th<\/sup> chapter in Biology for CBSE class 11. It has six concepts that talk about various aspects of the heart, blood, and the circulatory system.<\/p>\nBlood is a substance that mostly consists of plasma and other cellular material. Plasma is of straw color and is a viscous fluid that makes up for 55 percent of the blood. The blood has two major types of cells present in it, namely, the white blood cells and the red blood cells. While red blood cells live for about 120 days, white blood cells have a lifespan of only three or four days.<\/p>\n
Red blood cells are the ones that carry the hemoglobin pigment, which gives the blood its color.<\/p>\n
The chapter also talks about the human circulatory system that handles the flow of blood throughout the body. The primary organ of the human circulatory system is the heart. The heart pumps blood to the other parts of the body and has four parts. Two of them are the atria, and the other two are the ventricles.<\/p>\n
The heart is a muscular organ that contracts and expands to function. And this contraction and expansion at regular intervals are known as the \u2018cardiac cycle.\u2019 The cardiac cycle consists of two phases, namely, the diastole and systole. During the diastole phase, the heart ventricles relax. Similarly, during the systole phase, they contract and pump blood into the arteries.<\/p>\n
The autonomous nervous system controls the contraction and relaxation of the heart. When the heart contracts, the sympathetic nervous system acts to increase cardiac activity by increasing the heart rate and the strength of the ventricular contractions. Likewise, during the relaxation phase, the parasympathetic nervous system plays a prominent role in decreasing the heart rate and the strength of the ventricular contractions.<\/p>\n
The normal diastolic pressure of the heart is 80 mm Hg, while the expected systolic pressure is 120 mm Hg. Also, when these two pressures cross 90 mm Hg and 140 mm Hg, respectively, the person suffers from Hypertension.<\/p>\n
Similarly, when the arteries become narrow, a condition called coronary heart disease occurs. Coronary heart disease decreases the supply of blood to various other parts of the body.<\/p>\n
If there is a clog in the heart, then it can lead to a cardiac arrest, where the heart ceases to function.<\/p>\n
<\/span>Benefits of NCERT Solutions for Biology Chapter 18<\/strong><\/span><\/h2>\nNCERT solutions offer a way for students to understand the concepts of chapter 18 in Biology, which talks about the heart and the circulatory system. You can find below various benefits of going through NCERT solutions for class 11 Biology Chapter 18.<\/p>\n
<\/span>1. <\/strong>Logical Flow<\/strong><\/span><\/h3>\nThe chapter explains all the concepts logically so that the students will find it easier to understand them.<\/p>\n
<\/span>2. <\/strong>Designed by Experts<\/strong><\/span><\/h3>\nThe teachers who design NCERT solutions are experts in Biology. So, they will be able to explain all the concepts concisely.<\/p>\n
<\/span>Access NCERT Solution For Class 11 Biology Chapter 18<\/span><\/h2>\n<\/span>1. Name the components of the formed elements in the blood and mention one major function of each of them.<\/strong><\/span><\/h3>\nThe components of the formed elements in blood are as follows:<\/p>\n
\n- Erythrocytes or Red blood cells \u2013 They carry oxygen and contain the pigment, hemoglobin. Hemoglobin reacts with oxygen to form Oxyhemoglobin that carries oxygen to areas that are deprived of oxygen in the body.<\/li>\n
- Leucocytes or white blood cells \u2013 Lymphocytes are known to synthesize antibodies that neutralizes or kills germs. Neutrophils acts as a defense mechanism against bacteria known as phagocytosis.<\/li>\n
- Thrombocytes or blood platelets \u2013 They aid in coagulation of blood<\/li>\n<\/ul>\n
<\/span>2. What is the importance of plasma proteins?<\/strong><\/span><\/h3>\nSignificance of plasma proteins:<\/p>\n
Some of the plasma proteins are<\/p>\n
\n- Globulins \u2013 They are involved in the defense mechanism of the body, and are also referred to as immunoglobulins<\/li>\n
- Albumins \u2013They aid in maintaining the osmotic balance of the body<\/li>\n
- Fibrinogens \u2013 it plays a significant role in blood coagulation<\/li>\n<\/ul>\n
<\/span>3. Match Column I with Column II :<\/strong><\/span><\/h3>\n\n
\n\n\nColumn I<\/strong><\/td>\nColumn II<\/strong><\/td>\n<\/tr>\n\n(a) Eosinophils<\/strong><\/td>\n(i) Coagulation<\/strong><\/td>\n<\/tr>\n\n(b) RBC<\/strong><\/td>\n(ii) Universal Recipient<\/strong><\/td>\n<\/tr>\n\n(c) AB Group<\/strong><\/td>\n(iii) Resist Infections<\/strong><\/td>\n<\/tr>\n\n(d) Platelets<\/strong><\/td>\n(iv) Contraction of Heart<\/strong><\/td>\n<\/tr>\n\n(e) Systole<\/strong><\/td>\n(v) Gas transport<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n \n\n\nColumn I<\/strong><\/td>\nColumn II<\/strong><\/td>\n<\/tr>\n\n| (a) Eosinophils<\/td>\n | (iii) Resist Infections<\/td>\n<\/tr>\n | \n| (b) RBC<\/td>\n | (v) Gas transport<\/td>\n<\/tr>\n | \n| (c) AB Group<\/td>\n | (ii) Universal Recipient<\/td>\n<\/tr>\n | \n| (d) Platelets<\/td>\n | (i) Coagulation<\/td>\n<\/tr>\n | \n| (e) Systole<\/td>\n | (iv) Contraction of Heart<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/span>4. Why do we consider blood as a connective tissue?<\/strong><\/span><\/h3>\nBlood is a connective tissue as it is mesodermal derived and contains an extra-cellular matrix known as plasma. It is abundant and a widely distributed tissue in the body. Connective tissues link and bind, providing support to other organs of the body thereby transporting oxygen and other nutrients within the body, eliminating waste products from the body and flows throughout the body. Hence, it is considered as a connective tissue.<\/p>\n <\/span>5. What is the difference between lymph and blood?<\/strong><\/span><\/h3>\nThe difference between lymph and blood is as follows:<\/p>\n \n \n\n\nLymph<\/strong><\/td>\nBlood<\/strong><\/td>\n<\/tr>\n\n| It is a white tissue fluid<\/td>\n | It is a red liquid connective tissue<\/td>\n<\/tr>\n | \n| Lymph flows in the lymph vessels<\/td>\n | Blood flows in the blood vessels such as capillaries, arteries and veins<\/td>\n<\/tr>\n | \n| It contains white blood cells known as lymphocytes<\/td>\n | Blood contains red blood cells, haemoglobin, platelets and white blood cells<\/td>\n<\/tr>\n | \n| The exchange of nutrients and gases between the blood and cells takes place through the lymph<\/td>\n | Blood transports gases and other nutrients to the body.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/span>6. What is meant by double circulation? What is its significance?<\/strong><\/span><\/h3>\nDouble circulation, as the name suggests, is where the blood circulates twice in the heart. Double circulation is possible as the heart is divided into four chambers, the right and the left halves by the atrio-ventricular septum.<\/p>\n The two circulations are:<\/p>\n \n- Pulmonary circulation\n
\n- Blood in the right ventricle is pumped into the pulmonary arteries<\/li>\n
- For oxygenation, these pulmonary arteries transport deoxygenated blood to the lungs<\/li>\n
- The oxygenated blood is then sent to the left atrium from the lungs through the pulmonary veins<\/li>\n
- This type of circulation of blood is referred to as pulmonary circulation where blood is pumped via pulmonary blood vessels.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n
\n- Systemic circulation\n
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