STUDY OF CELLS - TISSUESBIOLOGY 10TH GRADE

TISSUES

Tissues : Groups of cells which have a common origin, with similar structure and function. They exhibit great variety in their structure including shapes of cells, thickness of cell walls and other characteristics.

Organ : Different types of tissues together take up a particular function and form an organ.

Organ System : A group of organs performing a set of common functions is called an organ system.

Histology : The branch of biology which deals with the study of tissues and their organization in organs, is called histology.

As we go higher up in the ladder of evolution, the body organization in plants and animals becomes more complex. The body consists of specialised tissues and organs to perform various metabolic activities. Thus, specialisation of the tissues in higher organisms has enabled them to perform life processes more efficiently.

PLANT TISSUES

In an angiosperm plant body there are different types of tissues to perform a variety of functions such as growth, protection, absorption, photosynthesis and conduction of water and minerals.

Plant Tissues – Different types of tissues

Meristematic Tissue Permanent TissueThese tissues have the capacity to divide. These tissues have lost the capacity of

division.

They have thin cellulose wall They have thick cellulose wall.

They produce permanent tissues. They are produced by meristematic tissue

They contain many small vacuoles in their cytoplasm

They contain only a single large vacuole in their cytoplasm

They do not have intercellular spaces. They have large intercellular spaces

They contain dense cytoplasm with prominent nucleus

They contain thin cytoplasm with normal nucleus

They are responsible for primary and secondary growth of plants.

These tissues add to various growth.

Kindly paste the below link to watch the you tube video on Plant tissues :

http://www.youtube.com/watch?v=uN_vBFyu_-g

PLANT TISSUES

In an angiosperm plant body there are different types of tissues to perform a variety of functions such as growth, protection, absorption, photosynthesis and conduction of water and minerals.

PLANT TISSUES (SIMPLE PERMANENT TISSUE)

PARENCHYMA COLLENCHYMA SCLERENCHYMALocation : Stem, Root, Leaves, Fruits and widely distributed

Location : Below Epidermis Location : Outermost boundaries of plants , parts, cortex, pit, hard seeds etc.

Function : • Stores and Assimilates food • Provides Mechanical Support

(turgidity) • Store waste products like

tannin, gum, resins, etc.

Function : • Provides Mechanical Support

and Elasticity • Manufacture sugar and starch

Function : • Provides Mechanical Support

and Strength

Oval and Sperical Elongated Long and Narrow cells

Living Cells Thickened with Cellulose Cells are thickened with Lignin

Simple permanent tissues are composed of cells which are similar in structure and function. There are three types of simple permanent tissues

PLANT TISSUES (COMPLEX PERMANENT TISSUE)

“Tissues which are composed of two or more types of cells but contribute to a common function are called complex tissues. Xylem and phloem are the complex permanent tissues. They together form the vascular bundle hence known as Vascular tissues”

Phloem and xylem are complex tissues that perform transportation of food and water in a plant. They are the vascular tissues of the plant and together form vascular bundles. They work together as a unit to bring about effective transportation of food, nutrients, Minerals and water

PLANT TISSUES (COMPLEX PERMANENT TISSUE)

Xylem Phloem Function : Transportation of food and nutrients such as sugar and amino acids from leaves to storage organs and growing parts of plant. This movement of substances is called translocation.

Function : Water and mineral transport from roots to aerial parts of the plant.

Movement : Bidirectional (Moves up or down the plant's stem from "source to sink")

Movement : Unidirectional (Moves up the plant's stem)

Occurrence : Roots, stems and leaves. transports sucrose to growth (roots and shoots) and storage regions of the plant (seeds fruit and swollen roots)

Occurrence : Roots, stems and leaves

Additional Functions : Forms vascular bundles with xylem

Additional Functions : Forms vascular bundles with phloem and gives mechanical strength to plant due to presence of lignin cells. The lignified secondary wall also makes the xylem waterproof and prevent it from collapsing under the pressure of water transpiration

Structure : Elongated, tubular shape with thin walled sieve tubes. The sieve tubes have pores at each end in the cross walls and microtubules that extend between sieve elements allowing longitudinal flow of material.

Structure : Tubular shape with no cross walls which allows a continuous column of water + facilitates more rapid transport within the xylem vessels. There are two types - protoxylem (first formed xylem) + metaxylem (mature xylem) depending on pattern of lignin.

Elements : Sieve tubes, companion cells, phloem parenchyma (loosely packed resulting in intercellular spaces which allows gas exchange), bast fibers, intermediary cells,

Elements : Tracheids, vessel elements, xylem parenchyma (loosely packed resulting in intercellular spaces which allows gas exchange), xylem sclerenchyma

Nature of tissue : Living tissue with little cytoplasm but no nucleus/tonoplast.

Nature of tissue : Dead tissue at maturity so it is hollow with no cell contents

Shape : Phloem is not star shaped. Shape : Xylem is star shaped.

PLANT TISSUES (COMPLEX PERMANENT TISSUE)

Xylem Phloem Function : Transportation of food and nutrients such as sugar and amino acids from leaves to storage organs and growing parts of plant. This movement of substances is called translocation.

Function : Water and mineral transport from roots to aerial parts of the plant.

Movement : Bidirectional (Moves up or down the plant's stem from "source to sink")

Movement : Unidirectional (Moves up the plant's stem)

Occurrence : Roots, stems and leaves. transports sucrose to growth (roots and shoots) and storage regions of the plant (seeds fruit and swollen roots)

Occurrence : Roots, stems and leaves

Additional Functions : Forms vascular bundles with xylem

Additional Functions : Forms vascular bundles with phloem and gives mechanical strength to plant due to presence of lignin cells. The lignified secondary wall also makes the xylem waterproof and prevent it from collapsing under the pressure of water transpiration

Structure : Elongated, tubular shape with thin walled sieve tubes. The sieve tubes have pores at each end in the cross walls and microtubules that extend between sieve elements allowing longitudinal flow of material.

Structure : Tubular shape with no cross walls which allows a continuous column of water + facilitates more rapid transport within the xylem vessels. There are two types - protoxylem (first formed xylem) + metaxylem (mature xylem) depending on pattern of lignin.

Elements : Sieve tubes, companion cells, phloem parenchyma (loosely packed resulting in intercellular spaces which allows gas exchange), bast fibers, intermediary cells,

Elements : Tracheids, vessel elements, xylem parenchyma (loosely packed resulting in intercellular spaces which allows gas exchange), xylem sclerenchyma

Nature of tissue : Living tissue with little cytoplasm but no nucleus/tonoplast.

Nature of tissue : Dead tissue at maturity so it is hollow with no cell contents

Shape : Phloem is not star shaped. Shape : Xylem is star shaped.

ANIMAL TISSUES

Animal tissues are more complex in structure and function when compared to plant tissues. The animal tissues can be broadly classified as follows.

ANIMAL TISSUES

Epithelial Tissue

EPITHELIAL TISSUE : You are familiar with the skin which is the outer covering of the body. The inner wall of the body is also lined with a similar tissue. These outer and inner layers are made up of a type of tissue called epithelial tissue.

• The epithetial tissue consists of a single layer of cells called simple epithelium. If it contains more than one layer, it is called stratified epithelium.

• Simple epithelium consisting of flat plate like cells is called squamous epithelium. It is found in the alveoli of lungs, and in oesophagus, in blood vessels, blood capillaries and chambers of the heart. This tissue is referred to as endothelium.

• It permits materials to diffuse through it. The epithelial tissue containing elongated cells is called columnar epithelium. It is found in the inner layer of the stomach, small intestine, pharynx, larynx and oviducts.

Simple Epithelium: A simple epithelium has a single layer of cells.

Stratified Epithelium: A stratified epithelium has multiple layers of cells.

Likewise, the shape of the cells on the free surface can be:

Cuboidal : Analogous to the shape of dice.Columnar : Analogous to the shape of bricks on an end.Squamous : Analogous to the shape of flat tiles on a floor.

By combining the terms for shape and layers, we can derive epithelial types such as stratified squamous epithelium or simple columnar epithelium.

ANIMAL TISSUES

Epithelial Tissue

The mucus secreted by the cells in the stomach protects the wall of the stomach from acidic contents and digestive enzymes. The mucus produced in the intestine lubricates the passage of food. The epithelium bearing numerous cilia is called ciliated epithelium.

Epithelium consisting of cube shaped cells is known as cuboidal epithelium. It forms the lining of many ducts such as pancreatic duct, salivary duct and sweat ducts.In many glands like salivary glands and thyroid gland, cuboidal epithelium is involved in secretion.

ANIMAL TISSUES

Epithelial Tissue

ANIMAL TISSUES - FUNCTIONS OF EPITHELIAL TISSUES

1. The epithelium forms a thick tough barrier and protects the underlying tissues in the form of external skin. The epithelium of the skin also helps in controlling the body temperature constant.

2. The ciliated epithelium helps in the movement of materials.

3. The epithelium cells in glands facilitate secretion.

4. Epithelium helps in absorption of nutrients and excretion.

5. The epithelium in sense organs contain receptor cells.

ANIMAL TISSUES – Tissue and Muscles

Muscular Tissue

MUSCULAR TISSUE

Muscular tissue is concerned with the movements of the body. It is made up of muscle cells, which appear like fibres. Hence they are called muscle fibres (myofibres). The muscle fibres are specialised cells capable of contraction and relaxation. This property is responsible for movement of limbs and bending of the body.

The movements of internal organs like heart, stomach and alimentary canal are caused by muscles. These muscles are not under the control of the animal. Hence they are called involuntary muscles.

The muscles of organs like limbs which are under the control of the animal, are called voluntary muscles.

The muscles are classified into three types based on the structure, function and location.They are (1) Unstriped muscles (2) Striped muscles (3) Cardiac muscles.

UNSTRIPED MUSCLES STRIPED MUSCLES CARDIAC MUSCLES

Made up of spindle shaped elongated muscle fibres without stripes (cross bands). They are also called smooth muscles.

Made up of elongated unbranched cylindrical fibres with striations are called striped muscles.

The heart is made up of special type of muscles called Cardiac muscles

A number of muscle fibres are held together by a membrane to form bundles called muscles

are usually attached to the bones and hence, are also known as skeletal muscles.

These muscle fibres are striped and branched.

The peristaltic movements of the oesophagus, intestine and stomach are due to these muscles. Smooth muscles are found in the wall of the body cavity

They are voluntary muscles and are responsible for locomotion

The branches are connected with one another in a criss-cross form. They are involuntary muscles. Physical exercises and games are necessaryto keep the muscles in good working condition

They are also found in kidneys, blood vessels and glands

They do not fatigue easily. They are responsible for the continuous heart beat throughout one’s life.

ANIMAL TISSUES – Tissue and Muscles Muscular Tissue

ANIMAL TISSUES – Tissue and MusclesConnective Tissue

CONNECTIVE TISSUES

The tissues which connect various other tissues of the body and provide support are called connective tissues. They occur in all parts of the body. Connective tissues basically consist of cells and fibres enclosed in a ground substance. The non-living substances like fibres and other materials surrounding the living cells form the matrix. It may be soft or hard or liquid. The connective tissues are identified on the basis of the nature of the matrix and classified into three types. They are (1) Loose connective tissues (2) Dense connective tissues (3) Fluid connective tissues.

LOOSE CONNECTIVE TISSUES : The fibres in the matrix are loosely arranged is called loose connective tissue. The areolar tissue, adipose tissue and reticular tissue are included under this group.

Areolar Tissue Adipose Tissue Reticular TissueFound below the skin. The fibres are loosely connected with one another. Air spaces are found in between the fibres. Hence, it is called areolar tissue.

The tissue consists of closely packed fat cells. The cellsare surrounded by fine reticular fibres.

Tendons are made up of fibrocytes and collagen fibres.

It binds the other tissues and provides a frame work. It consists of a particular type of cells which engulf bacteria and foreign bodies that enter the body

This tissue stores nutrients which areused as and when the body requires.

Reticular tissue provides framework for important organs such as liver, spleen, bone marrow, tonsils and mucous membrane lining in the respiratory tract and alimentary canal.

The nutrients and oxygen present in the blood pass through areolar tissue and reach other tissues.

It also provides insulation against cold and protects the body like a shock absorber.

It consists of reticular fibre

They also digest toxic substances and destroy them. Thus, they help in body defence.

ANIMAL TISSUES – Tissue and MusclesConnective Tissue

ANIMAL TISSUES – Tissue and Muscles Dense Connective Tissue

DENSE CONNECTIVE TISSUE :

The connective tissues consisting of hard matrix are called dense connective tissues. The cells are embedded in a dense matrix.

The major functions of dense connective tissues are :

They form the skeletal system of the body providing an internal supporting frame work.

They enclose the internal organs. The skull protects the brain, ears, eyes,nose and other organs in the face.

The rib cage protects heart and lungs. The vertebral column protects the spinal cord. The organs of digestion, excretion,

reproduction and many other organs in the abdomen are protected by the pelvic girdle and limbs are provided with support.

ANIMAL TISSUES – Tissue and Muscles Dense Connective Tissue

CARTILAGE TISSUE : BONE TISSUE :Cartilage takes up different functions depending on the type of matrix. The ‘C’ shaped cartilage rings in the trachea, bronchi and the cartilage in the rib cage help in their movement by binding the surrounding organs. The cartilages present in larynx, epiglottis, wall of the eustachian tube and pinna contains elastic fibres in the matrix. They are elastic and flexible. The cartilages found in between the vertebrae in the vertebral column chiefly contains collagen fibres. They bring about bending and stretching movements.

The bone tissue is the most abundant skeletal material found in the body. A large part of the body weight is due to the bone tissue. The bone tissue consists of cells embedded in a firm calcified matrix. The matrix chiefly consists of collagen fibres, proteins and inorganic salts like calcium phosphate, chlorides of potassium, sodium and magnesium. The structure of the bone is designed to withstand stress and strain. The long and strong bones of the limbs are filled with a fluid called bone marrow. which consists of fat and blood vessels. It produces blood cells.

Cartilage Tissue Bone Tissue

ANIMAL TISSUES – Tissue and Muscles Fluid Connective Tissue

FLUID CONNECTIVE TISSUES : The blood and the lymph are the liquid connective tissues of the body. They have a fluid matrix.

BLOOD TISSUE LYMPH TISSUE The fluid matrix of the blood tissue is called plasma. The red blood cells, white blood cells and platelets are found floating in it. The liquid nature of the plasma facilitates easy transport of the various substances from one part of the body to another.

The red blood cells are involved in supplying oxygen to every cell in the body.

They also remove carbon dioxide from the cells and transport it to the lungs.

The white blood cells help in body defence and are of different types.

Some of them destroy the bacteria and enable the body to fight against infections.

The platelets are tiny cell fragments which bring about the clotting of blood

Lymph is a colourless fluid similar to blood in structure. When the blood passes through capillaries, only red blood cells can squeeze into the capillaries. The rest of the fluid is called lymph tissue.

Lymph enters another set of capillaries known as lymphatic capillaries.

These capillaries form lymph glands or lymph nodes. The composition of lymph is similar to that of blood

except that it does not contain red blood cells and proteins.

The lymphatic vessels empty lymph into the circulatory system. Lymph produces antibodies which form an essential part of immune system of the body.

It contains a type of white blood cells (phagocytes) which remove bacteria and foreign bodies from the tissues.

ANIMAL TISSUES – Tissue and Muscles Nervous Tissue

Nervous Tissue is one of the basic characteristics of living organisms. This property is very well developed in nervous tissue. The nervous tissue responds to external and internal stimuli of the body. It transmits nerve impulses from all parts of the body to nerve centres very quickly and brings back the responses.

The structural and functional unit of nervous tissue is the ‘nerve cell’ or neuron. The part consisting of a prominent nucleus is the cell body. The short brush like structures arising from the cell body are called dendrites. The long extension of the cell body is the axon. The axon ends in a bunch of branches. The axon is covered by a fatty sheath called myelin sheath.

Dendrites carry the impulses towards the cell body. Axons carry the messages away from the cell body. There is a tiny gap between two successive neurons. This gap is known as synapse.

The impulses are transmitted from the axon of one neuron to the dendrite of another neuron across the synapse through chemical substances

Did you know ????

The longest bone

in the human

body is the thigh

bone calledFemur

The middle ear

bones are the

smallest bones

The red pigment

haemoglobin in RBC

absorbs oxygen and

becomes oxyhaemoglobin

Bone consists of 30% organic substances,

collagen fibres and glycoprotein. 70% is made up of salts out of which 85% is calcium phosphate.

The muscles can contract nearly100 times per

second, when a person is doing hard

work.

The human heart beats 65 times per

minute on an average. In 70 years

total number (70 x 365 x 24 x 60 x

65) of beats will be 2391480000. The

most wonderful pump ever! Help these

muscles to serve you for life time.

Avoid smoking, obesity, and using

saturated fats in the diet.

The fastest nerve

impulses inhumans

travel at 8 metres per

second