THE FUNDAMENTAL UNIT OF LIFE Robert Hooke (1665)observed honeycomb like dead cells in a thin slice of cork under microscope. He coined the term cell,

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1 THE FUNDAMENTAL UNIT OF LIFE Robert Hooke (1665)observed honeycomb like dead cells in a thin slice of cork under microscope. He coined the term cell, which means a small room or compartment. Anton Von Leeuwenhoek (1667):First saw and described living cell The scientist Robert Brown discovered the nucleus in the cell. Purkinje (1837) coined the term protoplasm. Huxley called protoplasm as physical basis of life. Camillo Golgi (1898),discovered Golgi bodies. The cell theory was presented by Matthias Jakob Schleiden (1838) and Theodor Schwann (1839). The cell theory states: 1 Ominis cellular de cellular i.e. New cells arise only from other pre existing living cells by the process of cell division. 2 All organisms are made up of one or more cells and the products of those cells. 3 All cells carry out life activities ( require energy, grow, have a limited size).

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4 PROKARYOTIC CELL CELL SIZE: generally small (1-10 μm or micron. NUCLEAR REGION: Not well defined and not surrounded by a nuclear membrane & known as nucleoids. CHROMOSOME: Single Chromosome NUCLEOLUS is absent, Ribosomes are small(70s type) Membrane -bound cell organelles are absent EUKARYOTIC CELL CELL SIZE: generally large. (5-500 μm NUCLEAR REGION: Well defined and surrounded by a nuclear membrane CHROMOSOME: More than one Chromosome NUCLEOLUS is present, Ribosomes are large(80s type) Membrane-bound cell organelles are present Eg -bacteria, blue green algae. Eg fungi, plant cell and animal cell.

5 PLANT CELL 1. CELL WALL: Plant cell has outer rigid cell wall which is made up of cellulose. 2. VACUOLES: Plant cell generally has large vacuoles. ANIMAL CELL 1. CELL WALL: cell wall is absent. 2. VACUOLES: Animal cell generally do not have vacuoles. 3. Plastids are present 3. Plastids are Absent 4. Nucleus lies on one side 4. Nucleus lies lies in the center Centrioles are Absent 5.Centrioles are present 6.Plant cells do not have lysosomes. 6.Animal cells have lysosomes

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9 PLANT CELL

10 CELL WALL The cell wall is a rigid organelle composed of cellulose (a type of carbohydrate)and lying just outside the cell membrane. The cell wall gives the plant cell it's box-like shape. it also protects the cell. The cell wall contains pores which allow materials to pass to and from the cell membrane. PLASTIDS Plastids are double membrane bound organelles. Plastids also have their own DNA and ribosomes. The plastid are of three types: 1.CHLOROPLAST: It contains the green pigment chlorophyll. is present in green parts specially in leaves and prepares starch by the process of photosynthesis. Plastids are found in the cytoplasm. 2.CHROMOPLAST - are coloured (mostly red/orange) plastids other than green and found in coloured parts of plants such as petals of the flower, pericarp(outermost covering of fruit) of the fruits etc. LEUCOPLAST It is White or colorless /white organelles which stores carbohydrates, protein and lipid. example - starch stored in a potato)

11 PLASMA MEMBRANE/ CELL MEMBRANE/UNIT MEMBRANE/SEMI PERMEABLE MEMBRANE/PLASMALEMMA Structure- a bilipid (two lipid layers) membranous layer composed of proteins and lipids. It is fluid like in nature. Function - The cell membrane separates the cell from its external environment, The plasma membrane allows or permits the entry and exit of some materials in and out of the cell. It also prevents movement of some other materials. The cell membrane, therefore, is called a selectively permeable membrane. Diffusion: movement of substance from high concentration to low concentration. Eg; exchange of carbon dioxide or oxygen with external environment. diffusion plays an important role in gaseous exchange between the cells as well as the cell and its external environment. OSMOSIS is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration. If water gets in side the cell it is ENDOSMOSIS and if water gets out of the cell it is termed as EXOSMOSIS OR PLASMOLYSIS).

12 HYPOTONIC SOLUTION. If the medium surrounding the cell has a higher water concentration than the cell, meaning that the outside solution is very dilute, the cell will gain water by osmosis. Such a solution is known as a hypotonic solution. ISOTONIC SOLUTION. If the medium has exactly the same water concentration as the cell, there will be no net movement of water across the cell membrane. Such a solution is known as an isotonic solution. HYPERTONIC SOLUTION If the medium has a lower concentration of water than the cell, meaning that it is a very concentrated solution, the cell will lose water by osmosis. Such a solution is known as a hypertonic solution.

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14 CYTOPLASM Structure - The jelly-like substance composed of mainly water and found between the cell membrane and nucleus. The cytoplasm makes up most of the "body" of a cell and is constantly streaming. Function - Organelles are found here and substances like salts may be dissolved in the cytoplasm. GOLGI BODY / APPARATUS Golgi apparatus, first described by Camillo Golgi. Golgi bodies are a system of membrane-bound vesicles arranged approximately parallel to each other in stacks called Cisternae. The Golgi Body temporarily stores protein which can then leave the cell via vesicles. Their main components are Cisternae, tubules and vesicles. Package & export proteins is main function of Golgi bodies. LYSOSOMES Lysosomes are small sac-like structures surrounded by a single membrane and containing strong digestive enzymes which capable of breaking down all organic material. when released can breakdown foreign materials entering the cell, such as bacteria or food, as well as old organelles. The lysosome is also known as a suicide sac or suicidal bag. lysosomes may burst and the enzymes digest their own cell.

15 NUCLEUS STRUCTURE - The largest organelle in the cell. It is dark and round, and is surrounded by the nuclear envelope/membrane it has outer nuclear membrane and inner nuclear membrane. The pores which are present on nuclear membrane allow the transfer of material from inside the nucleus to its outside. Chromosomes contain information for inheritance of features from parents to next generations in the form of DNA( Deoxyribo Nucleic Acid ) and protein molecules. The functional segments of DNA are called genes. In some organisms like bacteria, the nuclear region of the cell may be poorly defined due to the absence of a nuclear membrane. Such an undefined nuclear region containing only nucleic acids is called a nucleoid. Chromosomes are bundles of coiled DNA and are found in every cell that has a nucleus. In humans, there are 46 chromosomes in every nucleus of every body cell. In fact, every nucleus in the body has an identical set of chromosomes. In total, there are 23 pairs (or kinds) of chromosomes in a human nucleus. Mothers and fathers contribute a chromosome to make each pair. A human nucleus has roughly 20,000 genes. FUNCTION - The nucleus plays a central role in cellular activities & reproduction.

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18 The Endoplasmic Reticulum is a network of single membranous canals filled with fluid. They carry materials throughout the cell. The ER is the "transport system" of the cell.there are two types of ER: (1)Rough Endoplasmic Reticulum ( 2)Smooth Endoplasmic Reticulum ROUGH ENDOPLASMIC RETICULUM (RER) SMOOTH ENDOPLASMIC RETICULUM (SER). 1. RIBOSOMES - Present 1RIBOSOMES - Absent 2. POSITION - Mainly present near the nucleus 3.ORIGIN - Formed from outer nuclear membranes. 4.COMPONENT - Mainly formed of cisternae 5.FUNCTION- contributes for the protein synthes 2. POSITION - Mainly present near the cell membrane ORIGIN - Formed from RER by loss of ribosomes. 4.COMPONENT -Component - Mainly formed of tubules. 5.FUNCTION--synthesis of lipids.

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20 RIBOSOMES Ribosome are small particles which are found individually in the cytoplasm and also line the membranes of the rough endoplasmic reticulum. Ribosome helps in protein synthesis. MITOCHONDRIA The Mitochondrion is a capsule-like structure that are surrounded by a double membrane: (1) Inner membrane being highly folded and the (2) outer membrane. Its inner membrane is projected into numerous finger-like structures; called cristae. Mitochondria are the sites of cellular respiration. After cellular respiration, energy is stored in the form of ATP (Adenosine triphosphate); in mitochondria. Mitochondria have their own DNA and ribosomes. Therefore, mitochondria are able to make some of their own proteins.

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22 VACUOLES Vacuoles are fluid filled organelles enclosed by a membrane. They can store materials such as food, water, sugar, minerals and waste products. vacuole in plant cells is enclosed by a membrane termed the tonoplast. FUNCTIONS : vacuoles are isolating harmful materials, storing waste products, storing valuable water in a plant cell, helping maintain the pressure within a cell. contractile vacuole pumps water out of protist cells( for example Amoeba) to maintain a suitable concentration. FOOD VACUOLE : storage for molecules that is a food source for the cell. contractile vacuole and food vacuole are commonly found in protozoan such as Amoeba,Paramecium. CELL WALL The cell wall is found in plant cells, but not in animal cells. This is the outermost layer in the plant cell. It is stiff, rigid, nonliving, and made of cellulose. It provides support so that the plant can grow tall and protection. Some materials like water, oxygen, and carbon dioxide can pass through it.

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26 TISSUE : A group of cells having common origin, similar structure and performing a definite function is called a tissue. Meristematic tissues are present only at the growing regions like the shoot tip, root tip and cambium. MERISTEMATIC TISSUE Meristematic tissue are cells or group of cells that have the ability to divide. These tissues in a plant consist of small, densely packed cells that can keep dividing to form new cells. Meristems give rise to permanent tissues and have the following characteristics: (1) the cells are small (2)the cells walls are thin. (3) cells have large nuclei (4)vacuoles are absent or very small, and there are no intercellular spaces. Meristematic tissues is found in the following locations: 1 APICAL MERISTEMS: is present on root apex, stem apex, leaf buds and flower buds. They are responsible for growth in length, i.e. primary growth. 2.LATERAL MERISTEM: Lateral meristem is present along the side of the stem. They are responsible for growth in girth, i.e. secondary growth. 3.INTERCALARY MERISTEM: Intercalary meristem is present at the base of leaf or internodes. They are present on either side of the node.

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28 COLLENCHYMA

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31 PROTECTIVE TISSUES: Protective tissues are a part of plant tissue system. Protective tissues include EPIDERMIS AND CORK. EPIDERMIS:It is the outermost protective layer of plant organs.the epidermis is usually made of a single layer of cells.cells of epidermis are elongated and flattened, without intercellular space. They are living cells but their inner contents are similar to parenchyma cells. In leaves, epidermis bears small pores called stomata. Stomata present in the epidermis allow gaseous exchange to occur during photosynthesis and respiration.it also facilitates transpiration. FUNCTIONS: The function of epidermis is the protection of plant from injury and infection. Cuticle of epidermis also helps to reduce water loss by evaporation to prevent dessication. Cork (or phellem):

32 CORK Cork cells are dead cells without having intercellular spaces.they appear at the periphery of roots and stems when they grow older and increase in girth. They also have a chemical called suberin in their walls that makes them impervious to gases and water. FUNCTIONS: The function of cork in plant body is to provide protection. It protects plants from external injury and infection. It also prevents dessication(dessicationis the state of extreme dryness, or the process of extreme drying.). cork does not catch fire easily, it is used for insulation, shock-absorber. It is also used for making sports goods, such as shuttle-cock, table tennis paddles(a table tennis racket,also called a "paddle" or "bat") is used by table tennis players. ), cricket balls, etc.

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35 PARENCHYMA COLLENCHYMA (Gk. collen : glue) SCLERENCHYMA (Gk. Scleros: hard) Thin cell wall is made up of cellulose. No unequally thickened cell wall No pectin deposition is found at the corners. cell wall is made up of cellulose only. cell wall is made up of cellulose and Pectin. Unequally thickened cell wall due Pectin deposition is found at the corners. cell wall is made up of cellulose & Pectin. The walls of these cells are very thick and built up in a UNIFORM distribution of lignin around the entire margin of the cell. cell wall is made up of cellulose & lignin. Living or dead: They are living. Living or dead: They are living Living or dead: They are dead Intercellular space is present Intercellular space is absent. Intercellular space is absent. Shape - Isodiametric Shape - Polygonal. Cells are long, thickwalled and lignified with tapering ends.

36 PARENCHYMA COLLENCHYMA SCLERENCHYMA LOCATION: The cells are present in the epidermis, cortex, pith and pericycle. Meristematic cells are parenchymatous. FUNCTIONS: a) Storage of food materials. b) Chlorenchyma A special type of parenchyma present in leaf carries out photosynthesis. c) Aerenchyma helps aquatic plants in floating and gaseous exchange. LOCATION: It occurs in the peripheral part of elongating organs like stem and petiole, usually appearing as a continuous ring beneath the epidermis. FUNCTIONS: a) It gives mechanical support. b) It can resist bending and stretching caused by winds. c) It carries out photosynthesis if chloroplast are present. LOCATION: Sclerenchyma tissues are important components in fabrics such as flax, jute and hemp. Bark is composed of sclerenchyma. FUNCTIONS: a) It gives mechanical support.

37 TISSUES Living or Dead STRUCTURE FUNCTION 1. Xylem Tracheids Dead Long cells with pointed ends. Walls thick with lignin. Have pores on the walls All of them function as a unit to conduct water and minerals upward. 2. Xylem Vessels Dead Cells shorter and broader than tracheids. Walls thick with lignin and have pores. End walls open and the cells join to form a tube. 3. Xylem Fibres Dead Long cells with very thick lignin deposition on the walls, no pores on the walls. 4. Xylem Parenchyma Living Small thin walled cells with cellulose walls.

38 TISSUES Living or Dead STRUCTURE FUNCTION 1 Phloem SIEVE TUBE & SIEVE PLATE Living Elongated sieve elements join to to form sieve tubes ; cell wall of cellulose. End walls of the cells have perforations on them, which give them the name (sieve) All of them function as a unit to translocate food assimilated in the leaves by photosynthesis to 2. COMPANION CELL 3.PHLOEM FIBRES 4.PHLOEM PARENCHYMA Living Long, rectangular cells associated with seive cells. Cell wall is made up of cellulose. Dead Very long cells with thick lignified Walls. Living Elongated cells. Cell walls thin nd made of cellulose.

39 Phloem Parenchyma These cells store surplus water and food. They can start to divide when needed. (b) Sieve Tube Cells Their end walls have small pores called sieve plates. These cells join to form long pipelines, which are called sieve tubes. There is no nucleus in these cells. Their main function is to transport food. (c) Companion Cells In some plants, each sieve tube cell is accompanied by a companion cell. The companion cell has a nucleus. The corn cell controls the movement of food through sieve tubes. Xylem Tissue 1. This vascular tissue transports water in the plants and provides strength to the plant. 2. In this tissue, there are present xylem parenchyma and two types of thick walled dead cells. Long cells which are called vessel elements or cells. They are joined together to form long pipe-lines. These transport water from roots to leaves. Spindle shaped cells, which are called tracheicts. These provide strength to root and shoot etc. 3. Xylem conducts water in one direction that is from roots towards the stem and leaves.

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47 ANIMAL TISSUES Definition-A tissue is an aggregation of similar cells that perform a specific set of functions. The body is composed of over 25 kinds of tissues, classified as epithelial tissue, connective tissue, muscle tissue, and nervous tissue. Epithelial Tissue. 1.EPITHELIAL TISSUE covers body and organ surfaces, lines body cavities and forms various glands. It functions in protection, absorption, excretion, and secretion. The outer surface of epithelium is exposed either to the outside of the body. The deep inner surface is bound by a basement membrane. Epithelium is classified: A. SIMPLE EPITHELIUM a single layer is referred to as simple epithelium B. STRATIFIED EPITHELIUM the multi layered epithelium is called stratified and by the shape of the cells: squamous (flat), cuboidal, or columnar. The covering or protective tissues in the animal body are epithelial tissues Epithelial layers receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane. Epithelia can also be organized into clusters of cells that function as exocrine and endocrine glands.

48 NAME DESCRIPTION LOCATION FUNCTION A single layer of Diffusion flattened cells Simple Squamous squamous-flat, Simple Cuboidal Simple Columnar Stratified squamous A single layer of cube shaped cells with large prominent nuclei A single layer of tall cells with nuclei toward basement membrane, with microvilli and goblet cells Many layers of flattened cells. linings of the pericardium, and the linings of the alveoli of the lungs. and capillaries Lining kidney tubules and ducts of exocrine glands Lining the intestine Epidermis, mouth, throat, anus. Absorption and, secretion Protection, absorption, and secretion Protection

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53 NERVOUS TISSUE A tissue which is specialized to transmit messages in our body is nervous tissue. Brain, spinal cord and nerves are all composed of nervous tissue. Nervous tissue contains highly specialized unit cells called nerve cells or neurons. These cells are specialized for the conduction of impulse over great distance at great speed. A neuron consists of a cell body (citron or soma) with a nucleus and cytoplasm, from which long thin hair- like parts arise called Dendron's. Dendron's further branched out to form dendrites. From the distal part of citron arises a very long process called axon. Functions: The nervous tissue is responsible for the reception and transmission of information between different parts of the body. The dendrites receive impulses and the axon takes impulses away from the cell body. SYNAPSE :Space between two neurons. INTERNEURONS connect sensory neurons and motor neurons and carry impulses between them. They are concentrated in the brain and spinal cord

54 TYPES OF NEURON ON THE BASISS OF THEIR FUNCTIONS 1 MOTOR NEURON or "Efferent Neuron "Transmitting impulses from the Central Nervous System (CNS), and) which consists of the brain and spinal cord, to muscles & glands elsewhere in the body. 2 SENSORY NURONS that receive sensory signals from sensory organs and send them to the central nervous system. 3 Mixed Nerves Contain both motor and sensory nerve fibers running to/from a particular region of the body.

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56 Blood is a liquid connective tissue. Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal. Blood is liquid, with numerous cells and proteins suspended in it.average person has about 5 liters of blood. A liquid called plasma makes up about half of the content of blood. Plasma contains proteins that help blood to clot, and perform other functions. Blood plasma also contains glucose and other dissolved nutrients. About half of blood volume is composed of blood cells: 1 Red blood cells or erythrocytes are cells without nuclei - which carry oxygen from the lungs to all of the living tissues of the body and carry away carbon dioxide. 2 White blood cells or leukocytes - which fight infections white blood cells play an important role in the immune system by identifying, destroying, and removing pathogens, 3 Platelets or thrombocytes - smaller cells that help blood to clot Blood is conducted through blood vessels (arteries and veins)

57 Lymph is clear fluid and a liquid connective tissue. It does not contain Red blood cells. It contains more LYMPHOCYTES. The various functions of lymph include: 1)Nutritive: It supplies nutrition and oxygen to those parts where blood cannot reach. 2)Drainage: It drains away excess tissue fluid and the metabolites and in this way tries to maintain the volume and composition of tissue fluid constant. 3)Transmission of Proteins: Lymph returns proteins to the blood from the tissue spaces. 4)Absorption of Fats: Fats from the intestine are also absorbed through the lymphatics. 5)Defensive: The lymphocytes and monocytes of lymph act as defensive cells of the body. The lymph also removes bacteria from tissues.

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59 MUSCULAR TISSUE Muscle tissue is characterized by the ability to contract when stimulated. When muscle cells contract, they get shorter, generating force and often movement. Muscle cells contain filaments of two proteins: actin and myosin. There are three different types of muscle tissue: 1. Skeletal muscle: This tissue is composed of long, multinucleate cylindrical cells with visible striations (DARK BAND & LIGHT BAND). Skeletal muscle allows movement by being attached to bones in the body. Because skeletal muscle contraction is consciously controlled, it is known as a voluntary muscle. 2. Smooth muscle: Composed of short, cells that taper at the ends, smooth muscles are commonly involved in involuntary motions. Involuntary muscle contractions are not consciously controlled and occurs in places like the digestive tract an in the walls of blood vessels. 3. Cardiac (heart) muscle: Cardiac muscle tissue contains short, branched, striated cells, with one nucleus at the centre of each cell. Cardiac muscle cells within a fiber are joined to their neighbours by intercalated discs. Cardiac muscles are also involuntary muscles.

60 STRIATED (SKELETAL) MUSCLES NON-STRIATED (SMOOTH OR VISCERAL) MUSCLES 1. Striations present Absent Absent 2. Voluntary in action Involuntary Involuntary 3. Muscle fibers are long and cylindrical with blunt ends Muscle fibers are long spindle shaped with pointed ends CARDIAC MUSCLES Muscle fibers are short, cylindrical with flat ends 4. Fibers are unbranched Fibers are Unbranched Fibers are Branched 5. Fibers are multi-nucleated Uninucleated Uninucleated 6. Intercalated discs absent Absent Present 7. Numerous mitochondria and glycogen granules are present Less mitochondria and glycogen granules are present Numerous mitochondria and glycogen granules are present 8. Seen attached to skeleton Seen in internal organs 9. E.g. Biceps muscle E.g. intestinal muscles,blood vessel, urinary bladder etc. Seen in the walls of heart E.g. heart muscles

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63 CARTILAGE 1. It is soft elastic and flexible 2. Cells are known as chondrocytes 3. Matrix is non vascular (with out blood supply) 4. Matrix is a homogenous mass without lamellae 5. Matrix has a protein called Chondrin and organic in nature. 7. Matrix may or may not have calcium salts 8. Each Cartilage lacks blood supplygenerally. 9. Each lacunae has 2-3 chondrocytes 10. Bone marrow like structure is absent 11. Haversian systems is absent. BONE 1. It is hard, inelastic and tough 2. Cells are known as osteocytes. 3. Matrix is vascular (with blood supply) 4. Matrix occur in lamellae 5. Matrix has a protein called ossein. 6. Matrix is both organic and inorganic matter. 7. Matrix always have calcium salts predominantly calcium phosphates. 8. Bones are rich in blood supply. 9.Haversian systems canals is present.

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65 AREOLAR TISSUE 1. Areolar tissue is mainly connective in nature. 2. It usually fixes skin with the muscles. 3. It forms packaging the material in all organs between the muscles. 4. It has two types of fibers white and yellow. Location: Around blood vessels, nerves, and organs. Function: Provides strength, elasticity, support and immune system protection. ADIPOSE TISSUE 1. It is mainly concerned with the storage of fat Adipocyte is the main cell of this tissue. The cells are spherical or oval and are packed in a matrix. The matrix of the tissue consists of fibroblasts, macrophages and collagen fibers. 4. It is found around the kidneys, blood vessels and also heart. Location: Around organs, subcutaneous layer(between skin and muscle) Function: Store energy, provide protection, and insulate.

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68 TENDON 1 It is very strong, thick inflexible fibrous connective tissue. 2 It is composed of white collagenous fibres. 3 Fibroblasts occur in rows between the white collagenous fibres. 4 It helps to join a muscle to a bone. LIGAMENT It is elastic, flexible dense fibrous connective tissue. It is composed of yellow elastic fibres. Fibroblasts lie scattered in the matrix. It joins bones at the joints and holds them in position.

69 TENDON 1. It is composed of only collagen fibres LIGAMENT It is composed of collagen fibres and some elastin fibres 2. Fibres are seen as dense parallel bundles Fibres are densely crowded but not arranged in parallel bundles 3. Fibroblasts are seen in between fibre bundles 4. Tendon joins muscle to bone Fibroblasts are seen in between fibres Ligament joins bone to bone

70 CARTILAGE BONE 1. It is semi-rigid and flexible 1. It is rigid and strong 2. The matrix lacks blood vessels (non-vascular) 2. The matrix has blood vessels (vascular) 3. Non-calcified matrix 3. Calcified matrix 4. The matrix protein is chondrin 4. The matrix protein is ossein 5. Each lacuna in the matrix has 2 or 3 cartilage cells (chondrocytes) 6. The matrix is not arranged in lamellae 7. Haversian systems, canaliculi and Volkman s canals are absent 5. Each lacuna in the matrix has a single bone cell (osteocyte) 6. The matrix is arranged in lamellae 7. Haversian systems, canaliculi and Volkman s canals are present. 8. Growth is unidirectional 8. Growth is bidirectional