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Body Fluids and Circulation - Composition of blood, blood groups, coagulation of blood

Grade 11CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Blood is a fluid connective tissue consisting of plasmaplasma (55%55\%) and formed elements (45%45\%).

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Plasma contains 90−92%90-92\% water and 6−8%6-8\% proteins such as FibrinogenFibrinogen (clotting), GlobulinsGlobulins (defense mechanisms), and AlbuminsAlbumins (osmotic balance).

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Erythrocytes (RBCs) contain HemoglobinHemoglobin, a complex protein with Fe2+Fe^{2+} ions. A healthy adult has 12−1612-16 g of hemoglobin per 100100 mL of blood.

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Leucocytes (WBCs) are divided into Granulocytes (NeutrophilsNeutrophils, EosinophilsEosinophils, BasophilsBasophils) and Agranulocytes (LymphocytesLymphocytes, MonocytesMonocytes).

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The ABO blood grouping is based on the presence or absence of two surface antigens on RBCs, namely AA and BB.

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The RhRh antigen is present in nearly 80%80\% of humans (Rh+veRh^{+v e}). RhRh incompatibility between an Rh−veRh^{-v e} mother and Rh+veRh^{+v e} fetus can cause Erythroblastosis foetalisErythroblastosis\ foetalis.

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Coagulation is a cascade process involving the conversion of soluble FibrinogenFibrinogen to insoluble FibrinFibrin threads by the enzyme ThrombinThrombin.

📐Formulae

Serum=Plasma−Clotting Factors\text{Serum} = \text{Plasma} - \text{Clotting Factors}

Prothrombin→Thrombokinase+Ca2+Thrombin\text{Prothrombin} \xrightarrow{\text{Thrombokinase} + Ca^{2+}} \text{Thrombin}

Fibrinogen→ThrombinFibrin\text{Fibrinogen} \xrightarrow{\text{Thrombin}} \text{Fibrin}

Total RBC count≈5×106 to 5.5×106 per mm3\text{Total RBC count} \approx 5 \times 10^6 \text{ to } 5.5 \times 10^6 \text{ per } mm^3

💡Examples

Problem 1:

Calculate the amount of Hemoglobin in a patient if they have 55 Litres of blood and their concentration is 1414 g per 100100 mL.

Solution:

Total Hemoglobin = 14 g100 mL×5000 mL=700\frac{14 \text{ g}}{100 \text{ mL}} \times 5000 \text{ mL} = 700 g.

Explanation:

To find the total mass, the concentration (g/100mL) is multiplied by the total volume of blood in the same units (mL).

Problem 2:

An individual has blood group ABAB. Identify the antigens on their RBCs and the antibodies in their plasma.

Solution:

Antigens: AA and BB; Antibodies: None.

Explanation:

In ABAB blood group, both surface antigens AA and BB are present, which is why the plasma contains no antibodies against them (anti−Aanti-A or anti−Banti-B), making them universal recipients.

Problem 3:

What is the role of Ca2+Ca^{2+} in a blood injury site?

Solution:

Ca2+Ca^{2+} ions act as a cofactor for the activation of ThrombokinaseThrombokinase and the subsequent conversion of ProthrombinProthrombin to ThrombinThrombin.

Explanation:

Calcium ions (Ca2+Ca^{2+}) are essential for multiple steps in the blood coagulation cascade; without them, the clot cannot form efficiently.