The Circulatory System

The vein which brings oxygenated blood to the heart from the lungs:

1. Renal vein
2. Superior Vena Cava
3. Pulmonary vein
4. Coronary Vein

Answer

Pulmonary vein

Reason — Pulmonary veins are the blood vessels which carry oxygenated blood from lungs to the heart.
Renal vein carries deoxygenated blood from the kidneys to the heart. Superior vena cava brings deoxygenated blood from the upper body to the right atrium of the heart. Coronary vein carries deoxygenated blood from the heart muscles back to the heart.

The path which the blood flows through during pulmonary circulation is:

1. RA → RV → Pulmonary arteries → Lungs → Pulmonary veins → LA
2. LA → LV → Pulmonary veins → Lungs → Pulmonary arteries → RA
3. LA → LV → Aorta → Body → Vena Cavae → RA
4. RA → RV → Vena Cavae → Body → Aorta → LA

Answer

RA → RV → Pulmonary arteries → Lungs → Pulmonary veins → LA

Reason — Pulmonary circulation is the movement of blood from the heart to the lungs for oxygenation, then back to the heart again. At first, blood flows from the right side of the heart to the lungs and then returns to the left side of the heart (pulmonary circulation).

Karl Landsteiner classified human blood into four categories on the basis of proteins (antigens) found on the surface of the RBCs. Compatibility of blood groups must be checked during blood transfusion. Which of the following statements are incorrect ?

P. Blood group 'AB' is the universal donor as it does not contain any antibodies.

Q. Blood group 'AB' is the universal recipient as it contains both the antigens 'A' and 'B'.

R. Blood group 'O' is the universal recipient as it does not contain any antigens.

1. Only R
2. Only P and R
3. Only P and Q
4. Only Q and R

Answer

Only P and R

Reason — Blood group 'AB' has antigens A and B so people with AB blood group can receive blood from all types, while Blood group 'O' has neither antigen A nor antigen B, so people with blood group O can give their blood to all the groups but can only receive blood from O blood group. Hence, a person with AB blood group is called a universal recipient, and a person with O blood group is called a universal donor.
Blood group AB is not the universal donor. AB has both A and B antigens, so it cannot donate to all groups. Blood group O is NOT the universal recipient. It has no antigens, so it is the universal donor, not recipient.

Geetika's mother has certain ailments of the heart. She is often very stressed and has anxiety. Sometimes, she experiences her heart beating too hard or too fast and occasionally even skipping a beat. Which of the following heart-related conditions explains her problem ?

1. Hypertension
2. Heart attack
3. Palpitations
4. Cardiac arrest

Answer

Palpitations

Reason — Palpitations are caused by stress or anxiety. Sometimes certain types of food may also cause palpitations.
Hypertension is high blood pressure, usually without noticeable heartbeat sensations. A heart attack is a severe condition involving interruption of blood supply to the heart muscle, often with chest pain. Cardiac arrest is sudden stopping of the heart (life-threatening emergency).

Assertion (A): Veins carry blood away from the heart to different organs of the body.

Reason (R): Veins carry deoxygenated blood from most organs of the body except lungs.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is false but R is true.

Explanation — A is false because veins carry blood towards the heart, not away from it. Arteries carry blood away from the heart.
R is true because most veins carry deoxygenated blood from the body to the heart. The pulmonary veins are an exception as they carry oxygenated blood from the lungs to the heart.

Therefore, A is false but R is true is the correct option.

Assertion (A): None of the arteries carry deoxygenated blood in the human body.

Reason (R): Pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is false but R is true.

Explanation — A is false as the pulmonary artery is an exception, it carries deoxygenated blood.
R is true as pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs.

Therefore, A is false but R is true is the correct option.

Assertion (A): The walls of the atria are thinner as compared to those of the ventricles.

Reason (R): The atria are the 'receiving chambers' and need to pump blood a short distance i.e. into the ventricles, while ventricles are the 'distributing chambers' and they must pump blood with much greater force to the lungs and the rest of the body.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Explanation — A is true as the atria have thinner walls as they only need to pump blood a short distance into the ventricles.
R is true as atria are receiving chambers and only pump blood a short distance (to ventricles). Ventricles are pumping chambers that send blood to the lungs and the entire body, so they need thicker, stronger muscular walls.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Assertion (A): Capillaries are the finest blood vessels in the body, interconnecting arteries and veins.

Reason (R): The interconnection between arteries and veins is very significant because the exchange of water, nutrients, waste materials and respiratory gases occurs from arteries to veins and vice-versa through the capillaries only.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Explanation — A is true as capillaries are the smallest (finest) blood vessels and they connect arteries (via arterioles) to veins (via venules).
R is true as capillaries play a crucial role as this interconnection is crucial for the exchange of essential substances like water, nutrients, waste products, and respiratory gases from arteries to veins and vice-versa.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Match the items in Column A with those in Column B.

Answer

Name:

(a) The membranous structure which divides the heart into a right and a left portion.

(b) The structure responsible for starting electrical impulses that cause the heart to contract and relax in order to keep pumping blood.

(c) The scientist who identified different types of blood groups.

Answer

(a) Septum

(b) SA node (Sinoatrial Node)

(c) Karl Landsteiner

Name the three components of circulatory system

Answer

Three components of the circulatory system:

1. Heart
2. Blood vessels
3. Blood

Name the four blood groups on the basis of antigens

Answer

Four blood groups on the basis of antigen are:

1. A (A antigen)
2. B (B antigen)
3. AB (A and B antigens)
4. O (No antigens)

Name the two phases of double circulation

Answer

Two phases of double circulation:

1. Systemic circulation.
2. Pulmonary circulation.

Name the three principal fluids of human body

Answer

Three principal fluids of the human body:

1. Blood
2. Lymph
3. Tissue fluid

Name the three kinds of blood vessels

Answer

Three kinds of blood vessels are:

1. Arteries
2. Veins
3. Capillaries

Name the two types of blood circulation in the human body.

Answer

Two types of blood circulation are:

1. Pulmonary circulation
2. Systemic circulation

Define Circulatory system

Answer

The circulatory system comprises of the heart, blood and blood vessels which circulates blood throughout the body, thereby helping in the transport of nutrients, oxygen and carbon dioxide.

Define Blood

Answer

Blood is the circulating fluid contained in the heart and in the blood vessels such as arteries, veins and capillaries of the circulatory system. It helps in the transport of oxygen, carbon dioxide and digested food.

Define Lymph

Answer

Lymph is a pale yellow fluid contained within lymph vessels and lymphatic organs. It is part of the immune system and helps in defence against germs.

Define Artificial pacemaker

Answer

Sometimes a mechanical device called an artificial pacemaker is placed surgically in humans if their SA node is damaged or if the electrical conduction system of the heart has problems.

In which organ of our body does blood get oxygenated ?

Answer

Lungs

Which side of the heart (left or right) contains oxygenated blood?

Answer

The left side of the heart contains oxygenated blood.

Write important role(s) of Pericardial fluid.

Answer

Pericardial fluid protects the heart from shocks, jerks or any mechanical stress.

Write important role(s) of Aorta.

Answer

Aorta carries oxygenated blood from the heart to all parts of the body through its branches.

Write important role(s) of Vena cavae.

Answer

The two vena cavae (Superior Vena Cava and Inferior Vena Cava) bring deoxygenated blood from all the different parts of the body to the right atrium of the heart.

Give the functions of lymph.

Answer

Functions of lymph are —

1. Nutritive — It supplies nutrition and oxygen to those parts where blood cannot reach.
2. Drainage — It drains away excess tissue fluid and metabolites and returns proteins to the blood from tissue spaces.
3. Absorption — Fats in the intestine are absorbed through lymph vessels (or lymphatics).
4. Defence — Lymphocytes and monocytes of the lymph function to defend the body. The lymphatics also remove bacteria from the tissues.

Differentiate between the following pairs on the basis of what is indicated within the brackets:

Pulmonary artery and pulmonary vein (kind of blood)

Answer

Difference between Pulmonary artery and Pulmonary vein on the basis of the kind of blood:

Differentiate between the following pairs on the basis of what is indicated within the brackets:

Artery and vein (direction of blood flow)

Answer

Difference between Artery and Vein on the basis of direction of blood flow:

Differentiate between the following pairs on the basis of what is indicated within the brackets:

Closed and open vascular system (definition)

Answer

Difference between Closed and Open Vascular system on the basis of definition:

Differentiate between the following pairs on the basis of what is indicated within the brackets:

Bicuspid and tricuspid valve (location)

Answer

Difference between Bicuspid and Tricuspid valve on the basis of location:

Differentiate between the following pairs on the basis of what is indicated within the brackets:

Blood and lymph (composition)

Answer

Difference between Blood and Lymph on the basis of composition:

Name any four heart-related conditions that occur commonly in humans. Briefly explain the cause and symptoms of each of them.

Answer

The four heart related conditions common to humans along with their cause and symptoms are given below:

1. Palpitations — When the heart beats too hard or too fast or sometimes even skips a beat, it is called Palpitations. Palpitations are often caused due to stress or anxiety. Sometimes, certain types of food may also cause Palpitations.
2. Hypertension — This is a condition that occurs when blood flows through the blood vessels with a force greater than normal. This is also called High Blood Pressure. Hypertension can also strain the heart, damage blood vessels and increase the risk of heart attack or stroke.
3. Heart attack — A heart attack is a sudden interruption of blood supply to the heart. It usually occurs due to a blood clot that prevents the flow of oxygen rich blood to the cardiac muscle. As, a result a part of the cardiac muscle dies and causes a permanent damage to the heart. Some common symptoms of a heart attack include uncomfortable pressure, tightness or squeezing pain in the centre of the chest, discomfort or pain spreading beyond the chest to the shoulders, neck, jaw, teeth or one or both arms, shortness of breath , dizziness, sweating and nausea.
4. Cardiac Arrest — A cardiac arrest occurs when the heart suddenly stops pumping blood around the body. In cardiac arrest, a person suddenly loses consciousness and stops breathing or may have abnormal breathing. Some people experience chest pain, shortness of breath, or nausea before a cardiac arrest occurs. The common cause of cardiac arrest is coronary artery disease wherein the walls of the arteries thicken as a result of fat or plaque deposition. Less common causes include major blood loss, lack of oxygen, low potassium levels, heart failure and intense physical exercise.

Explain — (a) Universal donor (b) Universal recipient

Answer

(a) Universal donor — The blood of O group can be given to all the groups. As blood group O has neither antigen A nor B so it doesn't cause self-clumping with any antibodies making it compatible with all blood groups. Hence, a person with O blood group is called a universal donor.

(b) Universal recipient — A person with blood group AB is called a universal recipient since they can receive blood from a person with any blood group. As blood group AB has no antibodies, so there is no attack on the antigens of any blood group making it compatible to receive blood from all blood groups.

During surgical operations or during accidents, the patient may be given blood from outside to save his life. What is the technical name of this process ? Briefly explain the precautions to be observed and taken in this process.

Answer

This process is known as blood transfusion. The following precautions are to be observed for blood transfusion:

1. The compatibility of the donor's blood group with that of the recipient must be checked.
2. The donor should be healthy and medically fit to donate blood.
3. The donor's blood must be tested and confirmed to be free from infections.
4. The donor's haemoglobin level should be checked.
5. Sterile equipment should be used, and the collected blood should be stored properly in a blood bank.

Given alongside is a diagram of the human heart showing its internal structure. Label the parts marked 1 to 6, and answer the following questions.

(a) Which type of blood is carried by the blood vessel marked 2?

(b) Name the main artery which takes the blood from heart to different parts of the body?

(c) Which chamber of the heart receives deoxygenated blood from the body?

Answer

The parts marked 1 to 6 are labelled below:

• 1 → Left pulmonary artery

• 2 → Superior vena cava

• 3 → Left pulmonary vein

• 4 → Right auricle

• 5 → Left ventricle

• 6 → Right ventricle

(a) Deoxygenated blood is carried by the blood vessel marked 2 (Superior vena cava).

(b) Aorta

(c) Right auricle

Rohit, Rohan's elder brother, met with an accident on his way back from school and lost a significant amount of blood. At the hospital the doctor said he needed an immediate blood transfusion.
Rohan overheard the doctor asking about everyone's blood group in the family. Their father's blood group is O and their mother's blood group is AB. Based on the information given above, answer the questions that follow :

(a) Suppose Rohit's blood group is B. Which parent can give blood to him - his mother or his father ?

(b) If Rohan's blood group is A, can he donate blood to his brother ?

(c) Blood groups are said to be differentiated based on the presence of certain antigens. What are antigens and where are they found in the blood ?

Answer

(a) If Rohit’s blood group is B, then he can receive blood from B and O groups. His father has blood group O, so he can donate blood to Rohit. His mother (AB) cannot donate to B group because mother with AB blood group has both A and B antigens on the surface of their red blood cells.

(b) If Rohan’s blood group is A, Rohan cannot donate blood to his brother because blood group A cannot donate to B, because of incompatibility of antigens and antibodies.

(c) Antigens are special proteins present on the surface of red blood cells (RBCs). They determine a person’s blood group (A, B, AB, or O).