Unit 2: Body Fluids, Circulation, Digestion & Respiration

February 16, 2026

Semester 1
BP106RBT

Unit 2: Body Fluids, Circulation, Digestion & Respiration

Unit 2 delves into Human Physiology. it covers the life-sustaining fluids (Blood & Lymph), the pump that drives them (Heart/Circulation), the engine that fuels the body (Digestion), and the system that provides oxygen (Respiration). Mastering these systems is crucial as many drugs target receptors within these very pathways.
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Syllabus & Topics

  • 1Body fluids and circulation: Composition of blood, blood groups, coagulation of blood
  • 2Composition and functions of lymph
  • 3Human circulatory system: Structure of heart and blood vessels
  • 4Cardiac cycle, cardiac output and ECG
  • 5Digestion and Absorption: Alimentary canal and digestive glands
  • 6Role of digestive enzymes
  • 7Digestion, absorption and assimilation of digested food
  • 8Breathing and respiration: Respiratory system, Mechanism of breathing
  • 9Exchange of gases, transport of gases and regulation of respiration
  • 10Respiratory volumes

Learning Objectives

Explain the composition and functions of blood and lymph.
Describe the structure and functioning of the human heart.
Trace the path of food through the digestive tract and its breakdown.
Understand the mechanism of gas exchange in the lungs.
Define vital capacity and other respiratory volumes.

Frequently Asked Questions (FAQs)

Q1. What is the function of Lymph?

Lymph helps maintain fluid balance, transports fats from the digestive system, and plays an important role in immunity by carrying white blood cells throughout the body.

Q2. Describe the Cardiac Cycle.

The cardiac cycle is the sequence of events occurring during one heartbeat. It includes systole (contraction) and diastole (relaxation) of the atria and ventricles.

Q3. Role of Digestive Enzymes?

Digestive enzymes such as amylase, pepsin, and lipase break down complex food components—carbohydrates, proteins, and fats—into simpler forms that can be easily absorbed by the body.

Q4. Mechanism of Breathing?

Breathing consists of two phases:

  1. Inspiration

    • Diaphragm contracts

    • Chest cavity expands

  2. Expiration

    • Diaphragm relaxes

    • Chest cavity contracts

This process is controlled by pressure differences between the lungs and the atmosphere.

Q5. What is ECG?

ECG (Electrocardiogram) is a graphical recording of the electrical activity of the heart. It is commonly used to diagnose cardiac disorders such as arrhythmias and myocardial damage.