Structural Organisation in Animals

Quick Recall Box

• The human body is composed of approximately 37.2 trillion cells.
• Cells are the basic structural and functional units of living organisms.
• Tissues are groups of similar cells that work together to perform specific functions.
• Organs are structures composed of two or more types of tissues that work together to perform specific functions.
• Organ systems are groups of organs that work together to maintain homeostasis and overall health.
• The human body is composed of 11 major organ systems.

Table of Contents

1. Introduction to Structural Organisation in Animals
2. Why This Chapter Matters
3. Ayush's Note
4. Core Concepts
5. Shortcut Formula / Trick
6. Trap Questions / Exceptions
7. Practice MCQs
8. Related Notes Links
9. Last Updated Date

Introduction to Structural Organisation in Animals

Structural organisation in animals refers to the way in which cells, tissues, organs, and organ systems are arranged and function together to maintain homeostasis and overall health. The human body is composed of approximately 37.2 trillion cells, which are the basic structural and functional units of living organisms. These cells are organised into tissues, which are groups of similar cells that work together to perform specific functions. Tissues are then organised into organs, which are structures composed of two or more types of tissues that work together to perform specific functions. Finally, organs are organised into organ systems, which are groups of organs that work together to maintain homeostasis and overall health.

Why This Chapter Matters

This chapter is crucial for students preparing for the JEE and NEET exams, as it provides a foundation for understanding the structure and function of the human body. In the JEE Mains 2025 Session 1, 3 questions came from this topic, highlighting its importance. Additionally, understanding the structural organisation of the human body is essential for careers in medicine, research, and healthcare.

Ayush's Note

Core Concepts

Cell Structure

The cell is the basic structural and functional unit of living organisms. It is composed of several organelles, including the nucleus, mitochondria, and ribosomes. The nucleus contains the cell's genetic material, while the mitochondria generate energy for the cell through cellular respiration. The ribosomes are responsible for protein synthesis.

Tissue Organisation

Tissues are groups of similar cells that work together to perform specific functions. There are four primary types of tissues: epithelial, connective, muscle, and nervous tissue. Epithelial tissue forms the lining of organs and glands, while connective tissue provides support and structure to the body. Muscle tissue is responsible for movement, and nervous tissue transmits and processes information.

Organ Structure

Organs are structures composed of two or more types of tissues that work together to perform specific functions. Examples of organs include the heart, lungs, liver, and kidneys. Each organ has a unique structure and function that contributes to the overall health and well-being of the individual.

Organ System Structure

Organ systems are groups of organs that work together to maintain homeostasis and overall health. The human body is composed of 11 major organ systems, including the circulatory, respiratory, digestive, and nervous systems. Each organ system has a unique function and plays a critical role in maintaining the body's overall health.

Shortcut Formula / Trick

One shortcut formula that can be used to remember the different types of tissues is the acronym "ECMN", which stands for Epithelial, Connective, Muscle, and Nervous tissue.

Trap Questions / Exceptions

• What is the main function of the epithelial tissue? Wrong answer: To provide support and structure to the body. Right answer: To form the lining of organs and glands. Why students get it wrong: Epithelial tissue is often confused with connective tissue, which provides support and structure to the body.
• What is the primary function of the nervous tissue? Wrong answer: To transmit and process information. Right answer: To transmit and process information, as well as to control and coordinate the body's functions. Why students get it wrong: Nervous tissue is often underestimated, and its role in controlling and coordinating the body's functions is overlooked.

Practice MCQs

1. What is the basic structural and functional unit of living organisms? A) Cell B) Tissue C) Organ D) Organ system Answer: A) Cell
2. Which type of tissue forms the lining of organs and glands? A) Epithelial tissue B) Connective tissue C) Muscle tissue D) Nervous tissue Answer: A) Epithelial tissue
3. What is the primary function of the circulatory system? A) To transmit and process information B) To provide support and structure to the body C) To maintain homeostasis and overall health D) To transport oxygen and nutrients to cells Answer: D) To transport oxygen and nutrients to cells
4. Which organ system is responsible for controlling and coordinating the body's functions? A) Nervous system B) Circulatory system C) Respiratory system D) Digestive system Answer: A) Nervous system
5. What is the main function of the liver? A) To filter waste and toxins from the blood B) To produce bile and digestive enzymes C) To store glycogen and regulate blood sugar levels D) To produce antibodies and activate immune responses Answer: B) To produce bile and digestive enzymes

Related Notes Links

• Human Physiology Notes
• Cell Biology Notes

Last Updated Date

Last Updated: March 16, 2026

This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.