18

Q1. Lymphoid tissue is found in 

• Thymus
• Tonsils
• Lymph nodes
• All of the above

Solution

Thymus, tonsils and lymph nodes are lymphoid organs which are composed of lymphoid tissue.

Q2. Red cell count is carried out by

• Haemocytometer
• Haemoglobinometer
• Sphygmomanometer
• Electrocardiogram

Solution

The haemocytometer is a device used to count red blood cells. It consists of a thick glass microscopic slide with a rectangular indentation which creates a chamber. This chamber is engraved with a laser-etched of perpendicular lines. It is therefore possible to count the number of cells or particles in a specific volume of fluid, and thereby calculate the concentration of cells in the fluid.

Q3. Coronary heart disease is due to    

• Streptococcibacteria  
• Inflammation of pericardium  
• Weakening of the heart valves  
• Insufficient blood supply to the heart muscles  

Solution

Blood supply to the heart stops due to complete blockage of the coronary arteries which results in coronary heart disease which is also called atherosclerosis.  

Q4. A closed circulatory system occurs in

• Cockroach
• Tadpole/fish
• Mosquito
• Housefly

Solution

A closed circulatory system is usually a high pressure system in which blood flows in closed tubular structures called blood vessels (arteries, veins and capillaries). It is found in most of the annelids, cephalopods, among the molluscs and all vertebrates, including human beings. In this type of system, there is no direct contact between body tissues and blood.

Q5. If due to some injury the chordae tendineae of the tricuspid valve of the human heart is partially non-functional, what will be the immediate effect?

• The flow of blood into the pulmonary artery will be reduced.
• The flow of blood into the aorta will be slowed down.
• The pacemaker will stop functioning.
• The blood will tend to flow back into the left atrium.

Solution

If due to injury the chordae tendineae of the tricuspid valves of the human heart is partially non-functional, the flow of blood into the pulmonary artery is reduced due to backflow of blood into the right atrium. 

Q6. The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC because ‘O’ in it refers to having  

• Other antigens besides A and B on RBCs  
• Over dominance of ‘0’ on the genes for A and B types  
• One antibody only, either anti-A or anti-B on RBCs  
• No antigens A and B on RBCs  

Solution

Landsteiner divided human population into four groups based on the presence of antigens found in their RBCs. Each group represented a blood group. Thus, there are four types of blood groups - A, B, AB and O. The blood group ‘O’ does not contain any antigen on RBCs and can be given to any person. Hence, this blood group is called a universal donor.  

Q7. Which of the following is not a major organ of the lymphatic system?

• Lymph nodes
• Thymus
• Kidneys
• Spleen

Solution

The kidneys are not involved in the lymphatic system. It is a part of the excretory system.

Q8. Bundle of His is formed of  

• Nervous tissue supplied to ventricles  
• Nervous tissue supplied to heart  
• Muscular tissue supplied to ventricles  
• Muscular tissue supplied to heart  

Solution

Bundle of His is a collection of heart muscle cells for excitatory impulses which are rapidly transmitted from it to all parts of the ventricles.  

Q9. Another term for heart attack is

• Coronary thrombosis
• Myocardial infarction
• Cardiac arrest
• Ischaemia

Solution

Myocardial infarction is the medical term for a heart attack. It is the death of a part of the heart muscle which ends the blood supply to it.

Q10. The process of formation of RBCs is called

• Poikegenesis
• Leucopoiesis
• Erythropoiesis
• None of the above

Solution

Formation of erythrocytes is called erythropoiesis. Leucopoiesis is a form in which white blood cells (WBCs or leucocytes) are formed in the bone marrow. 

Q11. Which of the following engulfs pathogens rapidly?  

• Acidophils  
• Monocytes  
• Basophils  
• Neutrophils  

Solution

Neutrophils are granulocytes. The granules in granulocytes are actually lysosome and Golgi bodies. These are the chief phagocytic cells of the body and engulf the microbes by phagocytosis, so neutrophils are also called soldiers of the body.  

Q12. Blood cancer is known as

• Leukaemia
• Thrombosis
• Haemolysis
• Haemophilia

Solution

Blood cancer is known as leukemia and is characterised by uncontrolled division of leucocytes.

Q13. Antigens are present

• Inside the nucleus
• On the cell surface
• Inside the cytoplasm
• On the nuclear membrane

Solution

Antigens are foreign particles present on the surface of cells. When introduced in the blood, they initiate a specific immune response against themselves.

Q14. In ECG, the depolarisation of atria is indicated by  

• P-wave  
• Q-wave  
• R-wave  
• S-wave  

Solution

The P-wave is a small upward wave which represents electrical excitation or atrial depolarisation which leads to contraction of both the atria.  

Q15. ‘Dup’ sound is produced during the closure of

• Semilunar valves
• Bicuspid valve
• Tricuspid valve
• Bicuspid valve and tricuspid valve

Solution

The period between the end of one heart beat to the end of the next heart beat is called a cardiac cycle. The cardiac cycle is formed of three phases - atrial systole, ventricular systole and joint diastole. During a ventricular systole, the closing of auriculoventricular valves at the start of the ventricular systole produces the first heart sound called ‘lubb’ or systolic sound. During a joint diastole, the rapid closure of semilunar valves at the beginning of the ventricular diastole produces the second heart sound called ‘dup’.

Q16. The important function of lymph is to  

• Transport oxygen to the brain  
• Transport CO₂ to the lungs  
• Return RBCs to lymph nodes  
• Return interstitial fluid to the blood  

Solution

The important function of the lymph is to return the interstitial fluid to the blood.  

Q17. The removal of calcium from freshly collected blood

• Causes delayed clotting
• Prevents clotting
• Causes immediate clotting
• Prevents destruction of haemoglobin

Solution

Blood clotting starts when prothrombinase in the presence of Ca²⁺ converts inactive prothrombin to thrombin, which in turn converts dissolved fibrinogen protein to fine thread-like fibrin. The network of fibrin covers the wound in which blood corpuscles form a clot. If Ca²⁺ is removed, then it will prevent clotting.

Q18. Mark the odd one: 

• Monocyte
• Lymphocyte
• Neutrophil
• Erythrocyte

Solution

Monocyte, lymphocyte and neutrophil are white blood cells (WBCs), but erythrocyte is a red blood cell (RBC).

Q19. Which of the following has a closed circulatory system?  

• Arthropods  
• Molluscs  
• Platyhelminthes  
• Annelids  

Solution

In a closed circulatory system, the blood pumped by the heart is always circulated through a closed network of blood vessels. As fluid is regulated in better ways, it is more advantageous. The closed circulatory system is present in Annelids and Chordates.  

Q20. Blood enters the heart because muscles of the  

• Atria relax  
• Ventricles contract  
• Ventricles relax  
• Atria contract  

Solution

During ventricular systole, the AV valves remain closed. The atria are now relaxed, and pressure in the atria is low, even lower than the venous pressure. As a result, blood flows into the atria from the large, attached veins.  

Q21. The left atrium receives oxygenated blood through 

• Coronary artery
• Aorta
• Pulmonary artery
• Pulmonary vein

Solution

The left atrium is one of the chambers in the human heart which receives oxygenated blood from the pulmonary veins and pumps it to the left ventricle.

Q22. Erythropoiesis starts in  

• Kidneys  
• Liver  
• Spleen  
• Bone marrow  

Solution

Red blood cells are produced by the bone marrow which is called haemocytoblasts. Haemocytoblasts in red bone marrow give rise to mature RBCs.  

Q23. Haemophilia is

• Royal disease
• Faulty blood clotting
• Royal disease and faulty blood clotting
• Mosquito with a haemocoel

Solution

The most famous pedigree of haemophilia was discovered by Haldane in the royal families of Europe. In a haemophilic patient, the blood does not clot because of the lack of thromboplastin. It is X-linked and shows a characteristic criss-cross inheritance.

Q24. Which of the following is not a main function of lymph glands?  

• Forming WBCs  
• Forming antibodies  
• Forming RBCs  
• Destroying bacteria  

Solution

Cells of lymph nodes produce lymphocytes, synthesise antibodies and destroy bacteria by phagocytosis.  

Q25. The presence of RBC in the urine is

• Alkaptonuria
• Ureathiasis
• Haematuria
• Proteinuria

Solution

The presence of red blood cells (RBCs) in urine is called haematuria. 

Q26. The valve situated between the left atrium and the left ventricle is called     (1) Bicuspid valve  (2) Tricuspid valve  (3) Mitral valve (4) Eustachian tube   

• l, 2 and 3 are correct.  
• 1 and 2 are correct.  
• 2 and 4 are correct.  
• 1 and 3 are correct.  

Solution

The atrioventricular opening between the left atrium and the left ventricle is guarded by the bicuspid valve which is also called the mitral valve.     The right atrioventricular opening is guarded by the tricuspid valve.     The opening of the inferior vena cava is guarded by the Eustachian valve.  

Q27. Pacemaker is 

• AV node
• SA node
• Bundle of His
• Ventricular muscles

Solution

The pacemaker is the sinoatrial (SA) node as the heart beat originates from the SA node which may sometimes get damaged or defective, so the heart does not function properly. This can be remedied by the grafting of an artificial pacemaker.

Q28. The course of blood from the heart to the lungs and back to the heart is called

• Systemic circulation
• Pulmonary circulation
• Single circulation
• Double circulation

Solution

Pulmonary circulation carries the blood to and from the lungs. This is just one phase of the overall circulatory system. 

Q29. In adult man, normal blood pressure is 

• 100/80 mm Hg
• 120/80 mm Hg
• 100/120 mm Hg
• 80/120 mm Hg

Solution

Blood pressure is the pressure of the circulating blood against the walls of the arteries and veins and the chambers of the heart. The blood pressure is usually 120 mm Hg during the contraction of the heart (systole) and 80 mm Hg during the relaxation of the heart (diastole).

Q30. Find out the wrong match:  

• Eosinophils - Allergic response  
• Basophils - Secrete histamine and serotonin  
• Neutrophils - Phagocytic and eat foreign organisms  
• Monocytes - Secrete heparin  

Solution

Monocytes are leucocytes which are motile and phagocytic in nature and engulf bacteria and cellular debris. Basophils secrete heparin, serotonin and histamine.  

Q31. Rh factor is present in 

• All vertebrates
• All mammals
• All reptiles
• Man and rhesus monkey only

Solution

The protein named rhesus antigen is present on the surface of red blood cells in rhesus monkey and humans.

Q32. The mitral valve is present between

• Right atrium and right ventricle
• Left atrium and left ventricle
• Right and left ventricles
• Left ventricle and aorta

Solution

The atrioventricular opening between the left atrium and the left ventricle is guarded by the bicuspid valve which is also called the mitral valve.

Q33. The opening of the right atrium into the right ventricle of the human heart is guarded by

• Mitral valve
• Pulmonary semilunar valves
• Bicuspid valve
• Tricuspid valve

Solution

The right atrioventricular opening is guarded by the tricuspid valve, as it has three flaps.

Q34. Which blood cell secretes antibody?

• Lymphocyte
• Monocyte
• Eosinophil
• Neutrophil

Solution

Lymphocytes produce antibodies to destroy microbes; their toxins reject grafts and kill tumour cells.

Q35. The SA node is located in   

• Upper lateral wall of the left atrium  
• Lower lateral wall of the left atrium  
• Lower lateral wall of the right atrium  
• Upper lateral wall of the right atrium  

Solution

The SA node called the sinoatrial node lies in the wall of the right atrium near the opening of the superior vena cava.  

Q36. What would be the cardiac output of a person having 72 heart beats per minute and a stroke volume of 50 ml?

• 360 ml
• 3600 ml
• 7200 ml
• 5000 ml

Solution

Cardiac output (Q) is the volume of blood pumped by the heart, in particular by a ventricle, in a minute. Cardiac output is equal to the stroke volume (SV) multiplied by the heart rate (HR). So, the cardiac output will be 3600 ml.

Q37. Which of the following is a non-granulocyte?  

• Monocytes  
• Eosinophils  
• Basophils  
• Neutrophils  

Solution

Monocytes are agranulocytes; they have much cytoplasm without any granules.     Eosinophils, basophils and neutrophils are granulocytes which contain granules in their cytoplasm.  

Q38. Heart beat initiates from   

• Auriculoventricular node  
• Sinoauricular node  
• Bundle of His  
• Purkinje fibres  

Solution

The SA node is called ‘heart of heart’ because the heart beat originates from there.  

Q39. Sickle cell anaemia is due to

• Change of amino acid in the α-chain of haemoglobin
• Change of amino acid in the β-chain of haemoglobin
• Change of amino acid in both α and β chains of haemoglobin
• Change of amino acid in either α or β-chain of haemoglobin

Solution

The sixth amino acid from the amino terminal end of the β-chain of normal haemoglobin is glutamic acid, while it is valine in sickle cell haemoglobin. This replacement results in a change in confirmation of the haemoglobin molecule and RBC becomes sickle-shaped. 

Q40. Artery is a blood vessel which carries blood

• Away from the heart
• Towards the heart
• Has deoxygenated blood without exception
• None of the above

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