Human Body Systems

Overview

Human Body Systems is a core topic in the Science section of CG TET Paper II, targeting teachers for classes VI–VIII. This topic tests your understanding of how the major organ systems work individually and coordinate to maintain life. Questions typically focus on organs involved, their functions, sequence of processes, and common disorders.

For CG TET, expect 3–5 questions from this topic. Examiners frequently ask about the path of food/blood/air through the body, names of organs and their specific roles, and differences between related concepts (arteries vs veins, voluntary vs involuntary actions). A clear mental map of each system's structure and function is essential.

Mastering this topic also helps in the pedagogy section, as you may need to explain how to teach body systems using models, charts, or activity-based methods to upper primary students.

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Key Concepts

• **Digestive System** breaks down food into absorbable nutrients through mechanical (chewing, churning) and chemical (enzymes, acids) digestion.

• **Respiratory System** facilitates gas exchange—oxygen enters the blood and carbon dioxide is expelled—primarily through the lungs and alveoli.

• **Circulatory System** is a transport network where the heart pumps blood through arteries, veins, and capillaries to deliver oxygen and nutrients while removing waste.

• **Nervous System** controls and coordinates body activities through electrical signals; divided into Central Nervous System (brain, spinal cord) and Peripheral Nervous System.

• **Reproductive System** ensures continuation of species; involves production of gametes (sperm and ova) and, in females, supports development of the embryo.

• **Homeostasis** is the body's ability to maintain a stable internal environment through the coordinated action of all systems.

• **Reflex Action** is an automatic, rapid response to a stimulus that does not involve conscious thought (e.g., pulling hand from hot object).

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Formulas / Key Facts

### Digestive System | Organ | Function | |-------|----------| | Mouth | Mechanical breakdown; salivary amylase acts on starch | | Oesophagus | Pushes food to stomach via peristalsis | | Stomach | Gastric juice (HCl + pepsin) digests proteins | | Small Intestine | Complete digestion; absorption through villi | | Large Intestine | Absorbs water; forms faeces | | Liver | Produces bile (emulsifies fats) | | Pancreas | Secretes pancreatic juice (trypsin, lipase, amylase) |

### Respiratory System