Q1: 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
(a) E-C-A-D-B
(b) A-E-C-B-D
(c) B-D-E-C-A
(d) E-A-D-B-C
Ans: (a)
The electrical pathway for the conduction of an action potential through the heart is a precisely coordinated process, essential for maintaining the heart's rhythmic beating. To understand this conduction pathway, it’s important to know the roles of the specific components involved:
SA node (Sinoatrial node): Often referred to as the pacemaker of the heart. It initiates the electrical impulse, causing the atria to contract.
AV node (Atrioventricular node): Receives the impulse from the SA node and provides a slight delay, allowing the ventricles time to fill with blood before they contract.
AV bundle (Bundle of His): Transfers the electrical impulse from the AV node to the bundle branches.
Bundle branches: Conducts the impulses through the interventricular septum.
Purkinje fibers: Distribute the electrical impulse throughout the ventricles, stimulating them to contract uniformly and powerfully.
The correct sequence for the pathway of an action potential through the heart follows a route designed to efficiently coordinate the heartbeat starting from the initiation of the action potential to the consequential contraction of the heart muscles. The sequence is:
SA node (E): The pacemaker where the electrical activity originates.
AV node (C): Where the impulse is delayed slightly.
AV bundle (A): Conducts the impulse from the AV node to the bundle branches.
Bundle branches (D): Leads the impulse to the Purkinje fibers.
Purkinje fibers (B): Distributes the impulse throughout the ventricles.
By examining the options provided with the above understanding:
Option A: E-C-A-D-B
Option B: A-E-C-B-D
Option C: B-D-E-C-A
Option D: E-A-D-B-C
Option A (E-C-A-D-B) correctly reflects the order in which the electrical impulse travels through the cardiac conduction system, beginning with the SA node and ending in the Purkinje fibers. Hence, Option A is the correct answer.
Q2: Match List I with List II : (NEET 2024)
Choose the correct answer from the options given below :
(a) A-I, B-III, C-IV, D-II
(b) A-III, B-II, C-IV, D-I
(c) A-II, B-III, C-I, D-IV
(d) A-IV, B-II, C-I, D-III
Ans: (b)
Sol: The correct answer is option no. (B) as
A. P wave - III. Depolarisation of atria.
B. QRS complex - II. Depolarisation of ventricles.
C. T wave - IV. Repolarisation of ventricles.
D. T-P gap - I. Heart muscles are electrically silent.
Q1: Match List I with List II. (NEET 2023)
Choose the correct answer from the options given below :
(a) A-III, B-I, C-IV, D-II
(b) A-IV, B-III, C-II, D-I
(c)(d) A-II, B-IV, C-I, D-III
(d) A-I, B-II, C-III, D-IV
Ans: (a)
Q2: Which of the following are correct? (NEET 2023)
A. Basophil are the 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:
(a) D and E only
(b) C and E only
(c) B and C only
(d) A and B only
Ans: (c)
The correct answer is Option B : B and C only.
Q1: Given below are two statements: (NEET 2022 Phase 1)
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:
(a) Both statement I and statement II are incorrect
(b) Statement I is correct but statement II is incorrect
(c) Statement I is incorrect but statement II is correct
(d) Both statement I and statement II are correct
Ans: (c)
Q2: Which one of the following statements is correct? (NEET 2022 Phase 1)
(a) The tricuspid and the bicuspid valves open due to the pressure exerted by the simultaneous contraction of the atria
(b) Blood moves freely from atrium to the ventricle during joint diastole
(c) Increased ventricular pressure causes closing of the semilunar valves
(d) The atrio-ventricular node (AVN) generates an action potential to stimulate atrial contraction
Ans: (a)
Q3: A unique vascular connection between the digestive tract and liver is called______. (NEET 2022 Phase 2)
(a) Hepato-cystic system
(b) Hepato-pancreatic system
(c) Hepatic portal system
(d) Renal portal system
Ans: (c)
Q4: Arrange the following formed elements in the decreasing order of their abundance in blood in humans:
(a) Platelets
(b) Neutrophils
(c) Erythrocytes
(d) Eosinophils
(e) Monocytes
Choose the most appropriate answer from the options given below:
(a) (a), (c), (b), (d), (e)
(b) (c), (a), (b), (e), (d)
(c) (c), (b), (a), (e), (d)
(d) (d), (e), (b), (a), (c) (NEET 2022 Phase 2)
Ans: (b)
Option (b) is the correct answer as a healthy adult man has, on an average, 5 millions to 5.5 millions of RBCs (erythrocytes) mm–3 of blood.
Blood normally contains 1,50,000 – 3,50,000 platelets mm–3.
Neutrophils form 60-65 percent of the total WBCs, monocytes form 6-8 percent of the total WBCs and eosinophils form 2-3 percent of the total WBCs. The total WBCs are approximately 6000-8000 mm–3 of blood.
Thus, the formed elements in the decreasing order of their abundance in blood in humans: -
Erythrocytes – Platelets – Neutrophils – Monocytes – Eosinophils
Q1: Persons with 'AB' blood group are called as "Universal recipients". 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 antigens A and B on the surface of RBCs
(d) Absence of antigens A and B in plasma
Ans: (b)
Option (a) is correct because persons with 'AB' blood group contain antigens 'A' and 'B' but lack antibodies anti-A and anti-B in plasma. So, persons with 'AB' blood group can accept blood from persons with AB as well as the other groups of blood due to lack of antibodies in their blood. Therefore, such persons are called "Universal recipients".
Q2: Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins? (NEET 2021)
(a) Epinephrine
(b) Thrombokinase
(c) Thrombin
(d) Renin
Ans: (c)
Q1: The QRS complex in a standard ECG represents : (NEET 2020)
(a) Depolarisation of ventricles
(b) Repolarisation of ventricles
(c) Repolarisation of auricles
(d) Depolarisation of auricles
Ans: (a)
The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole.
Q2: Match the following columns and select the correct option. (NEET 2020)
Ans: (c)
Eosinophils are associated with allergic reactions and release histaminase, Basophils secrete histamine, serotonin, heparin etc. and are involved in inflammatory reactions, Neutrophils are phagocytic cells; Both B and T lymphocytes are responsible for immune responses of the body.
Q1: Match the Column - I with Column - II. (NEET 2019)
Select the correct option.
Ans: (b)
P wave represent atrial depolarization.
QRS complex '' ventricular ''.
T - wave '' depolarisation of ventricles.
Reduction in the size of T-wave indicates coronary ischemia.
Q2: 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 the ventricular systole is 50 mL? (NEET 2019)
(a) 125 beats per minute
(b) 50 beats per minute
(c) 75 beats per minute
(d) 100 beats per minute
Ans: (d)
Cardiac output = Stroke volume × Heart rate
Where stroke volume = End diastolic volume – End systolic volume
= 100 ml – 50 ml
= 50 ml
∴ 5000 mL = 50 mL × Heart rate
⇒ Heart rate = 5000 / 50 = 100 beats per minute.
Q1: Match the items given in Column I with those in column II and select the correct option given below. (NEET 2018)
Ans: (a)
The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve, whereas a bicuspid or mitral valve guards the opening between the left atrium and the left ventricle.
Q2: Match the items given in column I with (hose in column II and select the correct option given below. (NEET 2018)
Ans. (d)
Q1: Adult human RBCs are enucleated. Which of the following statement(s) is/are most appropriate explanation for this feature? (NEET 2017)
(1) They do not need to reproduce.
(2) They are somatic cells.
(3) They do not metabolise.
(4) All their internal space is available for oxygen transport.
(a) Only (1)
(b) (1), (3) and (4)
(c) (2) and (3)
(d) Only (4)
Ans: (d)
Red blood cells of adult humans do not have cell organelles including nucleus, Golgi bodies, mitochondria, ribosomes, etc. It increases the surface area of RBCs and enables them to contain more haemoglobin (the oxygen carrying pigment).
Q2: The hepatic portal vein drains blood to liver from (NEET 2017)
(a) Stomach
(b) Kidneys
(c) Intestine
(d) Heart.
Ans: (c)
In hepatic portal system, hepatic portal vein drains blood to liver from intestine.
Q1: Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body. (NEET 2016 Phase 2)
(a) Erythrocytes
(b) Leucocytes
(c) Neutrophils
(d) Thrombocytes
Ans: (d)
Thrombocytes are called blood platelets. They are minute disc-shaped cell fragments in mammalian blood. They are formed as fragments of larger cells found in red bone marrow; they have no nucleus. They play an important role in blood clotting and release thromboxane A2 , serotonin and other chemicals, which cause a chain of events leading to the formation of a plug at the site of the damage, thus preventing further blood loss. A reduction in their number can lead to clotting factors which will lead to excessive loss of blood from the body.
Q2: Serum differs from blood in (NEET 2016 Phase 2)
(a) Lacking globulins
(b) Lacking albumins
(c) Lacking clotting factors
(d) Lacking antibodies.
Ans: (c)
Serum is the fluid that separates from blood plasma on centrifugation. Serum is essentially similar in composition to plasma but lacks fibrinogen and other substances that are used in the coagulation process.
Q3: In mammals, which blood vessel would normally carry largest amount of urea? (NEET 2016 Phase 1)
(a) Hepatic Vein
(b) Hepatic Portal Vein
(c) Renal Vein
(d) Dorsal Aorta
Ans: (a)
Hepatic Vein, because the liver produces urea and other waste materials and then it pours it all in the right ventricle of the heart for oxygenation. The heart distributes the blood to various parts of the body from here. So the impure blood brought by the Hepatic Vein and other blood vessels get distributed through the aorta. This will automatically imply that the Renal Artery will contain lesser impure blood than the Hepatic Vein.
Q4. Blood pressure in the pulmonary artery is (NEET 2016 Phase1)
(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)
Arteries have higher blood pressure than vein because blood is forced inside them from heart and also their lumen is narrow.
Q5. Which one of the following is correct? (2015)
(a) Serum = Blood + Fibrinogen
(b) Lymph = Plasma + RBC + WBC
(c) Blood = Plasma + RBC + WBC
(d) Plasma = Blood – Lymphocytes
Ans: (c)
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