Case Study Questions Class 11 Biology Chapter 18 Body Fluids and Circulation
CBSE Class 11 Case Study Questions Biology Body Fluids and Circulation. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Body Fluids and Circulation.
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CBSE Case Study Questions Class 11 Biology Body Fluids and Circulation
CASE 1
Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements. Plasma is a straw coloured, viscous fluid constituting nearly 55 per cent of the blood. 90-92 per cent of plasma is water and proteins contribute 6-8 per cent of it. Fibrinogen, globulins and albumins are the major proteins. Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defence mechanisms of the body and the albumins help in osmotic balance. Plasma also contains small amounts of minerals like Na+, Ca++, Mg++, HCO3 –, Cl–, etc. Glucose, amino acids, lipids, etc., are also present in the plasma as they are always in transit in the body. Factors for coagulation or clotting of blood are also present in the plasma in an inactive form. Plasma without the clotting factors is called serum.
Erythrocytes, leucocytes and platelets are collectively called formed elements and they constitute nearly 45 per cent of the blood.
Erythrocytes or red blood cells (RBC) are the most abundant of all the cells in blood. A healthy adult man has, on an average, 5 million to 5.5 million of RBCs mm–3 of blood. RBCs are formed in the red bone marrow in the adults. RBCs are devoid of nucleus in most of the mammals and are biconcave in shape. They have a red coloured, iron containing complex protein called haemoglobin, hence the colour and name of these cells. A healthy individual has 12-16 gms of haemoglobin in every 100 ml of blood. These molecules play a significant role in transport of respiratory gases. RBCs have an average life span of 120 days after which they are destroyed in the spleen (graveyard of RBCs).
Leucocytes are also known as white blood cells (WBC) as they are colourless due to the lack of haemoglobin. They are nucleated and are relatively lesser in number which averages 6000-8000 mm–3 of blood. Leucocytes are generally short lived. We have two main categories of WBCs – granulocytes and agranulocytes. Neutrophils, eosinophils and basophils are different types of granulocytes, while lymphocytes and monocytes are the agranulocytes. Neutrophils are the most abundant cells (60-65 per cent) of the total WBCs and basophils are the least (0.5-1 per cent) among them. Neutrophils and monocytes (6-8 per cent) are phagocytic cells which destroy foreign organisms entering the body. Basophils secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions. Eosinophils (2-3 per cent) resist infections and are also associated with allergic reactions. Lymphocytes (20-25 per cent) are of two major types – ‘B’ and ‘T’ forms. Both B and T lymphocytes are responsible for immune responses of the body.
Platelets also called thrombocytes, are cell fragments produced from megakaryocytes (special cells in the bone marrow). Blood normally contains 1,500,00-3,500,00 platelets mm–3. Platelets can release a variety of substances most of which are involved in the coagulation or clotting of blood. A reduction in their number can lead to clotting disorders which will lead to excessive loss of blood from the body.
1.) Identity the correct statement
Statement 1 – Fibrinogens are absent in the plasma.
Statement 2 – Plasma without clotting factors is known as lymph.
Statement 3 – White blood cells are colourless.
Statement 4 –Haemoglobin is present in leucocytes.
a) Statement 1 and 2 are correct
b) Statement 2 and 3 are correct
c) Only Statement 3 is correct
d) All of the above statements are correct
2) ____________________ is iron containing complex protein present in blood
a) Globulins
b) Haemoglobin
c) Fibrinogen
d) Albumins
3.) Give reason – why erythrocytes are known as red blood cells?
4.) Enlist the type of Leucocytes with their categorisation.
5) What if number of thrombocytes are drastically reduced in blood?
Answer key
1.) c
2.) b
3.) Erythrocytes have a red coloured, iron containing complex protein named as haemoglobin. Haemoglobin gives the red colour to the Erythrocytes, hence the colour and name of these cells is Red Blood Cells.
4.) Leucocytes are also known as white blood cells. Leucocytes are categorised into two main categories of WBCs – granulocytes and agranulocytes.
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- Granulocytes – Neutrophils, eosinophils and basophils are different types of granulocytes.
- Granulocytes – Lymphocytes and monocytes are the agranulocytes.
5.) Platelets release a variety of substances which are involved in the coagulation or clotting of blood. A reduction in their number can lead to clotting disorders which will lead to excessive loss of blood from the body.
CASE 2
Blood of human beings differ in certain aspects. Various types of grouping of blood has been done. The ABO and Rh – are widely used all over the world.
ABO grouping is based on the presence or absence of two surface antigens (chemicals that can induce immune response) on the RBCs namely A and B. Similarly, the plasma of different individuals contain two natural antibodies (proteins produced in response to antigens). The distribution of antigens and antibodies in the four groups of blood, A, B, AB and O are given in Table.
From the above mentioned table it is evident that group ‘O’ blood can be donated to persons with any other blood group and hence ‘O’ group individuals are called ‘universal donors’. Persons with ‘AB’ group can accept blood from persons with AB as well as the other groups of blood. Therefore, such persons are called ‘universal recipients’.
Another antigen, the Rh antigen similar to one present in Rhesus monkeys (hence Rh), is also observed on the surface of RBCs of majority (nearly 80 per cent) of humans. Such individuals are called Rh positive (Rh+ve) and those in whom this antigen is absent are called Rh negative (Rh-ve). An Rh-ve person, if exposed to Rh+ve blood, will form specific antibodies against the Rh antigens. Therefore, Rh group should also be matched before transfusions. A special case of Rh incompatibility (mismatching) has been observed between the Rh-ve blood of a pregnant mother with Rh+ve blood of the foetus. Rh antigens of the foetus do not get exposed to the Rh-ve blood of the mother in the first pregnancy as the two bloods are well separated by the placenta. However, during the delivery of the first child, there is a possibility of exposure of the maternal blood to small amounts of the Rh+ve blood from the foetus. In such cases, the mother starts preparing antibodies against Rh antigen in her blood. In case of her subsequent pregnancies, the Rh antibodies from the mother (Rh-ve) can leak into the blood of the foetus (Rh+ve) and destroy the foetal RBCs. This could be fatal to the foetus or could cause severe anaemia and jaundice to the baby. This condition is called erythroblastosis foetalis. This can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the first child.
1.) Identify the incorrect statement
Statement 1 – Antigens are chemicals that can induce immune response.
Statement 2 – Antibodies are proteins produced in response to antigens.
Statement 3 – Blood group ‘O’ individuals are called as ‘universal donors’.
Statement 4 – Antibodies are proteins produced by antigen.
a) Statement 1 and 2 are incorrect
b) Statement 2 and 3 are incorrect
c) Only Statement 3 is incorrect
d) All of the above are incorrect
2.) _________________ indicates presence of both antigen A and antigen B on RCBs.
a) Blood group A
b) Blood group AB
c) Blood group B
d) Blood group O
3.) Enlist the names of different blood groups proposed by the ABO blood grouping system.
4.) Give reason –why persons with O blood group are known as universal donors?
5.) Give reason – why person with the blood group AB is called as universal recipient?
6.) What is mean by erythroblastosis foetalis?
Answer key
1.) c
2) b
3.) Different blood groups proposed by ABO blood grouping system are A, B, AB and O.
4.) Peron with Blood group O are known as the universal donors, because they lack antigens on the surface of their RBCs and hence, their blood can be used to carry out blood transfusions.
5.) A person who has group AB blood is able to receive blood from a person with any other blood type – A, B or O. Group AB blood contains red blood cells that have both antigens A and B and thus does not have reactive antibodies in its plasma to these antigens, which are found in some other blood types. Because of its ability to receive blood from different types blood groups, blood group AB is called universal recipient.
6.) Erythroblastosis foetalis is case of Rh incompatibility or mismatching has been observed between the Rh-ve bloods of a pregnant mother with Rh+ve blood of the foetus.
Rh antigens of the foetus not get exposed to the Rh-ve blood of the mother in the first pregnancy as the two bloods are separated by the placenta. However, during the delivery of the first child, there is a possibility of exposure of the maternal blood to small amounts of the Rh+ve blood from the foetus. In such cases, the mother starts preparing antibodies against Rh antigen in her blood. In case of her subsequent pregnancies, the Rh antibodies from the mother (Rh-ve) can leak into the blood of the foetus (Rh+ve) and destroy the foetal RBCs. This could be life threatening to the foetus or could cause severe anaemia and jaundice to the baby. This condition is called erythroblastosis foetalis.
CLASS 3
Human circulatory system, also called the blood vascular system consists of a muscular chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated.
Heart, the mesodermally derived organ, is situated in the thoracic cavity, in between the two lungs, slightly tilted to the left. It has the size of a clenched fist. It is protected by a double walled membranous bag, pericardium, enclosing the pericardial fluid. Our heart has four chambers, two relatively small upper chambers called atria and two larger lower chambers called ventricles. A thin, muscular wall called the interatrial septum separates the right and the left atria, whereas a thick-walled, the inter-ventricular septum, separates the left and the right ventricles. The atrium and the ventricle of the same side are also separated by a thick fibrous tissue called the atrio-ventricular septum. However, each of these septa are provided with an opening through which the two chambers of the same side are connected. The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve, whereas a bicuspid or mitral valve guards the opening between the left atrium and the left ventricle. The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are provided with the semilunar valves. The valves in the heart allows the flow of blood only in one direction, i.e., from the atria to the ventricles and from the ventricles to the pulmonary artery or aorta. These valves prevent any backward flow.
The entire heart is made of cardiac muscles. The walls of ventricles are much thicker than that of the atria. A specialised cardiac musculature called the nodal tissue is also distributed in the heart. A patch of this tissue is present in the right upper corner of the right atrium called the sino-atrial node (SAN). Another mass of this tissue is seen in the lower left corner of the right atrium close to the atrio-ventricular septum called the atrio-ventricular node (AVN). A bundle of nodal fibres, atrio-entricularpulm bundle (AV bundle) continues from the AVN which passes through the atrio-ventricular septa to emerge on the top of the interventricular septum and immediately divides into a right and left bundle. These branches give rise to minute fibres throughout the ventricular musculature of the respective sides and are called purkinje fibres. The nodal musculature has the ability to generate action potentials without any external stimuli, i.e., it is autoexcitable. However, the number of action potentials that could be generated in a minute vary at different parts of the nodal system. The SAN can generate the maximum number of action potentials, i.e., 70-75 min–1, and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. Our heart normally beats 70-75 times in a minute (average 72 beats min–1). ____________________ is the double walled membranous structure with the protective function.
a) Meninges
b) Pleura
c) Pericardium
d) Peritoneum
2.) _______________ is the patch of tissue present in the right upper corner of the right atrium.
a.) sino-atrial node
b.) sino-atrial septa
c.) atrio-ventricular node
d.) atrio-ventricular septa
3.) How many chambers are present in human heart? Name the chamber of heart?
4.) Give the name of valve present in between the left auricle and left ventricle?
5.) Give reason – why sino-atrial node is called as pacemaker of our heart?
Answer key
1.) c
2.) a
3.) Human heart has four chambers – two atria and two ventricles.
- The upper chambers are called the left and right atria.
- The lower chambers are called the left and right ventricles.
4.) The Bicuspid or mitral valve present in between the left auricle and left ventricle.
5.) The SA node is located in the wall of right auricle slightly below the opening of the superior vena cava. It has a unique property of self-excitation which enables it to act as the pacemaker of the heart. It spontaneously initiates a wave of contraction which spreads over both the auricles more or less simultaneously along the muscle fibres.
CLASS 4
Electro-cardiograph is used to obtain an electrocardiogram (ECG). ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle. To obtain a standard ECG, a patient is connected to the machine with three electrical leads (one to each wrist and to the left ankle) that continuously monitor the heart activity. For a detailed evaluation of the heart’s function, multiple leads are attached to the chest region.
Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity of the heart.
The P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria.
The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole.
The T-wave represents the return of the ventricles from excited to normal state (repolarisation). The end of the T-wave marks the end of systole. Obviously, by counting the number of QRS complexes that occur in a given time period, one can determine the heart beat rate of an individual. Since the ECGs obtained from different individuals have roughly the same shape for a given lead configuration, any deviation from this shape indicates a possible abnormality or disease. Hence, it is of a great clinical significance.
1.) Identify the correct statement
Statement 1 – T-wave represents the return of the ventricles from excited to normal state.
Statement 2 – P-wave represents the electrical excitation of the atria.
Statement 3 – QRS complex represents repolarisation.
Statement 4 – T-wave represents the return of the ventricles from normal to excited state.
a) Statement 1 and 2 are correct
b) Statement 2 and 3 are correct
c) Statement 3 and 4 are correct
d) All of the above statements are correct.
2.) _________________ represents the depolarisation of the ventricles.
a) P-wave
b) QRS complex
c) T-wave
d) ST-segment
3.) What represents the repolarisation of the ventricles?
4.) What is depolarisation of atria?
5) What represents the end of systole?
Answer key
1) a
2) b
3.) T-wave represents the return of the ventricles from excited to normal state i.e. repolarisation.
4.) Depolarisation of atria is electrical excitation of the atriawhich leads to the contraction of both the atria. It is represented by P-wave.
5) The end of the T-wave marks the end of systole. by counting the number of QRS complexes that occur in a given time period.
CASE 5
Disorders of circulatory system
High Blood Pressure (Hypertension) – Hypertension is the term for blood pressure that is higher than normal (120/80). In this measurement 120 mm Hg (millimetres of mercury pressure) is the systolic, or pumping, pressure and 80 mm Hg is the diastolic, or resting, pressure. If repeated checks of blood pressure of an individual is 140/90 (140 over 90) orhigher, it shows hypertension. High blood pressure leads to heart diseases and also affects vital organs like brain and kidney.
Coronary Artery Disease (CAD) – Coronary Artery Disease, often referred to as atherosclerosis, affects the vessels that supply blood to the heart muscle. It is caused by deposits of calcium, fat, cholesterol and fibrous tissues, which makes the lumen of arteries narrower.
Angina – It is also called ‘angina pectoris’. A symptom of acute chest pain appears when no enough oxygen is reaching the heart muscle. Angina can occur in men and women of any age but it is more common among the middle-aged and elderly. It occurs due to conditions that affect the blood flow.
Heart Failure – Heart failure means the state of heart when it is not pumping blood effectively enough to meet the needs of the body. It is sometimes called congestive heart failure because congestion of the lungs is one of the main symptoms of this disease. Heart failure is not the same as cardiac arrest (when the heart stops beating) or a heart attack (when the heart muscle is suddenly damaged by an inadequate blood supply).
1.) ______________ is the normal pumping blood pressure.
a) 120mm Hg
b) 104mm Hg
c) 80mm Hg
d) 90mm Hg
2.) ______________ is the normal resting blood pressure.
a) 120mm Hg
b) 104mm Hg
c) 80mm Hg
d) 90mm Hg
3.) What is difference between heart attack and Cardiac arrest?
4.) What is Angina?
4.) What is normal range of systolic and diastolic blood pressure in healthy individual?
Answer key
1.) a
2.) c
3.) Cardiac arrest is condition in which heart stops beating suddenly.
Heart attack is condition in which the heart muscle is suddenly damaged by an inadequate blood supply.
4) Angina is a symptom of acute chest pain appears when enough oxygen supply is not reaching the heart muscle
5) Normal range of systolic and diastolic blood pressure in healthy individual
- Normal pumping or systolic blood pressure is less than 120 mm Hg
- Normal resting or diastolic blood pressure is less than 80 mm Hg