Organ and Organ System
உறுப்பு மற்றும் உறுப்பு மண்டலம்
Do not confuse 'tissue' with 'organ'. A tissue is a cellular aggregate; an organ is a functional unit with a defined shape and specific physiological role. If you cannot distinguish the hierarchy, you will lose marks on the structural organization questions.
The idea
Tissues organize to form organs, and two or more organs performing a common function form an organ system. This hierarchy ensures efficient and coordinated activities of millions of cells.
Why it matters
It exists to facilitate division of labour, allowing the body to survive and function as a whole through coordinated physiological processes.
NEET lens
NCERT defines an organ as a structure where tissues are organized in specific proportions and patterns. When two or more organs coordinate to perform a common function, they constitute an organ system. Remember: this hierarchy is essential for the division of labor in complex multicellular organisms.
Introduction
An organ is a structure made of two or more tissues working together to perform a specific function. An organ system is a group of organs performing a related set of functions.
Core concept
Organ examples: heart (cardiac muscle + connective + epithelial + nervous tissues), leaf (epidermis + mesophyll + vascular). Organ systems: digestive (mouth, esophagus, stomach, intestines), circulatory (heart, vessels, blood), nervous, excretory, etc.
Go deeper
Hierarchy of organization: Cells → Tissues → Organs → Organ Systems → Organism. Each level adds more complexity and functional integration. Some organisms lack organ systems (flatworms have organs but no true systems).
From Class 10
Tissues form organs, and organs work together in systems. Let's define organ and organ system precisely.