Schooling · Class 9 · Science · Tissues in Action · Chapter on a page
CBSE Class 9 · Science · NCERT Exploration
Tissues in Action: chapter on a page
A cut of Shishya's notes for this chapter: the first paragraph of the introduction and the key ideas, formulas and facts, common mistakes and quick revision lists, word for word. Nothing is added or reworded; the worked examples are left out (they are on the chapter page).
About the notes: Written by Shishya's AI on 26 Sept 2026 from the chapter's title and class level, in Shishya's own words — not a copy or summary of the textbook. Read the official chapter for the book's own text, activities and exercises.
This note's current text has no applied fact-check on record.
Mind map
Drawn from the same notes by a fixed rule (no AI): each label is the item's own words — its bold term, its label before a colon, a short formula as written, or its first words.
The mind map as a list
- Key ideas
- A tissue is a group of cells that…
- Plants have two broad categories of…
- Meristematic tissue is found at root…
- Permanent tissues in plants include…
- Animal tissues are classified into…
- Epithelial tissue covers body…
- Connective tissue (blood, bone…
- Formulas and facts
- Tissue
- Meristematic tissue
- Parenchyma
- Collenchyma
- Sclerenchyma
- Xylem
- Phloem
- Worked examples
- Identifying tissue type from…
- Choosing the correct plant tissue
- Function-based reasoning
- Watch out for
- Confusing xylem and phloem
- Thinking all permanent tissues are…
- Mixing up striated and smooth muscle
- Believing epithelial tissue only…
- Calling blood a liquid rather than a…
What this chapter is about
In Class 8, you studied the cell as the basic unit of life. Now, in Class 9, you learn that cells do not work alone in complex organisms. Cells with similar structure and function group together to form tissues. A tissue is a collection of cells that perform a specific task more efficiently than a single cell could.
Key ideas
- A tissue is a group of cells that have a common origin, similar structure and work together to perform a particular function.
- Plants have two broad categories of tissues: meristematic tissues (cells that divide actively) and permanent tissues (cells that have stopped dividing and have taken up specific roles).
- Meristematic tissue is found at root tips, shoot tips and in the cambium; it helps the plant grow in length and girth.
- Permanent tissues in plants include simple permanent tissues (parenchyma, collenchyma, sclerenchyma) and complex permanent tissues (xylem, phloem).
- Animal tissues are classified into four main types: epithelial, connective, muscular and nervous.
- Epithelial tissue covers body surfaces and lines cavities; its cells fit closely together, offering protection and controlling exchange of materials.
- Connective tissue (blood, bone, cartilage, adipose, areolar) binds, supports and protects other tissues and organs.
- Muscular tissue (striated, smooth, cardiac) contracts to produce movement, while nervous tissue transmits electrical signals for coordination.
Formulas and facts to remember
- Tissue — A group of cells with similar structure and function that work together.
- Meristematic tissue — Plant tissue whose cells divide continuously, found at growing points (apical, lateral, intercalary).
- Parenchyma — Thin-walled, loosely packed cells that store food and allow gas exchange; chlorenchyma contains chloroplasts.
- Collenchyma — Cells with thickened corners providing flexibility and mechanical support in young stems.
- Sclerenchyma — Cells with thick, lignified walls that are often dead at maturity; provide rigidity (fibres, sclereids).
- Xylem — Complex tissue that transports water and minerals upward; consists of vessels, tracheids, xylem parenchyma, xylem fibres.
- Phloem — Complex tissue that transports food (prepared by leaves) to all parts; consists of sieve tubes, companion cells, phloem parenchyma, phloem fibres.
- Epithelial tissue — Forms protective coverings; types include squamous, cuboidal, columnar and ciliated, depending on cell shape.
- Connective tissue — Has cells scattered in an extracellular matrix; examples are blood, bone, cartilage, adipose tissue.
- Striated (skeletal) muscle — Voluntary, shows dark and light bands, attached to bones.
- Smooth muscle — Involuntary, spindle-shaped cells, found in the walls of stomach, intestines and blood vessels.
- Cardiac muscle — Involuntary, branched, found only in the heart, contracts rhythmically throughout life.
- Nervous tissue — Made of neurons; transmits impulses for rapid communication between body parts.
Common mistakes
- Confusing xylem and phloem → Remember: xylem carries water upward, phloem carries food in both directions; xylem cells are mostly dead, phloem sieve tubes are living.
- Thinking all permanent tissues are dead → Parenchyma and phloem have living cells; only sclerenchyma and mature xylem vessels are dead.
- Mixing up striated and smooth muscle → Striated muscle shows bands and is voluntary (skeletal); smooth muscle has no bands and is involuntary (internal organs).
- Believing epithelial tissue only protects skin → Epithelium also lines the mouth, intestines, blood vessels and respiratory tract.
- Calling blood a liquid rather than a tissue → Blood is connective tissue; its matrix (plasma) is liquid, and it contains cells (RBCs, WBCs, platelets).
Quick revision
- Tissue = cells with similar structure and function working together.
- Meristematic tissue divides; permanent tissue is specialised and usually does not divide.
- Xylem moves water up; phloem moves food to where it is needed.
- Epithelial tissue covers surfaces; connective tissue binds and supports.
- Skeletal muscle is voluntary; smooth and cardiac muscles are involuntary.
- Neurons in nervous tissue transmit electrical impulses for coordination.