Tissues-Notes 9th-Grade, Study notes of Biology

Download Tissues-Notes 9th-Grade and more Study notes Biology in PDF only on Docsity!

TISSUES

made with

Shobhit Nirwan B e s t H a n d w r i t t e n N o t e s C L A S S 9 t h

We know that all living organisms are composed of cells. Types of Cells Unicellular In unicellular organisms, a single cell performs all the functions. Eg- Amoeba Multicellular In multicellular organisms, there are millions of cells specialised to carry on a specific task. Eg- Human Being Cells specialised to perform a specific functions are grouped together to form a ‘cluster’. This cluster of cells is called tissue. #Kitaabi Definition: A group of cell that are similar in structure and as work together to achieve a particular function forms a tissue L.P. 1- What is tissue? Ans- A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue. L.P. 2- What is the utility of tissue in multi-cellular organisms. Ans- 1. They provide defined structure.

2. They provide mechanical strength.
3. They facilitate division of labor. [ NCERT Intext Pg61 ] Plant Tissues Cells specialised to perform a specific functions in plants are plant tissues. Characteristics of plant tissues:
4. Growth in plants occurs only in certain specific regions, this is due to dividing tissues located at the points.
5. These dividing tissues are also called meristematic tissues.
6. When the meristematic tissues takes up a specific role and lose the ability to divide - they form a specific type of permanent tissues.

-....--- -------- ~ -^ - i

I (^) I^ Y I (^) I I I (^) I I I I (^) I I I I (^) I I I (^) I^ I^ I I (^) I

I

I

• (^) -- ............. -- - (^) - --- I -- (^) -................. - I I I W (^) - -.................... -^ -^ d

19..--

X I (^) I I

I I^ i I I I I (^1) - - -................ - -

Permanent Tissues

The tissues that are completely grown and have lost the ability to divide are known as permanent tissues. This permanent shape, size and function is attained by the process called differentiation. Permanent Tissues Simple Permanent Tissue (^) Complex Permanent Tissue Parenchyma Collenchyma Sclerenchyma (^) Phloem Xylem Simple Permanent Tissue The tissues that are made of one type of cells and are structurally and functionally similar. A) PARENCHYMA Nature:

1. Most common simple permanent tissue
2. The cells are rounded or isodiametric
3. They are living cells.
4. They are generally loosely arranged, thus have large space between them.
5. The cell wall is thin. Occurrence:
6. Widely distributed in plant bodies such as stems, roots, leaves.

7. Found in soft part of plants, i.e. cortex of roots, ground tissues.

S (^) ----! I I I I^ I (^) I I

Function:

1. These tissues generally stores food.
2. Serves as a packing tissue- to fill the spaces between other tissue.
3. Transport of materials occurs through cells or cells wall of parenchyma cells.
4. It stores waste product of plants.
5. It maintains the shape and firmness of plants due to its turgid cells. B) COLLENCHYMA Nature:
6. Collenchyma tissue also consists of living cells.
7. Intercellular spaces are generally absent.
8. The cells are elongated in shape.
9. They often contain four chloroplasts. Occurrence:
10. Cells are located below the epidermis of dicotyledon stem and petiole.
11. The cells also occur in the midribs of dicot leaves. Function:
12. It provides mechanical support and elasticity.
13. It allows easy bending in various parts of a plant without actually breakng it.
14. When cells of collenchyma contain same chloroplast, they manufacture sugar and starch. (C) SCLERENCHYMA Nature:
15. They are dead cells and are devoid of protoplasm.
16. The cell walls of sclerenchyma are greatly thickened of lignin.
17. The cell of sclerenchyma are closely packed without intercellular spaces.

(B) Cork (or phellem):

1. It is a protective tissue found in the outer bark of woody plants, particularly in trees with secondary growth.
2. It is a dead, water-resistant, and durable tissue.
3. It contains a waxy substance called Suberin that makes d the tissue impervious to water and gases, providing excellent protection to plant.

Complex Permanent Tissue

Complex permanent tissues are those that consist of more than one type cells having a common origin. These cells coordinate to perform a common function i.e. to transfer water, mineral salts and food material to various parts of plant body. Xylem Phloem (Transport water) (Transport food)

• Both are conducting tissues.
• They are also called vascular tissues.
• Together both constitutes vascular bundle. XYLEM:

1. It consists of tracheids, vessels, xylem parenchyma and xylem fibres.
2. Tracheids and vessels have tubular structure which allows them to transport water vertically.
3. Xylem parenchyma stores food.
4. Xylem fibres are mainly supportive in nature. I I I I I I I i I I I I I I! 1- (^) - -........ -

PHLOEM:

1. Phloem is made up of five type of cells: sieve cells, sieve tubes, companion cells, phloem fibres and the phloem parenchyma.
2. Sieve tubes are tubular cells with perforated walls.
3. Except phloem fibres, other phloem cells are living cells.
4. Phloem transports food from leaves to other parts of the plant. L.P. 1: Name types of simple tissues? Ans- Parenchyma, Collenchyma and sclerenchyma. L.P. 2: Where is apical meristem found? Ans- They are found at growing tips and roots. L.P. 3: What tissue makes up the husk of coconut? Ans- Husk of coconut is made up of sclerenchyma tissues. L.P. 4: What are the constituents of phloem? Ans- Sieve cells, sieve tube, companion cells, phloem fibres and phloem parenchyma. [ NCERT Intext Pg65 ]

• 3.^ -- ............ - - -

I I I I I I I^ I S I I (^) I I I

I I I I I I I i I I (^) - - -............ - (^) - ↓

1. Covering or protective tissues in the animals are epithelial tissues.
2. It covers most organs and also forms a barrier to keep different body system separate.
3. These are tightly packed and form a continuous sheet.
4. Almost no intercellular space.
5. It has single layer of cells and as a result anything entering or leaving the body must cross atleast one layer of epithelium.
6. The permeability of cells of various epithelia plays an important role in regulating the exchange of materials between the body and external environment and also different parts of body.
7. All epithelium is separated from the underlying tissue by an extra cellular fibrous basement membrane. Basement Membrane: It is a thin, pliable sheet that provides support to tissue as well as supply nutrients and blood to epithelial cells. All epithelial cells are on basement membrane. Epithelial Tissue Simple Squamous Epithelium Stratified squamous epithelium Cuboidal epithelium Columnar (Ciliated) epithelium Epithelial Tissue

--^ i

I I I I "

!

i

I

i

I

---

I I I (^) I

Simple Squamous Epithelium Stratified squamous epithelium

• Cells are arranged in single layer.
• Oesophagus and the lining of mouth.
• Forms delicate lining
  • Cells are arranged in multiple layers.
  • skin
  • Prevents wear and tear. Cuboidal Epithelium: Cells are cube-shaped and are placed on a basement membrane. Location: Lining of kidney tubules as well as in the ducts of the salivary glands. Function: It helps in absorption of useful material from urine before is passed out. Ciliated Columnar Epithelium: In this, cell has hair like projection on the outer surface of epithelial tissue which helps in movement of particle. Location: In respiratory tract, in fallopian tube. Function: It helps in movement of particle. Eg: In respiratory tract, the movement of cilia pushes the mucous forward to clear it. Columnar Epithelium: These cells are tall and cylindrical like pillars. Location: Inner lining of the stomach and intestines. Function: It absorbs nutrients from digested food. I

Areolar Connective Tissue It is a type of connective tissue that support and helps to protect organs, muscles and many other tissues. Loose Connective Tissue In this, cells are embedded in loose gel like matrix. Location:

• Between skin and muscles.
• Around blood vessels and nerves. Function:
• It fills space inside the organ.
• Support internal organs.
• Helps in repair of tissues. Dense Connective Tissue In this, cells are embedded in type-1 Collagen-hard matrix. Tendons
• It connects muscle to bones.
• Fibrous tissue.
• Limited flexibility
• Great strength Ligament
• It connects bones to bones.
• Little matrix is present
• Considerable strength Adipose Connective Tissue It is formed from aggregation of fat cells. Location:
• Below skin
• Between internal organs Function:
• Cells of this tissue are filled with fat globules - Fat Reservation.
• It act as an insulation - storage of fats also lets it act as an insulator.

Skeletal Connective Tissue It forms the endoskeleton of the vertebrate body.

1. Cartilage It has extensive matrix of protein and sugar. Location: Nose tip, Ear pinnae Function: Support and flexibility to body parts.
2. Bones Characteristic

• It is a strong and non-flexible tissue.
• It is embedded in a hard matrix that is composed of calcium and phosphorus compounds. Function
• It forms the framework that supports the body.
• It also anchors the muscles and supports the main organs of body. Fluid Connective Tissue It makes connectivity in the body (i.e. present in whole body) Blood Characteristics
• Composed of blood cells.
• Blood cells move in liquid matrix Blood Plasma.
• Blood cells are of three types: RBC, WBC and Platelete Function Blood flows and transports gases, digested food, hormones and waste material to different parts of body. Lymph It is a colourless fluid in which one WBC is present.

L.P. 3: Give three features of cardiac muscles. Ans- 1. Heart muscles are cylindrical, branched and uninucleated.

2. They are involuntary muscles, cannot be controlled by us.
3. They are striated muscle fibre. L.P. 4: What are the functions of areolar tissue? Ans- 1. It fills space inside the organs.
4. Supports internal organs.
5. Helps in repair of tissues. I I I I I I I i I I (^) I I I I (^) I I (^) I I (^) I I (^) I (^1) - -- (^) -......... - (^) ---