CBSE Class 11 Biology Body Fluids and Circulation Assignments

Question. Assertion :- Myocardial Ischaemia common among persons having CAD (coronary artery diseases).
Reason :- Due to CAD there is insufficient \( O_2 \) supply to heart muscles.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Heart failure some time called congestive heart failure.
Reason :- Congestion of the lungs is one of the main symptoms of this disease.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Human heart is myogenic.
Reason :- Human heart capable of generating a cardiac contraction indepentent of nervous input.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Sympathetic nervous system increases cardiac output.
Reason :- It can increase the heart beat rate and strength of ventricular contraction.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Blood of Periplaneta is not responsible for transportation of respiratory gases.
Reason :- Haemolymph does not contain respiratory pigment.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Plasma contains 92% of water.
Reason :- Albumin provides the colloid osmotic pressure.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Neutrophills are granulocyte WBCs.
Reason :- All Granulocyte WBCs have dimorphic nucleus.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Human heart is surrounded by white fibrous connective tissue.
Reason :- Left ventricle is thickest chamber of heart.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- RBCs responsible for transportation of \( CO_2 \) from tissue to lungs.
Reason :- Carbonic anhydrase is fastest catalyst in RBCs.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- All the veins carry deoxygenated blood to the Atria of heart.
Reason :- Heart pump oxygenated blood into pulmonary artery.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The left ventricle gives rise to an ascending aorta from which the oxygenated blood is pumped to coronary arteries and systemic circulation of body.
Reason :- Pulmonary aorta receives deoxygenated blood from ventricle.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Blood pumped to ventricles do not enter back to atria.
Reason :- Chordae tendinae present in the wall of heart, hold the valves of heart.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Heart shows rhythmic contraction and relaxation in specific sequence.
Reason :- Human heart is myogenic organ.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The impulse travels all along the ventricles via bundle branches.
Reason :- Purkinje fibres spread throughout the ventricle wall.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Complete heartbeat consists of a systole and diastole of both atria & ventricles.
Reason :- The human heart beats at the rate of about 70-75 per minute in resting condition.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- High blood pressure cause haemorrhage and infarction in brain and heart.
Reason :- Calcium salts precipitate plaques, makes the wall of arteries stiff and rigid.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- QRS complex express ventricular depolarisation in ECG.
Reason :- Depolarisation occurs due to influx of \( Na^+ \) ions causes generation of action potential.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Lymphatic system provides immunity to body to fight against pathogen.
Reason :- Antigens are foreign particles and not harmful to us.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Heart failure is the same as cardiac arrest.
Reason :- In heart failure heart stop beating.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- SA node is pacemaker of heart.
Reason :- It can initiate and maintain rhythmic contraction of heart.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Heparin is an anticoagulant present in our blood, prevent coagulation.
Reason :- \( Ca^{++} \) is essential factor for clotting.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Mammals have double circulation of blood.
Reason :- Mammals have pulmonary and systemic circulation.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Blood group are decided on the basis of antigen present on R.B.C.
Reason :- Blood plasma have anti-antigen type of antibody.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Cardiac output of an athlete will be much higher than that of an ordinary man during excercise.
Reason :- They have altered the stroke volume as well as the heart rate and thereby the cardiac output.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Blood is a special connective tissue.
Reason :- Blood consist of a fluid matrix and formed elements and some fibres.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Fibrinogen, globulins are the major plasma proteins.
Reason :- Most of the plasma proteins are synthesised by liver.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Plasma without the clotting factors is called serum.
Reason :- Blood clotting help in homeostasis.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- RBCs are the most abundant formed elements is blood.
Reason :- A healthy individual has 12-16 mgs of haemoglobin in every 100 ml of blood.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Leucocytes are also known as white blood cells.
Reason :- They are without haemoglobin.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Basophils are involved in inflammatory reactions.
Reason :- Basophils secretes histamine, serotonin, heparin.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- O negative group individual are called universal donors.
Reason :- O negative blood can be donated to persons with any other blood group.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Erythroblastosis foetalis can be avoided by administering anti Rh antibodies.
Reason :- Anti Rh antibodies will trapped the Rh positive RBCs in mother's blood.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Calcium ions play a very important role in blood clotting.
Reason :- Thrombin is an enzyme.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Lymph is colourless fluid.
Reason :- Lymph is without most abundant formed elements.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- All vertebrates possess a muscular chambered heart.
Reason :- All vertebrates possess closed circulatory system.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Right atrio-ventricular valve is called tricuspid valve.
Reason :- It is formed of three muscular flaps or cusps.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The valves in the heart allows the flow of blood only in one direction.
Reason :- Any backward flow produces extra heart sound.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Left ventricle has thickest myocardium.
Reason :- Left ventricle pumps the blood into entire body.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Electrocardiogram is used to obtain an electrocardiograph.
Reason :- ECG is a graphical representation of the chemical activity of heart during a cardiac cycle.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- ECG has great clinical significance.
Reason :- The ECGs obtained from different individuals have roughly the same shape for a given lead configuration, any deviation from this shape indicates a possible abnormality or disease.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Normal activities of the heart are regulated intrinsically.
Reason :- Specialised muscles (Nodal tissue) present with in heart.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Adrenal medullary hormones can also increase the cardiac output.
Reason :- These hormone increase the rate of heart beat, the strength of ventricular contraction.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Human have a complete double circulation.
Reason :- Two circulatory pathways, namely pulmonary and systemic are present.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The state of heart when it is not pumping blood effectively enough to meet the need of the body known as heart failure.
Reason :- It is common among the women.
(a) A
(b) B
(c) C
(d) D
Answer: C

Very Short Answer Questions (1 mark each)

Question 1. Name the instrument used for measuring blood pressure.
Answer: Sphygmomanometer.
In simple words: A sphygmomanometer is the medical device wrapped around the arm to measure blood pressure.

Exam Tip: Remember the spelling of sphygmomanometer as it is a frequently asked one-mark term.

Question 2. What is a pace-maker?
Answer: A patch of modified heart muscle that initiates a wave of contraction (such as the SA node in the human heart).
In simple words: A pacemaker is the natural electrical generator in the heart that sets its beating rhythm.

Exam Tip: Mention the Sino-Atrial node (SA node) as the primary natural pacemaker of the human heart.

Question 3. Why is the SA node called pace-maker of the heart?
Answer: SA node being self-excitatory, initiates a wave of contraction in the heart.
In simple words: It generates electrical impulses on its own, dictating how fast the heart beats.

Exam Tip: Use the key scientific term "self-excitatory" or "autorhythmic" in your answer.

Question 4. Write the full form of SA node.
Answer: Sino-Atrial Node (also referred to as Sinu-Auricular Node).
In simple words: SA stands for Sino-Atrial, referring to its location near the sinus venosus and atrium.

Exam Tip: Always write both forms if unsure, but Sino-Atrial Node is standard in modern human physiology.

Question 5. What is lymph node?
Answer: A lymph node is a specialised structure in lymphatic vessel concerned with the filtration of foreign bodies by the lymphocytes.
In simple words: Lymph nodes act as tiny filters that trap germs and foreign particles from lymph fluid.

Exam Tip: Highlight "filtration of foreign bodies" and "lymphocytes" for full marks.

Question 6. A cardiologist observed an enlarged QRS wave in the ECG of a patient. What does it indicate?
Answer: QRS wave denotes ventricular contraction of heart which may be normal or abnormal (an enlarged QRS wave typically indicates ventricular enlargement or hypertrophy).
In simple words: A bigger QRS wave shows that the ventricles are working harder or are enlarged.

Exam Tip: Associate the QRS complex directly with ventricular depolarization and contraction.

Question 7. Name the enzyme that catalyses the formation of carbonic acid in erythrocytes.
Answer: Carbonic anhydrase.
In simple words: Carbonic anhydrase speeds up the reaction between carbon dioxide and water inside red blood cells.

Exam Tip: This enzyme is crucial for carbon dioxide transport in blood plasma and RBCs.

Question 8. What is systemic circulation?
Answer: The kind of blood circulation that is concerned with the supply of oxygenated blood from the left ventricle to all body parts and return of oxygenated blood to the right atrium of heart (systemic circuit carries oxygenated blood to tissues and deoxygenated blood back).
In simple words: Systemic circulation supplies oxygen-rich blood to the entire body and brings back used blood to the heart.

Exam Tip: Clearly mention the path: Left Ventricle -> Body Tissues -> Right Atrium.

Question 9. Give two examples of extra-cellular fluids.
Answer: Interstitial fluid and blood plasma.
In simple words: These are fluids found outside the cells in the body.

Exam Tip: Lymph and blood plasma are also accepted standard examples.

Question 10. What name is given to the blood vessels which generally bring blood to an organ?
Answer: Afferent blood vessel (or arteries/arterioles depending on systemic context).
In simple words: Afferent vessels carry blood towards an organ or structure.

Question 11. Which adrenal hormone accelerates the heart beat under normal conditions.
Answer: Noradrenaline (along with adrenaline).
In simple words: Hormones from the adrenal gland can speed up your heartbeat during excitement or stress.

Exam Tip: Adrenaline and noradrenaline are the key catecholamines affecting cardiac output.

Question 12. Name the blood vessel that carries blood from the intestine to liver.
Answer: Hepatic portal vein.
In simple words: The hepatic portal system routes nutrient-laden blood straight from the gut to the liver for processing.

Exam Tip: Portal systems start in capillaries and end in capillaries; memorize hepatic portal vein.

Question 13. Define cardiac cycle.
Answer: A regular sequence of three events (i) auricular systole (ii) ventricular systole and (iii) joint diastole during the completion of one heart beat.
In simple words: A cardiac cycle is one complete heartbeat consisting of contraction and relaxation phases.

Exam Tip: Mention both systole (contraction) and diastole (relaxation) across atria and ventricles.

Question 14. Name the protein found in RBCs.
Answer: Haemoglobin.
In simple words: Haemoglobin is the iron-containing pigment that makes blood red and carries oxygen.

Exam Tip: State that haemoglobin is a respiratory pigment.

Question 15. What happens to a person suffering from haemophilia?
Answer: The person suffering from haemophilia lacks clotting factors in blood, which result in the defective clotting mechanism. In case of injury the person is at a risk of blood loss.
In simple words: Haemophilia is a genetic disorder where the blood fails to clot normally, causing prolonged bleeding.

Exam Tip: Emphasize the deficiency of specific clotting factors (like Factor VIII or IX).

Short Answer Questions-II (2 marks each)

Question 16. Explain when and how the two sounds of heart are produced?
Answer: (i) 'Lubb', the first sound which is low pitched, is caused by the closure of bicuspid and tricuspid valves.
(ii) 'Dup', the second sound which is high pitched, is caused by the closure of semilunar valves.
In simple words: Heart sounds are created when heart valves snap shut, stopping backward blood flow.

Exam Tip: Link 'Lubb' with AV valves at the start of ventricular systole, and 'Dup' with semilunar valves at the end of ventricular systole.

Question 17. Define joint diastole. What are the constituents of the conducting system of human heart?
Answer: In a cardiac cycle when both atria and ventricles are in a diastole and are relaxed simultaneously is called a joint diastole.
Conducting system constitutes: SA node -> AV node -> Bundle of His -> Purkinje fibres.
In simple words: Joint diastole is when all four chambers of the heart are relaxed together, filling with blood.

Question 18. Give the names of various types of formed elements present in the blood.
Answer: Erythrocytes (RBCs), Lymphocytes, Monocytes, Neutrophils, Eosinophils, Basophils (WBCs), and Platelets (Thrombocytes).
In simple words: Blood cells and platelets are collectively called formed elements.

Exam Tip: Categorize them into RBCs, WBCs (granulocytes and agranulocytes), and platelets for a structured answer.

Short Answer Questions-I (3 marks each)

Question 19. Draw a diagram showing schematic plan of blood circulation in human.
Answer: Human circulation features a double circulation pattern consisting of the pulmonary and systemic circuits.
1. Right ventricle pumps deoxygenated blood into the pulmonary artery towards the lungs.
2. Lungs oxygenate the blood, which returns to the left atrium via pulmonary veins.
3. Left ventricle pumps oxygenated blood into the aorta for systemic distribution to all body tissues.
4. Deoxygenated blood returns from body tissues via vena cava to the right atrium.
In simple words: Blood flows through the heart twice in every complete circuit around the body.

Exam Tip: Draw clear arrows showing the separation of oxygenated and deoxygenated pathways.

Question 20. [Refer to NCERT textbook diagram of internal structure of human heart]
Answer: The human heart is a mesodermally derived muscular organ situated in the thoracic cavity, protected by a double-walled membranous bag called pericardium. It consists of four chambers: two relatively small upper chambers called atria and two larger lower chambers called ventricles. The walls (septa) separate these chambers to prevent mixing of oxygenated and deoxygenated blood.
In simple words: The human heart is a four-chambered muscular pump enclosed in the pericardium.

Exam Tip: Practice labeling all four chambers, valves, and major blood vessels clearly.

Question 21. What is lymph? Describe its circulation in brief.
Answer: Lymph is a clear, yellowish, slightly alkaline, coagulable fluid containing white blood cells in a liquid resembling blood plasma. It drains from intercellular spaces into lymphatic capillaries, moves through lymph vessels and lymph nodes where it is filtered, and eventually empties into large veins near the heart.
In simple words: Lymph is tissue fluid collected from body tissues that flows through lymphatic vessels back into the bloodstream.

Question 22. What is stroke volume? What is its relation with cardiac output?
Answer: During one cardiac cycle or one heart beat the volume of blood pumped by the heart is called stroke volume. This is normally 70 mL.
In one minute the heart beats about 72 times and the amount of blood pumped per minute is called cardiac output (Cardiac Output = Stroke Volume \(\times\) Heart Rate). This is usually \(70\text{ mL} \times 72 = 5040\text{ mL}\) or about 5 litres.
In simple words: Stroke volume is blood pumped per beat, while cardiac output is total blood pumped per minute.

Exam Tip: State the formula: Cardiac Output = Stroke Volume \(\times\) Heart Rate.

Question 23. A person suffering from fever is advised to take blood test. What may happen to his WBC count and why?
Answer: The WBC count of this person may show an increase from the normal range. As pathogens may be present in his body, so the body is producing more WBCs to fight against those pathogens. WBC count is a good tool to assess the presence of infection in a sick person.
In simple words: White blood cells increase during an infection because they act as the body's defense soldiers.

Exam Tip: Mention the term leukocytosis (abnormal increase in WBC count during infection).

Long Answer Questions (5 marks each)

Question 24. Draw a diagram to show the internal structure of human heart. Lable any two heart chambers, any two heart valves and chordae tendineae in it.
Answer: 1. Chambers: Right atrium, Left ventricle.
2. Valves: Tricuspid valve, Bicuspid (mitral) valve.
3. Supporting structures: Chordae tendineae attached to papillary muscles.
In simple words: The heart has four chambers and specialized valves with cords to keep blood flowing in one direction.

Exam Tip: Ensure clean lines and correct labeling of chordae tendineae connecting AV valves to ventricular walls.

Question 25. Describe the structure of human heart.
Answer: The human heart is a fist-sized, mesodermally derived muscular organ located in the mediastinum between the lungs. It is enclosed by the pericardium. It has four chambers: two thin-walled atria (receiving chambers) and two thick-walled ventricles (pumping chambers). The inter-atrial septum separates the two atria, and the interventricular septum separates the ventricles. The opening between the right atrium and right ventricle is guarded by the tricuspid valve, while the bicuspid (mitral) valve guards the left AV aperture. Semilunar valves guard the exits to the pulmonary aorta and systemic aorta.
In simple words: The heart is a muscular four-chambered pump divided into left and right sides with specialized valves.

Exam Tip: Break your description down systematically: location, coverings, chambers, septa, and valves.

Question 26. What is cardiac cycle? Describe the event that occur during it.
Answer: The cardiac cycle represents the sequential events in a single heartbeat, lasting about 0.8 seconds. The key phases are:
1. Joint Diastole: All four chambers are relaxed; blood flows passively into the ventricles.
2. Atrial Systole: Atria contract, pushing an additional 30 percent of blood into the ventricles.
3. Ventricular Systole: Ventricles contract, increasing pressure, causing AV valves to close (producing 'Lubb') and forcing semilunar valves open to eject blood into pulmonary artery and aorta.
4. Ventricular Diastole: Ventricles relax, semilunar valves close (producing 'Dup'), and the cycle resets.
In simple words: A cardiac cycle is the sequence of contraction and relaxation of heart chambers during one heartbeat.

Question 27. Explain Rh grouping and its incompatibility in humans.
Answer: The Rh factor is another antigen (Rhesus antigen) found on the surface of RBCs in most humans (Rh-positive). Individuals lacking this antigen are Rh-negative. Rh incompatibility is critically important during pregnancy: if an Rh-negative mother carries an Rh-positive foetus, the mother's immune system may form anti-Rh antibodies during the delivery of the first child when fetal and maternal blood mix. In subsequent pregnancies with an Rh-positive foetus, these maternal antibodies can cross the placenta and destroy the fetal RBCs, causing erythroblastosis foetalis (severe hemolytic anemia in the newborn).
In simple words: Rh incompatibility occurs when an Rh-negative mother's blood reacts against an Rh-positive baby's blood.