver) in response to low oxygen levels (hypoxia) in the blood. It stimulates the red bone marrow to produce more RBCs (Erythropoiesis). EPO production increases at high altitudes (less oxygen) - which is why athletes train at altitude to boost RBC production. Synthetic EPO is used medically for anaemia in kidney disease patients and is banned in sports (doping).
92
Which of the following correctly describes Sickle Cell Anaemia?
✓ Answer:
B
A genetic disorder where RBCs become sickle-shaped blocking blood vessels
Sickle Cell Anaemia is an autosomal recessive genetic disorder caused by a mutation in the beta-globin gene of haemoglobin. The abnormal Haemoglobin S (HbS) causes RBCs to become rigid, sickle (crescent) shaped under low oxygen conditions. These abnormal cells block small blood vessels causing severe pain (vaso-occlusive crisis), are fragile and break easily causing haemolytic anaemia, and have a shorter lifespan (~20 days vs 120 days for normal RBCs).
93
Which of the following is the correct statement about lymph?
✓ Answer:
B
Lymph is a colourless fluid that flows through lymphatic vessels and returns interstitial fluid to blood
Lymph is a colourless to pale yellow fluid that flows through the lymphatic system. It originates from interstitial (tissue) fluid - excess fluid that leaks out of capillaries into tissues. Key facts: it contains lymphocytes but NO RBCs, flows through lymphatic vessels > lymph nodes > thoracic duct > bloodstream (subclavian vein), contains chylomicrons (absorbed fats from lacteals), and lymph nodes filter lymph and trap pathogens.
94
Which of the following is the correct statement about heart sounds?
✓ Answer:
C
The lub (S1) is caused by the closing of mitral and tricuspid valves
The two heart sounds heard with a stethoscope: Lub (S1) is caused by closing of Mitral and Tricuspid (AV) valves at the beginning of ventricular systole. Dub (S2) is caused by closing of Aortic and Pulmonary (Semilunar) valves at the end of ventricular systole. Heart sounds are caused by valve CLOSURE, not opening. Abnormal sounds called Heart Murmurs are caused by turbulent blood flow due to defective valves.
95
What is the role of basophils in the blood?
✓ Answer:
B
Release of histamine and heparin during allergic and inflammatory reactions
Basophils are the rarest WBCs (0.5-1%). They release: Histamine (causes vasodilation and increased vascular permeability during allergic reactions), Heparin (a natural anticoagulant that prevents clotting at the site of inflammation), and Serotonin (involved in inflammatory responses). Basophils play a key role in hypersensitivity (allergic) reactions and are related to mast cells found in tissues. Their granules stain with basic (alkaline) dyes.
96
What is the condition called when there is insufficient blood supply to the heart muscle?
✓ Answer:
B
Myocardial Ischaemia
Myocardial Ischaemia is the insufficient blood (and oxygen) supply to the heart muscle (myocardium). It occurs when coronary arteries are narrowed by atherosclerosis, spasm, or thrombosis. Consequences: Mild/temporary = Angina Pectoris (chest pain, relieved by rest). Complete/prolonged = Myocardial Infarction (heart attack - permanent muscle death). Ischaemia literally means holding back blood (Greek: ischein = to hold, haima = blood).
97
Which of the following is the correct statement about varicose veins?
✓ Answer:
B
They are caused by weakened or damaged venous valves causing blood to pool in veins
Varicose Veins are enlarged, twisted, swollen veins that appear just under the skin, most commonly in the legs. They occur when venous valves weaken or become damaged, allowing blood to pool and accumulate in the vein, causing it to stretch and bulge. Risk factors: prolonged standing, obesity, pregnancy, and family history. Complications can include DVT and skin ulcers. Treatment: compression stockings, sclerotherapy, or surgery.
98
Which of the following is the correct statement about plasma proteins?
✓ Answer:
B
Albumin maintains osmotic pressure of blood
Major plasma proteins and their functions: Albumin (most abundant, ~60%) maintains osmotic/oncotic pressure of blood and transports fatty acids and drugs. Globulins include antibodies (immunoglobulins) for immune defense and transport proteins (transferrin, ceruloplasmin). Fibrinogen is essential for blood clotting (converted to fibrin). All plasma proteins are synthesized in the liver (except antibodies which are made by B lymphocytes).
99
Blood pressure is highest in which of the following blood vessels?
✓ Answer:
C
Arteries
Blood pressure is highest in arteries (especially the aorta ~120 mmHg systolic) and progressively decreases: Arteries (~120 mmHg) > Arterioles > Capillaries (~25-35 mmHg) > Venules > Veins (~10-15 mmHg) > Vena Cava (~5 mmHg). This pressure gradient drives blood flow from high pressure (arteries) to low pressure (veins). Veins need valves and skeletal muscle contraction to assist blood return to the heart.
100
What is the medical term for a fast heart rate above 100 beats per minute?
✓ Answer:
C
Tachycardia
Cardiac rate terminology: Tachycardia = heart rate above 100 bpm (tachy = fast). Bradycardia = heart rate below 60 bpm (brady = slow). Arrhythmia = any abnormal heart rhythm (irregular, too fast, or too slow). Fibrillation = rapid chaotic contractions (Atrial Fibrillation = AF, or Ventricular Fibrillation = VF, which is life-threatening). Tachycardia can be physiological (exercise, fear) or pathological (heart disease, fever, hyperthyroidism).