Grade 11 : Biology - Circulation System (Set 3)

Question 1

Which valve prevents the backflow of blood from the left ventricle into the left atrium during ventricular contraction (systole)?

Accepted Answer

B) Bicuspid (Mitral) valve

Answer

A) Tricuspid valve

Answer

C) Pulmonary semilunar valve

Answer

D) Aortic semilunar valve

Answer

E) Eustachian valve

Question 2

A healthy athlete at rest has a recorded resting heart rate of 75 beats/min and a stroke volume of 70 mL per beat.

Calculate the total cardiac output of this individual in liters per minute.

Accepted Answer

C) 5.25 L/min

Answer

A) 4.20 L/min

Answer

B) 4.90 L/min

Answer

D) 5.75 L/min

Answer

E) 6.00 L/min

Question 3

During the enzymatic cascade of blood clotting, which enzyme directly catalyzes the conversion of soluble fibrinogen into insoluble fibrin monomer threads?

Accepted Answer

C) Thrombin

Answer

A) Prothrombinase

Answer

B) Thrombokinase

Answer

D) Renin

Answer

E) Pepsin

Question 4

In a standard clinical Electrocardiogram (ECG) trace of a healthy individual, what physiological event is indicated by the QRS complex?

Accepted Answer

C) Ventricular depolarization

Answer

A) Atrial depolarization

Answer

B) Ventricular repolarization

Answer

D) Atrial repolarization

Answer

E) Ventricular joint relaxation

Question 5

An $ ext{Rh}^-$ mother carries an $ ext{Rh}^+$ fetus during her second pregnancy without receiving prophylactic anti-Rh immunoglobulin after her first delivery.

Which mechanism leads to Erythroblastosis Fetalis in the fetus?

Accepted Answer

A) Maternal IgG anti-Rh antibodies cross the placenta and lyse fetal RBCs.

Answer

B) Fetal anti-Rh IgM antibodies enter maternal circulation.

Answer

C) Incompatibility of ABO blood group antigens triggers maternal complement activation.

Answer

D) Fetal leucocytes destroy maternal red blood cells.

Answer

E) Direct destruction of fetal platelets by maternal fibrin.

Question 6

Which histological feature distinguishes systemic arteries from corresponding veins of comparable external diameter?

Accepted Answer

B) Arteries possess a thicker tunica media rich in smooth muscle and elastic fibers.

Answer

A) Arteries have a much wider lumen and thinner tunica media.

Answer

C) Arteries contain internal semilunar valves throughout their length.

Answer

D) Arteries lack the innermost tunica intima layer.

Answer

E) Veins have a significantly thicker elastic tunica media.

Question 7

Conduction Components:
1. AV Node (AVN)
2. Sinoatrial Node (SAN)
3. Purkinje fibers
4. Bundle of His

Identify the correct sequence of electrical impulse propagation through the conducting system of the human heart.

Accepted Answer

A) $	ext{SAN} ightarrow 	ext{AVN} ightarrow 	ext{Bundle of His} ightarrow 	ext{Purkinje fibers}$

Answer

B) $	ext{AVN} ightarrow 	ext{SAN} ightarrow 	ext{Purkinje fibers} ightarrow 	ext{Bundle of His}$

Answer

C) $	ext{SAN} ightarrow 	ext{Purkinje fibers} ightarrow 	ext{AVN} ightarrow 	ext{Bundle of His}$

Answer

D) $	ext{Bundle of His} ightarrow 	ext{SAN} ightarrow 	ext{AVN} ightarrow 	ext{Purkinje fibers}$

Answer

E) $	ext{AVN} ightarrow 	ext{Bundle of His} ightarrow 	ext{SAN} ightarrow 	ext{Purkinje fibers}$

Question 8

The hepatic portal vein transports absorbed nutrients and deoxygenated blood directly from the digestive tract to which organ prior to systemic circulation?

Accepted Answer

D) Liver

Answer

A) Kidneys

Answer

B) Lungs

Answer

C) Spleen

Answer

E) Pancreas

Question 9

The second heart sound ('Dubb') heard via phonocardiogram is produced by which specific physiological event?

Accepted Answer

C) Rapid closure of semilunar valves at the origin of aorta and pulmonary artery

Answer

A) Closure of the bicuspid valve

Answer

B) Closure of the tricuspid valve

Answer

D) Opening of atrioventricular valves during atrial systole

Answer

E) Flow of blood into the coronary sinus

Question 10

Which type of leucocyte represents the most abundant granular white blood cell in normal human blood and acts as the primary phagocytic responder to bacterial infection?

Accepted Answer

E) Neutrophils

Answer

A) Basophils

Answer

B) Eosinophils

Answer

C) Monocytes

Answer

D) Lymphocytes

Question 11

What effect does stimulation by sympathetic neural signals (via adrenergic nerves) have on cardiac function?

Accepted Answer

B) Increases heart rate, rate of action potential conduction, and ventricular contractility.

Answer

A) Decreases heart rate and reduces ventricular contraction force.

Answer

C) Decreases heart rate but selectively increases stroke volume.

Answer

D) Has zero impact on heart rate, altering only systemic blood pressure.

Answer

E) Causes complete inhibition of SA node automaticity.

Question 12

Which statement accurately describes human interstitial fluid/lymph compared to blood plasma?

Accepted Answer

C) Lymph is clear/colorless, devoid of erythrocytes, contains fewer proteins, but is rich in lymphocytes.

Answer

A) Lymph contains higher concentrations of erythrocytes and plasma proteins.

Answer

B) Lymph lacks cellular elements completely.

Answer

D) Lymph exhibits higher hydrostatic pressure than systemic arterial blood.

Answer

E) Lymph circulates rapidly due to direct muscular pumping from the left atrium.

Question 13

Which pair of animal phyla exhibits a strictly closed circulatory system where blood is continuously confined within vessels?

Accepted Answer

B) Annelida and Chordata

Answer

A) Arthropoda and non-cephalopod Mollusca

Answer

C) Hemichordata and Insecta

Answer

D) Echinodermata and Platyhelminthes

Answer

E) Crustacea and Arachnida

Question 14

Why are individuals with blood group $ ext{O}$ classified as universal RBC donors?

Accepted Answer

B) Their erythrocytes lack both A and B surface antigens (agglutinogens).

Answer

A) Their plasma contains no Anti-A or Anti-B antibodies.

Answer

C) Their red blood cells lack hemoglobin structures entirely.

Answer

D) They lack Rh factor membrane proteins.

Answer

E) Their red blood cells contain active thrombin inhibitors.

Question 15

The standard human cardiac cycle duration at rest is approximately 0.8 seconds.

What is the duration of joint diastole, during which all four heart chambers remain relaxed simultaneously?

Accepted Answer

C) 0.4 seconds

Answer

A) 0.1 seconds

Answer

B) 0.3 seconds

Answer

D) 0.7 seconds

Answer

E) 0.8 seconds

Question 16

Atherosclerosis (Coronary Artery Disease) is pathologically characterized by luminal narrowing caused by plaque deposition in which blood vessels?

Accepted Answer

C) Coronary arteries

Answer

A) Carotid arteries

Answer

B) Renal arteries

Answer

D) Pulmonary arteries

Answer

E) Subclavian arteries

Question 17

A patient's End-Diastolic Volume (EDV) is measured at 120 mL and End-Systolic Volume (ESV) is 50 mL.

Calculate the patient's Stroke Volume (SV).

Accepted Answer

B) 70 mL

Answer

A) 50 mL

Answer

C) 120 mL

Answer

D) 170 mL

Answer

E) 60 mL

Question 18

In a standard clinical blood pressure measurement of $120/80 ext{ mm Hg}$, what does the baseline figure of 80 mm Hg denote?

Accepted Answer

B) Diastolic arterial pressure during ventricular relaxation

Answer

A) Peak systolic arterial pressure during ventricular contraction

Answer

C) Mean pulse pressure within systemic capillaries

Answer

D) Hydrostatic pressure inside the pulmonary trunk

Answer

E) Venous pressure entering the right atrium

Question 19

Which divalent inorganic cation plays an indispensable cofactor role in key enzymatic steps of both intrinsic and extrinsic blood coagulation cascades?

Accepted Answer

C) $	ext{Ca}^{2+}$

Answer

A) $	ext{Na}^+$

Answer

B) $	ext{K}^+$

Answer

D) $	ext{Fe}^{2+}$

Answer

E) $	ext{Mg}^{2+}$

Question 20

Which anatomical chamber configuration and circulatory route pattern are characteristic of adult amphibians (e.g., frogs)?

Accepted Answer

B) 3 chambers (2 atria, 1 ventricle); incomplete double circulation

Answer

A) 2 chambers (1 atrium, 1 ventricle); single circulation

Answer

C) 4 chambers (2 atria, 2 ventricles); complete double circulation

Answer

D) 3 chambers (1 atrium, 2 ventricles); single circulation

Answer

E) 4 chambers (1 atrium, 3 ventricles); open circulation

Grade 11 : Biology - Circulation System (Set 3)