Class 11 Biology Chapter 15 Body Fluids and Circulation – Revision Notes

Quick revision notes for Class 11 Biology Chapter 15 (Body Fluids and Circulation). These Class 11 Biology Chapter 15 notes are ideal for quick revision just before exams.

Blood

• Plasma + formed elements (RBC, WBC, platelets).
• ABO and Rh blood group systems.
• Clotting: fibrinogen → fibrin (via thrombin).

Lymph

• Derived from plasma; fat absorption, immune defence.

Heart

• 4-chambered; myogenic beat via SA node (pacemaker).
• Cardiac cycle: systole/diastole; “lub-dub” from valve closure.

BP and ECG

• Normal BP ~120/80 mmHg.
• ECG: P wave (atrial), QRS (ventricular depolarization), T wave (ventricular repolarization).

One-Line Summary

Blood and lymph circulate through the body via the four-chambered, myogenically-beating heart, with the SA node as pacemaker, transporting gases, nutrients, and immune cells while blood group compatibility governs safe transfusion.

Written by Satish

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