Grade 11 : Biology - Circulation System (Set 2)

Question 1

Which component of human blood lacks a cell nucleus at functional maturity?

Accepted Answer

A) Red blood cells (Erythrocytes)

Answer

B) White blood cells (Leukocytes)

Answer

C) Lymphocytes

Answer

D) Monocytes

Question 2

Which heart chamber receives oxygenated blood coming directly from the lungs?

Accepted Answer

B) Left atrium

Answer

A) Right atrium

Answer

C) Right ventricle

Answer

D) Left ventricle

Question 3

The natural primary pacemaker of the human heart is the:

Accepted Answer

C) Sinoatrial (SA) node

Answer

A) Atrioventricular (AV) node

Answer

B) Bundle of His

Answer

D) Purkinje fibers

Question 4

Which blood vessel carries deoxygenated blood away from the heart to the lungs?

Accepted Answer

C) Pulmonary artery

Answer

A) Pulmonary vein

Answer

B) Systemic aorta

Answer

D) Superior vena cava

Question 5

The bicuspid (mitral) valve in the human heart prevents backflow between which two chambers?

Accepted Answer

B) Left atrium and left ventricle

Answer

A) Right atrium and right ventricle

Answer

C) Right ventricle and pulmonary artery

Answer

D) Left ventricle and aorta

Question 6

Which class of white blood cells is the most abundant in normal human blood?

Accepted Answer

D) Neutrophils

Answer

A) Basophils

Answer

B) Eosinophils

Answer

C) Monocytes

Question 7

What mechanical event in the heart generates the first heart sound ('lub')?

Accepted Answer

B) Closure of tricuspid and bicuspid (AV) valves

Answer

A) Closure of aortic semilunar valve

Answer

C) Opening of atrioventricular valves

Answer

D) Rapid filling of the atria

Question 8

In a standard electrocardiogram (ECG), the P wave represents which electrical event?

Accepted Answer

A) Depolarisation of the atria

Answer

B) Repolarisation of the atria

Answer

C) Depolarisation of the ventricles

Answer

D) Repolarisation of the ventricles

Question 9

Which plasma protein plays the major role in maintaining osmotic pressure in blood?

Accepted Answer

B) Albumin

Answer

A) Fibrinogen

Answer

C) Globulin

Answer

D) Prothrombin

Question 10

An individual with blood group O negative is considered a universal donor primarily because their red blood cells:

Accepted Answer

A) Lack both A and B surface antigens and Rh factor

Answer

B) Contain both anti-A and anti-B antibodies in plasma

Answer

C) Possess Rh antigen without A/B antigens

Answer

D) Lack plasma proteins completely

Question 11

Lymph differs primarily from blood plasma because lymph contains:

Accepted Answer

B) Fewer large plasma proteins and no RBCs

Answer

A) Higher red blood cell counts

Answer

C) No leukocytes

Answer

D) Higher glucose levels

Question 12

The innermost endothelial lining layer of mammalian blood vessels is called:

Accepted Answer

C) Tunica intima

Answer

A) Tunica media

Answer

B) Tunica externa

Answer

D) Pericardium

Question 13

In clinical diagnostics, standard resting blood pressure exceeding which values is categorized as hypertension?

Accepted Answer

C) 140/90 mmHg

Answer

A) 110/70 mmHg

Answer

B) 120/80 mmHg

Answer

D) 90/60 mmHg

Question 14

The hepatic portal vein carries blood directly from which organ system to the liver?

Accepted Answer

B) Gastrointestinal tract

Answer

A) Kidneys

Answer

C) Lungs

Answer

D) Brain

Question 15

What is the average stroke volume of each ventricle during a single heart contraction in a healthy resting adult?

Accepted Answer

B) 70 mL

Answer

A) 30 mL

Answer

C) 120 mL

Answer

D) 500 mL

Question 16

During blood coagulation, which active enzyme directly converts soluble fibrinogen into insoluble fibrin threads?

Accepted Answer

B) Thrombin

Answer

A) Prothrombin

Answer

C) Thrombokinase

Answer

D) Heparin

Question 17

Deposition of cholesterol, fats, and calcium narrowing the lumen of coronary arteries is termed:

Accepted Answer

B) Atherosclerosis

Answer

A) Angina pectoris

Answer

C) Heart failure

Answer

D) Arterial fibrillation

Question 18

If an individual's resting heart rate is 72 beats per minute, what is the approximate duration of one cardiac cycle?

Accepted Answer

B) 0.8 seconds

Answer

A) 0.1 seconds

Answer

C) 1.2 seconds

Answer

D) 60 seconds

Question 19

Which ECG wave denotes the repolarisation of the ventricles?

Accepted Answer

D) T wave

Answer

A) P wave

Answer

B) Q wave

Answer

C) QRS complex

Question 20

An open circulatory system, where blood flows through open body cavities (hemocoel), is characteristic of:

Accepted Answer

B) Arthropods and Molluscs

Answer

A) Annelids and Mammals

Answer

C) Amphibians and Reptiles

Answer

D) Birds and Fishes

Grade 11 : Biology - Circulation System (Set 2)