Body Systems

Overview

Body Systems is a core topic in the Environmental Studies (EVS) section of MAHA TET Paper I. This topic tests your understanding of how the human body functions through its five major organ systems: digestive, respiratory, circulatory, nervous, and excretory. For primary-level teaching, you must know the basic organs, their functions, and how these systems work together to keep the body alive and healthy.

Questions typically ask about organ identification, system functions, and simple cause-effect relationships (e.g., "What happens to food in the stomach?" or "Which organ pumps blood?"). Expect 2–4 questions from this topic. Mastery requires knowing organ names, their locations, their primary functions, and the correct sequence of processes within each system.

Key Concepts

• **System interdependence**: No system works alone. The circulatory system delivers oxygen (from respiratory) and nutrients (from digestive) to all cells, while the excretory system removes wastes produced by all systems.

• **Digestive system converts food to nutrients**: Food undergoes mechanical breakdown (chewing, churning) and chemical breakdown (enzymes, acids) to produce absorbable nutrients.

• **Respiratory system enables gas exchange**: Oxygen enters the blood and carbon dioxide exits at the alveoli in the lungs through diffusion.

• **Circulatory system is the transport network**: Blood carries oxygen, nutrients, hormones, and waste products; the heart is the pump; arteries carry blood away from the heart, veins carry blood toward it.

• **Nervous system controls and coordinates**: The brain processes information, the spinal cord relays messages, and nerves connect to every body part for sensation and movement.

• **Excretory system removes metabolic waste**: Kidneys filter blood to produce urine; skin removes some waste through sweat; lungs excrete carbon dioxide.

• **Organs have specialised structures**: Villi in the small intestine increase absorption area; alveoli in lungs increase gas exchange area; nephrons in kidneys filter blood.

Formulas / Key Facts

| System | Main Organs | Primary Function | |--------|-------------|------------------| | Digestive | Mouth, oesophagus, stomach, small intestine, large intestine, liver, pancreas | Break down food, absorb nutrients | | Respiratory | Nose, trachea (windpipe), bronchi, lungs, alveoli | Gas exchange — O₂ in, CO₂ out | | Circulatory | Heart, arteries, veins, capillaries, blood | Transport nutrients, oxygen, waste | | Nervous | Brain, spinal cord, nerves | Control, coordination, response | | Excretory | Kidneys, ureters, bladder, urethra, skin, lungs | Remove waste from body |