Tiêu đề Ex-2 Body Fluids and circulation(Q+Sol+Ans).docx.pdf ✅

55 BODY FLUIDS AND CIRCULATION EXERCISE – 2: Previous Year Questions 1. Which enzyme is responsible for conversion of inactive fibrinogen to fibrin? [NEET 2021] (a) Epinephrine (b) Thrombokinase (c) Thrombin (d) Renin Ans. (c) Sol. Thrombin acts as an enzyme to catalyze the breakdown of soluble plasma protein called fibrinogen into insoluble protein fibers called fibrin. The thin, long fibers of fibrin form dense network upon the wound and trap blood corpuscle to form a clot or coagulum or thrombosis. Thus, sealing the wound and preventing the blood loss. 2. Persons with AB blood group are called as universal recipient. This is due to [NEET 2021] (a) Presence of antibodies, anti-A and anti-B on RBCs (b) Absence of antibodies, anti-A and anti-B in plasma (c) Absence of antigen A and B on surface of RBCs (d) Absence of antigens A and B in plasma. Ans. (b) Sol. Persons with ‘AB’ group can accept blood from persons with AB as well as the other groups of blood because there is no antibody present in the blood plasma. Therefore, such persons are called ‘universal recipients.’ 3. The QRS complex in a standard ECG represents: [NEET 2020] (a) Depolarization of ventricles (b) Repolarization of ventricles (c) Repolarization of auricles (d) Depolarization of auricles Ans. (a) Sol. The QRS complex represents the depolarization of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole. 4. Match the following columns and select the correct option. [NEET 2020] (a) (1)-(iv); (2)-(i); (3)-(ii); (4)-(iii) (b) (1)-(i); (2)-(ii); (3)-(iv); (4)-(iii) (c) (1)-(ii); (2)-(i); (3)-(iii); (4)-(iv) (d) (1)-(iii); (2)-(iv); (3)-(ii); (4)-(i) Ans. (d) Sol. Eosinophils - Releases histamine, destructive enzymes. Basophils - are the cells with granules containing histamine. Neutrophils - are the phagocytic cells. They kill the microbes. Lymphocytes - are the cells that are part of the acquired immune system. They generate immune responses. 5. Which of the following condition cause erythroblastosis foetalis? [NEET 2020] (a) Mother Rh +ve and foetus Rh -ve (b) Mother Rh -ve and foetus Rh +ve (c) Both mother and foetus Rh +ve (d) Both mother and foetus Rh -ve Ans. (b) Sol. If the mother is Rh-ve and the child is Rh + , the maternal blood can be exposed to the Rh antigens of the baby’s blood during delivery. This leads to the development of antibodies against the Rh factor in the mother’s blood. If in the next pregnancy, she again has a Rh + child, her antibodies can cross the placenta and attack the foetal RBCs, causing haemolysis, which is the breakdown of erythrocytes. This may lead to the release of haemoglobin into the plasma which can damage many organs and cause anaemia and jaundice. This condition is called erythroblastosis foetalis. 6. Match the Column-I with Column-II [NEET 2019] Column-I Column-II (p) P-wave (i) Depolarisation of ventricles (q) QRS complex (ii) Repolarisation of ventricles (r) T-wave (iii) Coronary ischemia (s) Reduction in the size of T-wave (iv) Depolarisation of atria (v) Repolarisation of atria Select the correct option. (a) p → (iv); q → (i); r → (ii); s → (v)
56 BODY FLUIDS AND CIRCULATION (b) p → (ii); q → (i); r → (v); s → (iii) (c) p → (ii); q → (iii); r → (v); s → (iv) (d) p → (iv); q → (i); r → (ii); s → (iii) Ans. (d) Sol. In ECG P-wave represents depolarization of atria. QRS complex represents depolarization of ventricles. T-wave represents repolarization of ventricle i.e., return from excited to normal state. Reduction in the size of T-wave i.e., if the T-wave represents insufficient supply of oxygen i.e., coronary ischemia. 7. What would be the heart rate of a person if the cardiac output is 5L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL? [NEET 2019] (a) 75 beats per minute (b) 100 beats per minute (c) 125 beats per minute (d) 50 beats per minute Ans. (b) Sol. Cardiac output = stroke volume x Heart rate ⇒ Cardiac output = 5L or 5000 ml ⇒ Blood volume in ventricles at the end of diastole = 100 ml ⇒ Blood volume in ventricles at the end of systole = 50 ml Stroke volume = 100 - 50= 50 ml. So, 5000 ml = 50 ml x Heart rate So, Heart rate = 100 beats per minute. 8. All the components of the nodal tissue are autoexcitable. Why does the SA node acts as normal pacemaker? [NEET 2019] (a) SA node has the lowest rate of depolarization (b) SA node is the only component to generate Threshold (c) Only SA node convey the action potential to others (d) SA node has the highest rate of depolarization Ans. (d) Sol. SA node has the highest rate of depolarization. It can generate the action potential at a rate of 70-75 impulses per minute. 9. A specialized nodal tissue embedded in the lower corner of the right atrium close to atrio-ventricular septum delays the spreading of impulses to the heart apex for about 0.1 second. This delay allows- [NEET 2019] (a) The blood to enter aorta (b) The ventricles to empty completely (c) The blood to enter pulmonary arteries (d) The atria to empty completely Ans. (d) Sol. The nodal tissue present close to atrio- ventricular septum is AV node. This Av node transfer the action potential to the ventricles. There is a bit delay in the conduction of impulse which allows the atrium to empty completely. 10. Match the items given in Column I with those in Column II and select the correct option given below: Column I Column II a. Tricuspid valve i. Between left atrium and left ventricle b. Bicuspid valve ii. Between right ventricle and pulmonary artery c. Semilunar valve iii . Between right atrium and right ventricle [NEET 2018] (a) a-i, b-ii, c- iii (b) a-i, b-iii, c-ii (c) a-iii, b-i, c-ii (d) a-ii, b-i, c-iii Ans. (c) Sol. Tricuspid valve regulates the blood flow between the right atrium and right ventricle. The bicuspid valve regulates the blood flow between the left atrium and left ventricle. Whereas the semilunar valve regulates the blood flow between the right ventricle (deoxygenated blood) and the pulmonary artery (which carries deoxygenated blood to the alveoli in lungs). 11. Match the items given in Column I with those in column II and select the correct option given below: Column I Column II a. Fibrinogen i. Osmotic balance
57 BODY FLUIDS AND CIRCULATION b. Globulin ii. Blood clotting c. Albumin iii. Defense mechanism [NEET 2018] (a) a-i, b-iii, c-ii (b) a-i,b-ii, c-iii (c) a-iii, b-ii, c-i (d) a-ii, b-iii, c-i Ans. (d) Sol. Albumin present in the serum is a protein which helps in osmotic balance between blood vessels and tissues. Globulins especially gamma globulins are another serum protein which is known as immunoglobulin (example: IgA, IgG, etc.) are parts of various antibodies found in the immune system. Fibrinogen (factor I) is a glycoprotein complex made in the liver which is involved in blood clotting process. 12. Adult human RBCs are enucleate. Which of the following statement(s) is/are most appropriate explanation for this feature? [NEET 2017] a. They do not need to reproduce b. They are somatic cells c. They do not metabolize d. All their internal space is available for oxygen transport. (a) Only (d) (b) Only (a) (c) (a), (c) and (d) (d) (b) and (c) Ans. (a) Sol. Human RBCs in their juvenile stage contain a nucleus, as these cells mature, they lose the nucleus in order to create space for maximum possible oxygen transfer. The more space the cells hold, more haemoglobin it contains and can hold more oxygen in it. 13. The hepatic portal vein drains blood to liver from [NEET 2017] (a) Heart (b) Stomach (c) Intestine (d) Both b and c Ans. (d) Sol. Hepatic portal drains blood to liver via gastrointestinal tract that means it drains blood from both stomach and intestine to liver. 14. Blood pressure in the pulmonary artery is [NEET 2016] (a) Same as that in the aorta (b) More than that in the carotid (c) More than that in the pulmonary vein (d) Less than that in the venae cavae Ans. (c) Sol. Blood pressure is more in pulmonary artery is more than the pulmonary vein as arteries have a smaller lumen than veins, so the surface area is less in arteries than in veins. Pressure is inversely proportional to the surface area upon which the force acts and hence, the blood pressure in arteries is more than in vein. 15. Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body. [NEET 2016] (a) Erythrocytes (b) Leucocytes (c) Neutrophils (d) Thrombocytes Ans. (d) Sol. Thrombocytes also known as platelets are cells which allow the blood clot formation. Blood is allowed to clot or coagulate when the body is injured, be it a small papercut or a wound. The platelets are a part of a cascading coagulation process where a mesh like structure forms over the cut/wound not allowing external environment to interact with the internal environment of the body. 16. Serum differs from blood in [NEET 2016] (a) lacking globulins (b) lacking clotting factor (c) lacking albumin (d) lacking antibodies Ans. (b) Sol. Serum contains soluble components like antibodies, antigens, electrolytes, hormones and exogenous substances such as drugs and microorganisms and all proteins except that used in blood clotting. Blood serum is a watery fluid of the blood that separates when blood clots. Serum can be obtained from blood plasma from which the protein fibrinogen or clotting factors have been removed. Thus, serum contains no cells or clotting proteins. 17. Which one of the following animals has two separate circulatory pathways? [NEET 2015]
58 BODY FLUIDS AND CIRCULATION (a) Shark (b) Frog (c) Lizard (d) Whale Ans. (d) Sol. Whales have two separate circulatory pathways as they are mammals. Most mammals are said to have double circulation and whale is an aquatic mammal. 18. Erythropoiesis starts in [NEET 2015] (a) Kidney (b) Liver (c) Heart (d) Red bone marrow Ans. (d) Sol. It is a process that produces red blood cells. It is stimulated by decreased oxygen in circulation and is detected by the kidneys, which then secrete the hormone 'erythropoietin'. This hormone stimulates the red blood cell precursors., which then activates the production of red blood cells in hemopoietic tissues in the bone marrow. 19. Doctors use strethoscope to hear the sound produced during each cardiac cycle. The second sound is heard when [NEET 2015] (a) AV valves open up (b) Ventricular walls vibrate due to gushing in of blood through atria (c) Semilunar valve close down after the blood flows into vesicles from ventricles (d) AV node receives the signal from SA node Ans. (c) Sol. Normal sound of heart that can be heard through the stethoscope is "lupp-dupp". It is the basic sound of heart that can be obtained as a result of each cardiac cycle. The "lupp" is the first sound created due to the closure of mitral and tricuspid valves at the start of systole. The "dupp" is the second sound which is shorter and higher pitched than the first sound, and is produced by closure of the aortic and pulmonary valves, they are commonly referred as semilunar valves. 20. Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when: [NEET 2015] (a) AV node receives signal from SA node (b) AV valves open up (c) Ventricular walls vibrate due to gushing in of blood from atria (d) Semilunar valves close down after the blood flows into vessels from ventricles Ans. (d) Sol. The second sound or dub is heard when ventricular contraction ends. In other words, it means that the sound is heard due to the closing of semilunar valves after oxygenated blood flows from the left atrium via the aorta into the vessels, for transport throughout the body. 21. Which of the following is correct? [NEET 2014] (a) Plasma = blood- lymphocytes (b) Serum= blood + fibrinogen (c) Lymph= Plasma + RBC+WBC (d) Blood =Plasma +RBC+WBC+Platelets Ans. (d) Sol. Blood contains plasma and formed elements such as RBCs, WBCs and platelets. Plasma is the fluid part in shich all formed elements are present. When we remove clotting factors from plasma it is called serum. Lymph is formed from blood when blood lacks RBCs. 22. Person with blood group AB is considered as universal recipient because he has [NEET 2014] (a) Both A and B antigens on RBC but no antibodies in the plasma (b) Both A and B antibodies in the plasma (c) No antigen on RBC and no antibody in the plasma (d) Both A and B antigens in the plasma but no Antibodies Ans. (a) Sol. Person with blood group AB is considered as universal recipient because the antigens A and B is present over the RBC membrane and hence has no respective antibodies against it, as that would trigger an auto-immune condition which can be fatal. Hence, any blood group person be it: A, B, O or even AB can donate their blood to person with AB blood group. 23. Figure shows schematic plan of blood circulation in human with labels A to D. Identify the correct label and give its function: [NEET 2013]