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๐ฌ Think about it
You started life as a single cell. That one cell divided again and again to make your skin, muscles, bones and nerves. Scientists call this one of nature's greatest engineering marvels. Let us see how cells team up to build a whole body.
What is a tissue?
- A tissue is a group of cells similar in structure.
- These cells work together to perform a specific function.
- In multicellular bodies, different cell groups do different jobs.
Example:
Muscle tissue lets you move; nervous tissue carries messages.
How is the body organised, from cell to organism?
- Similar cells form a tissue.
- More than one type of tissue forms an organ.
- Different organs form an organ system.
- Organ systems together form an organism.
From a Cell to an Organism
Cell
↓
Tissue
Similar cells doing one job.
↓
Organ
More than one tissue together.
↓
Organ system
Different organs working together.
↓
Organism
What is division of labour, and why does it help?
- Different tissues take up different jobs.
- This sharing of work is called division of labour.
- It makes the body more efficient.
- It lets the body carry out complex life processes.
Example:
In a unicellular amoeba one cell does everything; in us, each tissue has its own task.
Important Points
- A tissue is a group of similar cells with one function.
- The order of organisation is cell → tissue → organ → organ system → organism.
- Division of labour among tissues makes the body efficient.
๐ญ Think It Over
-
How is the study of cells and tissues significant for understanding the life processes and human welfare?
It helps us understand growth and repair, and lets scientists grow tissues to treat disease and improve crops. -
How are tissues in plants and animals different, and why?
Plant tissues give support and help fixed plants grow; animal tissues allow movement, since animals move about. -
How is the division of labour at various levels of organisation in multicellular organisms correlated with their structure and function?
Each tissue's structure suits its job, so sharing work between specialised tissues makes the whole body work better.
โ Test Yourself
-
What is a tissue?
View Answer
A group of similar cells that work together to do one specific job. -
Put these in order: organ, cell, organism, tissue, organ system.
View Answer
Cell → tissue → organ → organ system → organism. -
What is division of labour?
View Answer
Different tissues doing different jobs, which makes the body efficient. -
How does an amoeba differ from us in division of labour?
View Answer
One amoeba cell does all jobs; in us each tissue has its own task.
Important Definitions
- Tissue — a group of cells similar in structure that work together to perform a specific function.
- Organ — a structure made of more than one type of tissue.
- Organ system — different organs working together.
- Division of labour — the sharing of different jobs among different tissues, which raises efficiency.
