The Circulatory System

Multiple Choice Type

(Select the most appropriate option in each case)

Question 1

Non-granular WBCs are:

1. lymphocytes and monocytes ✓
2. lymphocytes and basophils
3. eosinophils and basophils
4. eosinophils and monocytes

Question 2

White blood cells engulf bacteria in a process called:

1. diapedesis
2. phagocytosis ✓
3. active transport
4. passive transport

Question 3

The nearest organ to which the heart supplies oxygenated blood is

1. Lung
2. Stomach
3. Intestine
4. Heart itself ✓

Question 4

When a doctor is recording your pulse, he is pressing on your wrist exactly on a

1. vein
2. capillary
3. artery ✓
4. arteriole

Question 5

The blood vessel supplying blood to the kidney is

1. renal vein
2. renal artery ✓
3. dorsal aorta
4. hepatic vein

Question 6

Angina Pectoris is due to

1. defective nutrition
2. chest pain due to inadequate supply of oxygen to the heart muscle ✓
3. defective functioning of mitral valve
4. infection by a virus

Question 7

The chief function of lymph nodes is to

1. produce WBCs
2. produce hormones
3. destroy old RBCs
4. destroy pathogens ✓

Question 8

Heart sounds are produced due to

1. closure of tricuspid and bicuspid valves
2. rushing of blood through valves producing turbulence
3. closure of atrioventricular and semilunar valves ✓
4. entry of blood into auricles

Very Short Answer Type

Question 1

Given below are certain structures, write their chief functional activity.

(a) Blood platelets ..........

(b) Neutrophils ..........

(c) Erythrocytes ..........

(d) Lymphocytes ..........

(e) Bone marrow ..........

Answer

(a) Blood platelets → blood coagulation.

(b) Neutrophils → phagocytosis.

(c) Erythrocytes → transportation of gases.

(d) Lymphocytes → Produce antibodies.

(e) Bone marrow → destruction of old and weak RBC's/production of RBCs and WBCs.

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

Question 3

Name the following:

(a) Any one vein which starts from an organ and ends in another organ besides the heart.

Answer

Hepatic portal vein

(b) The kind of blood vessels which have no muscular walls.

Answer

Blood Capillaries

(c) The artery which carries deoxygenated blood.

Answer

Pulmonary artery

(d) The kind of blood cells which can squeeze out through the walls of one category of blood vessels.

Answer

White blood cells

(e) The smallest common blood vessels formed by the union of capillaries.

Answer

Venules

(f) The blood vessels which start from capillaries and end in capillaries.

Answer

Portal vein

(g) The phase of the cardiac cycle in which the auricles contract.

Answer

Atrial systole

(h) The valve present in between the chambers on the right side of the human heart.

Answer

Tricuspid valve

(i) The phase of the cardiac cycle in which the ventricles get filled with blood from the atrium.

Answer

Atrial systole

(j) The fluid found between the membranes of the heart.

Answer

Pericardial fluid

Question 4

Complete the following statements by filling in the blanks from the choices given in the brackets.

(a) The blood vessel that begins and ends in capillaries is the .......... (hepatic artery/hepatic portal vein/hepatic vein).

(b) A blood vessel which has small lumen and thick wall is .......... (capillary/lymphatic duct/artery/venule)

(c) The valve which prevents the back flow of blood in the veins and lymph vessels .......... (mitral valve/tricuspid valve/pocket-shaped valve).

(d) An anticoagulant present in the blood is .......... (heparin/hirudin/thromboplastin/calcium).

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 pocket-shaped valve.

(d) An anticoagulant present in the blood is heparin.

Question 5

Note the relationship between the first two words and suggest the suitable word/words for the fourth place:

(a) Lubb: Atrio-ventricular valve:: Dup: ..........

(b) Coronary artery: Heart::Hepatic artery: ..........

Answer

(a) Lubb: Atrio-ventricular valve:: Dup: Semilunar valves

(b) Coronary artery: Heart::Hepatic artery: Liver

Question 6

Give reason, why a mature mammalian erythrocyte lacks nucleus and mitochondria?

Answer

Mature erythrocyte have high capacity to accommodate more haemoglobin hence carry more oxygen molecules. Thus, a mature mammalian erythrocyte lacks nucleus and mitochondria so as to make place for the accommodation of more haemoglobin and hence more oxygen molecules. Lack of such organelles also provides the peculiar biconcave appearance of RBCs that aids in efficient diffusion.

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:

Question 2

Why is it necessary to know the blood groups before giving transfusion?

Answer

Sometimes it becomes necessary to inject blood into the body of patients undergoing surgical operation. This is called blood transfusion. It is important that the blood groups of the donor and the recipient should be compatible. So, to prevent the blood cells of the donor to be destroyed by the antibodies of the recipient it is necessary to know the blood group before transfusion.

Question 3

Differentiate between members of each of the following pairs with reference to phrases in brackets:

(a) Antibodies and Antibiotics (Source)

(b) Serum and Vaccine (Composition)

(c) Erythrocytes and leucocytes (function)

(d) Tricuspid and bicuspid valves (location)

Answer

(a) Difference between antibodies and antibiotics based on their source:

(b) Difference between serum and vaccine based on their composition:

(c) Difference between erythrocytes and leucocytes based on their function:

(d) Difference between tricuspid valve and bicuspid valve based on their location:

Question 4

When are the sounds "LUBB" and "DUP" produced respectively during heart beat?

Answer

The first sound "LUBB" is produced when the atrio-ventricular (tricuspid and bicuspid) valves get closed sharply at the start of ventricular systole. The second sound "DUP" is produced when at the beginning of ventricular diastole, the semilunar valves at the roots of aorta and pulmonary artery get closed.

Question 5

Why do people have a common belief that the heart is located on the left side of the chest?

Answer

The heart is right in the center between the two lungs and above the diaphragm. The narrow end of the roughly triangular heart is pointed to the left side and during working, the contraction of the heart is most powerful at this end giving a feeling that the heart is on the left side.

Question 6

Match the items in column A with those in column B. Rewrite the correct matching pairs.

Answer

Question 7

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

Answer

Descriptive Type

Question 1

Define the following terms:

(a) Circulatory system

(b) Blood

(c) Heart

(d) Diapedesis

(e) Phagocytosis

(f) Rh factor

Answer

(a) Circulatory system — The circulatory system is a network consisting of blood, blood vessels and the heart. This network supplies tissues in the body with oxygen and other nutrients, transports hormones and removes unnecessary watse products.

(b) Blood — Blood is the circulating fluid contained in the heart and in the blood vessels such as arteries, veins and capillaries of the circulatory system. Blood from the heart is pumped throughout the body using blood vessels.

(c) Heart — The heart is made of specialized cardiac muscle tissue that allows it to act as a pump within the circulatory system. Heart pushes the blood around the body and has different chambers such as right atrium, left atrium, right ventricle, left ventricle to prevent the mixing of oxygenated blood and carbon dioxide rich blood.

(d) Diapedesis — Diapedesis is the squeezing of leucocytes through the wall of capillaries into the tissues.

(e) Phagocytosis — Phagocytosis is the process in which most WBCs and particularly the neutrophils engulf particle-like solid substances, especially bacteria.

(f) Rh factor — Rh factor 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-)

Question 2

Distinguish between the following pairs:

(a) Systole and Diastole

(b) Arteriole and Venule

(c) Universal donor and Universal recipient

(d) Arteries and Veins

(e) Haemoglobin and Chlorophyll

Answer

(a) Systole and Diastole

(b) Arteriole and Venule

(c) Universal donor and Universal recipient

(d) Arteries and Veins

(e) Haemoglobin and Chlorophyll

Question 3

Give reasons/explain:

(a) The left ventricle has thicker walls than the right ventricle.

(b) The walls of right ventricle are thicker than those of the right auricle.

(c) Vitamin K is essential for the process of blood clotting.

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.

(c) Vitamin K acts as a catalyst that transforms some anticlotting proteins, which are always present, into clotting proteins when there is a cut or wound to the body. The mechanism of blood clotting involves the presence of calcium and other clotting factors. Thrombokinase activates an enzyme called prothrombin activator. The enzyme prothrombin activator then converts plasma protein prothrombin into thrombin. Thrombin is the enzyme which in turn converts fibrinogen into fibrin. Polymerized fibrin together with platelets forms a clot at the wound site. The prothrombin is a plasma protein synthesized in the liver. Vitamin K is essential for the synthesis of prothrombin. Hence, Vitamin K is essential for the process of blood clotting.

Question 4

Write important role/roles of the following:

(a) Tonsils

(b) Spleen

(c) Hepatic portal vein

(d) Basophils

(e) S.A.N.

Answer

(a) 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.

(b) 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.

(c) Hepatic portal vein — The hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents.

(d) Basophils — Basophils are a type of white blood cells. They are the least common type of granulocyte which release chemicals called histamine for inflammation which dilate blood vessels.

(e) S.A.N. — The sinoatrial node (SAN) is a region of cardiac fibres located in the right atrium. The electrical wave of stimulation is initiated here and extends over the two atria, causing them to contract. It is often referred to as the pacemaker of the heart.

Question 5

What is meant by the term 'Double circulation'? Distinguish between the two types of circulation in our body.

Answer

Double circulation is a process during which blood passes twice through the heart during one complete cycle. The flow of blood in the heart consists of two phases —

1. The short pulmonary (lung) circulation

2. The long systemic (general body) circulation

Difference between pulmonary and systemic circulation —

Question 6

Write the main steps in coagulation of blood in their correct sequence?

Answer

Coagulation of blood (or clotting) occurs in a series of steps as follows:

1. The injured tissue cells and the platelets which disintegrate at the site of the wound release a substance thrombokinase (also called thromboplastin).
2. The thrombokinase acts as an enzyme and with the help of calcium ions present in the plasma, it converts a substance prothombin (inactive) of the plasma, into thrombin (active). Vitamin K, a fat-soluble vitamin is essential for the production of prothombin.
3. Thrombin in the presence of calcium ions reacts with the soluble fibrinogen of the plasma to convert it into insoluble fibrin. Fibrin is a solid substance that forms threads. These microscopic threads of fibrin are sticky and form a mesh or network at the site of wound.
4. Blood cells are trapped in the network of the fibrin; the network then shrinks and squeezes out the rest of the plasma which is in the form of a clear liquid, the serum. The solid mass which is left behind is called clot (or thrombus).

Question 7

What are the functions of blood plasma?

Answer

The functions of blood plasma are —

1. Distributes heat in the body to maintain the body temperature.
2. Transports excretory materials from tissues to excretory organs.
3. Transports digested food from the alimentary canal to tissues.
4. Distributes hormones from the glands to their target site.

Question 8

State any five functions of the blood.

Answer

Five functions of blood are as follows:

1. Transport of digested food (in the form of simple sugars like glucose, amino acids, vitamins, mineral salts, etc.) from the alimentary canal to the tissues.
2. Transport of oxygen from the lungs to the tissues. It occurs by means of red blood cells in combination with haemoglobin in the form of an unstable compound oxyhaemoglobin, which on reaching the tissues breaks up to deliver oxygen.
3. Transport of carbon dioxide from the tissues to the lungs. It occurs partly in combination with haemoglobin and partly as solution in blood plasma.
4. Transport of excretory material from the tissues to the liver, kidney or the skin for elimination or to render them harmless.
5. Its white blood corpuscles protect the body from diseases by engulfing bacteria which may have entered the body.

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 and 3 respectively?

(d) What is the life span of the part labeled "1"?

(e) Name a soluble protein found in "4" which helps in clotting of blood.

Answer

(a) The parts indicated are as follows —

• 1 → Red Blood Cell (RBC)
• 2 → White Blood Cell (WBC)
• 3 → Blood Platelet
• 4 → Blood Plasma

(b) Two structural differences between red blood cells and white blood cells are:

(c) The main functions of the parts labelled 1, 2 and 3 are as follows:

1. Part 1 (Red Blood Cell) — Transport of respiratory gases to the tissues and from the tissues, transport of nutrients from the alimentary canal to the tissues.
2. Part 2 (White Blood Cell) — WBCs play major role in defense mechanism and immunity of the body.
3. Part 3 (Blood Platelet) — Blood platelets are the initiators of blood clotting.

(d) The average life span of a red blood cell (RBC) is about 120 days.

(e) Thromboplastin.

Question 2

Given below is a highly schematic diagram of the human blood circulatory system.

(a) Which part (state the number) represents the heart? Give reason in support of your answer.

(b) Which numbers represent the following respectively?

Aorta

Hepatic portal vein

Pulmonary artery

Superior vena cava

Renal vein

Stomach

Answer

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

(b) The numbers of the structures are mentioned below:

• Aorta → 5
• Hepatic portal vein → 7
• Pulmonary artery → 1
• Superior vena cava → 9
• Renal vein → 8
• Stomach → 10

Question 3

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 labeled 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 vessels referred to in (a) above does the exchange of gases actually take place?

Answer

(a) The blood vessels A, B and C are:

• A → Artery
• B → Vein
• C → Capillary

(b) The parts labeled 1-4 are:

• 1 → External layer made of connective tissue
• 2 → Lumen
• 3 → Middle layer of smooth muscles and elastic fibres
• 4 → Endothelium

(c) Two structural differences between Artery and Vein are:

(d) The kinds of blood that flow through A and through B are:

• A (Artery) → Oxygenated blood
• B (Vein) → Deoxygenated blood

(e) At the capillary level the actual exchange of gases takes place.

Question 4

The diagram given below 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) The phase is Ventricular Systole and Atrial Diastole.

(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) The parts numbered 1 to 6 are:

• 1 → Pulmonary Artery
• 2 → Aorta
• 3 → Pulmonary Vein
• 4 → Left Atrium
• 5 → Bicuspid Valve
• 6 → Right Ventricle

(d) Types of blood flowing through parts '1' and '2' are mentioned below:

• Part 1 (Pulmonary artery) → Deoxygenated blood
• Part 2 (Aorta) → Oxygenated blood

(e) Two valves — Bicuspid and Tricuspid valves are closed in this phase.

Question 5

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) The cell labelled 1 is a Red blood cell.

(b) Phenomenon occurring in A is Diapedesis.

(c) Two structural differences between red blood cells and white blood cells are:

(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.

Question 6

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) The types of blood vessels numbered 1 to 5 are:

• 1 → Arteriole
• 2 → Artery
• 3 → Venule
• 4 → Capillaries
• 5 → Vein

(b) Such an arrangement can be observed in the lungs.

Question 7

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 labeled 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) Functions performed by lymph are as follows —

1. Nutritive — Supplies nutrition and oxygen to those parts where blood cannot reach.
2. Drainage — It drains away excess tissues fluid and metabolites and returns proteins to the blood from tissue spaces.