Selina Concise Solutions for ICSE Class 10 Biology Chapter 6 The Circulatory System

Review Questions

A. Multiple Choice Type

(Select the most appropriate option in each case)

Question 1. Agranulocytes are:
(a) lymphocytes and monocytes
(b) lymphocytes and basophils
(c) eosinophils and basophils
(d) eosinophils and monocytes
Answer: (a) lymphocytes and monocytes
In simple words: Agranulocytes are white blood cells that don't have granules (tiny particles) inside them, and these are lymphocytes and monocytes.

📝 Teacher's Note: Use diagrams to show the difference between granulocytes (with visible granules) and agranulocytes (smooth appearance). Students often confuse these categories.

🎯 Exam Tip: Remember "A-granulo" means "without granules" - lymphocytes and monocytes have smooth cytoplasm without visible granules.

Question 2. White blood cells engulf bacteria in a process called:
(a) diapedesis
(b) phagocytosis
(c) active transport
(d) passive transport
Answer: (b) phagocytosis
In simple words: Phagocytosis is like white blood cells "eating" harmful bacteria to protect our body from infections.

📝 Teacher's Note: Demonstrate with an analogy of Pac-Man eating dots - this helps students visualize how white blood cells engulf bacteria.

🎯 Exam Tip: "Phago" means eating, "cytosis" means cell process - so phagocytosis = cell eating process.

B. Very Short Answer Type

Question 1. Given below are certain structures, write the term for the functional activity.
(a) Blood platelets and ……………………………
(b) Neutrophils and ……………………………
(c) Erythrocytes and ……………………………
(d) Lymphocytes and ……………………………
(e) Bone marrow and ……………………………
Answer:
(a) Blood platelets and blood coagulation
(b) Neutrophils and phagocytosis
(c) Erythrocytes and transportation of gases
(d) Lymphocytes and produce antibodies
(e) Bone marrow and destruction of old and weak RBC's/production of RBCs and WBCs

📝 Teacher's Note: Create a matching exercise where students connect each blood component with its function. This reinforces the structure-function relationship.

🎯 Exam Tip: Learn these as pairs - each blood component has one main function that examiners commonly test.

Question 2. Name the following:
(a) The cells which transport oxygen to the different parts of the human body.
(b) The cells that initiate blood clotting.
Answer:
(a) Red Blood Cells
(b) Blood Platelets

📝 Teacher's Note: Emphasize that RBCs are specialized for oxygen transport due to hemoglobin, while platelets are the smallest blood cells with a crucial clotting function.

🎯 Exam Tip: These are high-frequency exam questions - always write the full names "Red Blood Cells" and "Blood Platelets".

C. Short Answer Type

Question 1. Enumerate the structural differences between white blood cells and red blood cells.
Answer:
Structural Differences between White Blood Cells and Red Blood Cells:

📝 Teacher's Note: Use microscope slides to show actual differences. Students should observe the nucleus in WBCs and biconcave shape of RBCs.

🎯 Exam Tip: Present answers in tabular format for comparison questions - it's clearer and scores better marks.

Question 2. Why is it necessary to know the blood groups before giving transfusion?
Answer:
During blood transfusion it is necessary to know the blood groups before transfusion because it is important that the blood groups of the donor and the recipient are compatible. In case of an incompatible blood transfusion, the recipient develops antibodies that attack the antigens present on the RBCs of the donor causing the blood cells to clump together which may result in death.

📝 Teacher's Note: Explain using the lock-and-key analogy - wrong blood types are like wrong keys that cause a dangerous reaction in the body.

🎯 Exam Tip: Mention "clumping of blood cells" and "may result in death" - these are key points examiners look for.

Question 3. Differentiate between members of each of the following pairs with reference to phrases in brackets:
(a) Antibodies and antibiotics (Source)
(b) RBC and WBC (structure)
(c) serum and vaccine (Composition)
Answer:
(a) Antibodies are produced by lymphocytes in response to the entry of pathogens in the blood stream.
Antibiotics are the medicines extracted from some bacteria and fungi. Antibiotics destroy or inhibit the growth of pathogens.
(b) RBC: RBC is enucleated, biconcave, disc-like structure, flat in the centre while thick and rounded at the periphery.
WBC: WBC is nucleated and amoeboid in shape.
(c) Serum: The plasma from which the protein fibrinogen has been removed is called serum.
Vaccine: Vaccine is killed or living weakened germs which are introduced in the body to stimulate the production of antibodies against pathogens for a particular disease.

📝 Teacher's Note: Emphasize that antibodies are natural (made by body) while antibiotics are artificial (made in labs). This distinction is crucial.

🎯 Exam Tip: Always address the specific reference given in brackets - "Source," "structure," or "Composition" in your answer.

Question 4. Complete the following statement by filling in the blank from the choices given in the brackets.
An anticoagulant present in the blood is ………….(heparin, hirudin, thromboplastin, calcium).
Answer:
Heparin

📝 Teacher's Note: Explain that heparin prevents unwanted clotting in blood vessels, while thromboplastin promotes clotting at wound sites.

🎯 Exam Tip: Remember heparin is naturally present in blood, while hirudin comes from leeches - don't confuse them.

D. Long Answer Type

Question 1. What are the functions of blood plasma?
Answer:
The functions of blood plasma are:
(a) Transports of digested food from the alimentary canal to tissues.
(b) Transports excretory materials from tissues to excretory organs.
(c) Distributes hormones from the glands to their target site.
(d) Distributes heat in the body to maintain the body temperature.

📝 Teacher's Note: Use the analogy of plasma as the "highway system" of the body - it carries everything that needs to be transported.

🎯 Exam Tip: Write functions as separate points (a), (b), (c), (d) for clarity and full marks.

Question 2. What are the main steps in coagulation of blood?
Answer:
Blood clotting or coagulation occurs in a series of the following steps:
(a) The injured tissue cells and the platelets disintegrate at the site of wound to release thromboplastin.
(b) The thromboplastin with the help of calcium ions converts inactive prothrombin into active thrombin.
(c) Thrombin in the presence of calcium ions converts soluble fibrinogen into insoluble fibrin which forms a mesh or network at the site of wound.
(d) The blood cells trapped in this network shrink and squeeze out the plasma to leave behind a solid mass known as the clot.

📝 Teacher's Note: Demonstrate the clotting cascade using a step-by-step flowchart. Students should understand this is a chain reaction.

🎯 Exam Tip: Remember the sequence: Thromboplastin → Prothrombin to Thrombin → Fibrinogen to Fibrin → Clot formation.

Question 3. What are the following?
(a) Rh factor (b) Universal donor (c) Diapedesis.
Answer:
(a) Rh factor - It is an inherited antigen often found on the blood cells. Some individuals have these antigens and are thus Rh positive (Rh+) while others who do not have this antigen are Rh negative (Rh-).
(b) Universal donor - The person with blood group O is a universal donor as this type of blood can be given to persons with any blood group i.e. O, A, B, AB.
(c) Diapedesis - It is the squeezing of leucocytes through the wall of capillaries into the tissues.

📝 Teacher's Note: Explain Rh factor using pregnancy examples (Rh incompatibility). For diapedesis, show how WBCs squeeze through capillary walls like squeezing through a fence.

🎯 Exam Tip: For universal donor, always mention "blood group O" and list all groups it can donate to (O, A, B, AB).

Question 4. Is it possible for the blood to clot under the skin? Give reason in support of your answer.
Answer:
Blood clotting is not dependent on the exposure of blood to air. In fact, clotting can be caused by the movement of blood over a rough surface such as on cholesterol deposit inside of a blood vessel of the skin.

📝 Teacher's Note: Relate this to thrombosis and heart attacks - clotting inside vessels can be dangerous, unlike helpful clotting at wounds.

🎯 Exam Tip: Emphasize that clotting is triggered by rough surfaces, not air exposure - this clarifies a common misconception.

Question 5. State any five functions of the blood.
Answer:
The functions of the blood are:
(a) Transport of digested food from the alimentary canal to tissues. These substances are simple sugars like glucose, amino acids, vitamins, mineral salts, etc.
(b) Transport of oxygen in the form of an unstable compound 'oxyhaemoglobin' from the lungs to the tissues.
(c) Transport of carbon dioxide from the tissues to the lungs.
(d) Transport of excretory materials from the tissues to the liver, kidney or the skin for elimination.
(e) Distribution of hormones from glands to the target sites.
(f) Distribution of heat to keep the body temperature uniform.
(Any five)

📝 Teacher's Note: Group functions into transport (nutrients, gases, waste) and distribution (hormones, heat) to help students organize their answers.

🎯 Exam Tip: The question asks for five functions but provide six - this shows thorough knowledge and ensures full marks.

E. Structured / Application / Skill Type

Question 1. Given below is a diagram of a smear of human blood. Study the same and answer the questions that follow:
(a) Name the parts 1, 2, 3 and 4 indicated by guidelines.
(b) Mention two structural differences between the parts labelled '1' and '2'.
(c) What is the main function of the parts labelled 1, 2, 3 respectively?
(d) What is the life span of the part labelled '1'?
(e) Name a soluble protein found in '4' which helps in the clotting of blood.
Answer:
(a) (i) Red Blood Cell (RBC), (ii) White Blood Cell (WBC), (iii) Blood Platelet (iv) Blood Plasma.
(b) The red blood cells are minute biconcave disc-like structures whereas the white blood cells are amoeboid.
(c) Function of part 1 (RBC): Transport of respiratory gases to the tissues and from the tissues, transport of nutrients from the alimentary canal to the tissues.
Function of part 2 (WBC): WBCs play major role in defense mechanism and immunity of the body.
Function of part 3 (Blood Platelet): Blood platelets are the initiator of blood clotting.
(d) The average life span of a red blood cell (RBC) is about 120 days.
(e) Thromboplastin

📝 Teacher's Note: Use actual blood smear slides or high-quality diagrams. Students should be able to identify each component by shape and size.

🎯 Exam Tip: For diagram-based questions, always refer to parts by their numbers and full names as given in the question.

Review Questions

A. Multiple Choice Type

(Select the most appropriate option in each case)

Question 1. The nearest organ to which the heart supplies oxygenated blood is:
(a) Lung
(b) Stomach

📝 Teacher's Note: This appears to be an incomplete question - options (c) and (d) are missing. The answer would likely be related to coronary circulation.

🎯 Exam Tip: For questions about heart's blood supply, remember the heart supplies oxygenated blood to itself first through coronary arteries.

Question 1. The heartbeat is initiated and maintained by
(a) Liver
(b) Lungs
(c) Intestine
(d) Heart itself
Answer: (d) Heart itself
In simple words: The heart has its own built-in electrical system that starts and controls each heartbeat, like a natural pacemaker inside the heart muscle.

📝 Teacher's Note: Emphasize that the heart is myogenic (self-starting) unlike skeletal muscles that need nerve signals. Use the analogy of a car's engine that starts itself once the key is turned.

🎯 Exam Tip: Remember "myogenic" as the key term - the heart muscle generates its own electrical impulses through the SA node.

Question 2. When a doctor is recording your pulse, he is pressing on your wrist exactly on a
(a) vein
(b) capillary
(c) artery
(d) arteriole
Answer: (c) artery
In simple words: Doctors feel the pulse on arteries because they carry blood under high pressure from the heart, making the blood flow feel like rhythmic beats.

📝 Teacher's Note: Have students feel their pulse on the radial artery at the wrist. Explain that veins have low pressure so you can't feel a pulse in them.

🎯 Exam Tip: Pulse is always felt on arteries, never veins - arteries have muscular walls that create the pulsating sensation.

Question 3. The valve present between the right atrium and the right ventricle is the
(a) tricuspid valve
(b) bicuspid valve
(c) semi-lunar valve
(d) mitral valve
Answer: (a) tricuspid valve
In simple words: The tricuspid valve has three flaps and sits between the right upper and lower chambers of the heart, like a three-door gate.

📝 Teacher's Note: Use the memory trick "TRI-right" (tricuspid on right side) and "BI-left" (bicuspid on left side). Draw a simple heart diagram.

🎯 Exam Tip: Remember "tri" means three - tricuspid valve has three cusps and is on the right side of the heart.

Question 4. The blood vessel supplying blood to the kidney is the
(a) renal vein
(b) renal artery
(c) dorsal aorta
(d) hepatic vein
Answer: (b) renal artery
In simple words: Arteries always supply blood TO organs, while veins take blood AWAY from organs - so renal artery brings blood to kidneys.

📝 Teacher's Note: Emphasize the general rule: arteries supply blood to organs (except pulmonary artery), veins drain blood from organs (except pulmonary vein).

🎯 Exam Tip: When asked about blood supply TO any organ, the answer is almost always the artery named after that organ.

Question 5. Angina pectoris is due to
(a) defective nutrition
(b) inadequate supply of oxygen to the heart muscle
(c) defective functioning of mitral valve
(d) infection by a virus
Answer: (b) inadequate supply of oxygen to the heart muscle
In simple words: Angina is chest pain that happens when the heart muscle doesn't get enough oxygen, like a muscle cramp from lack of air.

📝 Teacher's Note: Relate to students' experience of muscle pain during exercise when muscles don't get enough oxygen. Discuss lifestyle factors that cause coronary artery blockage.

🎯 Exam Tip: Remember angina = heart muscle oxygen shortage, usually due to blocked coronary arteries reducing blood flow.

Question 6. The chief function of lymph nodes is to
(a) produce WBCs
(b) produce hormones
(c) destroy old RBCs
(d) destroy pathogens
Answer: (d) destroy pathogens
In simple words: Lymph nodes act like security checkpoints that filter out and destroy harmful germs before they can spread through the body.

📝 Teacher's Note: Explain why lymph nodes swell when you're sick - they're working overtime to fight infection. Use the analogy of water filters.

🎯 Exam Tip: Lymph nodes = body's filtration system for destroying pathogens, not for producing blood cells or hormones.

Question 7. Heart sounds are produced due to
(a) Closure of tricuspid and bicuspid valves
(b) Rushing of blood through valves producing turbulence
(c) Closure of aortic and pulmonary valves
(d) Entry of blood into auricles
Answer: (a) closure of tricuspid and bicuspid valves, (b) closure of aortic and pulmonary valves, (c) rushing of blood through valves producing turbulence
In simple words: Heart sounds come from valves snapping shut and blood rushing through them, like doors closing and water flowing through pipes.

📝 Teacher's Note: Demonstrate with hands clapping for valve closure. Explain LUBB (AV valves) and DUP (semilunar valves) sounds separately.

🎯 Exam Tip: All three options contribute to heart sounds - valve closures create the main sounds, turbulence adds to the complexity.

Question 1. What are the average values of blood pressure in a normal adult human?
Answer: The average values of blood pressure in a normal adult human are 100-140 mm for systolic pressure and 60-80 mm for diastolic pressure.
In simple words: Normal blood pressure is like 120/80 - the higher number when heart squeezes, the lower number when heart relaxes.

📝 Teacher's Note: Explain systolic vs diastolic using a garden hose analogy - pressure when you squeeze the trigger vs when you release it.

🎯 Exam Tip: Remember the units (mm Hg) and that systolic is always higher than diastolic pressure.

Question 2. Is it true that your heart beats more than one lac times per day?
Answer: Yes, the heart beats approximately 1,03,680 times in a day.
In simple words: Your heart beats about 70 times per minute, which adds up to over 100,000 beats every single day without stopping.

📝 Teacher's Note: Help students calculate: 70 beats/min × 60 min × 24 hours = 100,800 beats. This shows the heart's incredible endurance.

🎯 Exam Tip: Know the calculation: average heart rate (70/min) × minutes in a day (1440) = approximately 1 lac beats.

Question 3. Name the following:
(a) Any one vein which starts from an organ and ends in another organ besides the heart.
(b) The kind of blood vessels which have no muscular walls.
(c) An artery which carries impure (deoxygenated) blood.
(d) The kind of blood cells which can squeeze out through the walls of one category of blood vessels.
(e) The smallest common blood vessels formed by the union of capillaries.
(f) The blood vessels which start from capillaries and end in capillaries.
(g) The phase of the cardiac cycle in which the auricles contract.
(h) The valve present in between the chambers on the right side of the human heart.
(i) The phase of the cardiac cycle in which the ventricles get filled with blood from the atrium.
(j) The fluid found between the membranes of the heart.
Answer:
(a) Hepatic portal vein
(b) Blood Capillaries
(c) Pulmonary artery
(d) White blood cells
(e) Venules
(f) Portal vein
(g) Atrial systole
(h) Tricuspid valve
(i) Atrial systole
(j) Pericardial fluid
In simple words: These are specific parts of the circulatory system with unique functions, like portal veins that connect organs directly and WBCs that can squeeze through vessel walls to fight infections.

📝 Teacher's Note: Use diagrams to show portal circulation and explain why pulmonary artery is unique in carrying deoxygenated blood despite being an artery.

🎯 Exam Tip: Remember exceptions: pulmonary artery carries deoxygenated blood, portal veins connect organs, WBCs can migrate through vessel walls.

Question 4. Write the chief functional activity of each of the following:
(a) Blood platelets
(b) Neutrophils
(c) Erythrocytes
(d) Lymphocytes
(e) Bone marrow
Answer:
(a) Blood platelets are involved in blood clotting or coagulation. Blood platelets integrate at the site of injury to release thromboplastin which initiates the process of blood clotting.
(b) Neutrophils perform phagocytosis i.e. they engulf pathogens that enter the blood stream and destroy them.
(c) Erythrocytes transport oxygen from the lungs to the tissues in the form of an unstable compound oxyhaemoglobin and transport carbon dioxide from the tissues to the lungs.
(d) Lymphocytes produce antibodies against pathogens which enter the blood stream. In some cases they also perform phagocytosis.
(e) Bone marrow is involved in formation of RBCS and WBCs. It is also involved in the destruction of old and weak RBCs.
In simple words: Each blood component has a specific job - platelets seal cuts, neutrophils eat germs, RBCs carry oxygen, lymphocytes make antibodies, and bone marrow makes new blood cells.

📝 Teacher's Note: Use analogies: platelets as repair crew, neutrophils as security guards, RBCs as delivery trucks, lymphocytes as weapons factory, bone marrow as blood cell factory.

🎯 Exam Tip: Remember the main function of each: platelets - clotting, neutrophils - phagocytosis, RBCs - oxygen transport, lymphocytes - antibodies, bone marrow - blood cell formation.

Question 5. Complete the following statements by filling in the blanks from the choices given in the brackets.
(a) The blood vessels that begins and ends in capillaries is the ………………. (hepatic artery, hepatic portal vein, hepatic vein)
(b) A blood vessels which has small lumen and thick wall is …………………. (capillary, lymphatic duct, artery, venule)
(c) The valve which prevents back flow of blood in the veins and lymph vessels ……………… (mitral valve, tricuspid valve, semilunar valve).
Answer:
(a) The blood vessel that begins and ends in capillaries is the hepatic portal vein.
(b) A blood vessel which has small lumen and thick wall is artery.
(c) The valve which prevents the back flow of blood in the veins and lymph vessels is semilunar valve.
In simple words: Portal veins connect two capillary networks, arteries have thick walls to handle high pressure, and semilunar valves prevent backward blood flow.

📝 Teacher's Note: Draw cross-sections of arteries vs veins to show wall thickness differences. Explain why arteries need thick walls for high pressure.

🎯 Exam Tip: Remember artery structure: thick muscular walls, small lumen for high-pressure blood flow from the heart.

Question 6. Note the relationship between the first two words and suggest the suitable word/ words for the fourth place:
(a) Lubb: Atrioventricualr valves :: dup: …………………
(b) Coronary artery: Heart :: Hepatic artery : ……………
Answer:
(a) Lubb : Atrio-ventricular valve :: Dup : Semilunar valves
(b) Coronary artery : Heart :: Hepatic artery : Liver
In simple words: Heart sounds match valve closures - LUBB from AV valves, DUP from semilunar valves. Arteries are named after the organs they supply blood to.

📝 Teacher's Note: Help students understand analogies by identifying the pattern first, then applying it. Practice with similar organ-artery relationships.

🎯 Exam Tip: Learn the pattern: first heart sound (LUBB) = AV valves closing, second sound (DUP) = semilunar valves closing.

Question 7. Give reason, why a matured mammalian erythrocyte lacks nucleus and mitochondria?
Answer: A matured mammalian erythrocyte lacks a nucleus and mitochondria. The lack of a nucleus increases the surface area-volume ratio of RBCs, thus increasing the area for oxygen absorption. Also, the lack of a nucleus reduces the size of the cell, making it easy to flow through the blood vessels and more cells can be accommodated in a small area. The lack of mitochondria implies that the cell does not use any oxygen absorbed for respiration, thus increasing the efficiency of the cell to transport oxygen as all the oxygen absorbed is transported without any loss.
In simple words: RBCs lose their nucleus and mitochondria to become more efficient oxygen carriers - more space for hemoglobin and no oxygen wasted on their own needs.

📝 Teacher's Note: Compare to a delivery truck - removing the driver's cabin and engine allows more cargo space. Explain the trade-off: efficiency vs ability to repair.

🎯 Exam Tip: Two main reasons: increased surface area for oxygen binding and no oxygen consumption for their own metabolism.

Question 1. What does the term "double circulation" mean?
Answer: Blood flows twice in the heart before it completes one full round. The full round thus includes pulmonary and systemic circulation. In pulmonary circulation, blood enters the lungs through pulmonary arteries. Pulmonary veins collect the blood from the lungs and carry it back to the left atrium. In systemic circulation, blood from the left ventricle enters the aorta through which the blood is sent to the body parts. From the body parts blood is collected by veins and sent back to the heart. Therefore, the blood circulation in the human body is called double circulation.
In simple words: Blood makes two trips through the heart in one complete journey - once to pick up oxygen from lungs, then again to deliver it to the body.

📝 Teacher's Note: Draw a figure-8 diagram showing the two circuits. Emphasize that this allows high pressure for body circulation and low pressure for lung circulation.

🎯 Exam Tip: Remember the two circuits: pulmonary (heart-lungs-heart) and systemic (heart-body-heart), with blood passing through heart twice.

Question 2. When are the sounds "LUBB" and "DUP" produced respectively during heart beat?
Answer: The first sound LUBB is produced when the atrio-ventricular valves i.e. tricuspid and bicuspid valves close at the start of ventricular systole. The second sound DUP is produced at the beginning of ventricular diastole, when the pulmonary and aortic semilunar valves close.
In simple words: LUBB happens when the heart squeezes and the upper-lower valves shut, DUP happens when the heart relaxes and the exit valves shut.

📝 Teacher's Note: Have students clap twice in rhythm - first clap for LUBB (AV valves), second for DUP (semilunar valves). Link to ventricular contraction cycle.

🎯 Exam Tip: LUBB = AV valve closure at start of ventricular systole, DUP = semilunar valve closure at start of ventricular diastole.

Question 3. Why do people have a common belief that the heart is located on the left side of the chest?
Answer: People have a common belief that the heart is located on the left side of the chest because the narrow end of the roughly triangular heart is pointed to the left side and during its working the contraction of the heart is more powerful on the left side which can be felt.
In simple words: The heart's tip points to the left and beats more strongly on the left side, so that's where we feel it most, even though it's actually in the center.

📝 Teacher's Note: Have students place their hand in the center of their chest to locate the actual heart position, then feel the apex beat on the left.

🎯 Exam Tip: Heart is centrally located but apex (tip) points left, and left ventricle contracts more forcefully, creating the left-sided sensation.

Question 4. Differentiate between members of each of the following pairs with reference to the aspect asked within brackets:
(a) Erythrocytes and leucocytes (function)
(b) Artery and vein (direction of blood flow)
(c) artery and vein (type of blood primarily flowing through)
(d) Tricuspid and bicuspid values (location)
Answer:
In simple words: These pairs show key differences in the circulatory system - RBCs vs WBCs have different jobs, arteries vs veins flow different directions, and heart valves are in different locations.

📝 Teacher's Note: Use comparison tables to clearly show the differences. Emphasize that structure follows function in all these examples.

🎯 Exam Tip: Focus on the specific aspect asked - don't give general information, only answer what's requested in brackets.

(b) An artery carries blood away from the heart whereas a vein brings blood towards the heart.

(c) An artery generally contains oxygenated blood whereas a vein generally carries deoxygenated blood.

(d) Tricuspid valve is located between the right atrium and right ventricle of the heart whereas a bicuspid valve is located between the left atrium and left ventricle of the heart.

Question. Match the items in Column 'A' with those in column 'B' Rewrite the correct matching pairs.
Answer:

In simple words: This is a matching exercise where you pair heart and blood components with their functions or descriptions, like connecting SA node with pacemaker because it controls heart rhythm.

📝 Teacher's Note: Use real examples - show students how their pulse is controlled by the SA node, and explain that cardiac muscles work 24/7 unlike other muscles that get tired.

🎯 Exam Tip: Remember SA node = natural pacemaker, and cardiac cycle = one complete heartbeat which takes 0.85 seconds.

Question. The table below is designed to indicate the transport of certain substance in our body. Fill in the blanks with suitable answers.
Answer:

In simple words: Blood acts like a delivery truck - it picks up oxygen from lungs and food from intestines, delivers them everywhere, then collects waste like carbon dioxide and urea for disposal.

📝 Teacher's Note: Use the analogy of a postal service - blood is the delivery vehicle that picks up and drops off packages (substances) at different addresses (organs).

🎯 Exam Tip: Remember the direction - oxygen comes FROM lungs, waste goes TO disposal organs (lungs for CO2, kidneys for urea).

Long Answer Type

Question. What are the following?
(a) Endothelium (b) Lymph nodes
(c) Venule (d) diastole
Answer:
(a) Endothelium- It is the innermost layer of the muscular wall of an artery or a vein which faces the lumen.
(b) Lymph nodes- The structures from which fresh lymph channels arise which pour the lymph into major anterior veins.
(c) Venule- The smallest common blood vessel formed by the union of capillaries.
(d) Diastole- The relaxation of muscles of ventricles or atria.
In simple words: These are parts of the circulatory system - endothelium is the smooth inner lining of blood vessels, lymph nodes are like filters for infection, venules are tiny veins, and diastole is when the heart relaxes.

📝 Teacher's Note: Use analogies - endothelium is like the smooth inner surface of a water pipe, lymph nodes are like security checkpoints that filter out harmful substances.

🎯 Exam Tip: Remember diastole = relaxation (think "dial down"), systole = contraction. Venule is smaller than vein (like streamlet vs stream).

Question. Describe the structural differences between an artery and a vein
Answer:

In simple words: Arteries are like high-pressure water pipes with thick walls carrying blood away from heart, while veins are like return pipes with thin walls and valves to prevent backflow.

📝 Teacher's Note: Show students their wrist pulse (artery) vs blue veins on their hand. Explain that arteries are deeper and stronger because they handle high pressure from heart pumping.

🎯 Exam Tip: Remember "Away from heart = Artery", "Valves in Veins" (alliteration helps). Draw simple diagrams showing thick vs thin walls.

Question. What are the functions of tonsils and spleen?
Answer:
Tonsils: Tonsils are lymph glands located on the sides of the neck. They tend to localize the infection and prevent it from spreading it in the body as a whole.
Spleen: The spleen is a large lymphatic organ. The spleen acts as a blood reservoir in case of emergency such as haemorrhage, stress or poisoning. It produces lymphocytes and destroys worn out RBCs.
In simple words: Tonsils are like security guards at the throat entrance that catch germs before they spread, while spleen is like a blood bank that stores extra blood and cleans up old blood cells.

📝 Teacher's Note: Relate to students' experience - when throat hurts, tonsils are fighting infection. Explain spleen location (left side under ribs) and why athletes might have enlarged spleens.

🎯 Exam Tip: Write "Tonsils = infection control", "Spleen = blood storage + cleanup". Include specific functions like lymphocyte production and RBC destruction.

Question. How do you account for the following differences?
(a) The left ventricle has thicker walls than the right ventricle.
(b) The walls of the right ventricle are thicker than those of the right auricle.
Answer:
(a) The left ventricle pumps blood to the farthest points in the body such as the feet, the toes and the brain against the gravity while the right ventricle pumps the blood only up to the lungs. Therefore, the left ventricle has thicker walls than the right ventricle.
(b) The right ventricle pumps blood to the lungs for oxygenation whereas the right auricle receives the blood from vena cavae and passes it to the right ventricle. Therefore, walls of the right ventricle are thicker than those of the right auricle.
In simple words: Left ventricle needs stronger muscles because it pumps blood to your toes (long distance), while right ventricle only pumps to nearby lungs. Ventricles do more work than auricles so they need stronger walls.

📝 Teacher's Note: Use the analogy of different strength pumps needed for different jobs - like a garden sprinkler vs a fire hose. Left ventricle = fire hose strength, right ventricle = garden sprinkler.

🎯 Exam Tip: Always mention "against gravity" for left ventricle, and specify distances - "whole body" vs "only lungs". Compare ventricles to auricles by function.

Question. Give reason for the following:
(a) The walls of the left ventricle are thicker than the walls of all other chambers.
(b) Blood flowing away from the stomach and intestines is put into circulation via the liver and not directly
(c) The blood groups of both the donor and recipient must be known before transfusing blood.
(d) Only the veins and not the arteries are provided with valves.
(e) Atrial wall is less muscular than the ventricular wall.
(f) The arteries are deep seated in the body
Answer:
(a) The left ventricle pumps blood to the farthest points in the body such as the feet, the toes and the brain against the gravity. Thus, it requires greater force to push the blood. In order to with stand with the force applied the walls of the left ventricle are thicker than the walls of all the chambers.
(b) The blood from stomach and intestines enters the liver via hepatic portal vein because the liver monitors all the substances that have to be circulated in body. The excess nutrients such as glucose, fats are stores in the liver. Excess amino acids are broken down by the process deamination. Toxic substances are detoxified.
(c) During blood transfusion it is important that the blood groups of the donor and the recipient are compatible. In case of an incompatible blood transfusion, the recipient develops antibodies that attack the antigens present on the RBCs of the donor causing the blood cells to clump together which may result in death. The examination of Rh factor is also necessary for the blood transfusion. Therefore, the blood groups of both the donor and recipient must be known before transfusing blood.
(d) Veins carry the blood from the body part towards the heart while the arteries carry the blood from the heart. Veins carry the blood against the force of gravity. Therefore, only the veins and not the arteries are provided with valves.
(e) Atrial wall is less muscular than the ventricular wall because the major function of atria is to receive blood from the body and pump in into very next ventricles. While the ventricles pump the blood out of the heart. Right ventricle to the lungs and the left ventricle to all the body parts.
(f) Arteries are responsible to carry oxygenated blood from the heart to the tissues. The blood flows in the artery under high pressure and in spurts. If arteries are located superficially then there is a high possibility of their damage which could lead to a lot of blood loss. To prevent this damage and blood loss, the arteries are deep seated in the body.
In simple words: These are safety and efficiency features - left ventricle is strongest because it works hardest, liver checks all food before circulation, blood matching prevents dangerous reactions, valves stop backflow in veins, atria just collect while ventricles pump, and arteries hide deep for protection from injury.

📝 Teacher's Note: Connect to real life - show how leg veins have valves (press on hand veins), explain why blood type matters in emergencies, relate liver function to food processing.

🎯 Exam Tip: For blood groups mention "clumping" and "death", for valves mention "against gravity", for liver mention "detoxification". Use specific examples like feet/toes for left ventricle.

Structures/ Application / Skill Type

Question. Given below are the diagrammatic sketches of two kinds of blood vessels.
(a) Identify the two kinds of blood vessels A and B.
(b) name the parts numbers 1 to 6
(c) Mention any two main differences between A and B.
Answer:
(a) A is artery, B is vein.
(b) 1- Endothelium of the artery,
2 - Middle layer of smooth muscles and elastic fibres of the artery,
3 - External layer of connective tissue of the artery,
4 - Endothelium of the vein,
5 - Middle layer of smooth muscles and elastic fibres of the vein,
6 - External layer of connective tissue of the vein.
(c) An artery has thick muscular walls and a narrow lumen. It carries blood away from the heart towards any organ.
A vein on the other hand has thin muscular walls and a wider lumen. It carries blood away from an organ towards the heart.
In simple words: Picture A shows an artery (thick-walled pipe for high pressure), Picture B shows a vein (thin-walled pipe with wider opening), each has three layers like a sandwich.

📝 Teacher's Note: Point out the visible thickness difference in diagrams. Explain why arteries need thick walls (high pressure from heart) and veins need wide space (slow return flow).

🎯 Exam Tip: Label all three layers clearly - endothelium (inner), muscle layer (middle), connective tissue (outer). Remember thick walls = artery, thin walls = vein.

Question. Given below is a highly schematic diagram of the human blood circulatory sytem.
(a) which part (state the number) represents the heart? Give reason in support of your answer.
(b) Which numbers represent the following respectively?
Aorta
Renal Vein
Hepatic portal vein
Pulmonary artery
Stomach
Dorsal aorta
Superior vene cava
Answer:
Note: The diagram referenced in this question is not visible in the provided content, so specific number answers cannot be provided. However, the heart would be identified as the central pumping organ from which major vessels originate and to which they return.
In simple words: This question asks you to identify different parts of the circulatory system on a diagram - heart is the central pump, arteries carry blood away from heart, veins return blood to heart.

📝 Teacher's Note: Use a simplified circulatory system diagram showing heart at center with major vessels. Emphasize that aorta is the largest artery, vena cava are the largest veins.

🎯 Exam Tip: Remember aorta = main artery from heart, pulmonary artery goes to lungs, portal vein goes to liver, superior vena cava returns blood from upper body.

Solution 2:
(a) The structure 3 represents the heart. It forms the centre of double circulation and is located between the liver and the head (as per the diagram). Also the blood circulation (indicated by 1) begins from heart to lungs.
(b)

📝 Teacher's Note: Use the diagram to explain how blood flows in a complete circuit - students often get confused about which vessels carry oxygenated vs deoxygenated blood. Point out that the hepatic portal system is unique as it connects two capillary beds.

🎯 Exam Tip: Always match the numbers carefully with the diagram and remember that hepatic portal vein carries nutrient-rich blood from intestines to liver for processing.

Question 3. Given diagram shows a simple diagram of the circulation of blood in a mammal showing the main blood vessels, the heart, lungs and body tissues. The blood vessel, labelled 6, contains deoxygenated blood and the valve leading to it has three semi-lunar pockets.
(a) Name the blood vessels and organs marked by numbers 1 to 8.
(b) What is meant by the term 'double circulation' of blood in mammals?
(c) What is diastole?
[There is an "error" in the diagram. According to the usual practice the pulmonary (lung) circulation is shown upward and the systemic downward, but here it is reversed].
Answer:
(a)

(b) Blood flows twice in the heart before it completes one full round. The full round thus includes pulmonary and systemic circulation. For this reason, the blood circulation in the human body is called double circulation.
(c) The relaxation of muscles of ventricles or auricles is known as diastole.

📝 Teacher's Note: Emphasize that double circulation prevents mixing of oxygenated and deoxygenated blood, making it more efficient than single circulation found in fish. Use hand gestures to trace the blood path.

🎯 Exam Tip: For diastole definition, always mention "relaxation of heart muscles" and specify both ventricles and atria to get full marks.

Question 4. The diagram below shows part of the capillary bed in an organ of the human body. Some of the blood arriving at the capillaries at points labelled A, moves out into the spaces between the tissue cells. Study the diagram and answer the questions that follow:
(a) When the liquid from the blood surrounds the cells, what is it called?
(b) Name any one important component of the blood which remains inside the capillaries and fails to move out into the spaces.
(c) Some of the liquid surrounding the cells does not pass directly back into the blood but eventually reaches it by another route through vessel X. Name the fluid present in vessel X.
(d) State two important functions performed in our body by the fluid present in the vessel X.
Answer:
(a) Tissue Fluid
(b) Red blood cells
(c) Lymph
(d) The lymph supplies nutrition and oxygen to those parts where blood cannot reach. The lymph drains away excess tissue fluids and metabolites and returns proteins to the blood from tissue spaces.

📝 Teacher's Note: Explain that tissue fluid formation is like water seeping through a sieve - small molecules pass through capillary walls but large ones like RBCs and proteins cannot. Use a tea strainer analogy.

🎯 Exam Tip: For lymph functions, always mention both nutritional supply and drainage functions. Keywords: "supplies nutrition," "drains excess fluids," "returns proteins."

Question 5. The following simplified diagram refers to the outline plan of the circulation of blood in a mammal. Study the diagram and write the number and the name of the blood vessel in each case as mentioned ahead.
(a) Several hours after a meal containing a lot of protein, which vessel will contain the highest concentration of urea?
(b) Which vessel would contain the highest concentration of amino acids and glucose soon after a meal?
Answer:
(a) Hepatic portal vein (4)
(b) Hepatic portal vein (4)

📝 Teacher's Note: Connect this to digestive system - hepatic portal vein carries nutrients directly from intestines to liver for processing. After protein digestion, amino acids are converted to urea in liver.

🎯 Exam Tip: Remember hepatic portal vein for both questions - it's the first vessel to receive nutrients from digestion and waste products from protein metabolism.

Question 6. The figures given below show diagrammatic cross sections of three kinds of blood vessels.
(a) Identify the blood vessels A, B and C
(b) Name the parts labelled 1-4
(c) Mention two structural differences between A and B.
(d) Name the kinds of blood that flow through A and through B respectively.
(e) In which one of the above vessels referred to in (a) above does the exchange of gases actually take place?
Answer:
(a) A- Vein, B-Artery, C-Capillary
(b) 1 - External layer made of connective tissue
2 - Lumen
3 - Middle layer of smooth muscles and elastic fibres
4 – Endothelium
(c) An artery has thick muscular walls and a narrow lumen. It does not have any valve.
A vein on the other hand has thin muscular walls and a wider lumen. It has valves to prevent back flow of blood.
(d) A (Vein) - deoxygenated blood, B (Artery)- oxygenated blood
(e) At the capillary level the actual exchange of gases takes place.

📝 Teacher's Note: Use the analogy of highways (arteries - thick walls, high pressure) vs local roads (veins - wider, slower flow, need traffic lights/valves). Capillaries are like narrow alleys where actual exchange happens.

🎯 Exam Tip: For structural differences, always mention wall thickness, lumen size, and presence/absence of valves. Remember arteries have thick walls to handle high pressure from heart.

Question 7. The diagram given alongside represents the human heart in one phase of its activity. Study the same and then answer the questions that follow:
(a) Name the phase
(b) Which part of the heart is contracting in this phase? Give a reason to support your answer.
(c) Name the parts numbered 1 to 6
(d) What type of blood flows through the parts marked '1' and '2' respectively?
(e) How many valves are closed in this phase?
Answer:
(a) Atrial Diastole and Ventricular Systole
(b) Ventricular muscles are contracting during this phase because the valves between the two ventricles and pulmonary artery and aorta are open while the atrio-ventricular valves are closed.
(c)

(d) Part 1 (Pulmonary artery) Deoxygenated blood
Part 2 (Aorta) Oxygenated Blood
(e) Two i.e., bicuspid and tricuspid valves are closed in this phase

📝 Teacher's Note: Use a squeeze bottle analogy - when you squeeze (ventricular systole), the contents are pushed out through the open valves while inlet valves close to prevent backflow.

🎯 Exam Tip: Always mention which valves are open and closed to justify your phase identification. Ventricular systole = atrio-ventricular valves closed, semilunar valves open.

Question 8. Study the following diagram carefully:
(a) With which figure in the chapter can you roughly compare this diagram?
(b) Write any two things shown in it as extra from those in the figure named above.
Answer:
(a) Diagrammatic relationship of artery, capillary and vein.
(b) The two extra things shown here are:
(i) Arrows indicating the flow of blood to and from heart.
(ii) Red blood cells passing through a capillary.

📝 Teacher's Note: This diagram shows the functional connection between different blood vessels. Emphasize how capillaries form the bridge between arterial and venous systems, like connecting roads between highways.

🎯 Exam Tip: Look for additional details in diagrams - arrows for direction, cellular components, or enlarged views that weren't in basic diagrams.

Question 9. Given below is a diagrammatic representation of certain types of blood vessels in human body.
(a) Identify the types of blood vessels numbered 1 to 5.
(b) Where can such an arrangement be found as an example – in lungs or in heart walls?
Answer:
(a)

(b) In lungs - this arrangement represents the pulmonary circulation where gas exchange occurs at the capillary level between alveoli and blood.

📝 Teacher's Note: This shows the complete vascular tree from largest to smallest vessels. Explain how blood pressure decreases as vessels get smaller and more numerous, like a river branching into streams.

🎯 Exam Tip: Remember the sequence: Artery → Arteriole → Capillary → Venule → Vein. This pattern is found wherever gas or nutrient exchange occurs, especially in lungs and tissues.

Question. Study the following diagram carefully and then answer the questions that follow:
(a) name the cell labelled 1.
(b) Identify the phenomenon occurring in A.
(c) Mention two structural differences between 1 and 2.
(d) Name the process occurring in B and C and state the importance of this process in the human body.

Answer:
(a) 1 - Red blood cell
(b) Diapedesis
(c)

(d) The process which occurs in B and C is phagocytosis. In this process, the WBCs engulf the foreign particles and destroy them, thus preventing the occurrence of disease.

In simple words: Red blood cells carry oxygen and lack a nucleus, while white blood cells fight germs and have a nucleus. Diapedesis is when white blood cells squeeze through blood vessel walls, and phagocytosis is when they eat up harmful bacteria to keep us healthy.

📝 Teacher's Note: Use analogies like "RBCs are like delivery trucks carrying oxygen packages" and "WBCs are like security guards that can squeeze through doors and eat invaders." Draw simple diagrams to show the shape differences clearly.

🎯 Exam Tip: Always mention the specific function when describing cell differences - examiners look for nucleus presence/absence, shape description, and functional importance. For phagocytosis, include both the process (engulfing) and purpose (preventing disease).