NCERT Solutions for Class 11 Biology Chapter 18 : Body Fluids and Circulation
Biology is the study of living organisms and how organisms interact with the environment. Body Fluids and Circulation NCERT Solutions for Class 11 Biology Chapter 18 breaks down the solutions into detailed steps and explains the answer thoroughly, which helps you understand the pattern of questioning and a way to increase your score in a exams.
NCERT Solutions for chapter 18 biology class 11 are prepared by our team of highly professional, qualified and experienced faculties. In case you have a doubt we have a team of teachers who are just a click away to solve your doubt any time.
In NCERT Solutions for Class 11 Biology Chapter 18, you will understand about blood, lymph (tissue fluid), plasma, circulatory pathways, double circulation, regulation of cardiac activity and disorders of circulatory system, formed elements, blood groups, coagulation of blood, human circulatory system, cardiac cycle and electrocardiography (ECG).
In body Fluids and Circulation NCERT, you will learn about the composition and properties of blood and lymph (tissue fluid) and the mechanism of circulation of blood, functions of the circulatory system, components of blood, functions and different types of blood cells. Let us now discuss the subtopics included in Chapter 18.
Access NCERT Solutions for Class 11 Biology Chapter 18 : Body Fluids and Circulation
Page Number 289
Name the components of the formed elements in the blood and mention one major function of each of them ?
Blood is a fluid connective tissue.It is composed of plasma(55%) and formed elements/blood corpuscles(45%).
There are three types of formed elements(blood corpuscles):
1) Erythrocytes (red cells)
2) Leukocytes (white cells)
3) Platelets (thrombocytes)
Erythrocytes (RBC) - Most abundant type of blood cells. Their main function is transport of respiratory gases,mainly oxygen, but they also carry some carbon dioxide.
They also maintain the viscosity and pH of blood.
Leukocytes (WBC) - These cells have an important function in defence and immunity. They detect foreign or abnormal (antigenic) material and destroy it, through a range of defence mechanisms.
There are two main types:
Granulocytes (polymorphonuclear leukocytes)- neutrophils, eosinophils and basophils
Agranulocytes - monocytes and lymphocytes
Platelets (Thrombocytes) - These are very small discs, 2-4 micrometer in diameter. They are responsible for coagulation or clotting of blood.
What is the importance of plasma proteins?
Plasma is the colourless fluid of blood which helps in the transport of food, CO2, waste products, and salts. It constitutes about 55% of blood. About 6.8% of the plasma is constituted by proteins such as fibrinogens, globulins, and albumins.
Fibrinogen is a plasma glycoprotein synthesised by the liver. It plays a role in the clotting of blood.
Globulin is a major protein of the plasma. It protects the body against infecting agents.
Albumin is a major protein of the plasma. It helps in maintaining the fluid volume within the vascular space.
Why do we consider blood as a connective tissue?
Connective tissues have cells scattered throughout an extracellular matrix. They connect different body systems. Blood is considered as a type of connective tissue because it connects the body systems, transports oxygen and nutrients to all the parts of the body, and removes the waste products. Blood has an extra-cellular matrix called plasma, with red blood cells, white blood cells, and platelets floating in it.
What is the difference between blood and lymph?
|1. It is the red-colored fluid connective tissue that contains RBCs.|
| 1. It is a colorless fluid connective tissue in which RBCs are absent.|
| 2. It is associated with the circulation of oxygen and carbon dioxide.|| 2. It helps in body defence and is a part of immune system.|
| 3. It contains plasma, RBCs, WBCs, platelets, and proteins.|| 3. It contains plasma, fewer WBCs, and platelets. It lacks proteins.|
What is meant by double circulation? What is its significance?
- Double circulation is a process during which blood passes twice through the heart during one complete cycle. This type of circulation is found in amphibians, reptiles, birds, and mammals. However, it is more prominent in birds and mammals as in them the heart is completely divided into four chambers – the right atrium, the right ventricle, the left atrium, and the left ventricle.
The movement of blood in an organism is divided into two parts:
(i) Systemic circulation
(ii) Pulmonary circulation
- Systemic circulation involves the movement of oxygenated blood from the left ventricle of the heart to the aorta. It is then carried by blood through a network of arteries, arterioles, and capillaries to the tissues. From the tissues, the deoxygenated blood is collected by the venules, veins, and vena cava, and is emptied into the left auricle.
- Pulmonary circulation involves the movement of deoxygenated blood from the right ventricle to the pulmonary artery, which then carries blood to the lungs for oxygenation. From the lungs, the oxygenated blood is carried by the pulmonary veins into the left atrium.
Hence, in double circulation, blood has to pass alternately through the lungs and the tissues.
- Significance of double circulation:
The separation of oxygenated and deoxygenated blood allows a more efficient supply of oxygen to the body cells. Blood is circulated to the body tissues through systemic circulation and to the lungs through the pulmonary circulation.
Write the differences between.
(a) Blood and Lymph
(b) Open and closed system of circulation
(c) Systole and diastole
(d) P- wave and T- wave
(a) Blood and Lymph
|It is a colourless fluid.||It is red-coloured fluid.|
|It contains plasma and lesser number of WBCs and platelets.||It contains plasma, RBCs, WBCs, and platelets.|
|It transports nutrients from the tissue cells to the blood, through lymphatic vessels.||It transports nutrients and oxygen from one organ to another.|
|It helps in body defence and is a part of the immune system.||It helps in the circulation of oxygen and carbon dioxide.|
(b) Open and Closed system of circulation
|Open system of circulation||Closed system of circulation|
|In this system, blood is pumped by the heart, through large vessels, into body cavities called sinuses.||In this system, blood is pumped by the heart, through a closed network of vessels.|
|The body tissues are in direct contact with blood.|
The body tissues are in indirect contact with blood.
|Blood flows at low pressure.||Blood flows at high pressure.|
Blood flow cannot be regulated.
Blood flow can be regulated
|This is present in arthropods and molluscs.||This is present in annelids, echinoderms, and vertebrates.|
(c) Systole and Diastole
|It is the contraction of the heart chambers to drive blood into the aorta and the pulmonary artery.||It is the relaxation of the heart chambers between two contractions.|
|Systole decreases the volume of the heart chambers and forces the blood out of them.||Diastole brings the heart chambers back into their original sizes to receive more blood|
(d) P-wave and T-wave
|In an electrocardiogram (ECG), the P-wave indicates the activation of the Sino-atrial node.||In an electrocardiogram (ECG), the T-wave represents ventricular relaxation.|
|During this phase, the impulse of contraction is generated by the SA node, causing atrial depolarisation.||During this phase, the ventricles relax and return to their normal state.|
|It is of atrial origin.||It is of ventricular origin.|
Describe the evolutionary change in the pattern of heart among the vertebrates.
Heart is a hollow muscular organ present in all vertebrates which pump blood to whole of the body. Evolutionary change in the heart is observed on the basis of separation of oxygenated and deoxygenated blood for efficient oxygen transport to the body.
Fish heart- It is made up of 2 chambers- one auricle and one ventricle. Since there is no division of auricles and ventricles, deoxygenated blood passes through it which enters the gills for oxygenation. It has two additional chambers such as sinus venosus and conus arteriosus.
Amphibian heart- It has 3 chambers- 2 auricles and one ventricle. The auricles are divided by a septum while ventricle is undivided. Additional chambers such as sinus venosus and conus arteriosus are also present. The deoxygenated blood from whole body enters the right auricle while oxygenated blood enters the left auricle from the lungs and ultimately two types of blood get mixed up in ventricle.
Reptilian heart- It is incompletely 4 chambered except in crocodiles, alligators and gharials. They have only one accessory chamber called sinus venosus. The reptilian heart also shows mixed blood circulation.
Avian and mammalian hearts- It is made up of four chambers- 2 auricles and two ventricles. These two pairs of chambers separate oxygenated and deoxygenated blood. The upper two chambers are called atria and the lower two chambers are called ventricles. The chambers are separated by a muscular wall that prevents the mixing of the blood rich in oxygen with the blood rich in carbon dioxide.
Why do we call our heart myogenic?
- In the human heart, contraction is initiated by a specially modified heart muscle known as the sinoatrial node. It is located in the right atrium. The SA node has the inherent power of generating a wave of contraction and controlling the heartbeat.
- Hence, it is known as the pacemaker. Since the heartbeat is initiated by the SA node and the impulse of contraction originates in the heart itself, the human heart is termed as myogenic. The hearts of vertebrates and mollusks are also myogenic.
Sino-atrial node is called as the pacemaker of our heart. Why?
The sino-atrial (SA) node is a specialised bundle of neurons located in the upper part of the right atrium of the heart. The cardiac impulse originating from the SA node triggers a sequence of electrical events in the heart, thereby controlling the sequence of muscle contraction that pumps blood out of the heart. Since the SA node initiates and maintains the rhythmicity of the heart, it is known as the natural pacemaker of the human body.
NCERT Solutions for Class 11 Biology Chapter 18 : Body Fluids and Circulation
NCERT Solutions for Class 11 Biology Chapter 18 Body Fluids and Circulation – Brief Overview
18.1 – Blood
In this, you will study about the blood which is a fluid connective tissue composed of a fluid matrix, plasma, and the blood corpuscles, its uses, its composition.
18.1.1 – Plasma
In this, you will study about plasma which is a liquid part of the blood which is straw-colored, viscous fluid.
18.1.2 – Formed Elements
In this, you will study about formed elements which are erythrocytes, leucocytes, and platelets.
18.1.3 – Blood Groups
In this, you will study about blood group, the main types of grouping are ABO and Rh.
18.1.4 – Coagulation of Blood
In this, you will study about clotting of blood when an injury in blood vessel happens.
18.2 – Lymph (Tissue Fluid)
In this, you will study about tissue fluid which consists of a fluid matrix, plasma, white blood corpuscles or leucocytes, its functions.
18.3 – Circulatory Pathways
In this, you will study about the circulatory system and its types i.e. open circulatory system, closed circulatory system.
18.3.1 – Human Circulatory System
In this, you will study about the human circulatory system which is a closed circulatory system consists of the heart, blood capillaries, arteries, veins, lungs.
18.3.2 – Cardiac Cycle
In this, you will study about the circulation of blood from lung to heart and heart to the organs of the human body.
18.3.3 – Electrocardiograph (ECG)
In this, you will study about electrocardiograph which is a graphical representation of the electrical activity of the heart during the cardiac cycle.
18.4 – Double Circulation
In this, you will study the double circulation of blood which is the flow of same blood twice through the heart once in oxygenated form and other in deoxygenated form.
18.5 – Regulation of Cardiac Activity
In this, you will study about special neural centre in medulla oblongata moderates the cardiac function by ANS which contains Sympathetic nerve, parasympathetic nerve
18.6 – Disorders of Circulatory System
In this, you will study about hypertension, coronary artery disease, angina, heart failure, coronary thrombosis.
Frequently Asked Questions on NCERT Class 11 Biology Chapter 18 : Body Fluids and Circulation
Q1. What concepts can I learn from Body Fluids and Circulation NCERT Solutions for Class 11 Biology?
- 18.1 – Blood
- 18.2 – Lymph (Tissue Fluid)
- 18.3 – Circulatory Pathways
- 18.4 – Double Circulation
- 18.5 – Regulation of Cardiac Activity
- 18.6 – Disorders of Circulatory System
Q2. What are the advantages of Toppr NCERT Solutions for Class 11 Biology Chapter 18 Body Fluids and Circulation
Answer: Referring to NCERT Solutions for CBSE Class 11 Biology Chapter 18 Body Fluids and Circulation is beneficial during exam preparations. These well-prepared solutions allow students to have a better understanding of the chapter. By downloading Toppr NCERT Solutions for Class 11 Biology Chapter 18, students can find the explanation to the exercise questions asked in the exam. The material is prepared by subject matter experts to help students understand how to write answers in the exam.