Free NEET Biology multiple-choice questions on Body Fluids and Circulation. Attempt each question and reveal the answer with a full explanation.
Organisms that are able to maintain homeostasis by physiological (and sometimes behavioral) means which ensures constant body temperature are called: Regulators Conformers Migrators Suspender How do parasympathetic neural signals affect the working of the heart ? Reduce both heart rate and cardiac output. Heart rate is increased without affecting the cardiac output. Both heart rate and cardiac output increase. Heart rate decreases but cardiac output increases. All the components of the conducting system can generate an action potential for the contraction of heart muscle, but the sino-atrial node acts as the pacemaker because : The sino-atrial node has a lower inherent rate of depolarisation All the other components in heart cannot conduct the action potential Only the sino-atrial node is auto-excitable and auto-rhythmic The sino-atrial node has a higher inherent rate of depolarisation In the heart, as the action potential reaches the AV node from the SA node, there is a delay of the action potential. This delay is important because : (1) It allows right atria to receive the blood from vena cava (2) It allows atria to rest (3) It allows a stronger right atrial contraction (4) It allows ventricles to receive all the blood from the atria The QRS complex in a standard ECG represents Depolarisation of auricles Depolarisation of ventricles Repolarisation of ventricles Repolarisation of auricles Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins? Renin Epinephrine Thrombokinase Thrombin Persons with 'AB' blood group are called as "Universal recipients". This is due to : Absence of antigens A and B in plasma Presence of antibodies, anti-A and anti-B, on RBCs Absence of antibodies, anti-A and anti-B, in plasma Absence of antigens A and B on the surface of RBCs Which of the following statements are correct? A. Basophils are most abundant cells of the total WBCs B. Basophils secrete histamine, serotonin and heparin C. Basophils are involved in inflammatory response D. Basophils have kidney shaped nucleus E. Basophils are agranulocytes Choose the correct answer from the options given below: D and E only C and E only B and C only A and B only Following are the stages of pathway for conduction of an action potential through the heart A. AV bundle B. Purkinje fibres C. AV node D. Bundle branches E. SA node Choose the correct sequence of pathway from the options given below E-C-A-D-B A-E-C-B-D B-D-E-C-A E-A-D-B-C Match List I with List II : array llll ; & List I & ; & List II A. & P wave & I. & Heart muscles are electrically silent. B. & QRS complex & II. & Depolarisation of ventricles. C. & T wave & III. & Depolarisation of atria. D. & T-P gap & IV. & Repolarisation of ventricles. array Choose the correct answer from the options given below : A-I, B-III, C-IV, D-II A-III, B-II, C-IV, D-I A-II, B-III, C-I, D-IV A-IV, B-II, C-I, D-III The WBC count of a person’s blood sample is 8000/cu mm. How many eosinophils and lymphocytes would be in the same blood sample approximately? 300 – 500/cu mm and 500 – 700/cu mm respectively 300 – 500/cu mm and 1200 – 1500/cu mm respectively 100 – 120/cu mm and 160 – 200/cu mm respectively 160 – 240/cu mm and 1600 – 2000/cu mm respectively Which one of the following has an open circulatory system ? (1) Pheretima (2) Periplaneta (3) Hirudinaria (4) Octopus The movement of protons from the thylakoid lumen to the stroma through ATP synthase is: Facilitated diffusion Simple diffusion Active transport Osmosis Cytochrome c is a small protein attached to the outer surface of the: Inner mitochondrial membrane Outer mitochondrial membrane Thylakoid membrane Stroma lamellae Cytochrome c, a mobile electron carrier in the ETS, is located: On the outer surface of the inner mitochondrial membrane In the mitochondrial matrix On the inner surface of the inner mitochondrial membrane In the intermembrane space as a soluble protein During the mitochondrial Electron Transport System, which complex is inhibited by Cyanide ( CN - )? Complex IV Complex I Complex II Complex III In the mitochondrial Electron Transport System, Complex IV contains which of the following components? Cytochromes a and a 3 , and two copper centers Cytochromes b and c 1 FMN and Fe-S centers FADH2 and Ubiquinone The volume of blood pumped out by each ventricle per minute is called cardiac output. It is calculated as: Stroke Volume Heart Rate Tidal Volume Respiratory Rate Blood Pressure Resistance End Diastolic Volume - End Systolic Volume During forceful expiration, which set of muscles contracts to decrease the thoracic volume? Internal intercostal and abdominal muscles External intercostal and diaphragm Internal intercostal and diaphragm External intercostal and abdominal muscles The first heart sound 'Lub' is associated with which event of the cardiac cycle? Closure of the tricuspid and bicuspid valves Closure of the semilunar valves Opening of the semilunar valves Opening of the bicuspid and tricuspid valves During a cardiac cycle, atrial systole increases the flow of blood into the ventricles by about: 30 percent 70 percent 10 percent 50 percent In double circulation, the 'Pulmonary Circulation' specifically refers to the flow of blood between: Right ventricle and Left atrium Left ventricle and Right atrium Right atrium and Right ventricle Left atrium and Left ventricle The majority of carbon dioxide produced by our body cells is transported to the lungs- (1) Dissolved in the blood (2) As bicarbonates (3) As carbonates (4) Attached to hemoglobin In a standard cardiac cycle of 0.8 seconds, what is the duration of 'Joint Diastole' where all four chambers are in a relaxed state? 0.4 seconds 0.1 seconds 0.3 seconds 0.5 seconds Which of the following clinical conditions is correctly defined as the state when the heart stops beating completely? Cardiac arrest Heart failure Heart attack Angina During inspiration, the contraction of which muscles increases the volume of the thoracic chamber in the antero-posterior axis? Diaphragm External inter-costal muscles Internal inter-costal muscles Abdominal muscles Which of the following describes the correct sequence of events during a single cardiac cycle? Atrial systole, Ventricular systole, Joint diastole Ventricular systole, Atrial systole, Joint diastole Joint diastole, Ventricular systole, Atrial systole Atrial systole, Joint diastole, Ventricular systole In a standard ECG, the QRS complex represents which of the following electrical activities? Depolarisation of ventricles Depolarisation of atria Repolarisation of ventricles Repolarisation of atria The duration of a cardiac cycle is 0.8 ,seconds . If a person's heart rate is 75 ,beats per minute and the stroke volume is 70 ,mL , what is the Cardiac Output? 5250 ,mL/min 5000 ,mL/min 7000 ,mL/min 6000 ,mL/min During the 'Cardiac Cycle', which phase is characterized by the closure of AV valves and the first heart sound (Lub)? Ventricular systole Atrial systole Ventricular diastole Joint diastole The neural center that can moderate the cardiac function through the Autonomic Nervous System (ANS) is located in the: Medulla oblongata Cerebrum Pons Thalamus To obtain a standard ECG, three electrical leads are connected to a patient. Where are these leads specifically attached? One to each wrist and to the left ankle One to each wrist and to the right ankle One to each ankle and to the left wrist Both to the chest and one to the wrist The stimulation of the Vagus nerve (Parasympathetic) results in which of the following effects on the heart? Decrease in heart rate Increase in heart rate Increase in ventricular contraction strength No effect on the heart Compared to blood our lymph has : More RBCs and less WBCs No plasma Plasma without proteins More WBCs and no RBCs In a standard ECG, the repolarization of atria is usually not seen because: It is masked by the large QRS complex Atria do not undergo repolarization It occurs during the T-wave The electrical signal is too weak to be picked up When we experience altitude sickness at high altitudes, the body compensates for low oxygen availability by: Increasing RBC production and decreasing the binding affinity of hemoglobin. Decreasing RBC production and increasing the breathing rate. Increasing the binding affinity of hemoglobin and decreasing breathing rate. Increasing RBC production and increasing the binding affinity of hemoglobin. At high altitudes, the body compensates for low oxygen availability by decreasing the binding affinity of and increasing the rate of . Hemoglobin; Breathing Myoglobin; Heartbeat Hemoglobin; Digestion Erythrocytes; Circulation Which of the following substances, if introduced into the blood stream, would cause coagulation of blood at the site of its introduction - Thromboplastin Fibrinogen Heparin Prothrombin A drop of each of the following, is placed separately on four slides. Which of them will not coagulate? blood serum sample from the thoracic duct of lymphatic system Whole blood from pulmonary vein blood plasma. In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart ? P-depolarisation of the atria R-repolarisation of ventricles S-start of systole T-end of diastole Figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its function/s. A – Pulmonary vein – takes impure blood from body parts, P O 2 =60 mm Hg B – Pulmonary artery – takes blood from heart to lungs, P O 2 =90 mm Hg C – Vena Cava – takes blood from body parts to right auricle, P CO 2 =45 mm Hg D – Dorsal aorta – takes blood from heart to body parts, P O 2 =95 mm Hg Reduction in pH of blood will :- (1) reduce the rate of heart beat. (2) reduce the blood supply to the brain. (3) decrease the affinity of hemoglobin with oxygen. (4) release bicarbonate ions by the liver. Blood pressure in the pulmonary artery is : (1) same as that in the aorta. (2) more than that in the carotid. (3) more than that in the pulmonary vein. (4) less than that in the venae cavae. Match the items given in Column I with those in Column II and select the correct option given below : a i, b ii, c iii a i, b iii, c ii a iii, b i, c ii a ii, b i, c iii Globulins contained in human blood plasma are primarily involved in - Clotting of blood Defence mechanisms of body Osmotic balance of body fluids Oxygen transport in the blood Match the items given in Column I with those in Column II and select the correct option given below : (i) (iii) (ii) (i) (ii) (iii) (iii) (ii) (i) (ii) (iii) (i) What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL? (1) 125 beats per minute (2) 50 beats per minute (3) 75 beats per minute (4) 100 beats per minute Match the Column-I with Column-II array ll Column-I & Column-II (a) P - wave & (i) Depolarisation of ventricles (b) QRS complex & (ii) Repolarisation of ventricles (c) T - wave & (iii) Coronary ischemia (d) Reduction in the size of T-wave & (iv) Depolarisation of atria ; & (v) Repolarisation of atria array Select the correct option. (a) (ii) (b) (iii) (c) (v) (d) (iv) (a) (iv) (b) (i) (c) (ii) (d) (iii) (a) (iv) (b) (i) (c) (ii) (d) (v) (a) (ii) (b) (i) (c) (v) (d) (iii) Given below are two statements : Statement I : The coagulum is formed of network of threads called thrombins. Statement II : Spleen is the graveyard of erythrocytes. In the light of the above statements, choose the most appropriate answer from the options given below : Both Statement I and Statement II are incorrect Statement I is correct but Statement II is incorrect Statement I is incorrect but Statement II is correct Both Statement I and Statement II are correct Which one of the following statements is correct? The tricuspid and the bicuspid valves open due to the pressure exerted by the simultaneous contraction of the atria Blood moves freely from atrium to the ventricle during joint diastole. Increased ventricular pressure causes closing of the semilunar valves. The atrio-ventricular node (AVN) generates an action potential to stimulate atrial contraction Match List I with List II. array ll List I & List II A. P-wave & I. Beginning of systole B. Q-wave & II. Repolarisation of ventricles C. QRS complex & III. Depolarisation of atria D. T-wave & IV. Depolarisation of ventricles array Choose the correct answer from the options given below : (1) A-III, B-I, C-IV, D-II (2) A-IV, B-III, C-II, D-I (3) A-II, B-IV, C-I, D-III (4) A-I, B-II, C-III, D-IV Cardiac activities of the heart are regulated by: A. Nodal tissue B. A special neural centre in the medulla oblongata C. Adrenal medullary hormones D. Adrenal cortical hormones Choose the correct answer from the options given below : A, B and D Only A, B and C Only A, B, C and D A, C and D Only Select the incorrect statement with reference to Rh grouping. A. Erythroblastosis foetalis is a condition observed having foetus with Rh-ve blood and mother with Rh+ve blood. B. Rh antigen is observed on RBCs in the majority of human beings. C. Before blood transfusion, Rh group should also be matched. D. Rh incompatibility is observed when a pregnant mother is Rh-ve and the foetus is Rh+ve. E. Erythroblastosis foetalis can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the second child. Choose the answer from the options given below : A and B only C and D only A and E only B and C only The number of action potentials generated by sino-atrial node (SAN) in a healthy human is per minute. 28 - 30 70 - 75 100 - 110 120 - 140 Which of the following statements is incorrect? Blood coagulates in response to an injury Blood clot consists of fibrins Fibrin is produced from fibrinogen Fibrinogen is produced from fibrin The most abundant intracellular cation is Na + Ca ++ H + K + The opening between the right atrium and the right ventricle is guarded by . bicuspid valve tricuspid valve semilunar valve sino-atrial node The diagram given here is the standard ECG of a normal person. The P-wave represents the Contraction of both the atria Initiation of the ventricular contraction Beginning of the systole End of systole Approximately seventy percent of carbon-dioxide absorbed by the blood will be transported to the lungs : as bicarbonate ions in the form of dissolved gas molecules by binding to R.B.C. as carbamino - haemoglobin Person with blood group AB is considered as universal recipient because he has : both A and B antigens on RBC but no antibodies in the plasma. both A and B antibodies in the plasma. no antigen on RBC and no antibody in the plasma. both A and B antigens in the plasma but no antibodies.