Structure Organisation in Animals

Structure Organisation in Animals INTRODUCTION Tissue : A organised group of cells similar in structure, function and origin. In a tissue cells my be dissimilar in structure and function but they are always similar in origin. Word animal tissue was coined by - Bichat N. Grew coined the term for Plant Anatomy. Study of tissue - Histology Histology word was given by - Mayer Father of Histology - Bichat Study of tissue is also called Microscopic anatomy. Founder of microscopic anatomy - Marcello Malpighi Based on functions & location tissues are classified into four types : EPITHELIAL TISSUE Word epithelium is composed of two words Epi - Upon Thelio - grows A tissue which grows upon another tissue is called Epithelium. Cover external or internal surface. Cells are either single layered or multilayered. Cells are compactly arranged and there is no intercellular matrix. Cells of lowermost layer always rest on a non living basement membrane. Cells are capable of division and regeneration throughout the life. Free surface of the cells may have fine hair cilia or microvilli or may be smooth. Epithelial tissue is non-vascularised. Due to absence/less of intercellular spaces blood vessels, lymph vessels are unable to pierce this tissue so blood circulation is absent in epithelium. Hence cells depend for their nutrients on underlying connective tissue. Between epithelium & connective tissue, a thin non living acellular basement membrane is present which is highly permeable. 93 Basement membrane consist of 2 layers. (a) Basal lamina : made up of glycoprotein, and secreted by epithelium cells. (b) Fibrous lamina : Formed of collagen and reticular fibres suspended in mucopolysaccharide which is matrix of connective tissue. - So basement membrance is secreted by both epithelium and connective tissue. - Structure Organisation in Animals Specialized junctions between epithelial cells: - - To provide mechanical support for the tissue plasma membrane of adjacent epithelial cells modified to form following structures called as Intercellular Junctions. - Tight junctions (Zonula occludens) : help to prevent substances from leaking across the tissue. Mucopolysaccharide is present in the form of Hyaluronic acid which is composed of 2 components-N acetylglucosamine & glucuronic acid. Both these components are found in alternate form. - NAG - GA - NAG - Plasma membranes in the apical parts become tightly packed together or are even fused. Interdigitations : These are interfitting, finger like processes of the cell membranes of the adjacent cells. Intercellular Bridges : These are minute projections that arise from adjacent cell membrances. They make contact with one anther. 94 - - - - - - Structure Organisation in Animals Cillia or Kinocilia Gap Junctions : Facilitate the cells to communicate with each other by connecting the cytoplasm of adjoining cells, for rapid transfer of ions, small molecules and sometimes big molecules. Intermediate Junctions (= Zonula adherens): These usually occur just below tight junctions. There is no intercellular filaments between the adjacent cell membranes. They probably serve anchoring functions. Desmosomes ( =Macula adherens) : Perform cementing to keep the neighbouring cells together. These are like zonula adherens but are thicker and stronger and are disc like junctions. They have intercellular protein. The microfilaments which extend from Plasma membrane are called tonofibrils. Long cylindrical protoplasmic process. Motile and contractile Movement of cilia is always in uniform direction. Originated from basal granule or kinetosome. Diameter of cilia is same from base to apex. In internal structure of cilia 9 + 2 arrangement of microtubules is present. They helps in conduction e.g. - Fallopian tube. - Trachea. - Fallopian tube - Uterus. - Ependymal epithelium : (Inner lining of ventricles of brain & central canal of spinal cord. Function of cilia is to conduct substances in CSF.) Hemidesmosomes (single sided desmosomes) Steriocilia are similar to desmosomes, but the thickening of Long cytoplasmic process cell membrane is seen only on one side. Non motile, non contractile Hemidesmosomes join epithelial cells to basal Basal granule is absent lamina (outer layer of basement membrane). Plasma membrane is thick & rigid. Specialised functional structures shown by Base of stereocilia is broad & apical part is Epthelial Cells : narrow so they are conical in shape. Plasma membrane of free end get modified to form 3 types of functional structures. They increase surface area . Microvilli Vasadeferens Minute protoplasmic process which are non motile, non contractile. eg. Epididymis Origin of Epithelial Tissue It is the only tissue which originated from all the three primordial germinal layers. eg. - Help in absorption, secretion, excretion - Increase surface more than 20 times. (i) - Present in the wall of Intestine, Gall bladder, Proximal convoluted tubule etc. Ectodermal - Epidermis (stratified squamous epitheliium) (ii) Mesodermal - Mesothelium (simple squamous Epithelium) (iii) Endodermal - Endothelium (simple squamous Epithelium) 95 Structure Organisation in Animals Types of Epithelial Tissue Simple Squamous Epithelium eg. - Unilayered. Cells are flat or scale like in shape A flattened/rounded nucleus present. Cells appear rectangular in shape. It is also called pavement epithelium / Tesselated epithelium due to its wavy appearance. This epithelium is associated with filtration & diffusion - Bowman's capsule (Podocyte) Descending limb & thin part of ascending limb of loop of Henle. Rete Testis, Eye lens epithelium, Alveoli of lungs (Pneumocytes) Small bronchioles Mesothelium - Covering of coelom is called as mesothelium. (Tesselated) Visceral & Parietal peritoneum. Visceral and parietal pleura, Visceral and Parietal pericardium. - Endothelium - Inner lining of blood vessels and lymph vessels. (Tesselated) - Inner lining of heart wall (Tesselated). 96 Structure Organisation in Animals Simple Cuboidal Epithelium - Basement membrane is present. MODIFICATIONS Cells are cube like in shape Brush bordered cuboidal epithelium where microvilli are present on free surface of cuboidal A rounded nucleus is present in the centre of cell. cells Cells are same in length & width so they appear eg.: PCT of nephron. square shaped in vertical section. This epithelium helps in absorption, secretion & Ciliated cuboidal epithelium when cilia present excertion. on free end of cuboidal cells then It also form gametes in gonads. Collecting duct / Tubule. Mostly cuboidal cells are found in glands. SIMPLE COLUMNAR EPITHELIUM Basement membrane is present. Cells are pillar or column like in shape. Elongated nucleus is present at the base of cell. It helps in absorption and secretion. eg. Bile Duct of Liver MODIFICATIONS eg. (1) - Vesicles of Thyroid gland - Pancreatic duct - Secretory unit of sweat glands (2) - Secretory duct of salivary glands (secretory unit of salivary glands is composed is stratified cuboidal epithelium.) - Iris - Choroid - Ciliary body of eye - Thick part of ascending limb of loop of henle - DCT - In gonads this epithelium is also called as Germinal epithelium (testis & ovaries) where cuboidal cells divide to form egg & sperm. - It is found in peripheral region of ovary & in the wall of seminiferous tubules in Testis. Brush Bordered Columnar epithelium : Microvilli are present at free end of epithelium. e.g., Gall bladder Glandular columnar epithelium : Unicellular mucous secreting goblet cells are also present in between columnar cells. eg., Stomach, Colon, Rectum Fig.: Glandular epithelium : (a) Unicellular (b) Multicellular 97 (3) (4) Glandular Brush bordered columnar (1) epithelium : Microvilli present on free end of columnar cells & in between these cells goblet cells are also (2) present. e.g., Duodenum, IIeum,Caecum. Ciliated Columnar epithelium : Structure Organisation in Animals Pseudostratified Non-ciliated Epithelium. Parotid Salivary gland, Middle part of male urethra. Pseudostratified ciliated glandular epithelium : In this epithelium cillia are present at free end of long cells and goblet cells are also present in this epithelium. Trachea, Bronchi, Respiratory epithelium of nasal chambers. Special Types of Epithelium (a) (5) Fig.: Simple epithelium : Columnar cell bearing cilia Cilia are present on free end of columnar cells. eg., eg., Fallopian Tube, Ependymal epithelium Steriociliated columnar epithelium : Steriocilia present on free end of columnar cells. eg., Epididymis, Vasa Deferens PSEUDOSTRATIFIED EPITHELIUM It appears billayered as two types of cells are present. eg., Long cells, Short cells. But all the cells are present on single basement membrane so its unilayered. - All these cells are pillar like in shape so it is also modification of columnar epithelium. In long cells, elongated nucleus is present at the (b) base of cell & are ciliated Short cells have rounded nucleus present in the centre of cell, lack (c) cilla and secrete mucus. Neuro sensory epithelium : In between piller shaped supporting cells modified sensory cells are present. On the free end sensory hair is present. Base of these cells is attached with sensory nerve. - Gustatory Epithelium - Cover taste bud of tongue and receive taste sensation. - Olfactory epithelium - Schneidarian membrane receive smell sensation. - Stato - acoustic - Lining of internal ear. - In retina of eye receive optic sensation. Myoepithelium : Around mammary and sweat gland. Pigmented epithelium (Cuboidal) : In Retina of eye. 98 COMPUND EPITHElIUM (1) Transitional epithelium - Stretcheable. (also called Plastic epithelium) (2) Stratified epithelium - Non-stretcheable. TRANSITIONAL EPITHELIUM - (UROTHELIUM) - It is only tissue in which basement membrane is absent. - Innermost layer directly rest upon underlaying connective tissue. - In this epithelium 4-6 layer of cells are present. STRATIFIED EPITHELIUM Structure Organisation in Animals Inner most layer of cells is composed of cube like cells. Middle 2-4 layers are composed of pear shaped or umbrella shaped cells. Outermost 1 or 2 layers are of oval shaped cells. These different shape of cells appears only in resting stage. When this tissue is stretched, all the cell become flattened. At outermost layer a thin cuticle is present which makes this tissue water proof. Cells are interconnected by interdigitation. eg. Renal Pelvis, Ureter, Urinary Bladder, Proximal part of male urethra. STRATIFIED SQUAMOUS EPITHELIUM Stratified epithelium possess many layer of epithelial cells, the deepest layers is made up of cuboidal/Columnar cells. On the basis of shape of the cells of outermost layer it is of four types. Innermost layer of cells are of cuboidal or columnar shaped. (1) Stratified squamous epithelium - (2) Stratified cubical epithelium These cells are interconnected with Desmosomes which provide rigidity or mechanical support. (3) Stratified columnar epithelium - Cells of outermost layer are scale like flat cells. (4) Stratified ciliated columnar epithelium - These cells have high Mitotic index They divide to form layer of Stratified epithelium so this layer is called as Germinativum layer. Middle layers are made up of polygonal cells. On the basis of presence or absence of Keratin protein in the outer most cells this epithelium is of two types. 99 Keratinized Stratified squamous epithelium . Structure Organisation in Animals STRATIFIED CILIATED Hard water proof keratin protein is present in COLUMNAR EPITHELIUM scaly cells and cells become non nucleated dead eg., Larynx; upper part of soft palate. cells. Uterus, Buccal cavity of frog. Functional classification of epithelial tissue: Functionally epithelial tissues can be classified as follows : eg., Epidermis of skin, Scale, Horn, Nails, Feathers (a) Germinal epithelium : It is present in testis and ovaries. Its cells produce Sperms and Ova. (b) Pigmented epithelium : It is present in retina of eye. It possess pigment which give colour to the retina. (c) Sensory epithelium : It is found in retina of eye, internal ear, nasal chamber and tongue. It perceives stimuli and conducts impulses. Non Keratinized Stratified squamous epithelium. Keratin protein is absent. Cells are nucleated & (d) Living. Glandular epithelium : It is present in glands and secrete fluid (Secretion) eg., Buccal cavity or oral cavity of mammals, Inner (e) Absorptive epithelium : It is found in nephron lining of cheeks, Inner lining of lips, Lining of hard of kidneys, stomach, intestine, It helps in palate, Lining of Tonsils, Lower part of soft absorption of food in stomach and intestine and palate, Pharynx, Oesophagus, Anal canal, Lining liquid materials in nephron. of vagina, Cornea of eye. GLANDS OF EPITHELIUM STRATIFIED CUBICAL EPITHELIUM A cell or group of cells which secrete chemical Outermost layer of cells are cube like & cells are substances are called glands. nucleated & living. All glands are composed of Epithelium tissue. Middle layer - polygonal shaped cells. Glands originate from all three germinal layers. eg., Secretory duct of sweat glands, mammary glands The cells are generally columnar or cuboidal. and sebaceous gland. Secretory unit of salivary glands, sebaceous gland. Female Urethra ; TYPES OF GLANDS (A) On the basis of number of cells Part of anal canal. Conjunctiva of eye. (a) Unicellular gland consist of isolated glandular cells. Life STRATIFIED COLUMNAR EPITHELIUM It consists of columnar cells in both superficial as well as in basal layers. Cells are nucleated. Cilia absent on free end. span of 2-3 days Eg. Mucosa of stomach, Intestine, T rachea, nasal (b) Multicellular glands Consist of cluters of cells. Formed by invagination of Epithelial cells Eg. Rest glands chamber (Goblet cells), Paneth cells (Intestine) eg. Distal part of male urethra, Epiglottis 100 Structure Organisation in Animals Fig.: Glandular epithelium : (a) Unicellular (b) Multicellular (C) (a) (b) (c) (D) On the basis of presence of secretory duct glands are of 3 types Endocrine glands - Secretory duct absent Exocrine gland - Secretory duct present. Heterocrine/mixed gland - Both endocrine & exocrine parts are present. On the basis of nature of secretion - 3 types of glands are there. Eccrine/Acrine/Merocrine gland In these glands secretory cells secrete substances by simple diffusion (Exocytosis). No part of cytoplasm is destroyed in secretion. Maximum sweat glands of humans, Paws of rabbit, Goblet cells, Salivary gland, Tear gland, Intestinal gland, Mucous gland. Apocrine gland In this type of glands secretory products are collected in apical part of secretory cell. Apical portion is also shed along with secretory matter. Secretory cells gain their lost part of cytoplasm by process of regeneration. Mammary glands. Sweat gland of Arm pit, pubic region, skin around anus, lips, nipples etc. Largest sweat gland of body are found around nipples. - Areola mamme. In Rabbit seat glands of this type are found on lips and skin around lips. 101 Structure Organisation in Animals Holocrine glands The production or secretion is shed with whole cell leading to its destruction. i.e Example : Sebaceous, meibomian & Zeis gland. CONNECTIVE TISSUE All connective Tissue in the body are developed from Mesoderm. O. Hartwig called them Mesenchyme because they originated from embryonic mesoderm. Only connective Tissue consititute 30% of total body weight. Most abundant and widely distributed in the body. (Muscle - 50%, Epithelium - 10% Nervous - 10%) On the basis of matrix (Polysaccharides) connective tissue is of 3 types 1. Connective Tissue Proper - Matrix soft and fibrous 2. Connective Tissue Skeleton - Dense and mineralized matrix. Due to deposition of minerals it becomes hard. 3. Connective tissue Vascular - Liquid and fibres free matrix In all except blood, the cells secrete fibres of structural proteins called collagen or elastin. CONNECTIVE TISSUE PROPER Connective Tissue Proper is composed of three components (A) Different types of cells. (B) Fibres. (C) Matrix. CELLS OF CONNECTIVE TISSUE PROPER FIBROBLAST CELLS Largest cell of connective tissue proper. Maximum in number. Cell body and nucleus both are oval shaped. Branched cytoplasmic process arise from these cells so they appear irregular in shape. Rich in rough ER because main or primary function is to produces fibres. Fibres are composed of protein. Chief matrix producing cells. Undifferentiated cells of conn. Tissue because they can be modified into Osteoblast & Chondrioblast cells to produce bone & cartilage. Function : (1) To produce fibres (2) To secrete matrix. 102 PLASMA CELL - CART WHEEL CELL Structure Organisation in Animals Monolocular adipocytes/ White fat tissue-cell - Less in number. - - Amoeboid in shape In these cells single large and central fat globule is present. - Chromatin material is arranged like spokes in wheel so they are also called as Cart wheel cells. Formed by the division of lymphocytes. So they - nucleus & Cytoplasm is peripheral and Cytoplasm is less in amount. - are also called as clone of lymphocytes. Function : Produce, Secrete & transport antibody. Multilocular adipocytes/Brown fat tissue cell - In these cell 2-3 fat globules are distributed in the cytoplasm around nucleus - Cytoplasm is more in quantity. MAST CELLS/MASTOCYTES - Numerous , amoeboid and small in size. - Structurally and functionally similar to basophils. 2-3 lobed S-shaped nucleus - - Due to compression of fat globule, nucleus become flattened in shape . These adipocytes form White Fat. Nucleus is rounded & found in the centre These adipocytes form Brown Fat. Cytoplasm contains basophilic granules which can MESENCHYMAL CELLS be stained with basic dye Methylene Blue. Less in numbers . Small sized with cytoplasmic It is important cell of connective tissue proper as process having irregular shape. they perform important functions. (a) Histamine - Oval shaped nucleus - Histamine is a protein, a vasodilator - - Increase permeability of blood capillaries. - Take part in allergy and inflammatory reactions. These are undifferentiated cells of connective tissue because they can transform into any cell of connective Tissue proper. (Totipotent in nature) (b) Secotonin - - Also called as 5-Hydroxy tryptamine - It is a protein, a vasoconstrictor & decrease blood circulation but increases blood pressure. MACROPHAGES/ A the site of cut or injury serotonin decrease blood loss. - It is 2nd largest in size and in number. - Amoeboid in shape with bean or kidney shaped nucleus. (c) Function : To form other cells of connective tissue. HISTEOCYTE/CLASMATOCYTES. Heparin - A mucopolysaccharide, a natural anticoagulant, prevents clotting of blood in blood vessels by preventing the conversion of prothrombin into thrombin. Cytoplasm quantity is more a granular but due to presence of more number of lysosome it appears granular. - - Oval shaped stores fat. Phagocytic in nature, destroy bacteria & viruses by phagocytosis. They arises by the fusion of monocytes - Fat is collected in the form of fat globule formed by the fusion of small oil droplets. - On the basis of number of fat globules adipocytes are of two types. Also called as scavenger cells of connective tissue because they destroy dead or damaged cells to clean connective tissue. ADIPOSE CELLS/FAT CELLS 103 Structure Organisation in Animals Macrophages are named differently in different Reticular Fibres : organs. Precursor of Collagen fibres, delicate with no Lung - Dust cells Liver - Kupffer cells Blood - Monocytes Brain - Microgleal cells Thymus gland - Hessels granules Spleen Reticular cells - elasticity - Also known as Arzyrophil fibre since they can be stained with silver salts. - They are composed of recticulin protein highly branched fibres which always form dense network - These are mainly distributed in lymphoid organs like spleen or lymph nodes LYMPHOCYTES - MATRIX Less in number and small in size having amoeboid Matrix is composed of Mucopolysaccharide shape. which is present in the form of Hyaluronic acid. A large nucleus is present cytoplasm is present as peripheral layer. Cytoplasm quantity is less. TYPE OF CONNECTIVE TISSUE PROPER Produce, transport & secretes antibodies. They divide to form plasma cells of connective tissue proper. FIBRES Collagen fibres (White fibres) - They are shining white fibres composed of collagen protein (Tropocollagen). - It is present in maximum quantity in vertebrates, (only collagen fibres constituted one third part of connective tissue fibres in human beings.) - They are wavy & tough fibres always arranged in bundle called fascia. - On boiling they convert into gelatin. - They can be digested by Pepsin enzyme. CONNECTIVE TISSUE PROPER : Loose Connective Tissue : It consists of cells scattered within an amorphous mass of proteins that forms a ground substance. The gelatinous material is strengthened by a loose scattering of protein fibres such as collagen, elastin, which makes tissue elastic and reticulin which supports the tissue by forming a collagenous meshwork. Elastic fibres - (Yellow fibres) - Precursor in colour and composed of elastin protein. - They are branched fibres but always arranged singly. Branches of these form network. - In these fibres maximum elasticity is present. AREOLAR CONNECTIVE TISSUE - They are highly resistant to chemicals. - Also known spongy tissue. - When boiled they do not dissolve. - It is most widely distributed tissue in the body. - They can be digested by trypsin enzyme. - In this tissue maximum intercellular space or substances/matrix is present. 104 Structure Organisation in Animals Fig.: Loose connective tissue : Areolar tissue - - Due to irregular arrangement of bundle of collagen ADIPOSE CONNECTIVE. TISSUE fibres many gaps are present. These spaces called Modification of Areolar connective tissue. But in Areolae. areolae major component is adipocytes which In areolae other components of connective tissue store fats. are distributed like fibres, cell & matrix. Located mainly beneath the skin. - Few elastic fibres are present but reticular fibres are completely absent. Blood vascular system is also present in this tissue. - Mast cells, Macrophage & Fibroblast are present more in amount. - It occurs beneath the epithelia of many visceral organs skin and in the walls of blood vessels. Fibroblast is the main cell. If this tissue is treated with alcohol (organic solvent) Fat will be dissolved completely and adipocytes will become vacuolated. - This tissue can be stained with sudan solution. eg., Tela Subcutanea - A thin continuous layer which connect skin with underlying skeletal muscles (Pannicules carnosus). In mammals skin is tightly attached with muscles. While in frog it is present in the form of septum so skin is loosely attached with muscles. Endomysium - Around single muscles fibre. Fig.: Adipose Tissue Perimysium - Around bundle of muscle fibre. Outside of semniferous Tubules. - Medulla of ovary Sub mucosa of trachea, Bronchi, Intestine - On the basis of adipocytes 2 type of fats are found in animals. 1. White fat, 2. Brown fat White fat : The areolar tissue joins different tissues and forms the packing between them and helps to keep the organs in place and in normal shape. It is composed of monolocular adipocytes. Produce less energy. eg., Panniculas adiposus - A thin continuous layer of white fat under the dermis of skin. 105 Structure Organisation in Animals In hibernating animals during hibernation they obtain energy from stored brown fat. - Panniculas adiposus is absent in rabbit. Blubber - Thick layer of white fat found under dermis of skin. Found in whale, seal, elephants. Maximum thickness of this layer is found in Blue Dense Connective Tissue : whale (80 cm) Fibres and fibroblasts are compactly packed in the dense connective tissues. Orientation of fibres eg., Hump of camel, Tail of marino sheep, Yellow Bone marrow. show a regular or irregular pattern and are called dense regular and dense irregular tissues. Brown fat : In the dense regular connective tissues, the It is composed of multilocular adipocytes. collagen fibres are present in rows between many It produces 20 times more heat than white fat. parallel bundles of fibres e.g. tendons and Brown colour of fat is due to Cytochrome ligaments. Pigment. Dense irregular connective tissue has fibroblasts Cold resistance device in new born baby is due and many fibres (mostly collagen) that are oriented to presence of brown fat. It accounts for 5-6 in different directions. This tissue is present in the percent of body wt. skin, in perineurium and bones as periosteum. Fig.: Dense Connective Tissue (a) Dense Regular, (b) Dense Irregular WHITE FIBROUS CONNECTIVE TISSUE - Cord (Dense regular) Bundle of collagen fibres are more in quantity & 1. other components of connective tissue proper 2. are less in quantity. It has great tensile strength Bundle of collagen fibres & matrix are distributed in regular parttern (alternate pattern). Fibroblast cells are arranged in a series. Mast cells are scattered in matrix. eg. Tendon connects muscles & bones. - Yellow fibres & reticular fibres are completely absent. - Its presence at joints between skull bones makes them immovable. Sheath (Dense Irregular) On the basis of arrangement of fibres and matrix In this form there is irregular pattern of fibres & this tissue occurs in two forms matrix. Cells and fibres are criss - crossed - Strongest tendon of the body is Tendocalcaneus Tendon. This tendon connects Gastrocnemius muscles of shank with calcaneum bone of ankle. arranged. 106 Structure Organisation in Animals eg. - Pericardium RETICUlAR FIBROUS / - Periosteum - Outer covering of bone. LYMPHOID TISSUE - Perichondrium - Outer covering of cartilage. - It is mostly found in lymphoid organs. - Epimysium - Covering of muscle. - Matrix of this tissue is like lymph. - Renal capsule - Around Kidney. - Reticular fibres are more in amount & form dense network around star shaped reticular cells. (Phagocytic in function) - Duramater - Outermost covering of brain. - Lymphocyte cells are also more in number. - Cornea of eye - Provide support and strength and form the stroma (Frame work) of soft organs. eg. - Spleen - Tunica Albugenia - Covering of Testis. - Splenic capsule - Covering of spleen. - Trachea - Bronchi - Oesophagus. - Lymph nodes (Tonsils, Peyer's Patches). - Glison's capsule - Around lobe of liver. - Cortex of ovary. YELLOW FIBROUS - Endosteum (covering of bone marrow cavity) CONNECTIVE TISSUE - Lamina Propria, Trachea, Bronchi , Intestine - Yellow fibres are more in quantity but collagen MUCOID CONNECTIVE TISSUE fibres are also present. Also called Embryonic Tissue because it is Reticular fibres are absent. mainly found during embryonic life. On the basis of distribution of fibres & matrix Matrix is in abundance. they are of two types. Few collagen fibres & fibroblast cell may be Cord (Dense regular) : present. Bundle of collagen fibres & matrix distributed in Matrix is composed of jelly like material called a regular pattern & in matrix yellow fibres form Wharton's Jelly. network. eg. Ligaments - A structure which eg., Umbilical cord (connect Placenta with foetus) connects Bones. Viterous humor - In vitreous body of eye. Strongest Ligament of body is Ilio-fermoral ligament connects IIium bone of pelvic girdle with femur bone of Hind limb. - In quadrupeds like cow & buffalo strongest ligament is ligamentum nuchea present in the between two cervical vertebrae. Sheath (Dense irregular) eg. Irregular distribution of fibres and matrix with Elastic fibre. Comb of cock. PIGMENTED CONNECTIVE TISSUE It is a modification of areolar connective tissue but in areolae pigmented cells are more in number known as Chromatophores which provide colouration. Melanophore - Melanin - Black - Wall of Alveoli of lungs Guanophore - Guanine - White - Wall of small bronchioles Xanthophore - Xanthophil -Yellow - Wall of lymph vessels & Blood vessels eg.- Dermis of frog skin - True vocal cords - Iris & choroids of eye. 107 Structure Organisation in Animals SUPPORTIVE CONNECTIVE TISSUE - Matrix is dense mineralized. Due to deposition of minerals it becomes hard. - Also known as Skeletal Tissue form skeleton of body. - It is of 2 types 1. Cartilage - Solid, semi-rigid, flexible conn. tissue. 2. Bone - Solid, rigid conn. tissue. Hyaline Cartilage CARTILAGE - Outer most covering of cartilage is called Perichondrium which is composed of white fibres connective tissue. - Cartilage producing cells are arranged on periphery known as Chondrioblast. - These are active cell & divide to form chondriocytes, and synthesize the matrix of cartilage. - Mature cells of cartilage are called Chondriocytes. - They are found in vacuole like space in matrix called Lacuna in which 2-3 Chondrocytes are present. - Chondrioclast are cartilage destrolying cells. - Maxtrix of cartilage is called Chondrin composed of Chondromucoprotein having Chondroitin-6sulphate and Mucopolysaccharide (Hyaluronic acid) - White fibrous Cartilage Yellow elastic fibrocartilage Matrix of cartilage provides rigidity & elasticity Type of Cartilage to cartilage. There are following types of cartilage. Blood circulation is absent in the matrix of 1. Hyaline Cartilage. cartilage. 2. Fibrous Cartilage (a) Elastic cartilage (b) white fibrous cartilage 3. Calcified Cartilage. 108 Structure Organisation in Animals White fibrous cartilage Hyaline cartilage Perichondrium is absent because complete white Most of the part of embryonic skeleton is fibrous connective tissue is converted into composed of this cartilage. cartilage. Therefore, maximum bones of body are In matrix bundle of collagen fibres are more in cartilaginous bones because they are developed quantity so it is strongest cartilage. from cartilage. eg., Pubic symphysis Outermost covering Perichondrium is present. Pubis bone (Half part of pelvic girdle osinnomineta) are interconnected by pubic Matrix of this cartilage is glass like clear or symphysis. hyaline matrix. - Fibres are completely absent in the matrix of this Intervertebral disc cartilage. Only few collagen fibres may be A pad of cushion like structure which absorb present. mechanical shock and jerks and protect vertebral column. Central part of this disc is soft called as Colour of matrix is bluish and it is transluscent. Nucleus pulposus. (remnant of embryonic eg. Nasal septum. Notochord) Slight elongation of body after death 'C' shaped rings of trachea and Bronchi. or in sleeping posture is due to relaxation of this (Incomplete in dorsal surface) disc. Sternal part of ribs. (Costal cartilage) Calcified cartilage Larynx : Thyroid, Cricoid, Arytenoid. It is modified hyaline cartilage but due to Maximum part of Larynx is composed of hyaline deposition of calcium salts its matrix becomes cartilage. hard like bones. It is hardest cartilage of the body Articular cartilage - At the junction of two long Ca salt deposits in the form of Hydroxy apatite bones on articular surface. Ca10(PO4)6(OH)2. At the end of long bone periosteum is absent and eg., - Pubis of frog's pelvic girdle. Hyaline cartilage is present. - Supra scapula of pectoral girdle - Head of Femur & Humerus Fibrous cartilage Elastic cartilage eg. BONE Study of Bone - Osteology Perichondrium is present. Process of bone formation - Ossification In the matrix yellow fibres form network so it is Hardest Tissue - Bones highly flexible cartilage of body (Softest Tissue - Blood.) Colour of matrix is pale yellow. Hardest substance - Enamel. (It is not a group of Tip of Nose cell but it is formed by the secretion of ameloblast cells of teeth.) Ear Pinna Outermost covering of bone is Periosteum Epiglottis composed of white fibrous connective tissue. Larynx - Cartilage of santorini Bone producing cell called Osteoblast. They divide to form Osteocyte & synthesize organic Wall of Eustachian tube part of matrix. 109 Structure Organisation in Animals Mature cell of bone is called Osteocyte which is Metaphysis found in Lacuna. Only one osteocyte is found in It form little part between epiphysis & Diaphysis. lacuna. In this region epiphyseal plate is present which is made up of osteoblast cells. They divide to form Bone destroying cells are Osteoclast cells. osteocyte and also synthesize matrix of bone, so Structure of long bone : epiphysial plate is responsible for elongation of bone. After complete development of long bone this plate is destroyed. So a complete developed bone shows 2 regions while in a developing bone 3 regions are found. Spongy Bones Haversian system is absent. Marrow cavity is present in the form of Trabeculae filled with RBM. So all spongy bones of body are haemopoietic Ribs, Pubis, Sternum, Vertebrae, Clavicle, End of long Bones, Scapula - - Long bone has three region Compact Bone Haversian system is present. Diaphysis of long bone. Dipolic/Heterotypic Middle part of bone is composed of spongy (b) Diaphysis bone, in which Trabeculae is filled with RBM. (c) Metaphysis This bone is covered by compact bone on upper Epiphysis & lower surface. Ends of long bone is called Epiphysis. This part All flat bones of skull. is composed of spongy bone. Pneumatic Bone (a) Epiphysis - Cavity is present in the form of Trabeculae filled with red bone marrow. Diaphysis - Middle part or shaft of long bone is diaphysis which is composed of compact bone. In the matrix air filled spaces are present so bone become light in weight. Bones of birds. INTERNAl STRUCTURE OF In this region hollow cavity is present called bone MAMMALS BONE It has following major structures. marrow cavity filled with yellow bone marrow composed of white fat. Function is storage of 1. Periosteum 2. Matrix fat. 3. Endosteum 4. Bone marrow cavity 110 1. PERIOSTEUM - Outermost covering consists of two layers. - Outer layer consist of WFCT in which blood circulation is present. - - 2. Inner layer - consists of single layer of osteoblast cells. These cells are cube like in shape in which oval shaped nucleus & basophilic granules are present in cytoplasm. They divide to form osteocyte and secrete layer of matrix. MATRIX It is composed of inorganic & organic compounds. Inorganic Part - 65 - 68% Ca3(PO4)2 - 80% max. rest 20% CaCO3, Mg3(PO4)2, Flourides. 1. 2. 3. - Organic part - 32-35% Ossein in which bundle of collagen fibres suspended in sulphated mucopolysaccharide. Structure Organisation in Animals Haversian canals are central Longitudinal canals which are arranged parallel to long axis of bone. In this canal 1 or 2 blood capillaries and nerve fibres are present. Volkman canals are transverse/horizontal or oblique canals. Haversian canals are interconnected by means of volkmann's canal. Matrix of bone is synthesized in the form of layer called Lamellae. On the basis of arrangement 3 types of lamellae are present in the matrix. Haversian lamellae Interstitial lamellae Circumferential lamellae. Haversian lamellae are Concentric layers of matrix which are present around Haversian Canal. Between these lamellae layer of Osteocyte cells are also present. Haversian canal, Haversian lamellae & Osteocyte form Haversian system or Osteon. Sharpey's fibre - extra bundle of collagen fibres which are present in the outermost layer of matrix called Sharpey fibres. They are also found in the cement of teeth which provide extra mechanical support to bone & teeth. - In the matrix of bone 2 types of canals are present. 1. Haversian canal 2. Volkmann's canal - - (1) (2) - Presence of Haversian system is a typical feature of mammalian compact bones. Osteocyte are present in the lacuna.Each Osteocyte is inter connected with adjacent Osteocyete by their cytoplasmic process. Cytoplasmic process of Osteocyte are present in the canals of lacuna called as canaliculi. Interstitial lamellae are present in the space between 2 haversian systems Circumferential lamellae are of 2 types. Outer circumferential lamellae : These are present around all haversian system. These are peripheral layers of matrix. Inner circumferential lamellae Present around bone marrow cavity. 111 3. Structure Organisation in Animals Flat bones of skull - Parietal Bone, Frontal, Larymal, Temporal ENDOSTEUM Endosteum consist of 2 layers. (a) (b) 4. Bones of upper Jaw - Maxilla, Palatine Towards bone marrow cavity lined with layer of reticular fibrous connective tissue. Bones of lower Jaw - Mandible (Human)/Dentary (other mammals) Towards matrix of bone line with layer of Osteoblast cell. They divide to form osteocyte Sesamoid Bones & synthesize matrix. So growth of bone is These bones are developed by the ossification bidirectional (Periphery and central region). While of tendons at the joints. Growth of cartilage is eg., Pisciform (wrist bone) of man and rabbit. unidirectional. (One out of 8 carpals in man and 1 out of 9 BONE MARROW CAVITY carpals in Rabbit). - In the central region hollow cavity is present which Patella (knee bone) Largest sesamoid bone. is filled with YBM. It is composed of white fat & its function is collection of fats or storage of fats. Visceral Bones If ossification take place in the visceral organs TYPE OF BONES then visceral bones are formed. These are rare On the basis of development or location of bones, found in few animals. In rabbit & man ossification bones are four types. these bones are absent. Cartilagenous bones/Replacing Endochondral bone - / These bones are developed from cartilage or they are formed by the ossification of cartilage. In the formation of these bones 2 types of cells are required. eg., Os Cardis : Present in inter ventricular septum of Deer's heart Os Palpebrae : In the eyelid of crocodile Os Penis (Baculum ) : In the Penis of rodents, rat, shrew, Bat, Whale, Tiger. Os rostralis : In the snout of pig. 1. Chondrioclast - Which reabsorb cartilaginous matter. 2. Osteoblast - Which deposit bony matter into Table : Difference between a Dried bone and a Decalcified bone cartilage so cartilage is replaced by bone. Hence these bone are also called as replacing bones. eg., Maximum bones of our body like limb bones (Fore & Hindi), Ribs ; vertebrae Girdle bones except clavicle. Os falciparum : Palm of mole Membranous bones/Dermal bones/Investing bones - These bones are developed from the connective tissue of dermis or formed by ossification in the connective tissue of dermis. e.g., Sternum, Nasal Bone, Clavicle, Vomer Bone, Skull bones. 112 FLUID CONNECTIVE TISSUE There are two types of Fluid connective tissue : (1) Blood (2) Lymph Matrix is liquid & fibre free 2. Structure Organisation in Animals PLASMA - Matrix of blood is called Plasma. - It is pale yellow in colour due to Urobillinogen. (Billirubin) 1. BLOOD - Study of Blood - Haematology Process of blood formation Haemopoiesis. Colour - Red Composition of plasma PH - 7.4 (Slightly alkaline) Water : 90% - 92% By weight - 7 to 8% of body weight Solid part : 8 - 10% By volume - 5 - 6 litres in male and 4-5 litres in female. In which inorganic and organic compounds are Blood is a false connective tissue because present. Cells of blood have no power of division. Inorganic part of plasma - 0.9% in which Fibres are completely absent in blood. 1. Ions Na+ , K+, Ca++ Matrix of blood is produced and synthesized by Cl- , HCO3+, SO4- 2, PO4-3 liver and lymphoid organs. Cl- , > Na+ a. b. c. Composition of Blood Liquid Part - Matrix - Plasma 55% Solid Part - Blood corpuscles - 45% (RBC, WBC & Platelets) [Formed Elements] Packed cell volume (PVC)% volume or Total number of blood corpuscles is blood. Haematocrit Volume : % volume or only number of RBC in blood. PVC HV because 99% of Packel cell volume is completed by RBC & in rest 1% WBC & Platelets are present. 2. Salts - NaCl, KCl, NaHCO3, KHCO3 Maximum : NaCl (also called as common salt.) 3. Gases - O2, CO2, N2 Each 100 ml of plasma contains 0.29% O2, 0.5% N2, 5% CO2 Present in dissolved form Organic Part of Plasma - 7% - 9% Proteins 6 - 7% Maximum Albumin 4% (Max.) - Produced and synthesized by liver - Responsible to maintain BCOP (28 - 32 mm Hg.) Globulin : - 1.5% - 2.5 % 113 (i) (ii) Ratio of Albumin & Globulin is 2 : 1. Produce and secreted by liver and Lymphoid organs. Transport or carry substance in body. Destory bacteria virus & toxic substances. In blood 3 types of Globulins are present. -Globulin - Produced by liver. eg., Ceruloplasmin - Cu carrying protein. -Globulin - Produced by liver eg., Transferin - Fe carrying protein. (iii) Structure Organisation in Animals -Globulin - Produced by Lymphoid organs Present in the form of antibodies which destroy Bacteria, Virus & Toxic substance. Also called Immunoglobulins .These are of 5 types. (IgG, IgA, IgM, IgE, IgD) Prothrombin - 0.3% Produced by liver Fibrinogen - 0.3% Prodcued by liver - Largest plasma protein . - Help in blood clotting. Digested Nutrients BLOOD CORPUSCLES Erthrocytes (Red blood Corpuscles) Urea, Uric acid, Creatine, Creatinine Mammalian RBC's are Biconcave, circular & Normal blood urea level 17-30 mg% enucleated. If blood urea becomes more than 40 mg this At the time of origin nucleus is present in the RBC condition is called Uremia in which R.B.C. but it degenerates during maturation process. become irregular in shape called burr cell which Biconcave shape of RBC increase surface area. are destroyed in spleen so uremia is a type of Due to absence of nucleus & presence of anaemia. biconcave shape more Haemoglobin can be filled in RBC. Anticoagulant Exception :- Camel & Lama are mammals with Heparin-A Mucopolysacchride which prevent bioconvex, oval shaped & nucleated RBC. clotting of blood in blood vesels. Waste Products Defence compounds 1. Lysozyme, 2. Properdin Hormones - Secreted by endocrine glands which are transported by blood plasma. 114 - - - - Structure Organisation in Animals In RBC Endoplasmic Reticulum is absent so Heam (Iron and Porphyrin) endoskeleton is composed of structural protein, Iron Present in the form of Fe+2 fats and Cholesterol present in the form of Prophyrin is composed of Acetic acid and network called stromatin which is a spongy Glycene amino acid. cytoskeleton. Each molecule of Hb carries 4 molecules of O2 Due to presence of stromatin spongy cytoskeleton 1 gm Hb carries 1.34 ml O2 & flexible Plasma Membrane RBC (7. 5) can 100 ml blood contain 15 gm Hb pass through less diameter blood capillaries (5) 100 ml blood transport 20 ml O2 Plasma Membrane of RBC is called Donnan's Globin: Each molecule of globin protein is membrane. It is highly permeable to some ions composed of 4 polypeptide chains. Polypeptide like Cl & HCO3 ions and impermeable to Na+ & chains are of 4 types. K+ inos. It is called Donnan's phenomenon. 1.  polypeptide chain having 141 Amino Acids In RBC higher cell organelles like Mitochondria 2.  polypeptide chain having 146 Amino Acids & Golgi complex is absent. 3.  polypeptide chain having 146 Amino Acids Due to absence of Mitochondria anaerobic 4.  polypeptide chain having 146 Amino Acids respiration takes place in RBC. - In RBC enzyme of glycolysis process are present, while enzyme of Kreb's cycle are absent. - In RBC carbonic anhydrase enzymes is present which increases rate of formation & dissociation of carbonic acid by 5000 times. (Fastest catalyst (with zinc)) - Antigen of blood group is present on the surface of RBC. - If Rh Antigen is present then it is also found on the surface of RBC. - Single RBC is pale yellow in colour while group of RBC appear red in colour. - In RBC. red coloured respiratory pigment Haemogobin is present. - In each 26.5 crores molecules of Hb are present - Molecular weight of each molecule of haemoglobin 67,200. - In composition of RBC 60% H2O & 40% solid part is present. Only Hb. Constitutes 36% of total weight of RBC and 90% on of dry weight. Haemoglobin It is composed of two components 1. Heam - 5% 2. Globin - 95% On the basis of these polypeptide chains 3 type of Hb are formed in human Hb A (Adult Hb) 2 + 2 Hb A2 (Adult-2) 2 + 2 HbF (Foetal Hb) 2 + 2 (Oxygen binding capacity of foetal Hb is more than adult Hb) Size of RBC Human - 7.5 Rabbit - 6.9 Frog - 35 Largest RBC- Amphiuma 75-80 (Class Amphibia) Smallest RBC-Musk Deer 2.5. (Class Mammalia) Largest RBC among all mammals in Elephant 9-11 Change in the size of RBC is called as Anisocytosis Due to Vit. B12 deficiency RBC become larger in size called as Macrocytes. These are immature RBC which are destroyed in spleen. In these RBCs amount of haemoglobin is normal. Due to Fe deficiency RBC become smaller in size called as Microcytes. They are also destroyed in spleen. In these RBCs amount of haemoglobin is less. 115 Shape of RBC - 1. - Biconcave - Change in the shape of RBC is called as Poikilcoytosis. - Uremia-RBC become irregular in shape. Structure Organisation in Animals Macrocytic Normochromic anaemia - Due to Vit. B12 deficiency macroytes are formed which are destroyed in spleen. In Macrocytes % of Hb is normal. 2. - Sickle cell anaemia-RBC become sickle shaped. Microcytic/Hypochromic anaemia - Due to Fe deficiency microcytes are formed. - If RBC is kept in Hypertonic solution it will shrink 3. (crenation). Normocytic/Normochromic Anaemia - Excess blood loss. - In Hypotonic solution it will burst. - Formation of RBC 0.8-1% NaCl solution is isotonic for RBC. (0.9% Process of formation of RBC is called of NaCl) Erythropoiesis. 80-100 mg% of glucose is also isotonic. - Organs which produce RBC's called Erythropoietic organs. - Hormone which stimulate Erthyropoiesis is called Erythropoietin synthesize by Kidney. Life span of RBC Human - 120 days New Born Baby - 100 days Rabbit - 80 days - 1st RBC is produced by yolk sac. Frog - 100 days - During embryonic life RBC are produced by Liver, Spleen, Placenta, Thymus gland. - In adult stage RBC is produced by RBM which filled in Trabeculae of spongy bones. - Kidney is an erthyropoietic organ in frog. - 1% RBC are destroyed daily but in same number new RBC are entered in the blood. - Destruction of RBC occur in spleen. So spleen is called Grave yard of RBC. - Spleen stores excess blood corpuscles so it is called Blood Bank of body. - In resting and slow flowing blood, the RBC form pile called Roulaux by adhering together due to surface tension. Fibrinogen favours rouleaux condtion. - Minute bits of disintegrated red blood corpucles in known as Haemoconia Avg. life span of RBC in all mammals 120-127 days. Radioactive chrominum method is used to estimate life span of RBC RBC count Number of RBC in per cubic mm of blood is called RB count. - - Increase in the RBC count condition is called polycythemia. This condition occurs at hill station. Ghost of RBC is made up of its plasma membrance. Decrease in RBC count condition is called Anaemia. 116 Structure Organisation in Animals Table : Difference between different types of Leucocytes Characte Lymphocytes Monocytes Eosinophils Basophils Neutophils Number/ percentage 30% 5.3% 2.3% 0.4% 62% Granules in cytoplasm Staining of cytoplasm Nucleus Absent Absent Coarse Coarse Fine Eosinophilic Basophilic Neutrophilic Rounded Bean-shaped Bilobed Site of Formation Lymph nodes, spleen, thymus, tonsils, Peyer's patches, Bone marrow Few days or even years Bone marrow Bone marrow S-shaped 3-lobed Bone marrow Multilobed (3 – 7) Bone marrow 10-20 hours in the blood tissue, months or even years 4-8 hours in blood and 4 to 5 days in tissue 4-8 hours in blood and 4 to 5 days in tissue 4-8 hours in blood and 4 to 5 days in tissue Antibody formation Phagocytic Important role in immunity anti-allergic Secretion of heparin, histamine and serotonin Phagocytic Life span Function es 117 Structure Organisation in Animals LEUCOCYTES (WBC) - BASOPHILS WBC (White Blood Corpuscles) are also called as leucocytes because they are colourless. TLC =Total leucocyte count. Number of WBC/ mm3 8000 - 11000/mm3 Leucocytosis : - Increase in TLC. This condition occur in Bacterial & Viral infection. Minimum in number Amoeboidal in shape Size 8 -10 Smallest granulocytes Their main function is to secrete & transport Heparin, Histamine & Serotonin produced in liver. Leucocytopenia :- Decrease in TLC. Normally TLC increases in Bacterial & Viral infection but NEUTROPHILS/HETEROPHILS in typhoid & AIDS, TLC decreases. Maximum in number Leukemia :- Abnormal increase in TLC (more Amoeboid in shape than 1 Lakh) it is called as blood cancer. Size 10-12 - On the basis of nucleus & nature of cytoplasm, Leucocyte are of 2 types. Granulocytes - Counting of lobes of Neutrophils is called Arneth count. - They are active, motile WBC - In their cytoplasm granules may be present which can be stained by specific dye. - Nucleus may be multilobed and lobes are interconnected by protoplasmic strand. - Phagocytic in nature Produced in Bone marrow - Destroy Bacteria & Viruses by phagocytosis. - They are (i) Acidophils, (ii) Basophils & (iii) Neutrophils Agranulocytes They can squeeze & comes out from the wall of blood capillaries in Tissue. This phenomenon is called Diapedesis. Due to their smaller size & Phagocytic nature they are called Micropoliceman. Help in sex detection. In female neurophils barr body is attached with lobe of nucleus which is formed by the modification of x chromosomes. - Cytoplasm is clear & granular - Nucleus do not divide in lobes so called as Mononuclear WBC. - - Produced in Bone marrow MONOCYTES Barr body is absent in male. They are of 2 types (i) Monocytes (ii) Lymphocytes ACIDOPHILS/EOSINOPHILS - Size 12-20 - Amoeboid in shape. - Active motile WBC. - Size 10-14 - Phagocytic nature. - In parasitic infection they act as lysosome. They attach with the surface or body wall of parasite and synthesize enzymes which dissolve body wall of parasite & destroy them. - Increase in number of acidophils condition is eosinophilia which occurs in Taeniasis, Ascariasis, Hay fever (parasitic infection) Largest Blood Corpuscles. Power of Diapedesis is present. Destroy Bacteria & Viruses by phagocytosis so called Macropoliceman. Also called scavenger of blood because they engulf damaged or dead & minute bits of blood corpuscles. 118 LYMPHOCYTES - Amoeboid in shape. - Size 6-16 (smallest WBC) - Lymphocytes are of 2 types. - T-LYMPHOCYTES - 1. 2. 3. Structure Organisation in Animals Decrease in number of Blood Platelets is called Thrombocytopenia. Critical count of Thromocytes is 40,000/mm3. If number is less than critical count then red spot or rashes appears on the skin called Purpura disease. Produced in bone marrow but mature in thymus Function gland. On the basis of function T-Lymphocyts Repair endothelium of blood vascular system by are of 4 types the formation of platelet plug because they have T-Killer/Cytotoxic : - Direct kill Bacteria or tendency to attach on gelatinous or mucilaginous Viruses surface. T-Helper : - Stimulate B-lymphocytes to produce Synthesize Thromoboplastin which help in blood antibody. clotting. T-Suppressor : - Suppress T killer & protect immune system. - Synthesize serotonin. T-memory : - Stones profile of bacteria or virus BLOOD CLOTTING Blood flows from cut or wound but after some or protein. times it stops automatically. It is called clotting of B-LYMPHOCYTES blood. Produced in bone marrow and mature in bone Bleeding time 1-3 min. marrow. Its function is to produce, synthesize & Clotting time 2-8 min. transport antibodies Some times clots are also formed in intact blood vessels which are of 2 types. PLATELETS Thrombus Clot Also known as Thrombocytes Static clots which grow bigger & ultimately block Found only in mammals while in other vertebrates, the blood vessels. Spindle corpuscles are present which perform If this clot is formed in the coronary vessels then same function. called as Coronary Thrombosis which can cause They are non nucleated and derived from heart attack. Megakaryocyte cells of bone marrow. If form in brain, then called as Cephalic In shape platelets are disc like, oval shaped or Thrombus causes paralysis. biconvex. Embolus clot While spindle corpuscles are spindle in shape & Moving clots which flow with blood & ultimately round nucleus is present in the centre. dissolve in blood. In their cytoplasm basophilic granules are present More harmful due to their moving nature. which can be stained by methylene blue. Machanism of blood clotting Maximum part of cytoplasm is composed of (Enzymes Cascade theory) contractile protein Thrombosthenin. Proposed by Macfarlane & Co-workers. Size 2-3 4. - Life span - 2-4/5 days - Count - 1.5-4.5 lakh/mm3 - According to this theory there are 3 steps in blood clotting. 119 Structure Organisation in Animals IX - Christmas factor 1. Releasing of Thromboplastin- - Injured tissue synthesize exothromboplastin and platelets synthesize endothromboplastin. X - Stuart factor Both these thromboplstin react with plasma proteins in the presence of Ca++ ions to form XII - Hagman factor - XI - PTA (Plasma Thormboplastin Anticedent) XIII - FSF Factors (Fibrin stabilizing factor) Prothrombinase enzymes. (Thrombokinase) (Laki Lor and factor). - This enzymes inactivate Heparin. (Antiheparin) 2. Conversion of Prothrombin into Thrombin - Prothrombinase enzymes convert inactive prothrombin into active Thrombin in the presence of Ca++ ion. Hirudin - found in leech. 3. Conversion of fibrinogen into fibrin Cumerin - obtain from plants - Fibrinogen is soluble protein of plasma. Thrombin protein polymerise monomers of fibrinogen to form insoluble fibrous protein fibrin. Warfarin - obtain from plants - - - Anophelin - found in female Anophelese. Lampredin - found in Peteromyzon (Lamprey) Fibrin form network on cut in which blood corpuscles got trapped. This form clotting of blood. Sodium oxalate EDTA (Ethylene diamine tetra acetic acid) These chemicals act as Calcium binding units and remove Ca+2 ions from blood. = Plasma Plasma - fibrinogen and large protein = Serum Clotting Factors :- Blood Groups - Antigen of blood groups is present on the surface of RBC also called as agglutinogen. - Antibody for blood group antigen is present in serum (Plasma) called agglutinin. - 13 factors help in blood clotting. - These factors are mainly produced in liver. - Vitamin K is required in the synthesis of these clotting factors. - To collect blood in bottle in blood bank artificial anticoagulants are used like Sodium citrate After clotting a pale yellow liquid oozes from clot called Serum. In which antibodies are found. Blood - Corpuscles Other natural anticoagulants are These factors are represented in Roman number. Antigen & Antibody are special type of glycoproteins. - Blood groups are of 4 type A, B, AB, O VII - Proconvertein - A, B, O discovered by Landsteiner. VII - AHG Anti Haemophelic Globin - AB discovered by De Castello & Struli. - Blood group O is universal donar & Blood group is AB is universal acceptor. I - Fibrinogen II - Prothrombin III - Thromboplastin IV - Ca+2 (cofactor in each step of blood clotting) V - Proaccelerin VI - Accelerin (Rejected) (Absent in Haemophilia-A) 120 1. - Blood groups are example of multiple alleles. - For gene of blood group 3 alternatives are present. - Gene A & B are dominant gene. They can give their expression in homozygous and hetrozgous 2. condition so blood groups A & B are due to dominant gene A&B - - Gene O is recessive gene which gives its expression in homozygous condition. Blood Group O is due to recessive gene. If mother is Rh- & father is Rh+ then offspring is also Rh+ In this case 1st pregnancy is completely successful but at 1st delivery Rh antibody is formed in mother's blood due to damaged blood vessel so in next pregnancy death of foetus will occur in the earilier stage due to agglutination of blood called erythroblastosis foetalis. To destroy Rh antibody medicines are used like Rhogam, Rholin, Anti D. MUSCULAR TISSUE Origin - I0 I0 O Structure Organisation in Animals If Rh blood is transfused to Rh- then 1st blood transfusion complete successfully but during Ist blood transfusion Rh antibodies are formed in receiver's blood so in next blood transfusion. agglutination of blood takes place. + It develop from the mesoderm of embryo. Special property Blood group AB is an example of co-dominance Contractibility is the special property of in which both dominant gene A&B are present. muscular tissue. The cells of muscular tissue can IAIB AB shorten considerably and return to original relaxed state. The muscle cells contract in a definite RH FACTOR direction. Discovered by Landsteiner & Weiner in Rhesus Functions of muscular tissue monkey. Muscles support the bone and other structure. Rh antigen is due to dominant gene. So if one of - - the gamete possess gene of Rh factor, its off spring will be always Rh + Ve If antigen is present then Rh+ - If antigen is absent then RhIn India % ratio of Rh is - Muscles are required for delivering a baby.  40% to 50% of body weight is contributed by muscles. - 97% Rh- - 3% (a) Muscles are of three types Rh+ - 80% (b) Striated muscles - - 20% (c) Unstriated muscles (d) Cardiac muscles Rh - Muscles brings movements of the body parts and locomotion of individual. Rh+ TYPES OF MUSCLES In World - Muscles are responsible for heart beat production of sound, etc. + In Rh antibody is absent for this antigen - Rh antibody is also absent in Rh blood But 121 Structure Organisation in Animals STRIATED MUSCLES Fig.: Skeletal (Striated) muscle tissue Structure Striated muscle fibre is also called stripped. skeletal or voluntary muscle fibre. These muscle fibres occurs in bundles and are attached to the skeleton. Each muscle fibre is surrounded externally by a delicate membrane sarcolemma. In each fibre many nuclei appears at irregular interval, so each fibre is syncytial. The cytoplasm (Sarcoplasm) of each fibre possess large number of myofibrils which are tightly packed. Each myofibril possess dark and light bands alternating with each other. Detailed structure of a myofibril Fig. Structure of Vertebrate Striated Muscle at Magnification - -  - myofilaments arranged longitudinally. The primary The dark band of myofibril is called A-bands myofilament is made of a protein called myosin (Anisotropic bands). Each A band possess a whereas secondary myofilament is made up of 3 light zone called H-zone or Henson's protein actin tropomyosin, troponin. Besides actin membrane in the middle. and myosin muscle fibre also contain calcium ion, The light band of myofibril is called I-bands a phosphate and adenosine triphosphate (ATP) (Isotropic bands). Each I-band possess a thin The primary filament remain confined to A bands dark z-disc or krause's membrane in the middle. only. Krause's membrane is also called Dobie's line Location or Zwischencheibe line. Striated muscles are found in the muscle of limbs, The portion between two disc is called a sarcomere. tongue, pharynx, beginning of oesophagus, etc. Sarcomere are the functional units of myofibrils. Each sarcomere has two types of myofilaments; Function a coarse or primary and fine or secondary These muscles are under control of will. 122 Structure Organisation in Animals UNSTRIATED MUSCLE CARDIAC MUSCLES Structure Cardiac muscle fibres shows character of both striped and unstriped muscles, fibres in some characteristic, but also have some peculiar characters of its own. Similarities with striated muscle fibres : Cylindrical, high vascularization, having more mitochondria and glycogen granules in the sarcoplasm; and having light and dark bands. Fig.: Smooth (Unstriated) muscle tissue Structure Unstriated muscle fibre is also called smooth, involuntary, unstriped or visceral muscles. Each fibre is elongated or spindle shaped, having single oval nucleus surrounded by cytoplasm. Each muscle fibre possess longitudinally myofibrils arranged. The fibre is enclosed by plasma membrane and unlike striated muscle there is no sarcolemma. Several of muscles fibre are joined together in bundles by loose connective tissue. Location Unstriated muscles are found in stomach, intestine, lungs, urinary bladder, urinogenital tract, iris of eye, dermis of skin, posterior part of oesophagus and arrector pilli muscles of hairs. Function These muscle fibres help in peristalsis. It causes slow and prolonged contraction which is involuntary i.e. not under control of will but are controlled by autonomic nervous system. Single-unit smooth muscles (i) Multi-unit smooth muscles They have num ber of muscle fibres closely joined together. (i) They have number of muscle fibres not so closely joined. (ii) all the fibres contract together as a single unit, automatically and rhythm ically. e.g. Walls of hollow visceral organs like stomach, intestine, urinary balder etc. (ii) The individual fibres contract s separate units more of less as independent muscle e.g. hair roots, and on the walls of large blood vessels. Similarities with smooth muscle fibres Uninucleate; involuntary, covered by plasma membrane. Fig.: Cardiac Muscle Tissue Unique character - Cardiac muscles fibre are joined with each other by flat dense zig-zag junctions, called intercalated discs or booster rings. - Cardiac muscle fibre is supplied by both central nervous system and autonomic nervous system. - These muscles never get fatigued, blood capillaries penetrate the cardiac muscles fibres. They have the property of contraction even when they are isolated from the body temporarily. - Shows long refractory period. Location : These muscle fiber are found in the wall of heart and have very rich blood supply. 123 Structure Organisation in Animals Differences between striated, non striated and cardiac muscles. S.No. 1. Striped Also called striated, skeletal and voluntary muscle Unstriped Also called non-striated, smooth, visceral and involuntary muscle Cardiac Also called heart muscle 2. Occur in the body wall, limbs, tongue, pharynxand begining of oesophagus Occur in the wall of hollow viscera, iris of the eye and dermis of the skin. Occur in the walls of heart, pulmonary veins and superior venacava. 3. Have numerous mitochondriaand glycogen granule Have less numerous itochondria and glycogen granules Have numerous mitochondria and glycogen granules 4. T-tubule system well developed T-tubule system lacking T-tubule system well developed 5. No intercalated discs No intercalated discs Intercalated discs occur between the end of fibres. 6. Voluntary Involuntary Involuntary 7. Fibres unbranched Fibres unbranched Fibres join by short oblique bridges 8. Blood supply is abundant, capillaries lie on the surface of fibres Blood supply is scanty, capillaries lie on the surface of fibres Blood supply is abundant, capillaries penetrate the fibres, Lymphatic capillaries also present Uninucleate, nucleus at the centre Mostly uninucleate, Nucleus at the centre. My ofibrils distinct and with faint alternating light and dark bands 9. Multinucleate, nuclei just near the sarcolemma 10. Myofibrils large and prominent, show distinct alternating light and dark cross bands, hence striped Myofibrils indistinct and do not have light and dark bands, hence unstriped 11. Contract quickly and power-fully, but cannot maintain contraction for a long time, hence soon get fatigued. Contract quickly, Powerfully Contract slowly and mildly, but can remain contracted for and rhythmically, non-fatigue. a long time, are not fatigued. indefatigable 12. Innervated by motor nerves from central nervous system (neurogenic) Innervated by nerves from autonomic nervous system (neurogenic) Innervated by nerves from central and autonomic nervous systems (neurogenic + Myogenic) 124 Structure Organisation in Animals NERVOUS TISSUE Cyton Cyton is also called cell body or soma, its shape is variable. Nervous tissues originate from ectoderm of embryo. Its cytoplasm is granular called neuroplasm, within Special properties neuroplasm has a prominent spherical nucleus The special properties of the cells of nervous golgibodies, endoplasmic reticulum lysosome, fat tissues are excitability and conductivity. globules, Nissl's granules and neurofibril is found. The cells of nervous tissues are specialized for Nissl's granules are comparatively large and receiving stimuli and transmitting message. irregular masses of ribosomes and rough endoplasmic reticulum. It is believed that These tissue forms nervous system of the body Nissl's granules synthesize protein in the and include the following parts : cell. Nissl's granules are made up of m-RNA, ER, Ribosomes and has affinity for basic dyes. A mature neuron cannot divide. Nerve processes The nerve processes are also called neurites. Composition Nerve processes can be divided into two partsNervous tissue is formed of four types of cells (a) Dendrites (b) Axon Neurons (a) Dendrites Neuroglia Dendrites may be one or several. It is branched Neuro-secretory cells structure. Ependymal cells (b) Axon It is single, long and cylindrical process whose Neurons main function is to conduct the nerve impulses A neuron is a nerve cell with all its branches, away from the cyton, so, axon is efferent in nature. Neuron is formed from neuroblast. It is the longest nerve process of a neuron. It is structural and functional unit of nervous Note : system. Giant squid (loligo) has axon of about 1500 m in Epineurium diameter. Perineurium Neurons with very long axon is called golgi type I. Nerve fibres Axon possess only neuro-fibrils. (Nissls Granule, Fasciculi Golgi body, Ribosome, fat globules are absent). Blood vessel The part of cyton from where the axon arises is Fat cells called axon hillock. Some axon also gives rise to Endoneurium side branches called collateral fibres.  Neuron is the longest cell of the body. The plasmalemma of axon is called axolemma Structure : Neurons is formed of two parts whereas cytoplasm is called axoplasm. The axon ends in a group of branched, the terminal (A) Cyton arborization, ends of terminal arborization possess (B) Nerve processes knob like structure called synaptic knob or synaptic buttons. Origin - 125 Structure Organisation in Animals Synapse  Acetylcholine or adrenaline is produced by the secretory vesicles of the synaptic knobs. - Synaptic knobs comes to lie very close to the dendrons of next neuron to form the synapses. Types of neurons There is a microscopic gap of about 200A called synaptic cleft. - The nerve impulses are transmitted from axon to dendron with the help of chemical called neurotransmitters which is either acetylcholine or adrenalin (epinephrine) 126 - - - On the basis of number of dendron and axon neurons are of 3 types Unipolar neuron - The neuron having a single process the axon are called unipolar neuron. e.g.Unipolar nervous system occurs in embryo. Bipolar neuron - The neuron having one dendron and an axon at the opposite pole of the cell are known as bipolar neuron. e.g. Bipolar neuron occur in retina of eye, Olfactory epithelium, Organ of Corti, Taste bonds. Multipolar neuron : The neuron which have many dendrons and one axon are termed as multipolar neuron. e.g. Multipolar neuron occur in nervous system of adults. Structure Organisation in Animals On the basis of functions neurons are of 3 typesSensory or afferent neuron - They connect Sensory organs with central nervous system and brings sensory impulses into it. Motor or efferent neuron - They connect central nervous system with the effectors. (muscles and glands) and carry motor impulses to them. Interneurons or adjustor neuron - They are present in the central nervous system (Brain and spinal cord) and connect two or more neurons for distant transmission of impulses. Nerve fibres An axon of a neuron is covered with one or two Medullated or myelinated nerve fibre sheaths. In these nerve fibres around the nerve a sheath of fatty substance is formed which is termed as On the basis of presence or absence of sheaths medullary sheath or myelin sheath. on nerve fibre, nerve fibres are of two types - Medullated or myelinated nerve fibre - Non medullary nerve fibre - The medullary sheath is not continuous and point of absence of medullary sheath is called nodes of Ranvier. The part of medullated nerve fibre between two adjacent nodes is called an internode. Medullary sheath forms an insulating coat and prevents loss of energy during conduction of nerve impulse. 127 - The medullary sheath and node of ranvier are surrounded by a transparent cellular outer covering known as neurolemma of Schwann cell. - Just beneath the neurolemma a thin layer of cytoplasm lies, which contains nuclei to form Schwann cells (Sheath cells) at intervals. These nuclei are termed nuclei of Schwann cell. - Medullated nerve fibre are found in brain spinal cord, cranial and spinal nerves. In the central nervous system, medullated nerve fibres form white matter. Structure Organisation in Animals The non medullated nerve fibres exists in autonomic nervous system. In central nervous system non medullated nerve fibre are found in grey matter. Functionally the nerve fibres are of two types : Afferent or Sensory fibre - Afferent fibre carries the sensory impulse from the receptor organs to the central nervous system (brain and spinal cord). Efferent or motor fibre - Efferent fibre carries impulses from the central nervous system to the various effector organs (muscles and glands). Non-medullated (Non myelinated) nerve fibre - In these nerve fibre no medullary sheath is found. Neuroglia or Glial Cells These are non nervous cells which lie between the The axon is surrounded by neurilemma and just neurons of CNS, ganglia and retina of the eye. below neurilemma a layer of cytoplasm containing These are many times (10 times approx) more nuclei at intervals is present. The node of Ranvier numerous than neurons. and internode are not present. Types of neuroglial cells Neuroglia cells are of following types Ependymal cells Microglia cell - These are spindle shaped small cells. These cells form an epithelium called ependyma that lines the ventricles of brain and the central Astrocytes - These are highly branched. canal of the spinal cord. The cells are generally Oligodendrocytes - These have few branched ciliated. processess which resemble dendrons of the neuron. Neurosecretory cells Functions These are special type of neurons of the These act as packing cells between neurons. hypothalamus of brain. These are endocrine in These provide nutrition to neurons function and release neurohormone (releasing factor) through portal system to anterior most These act as phagocyte and consume micro organism. lobe of pituitary gland where they regulate secretion of harmones TSH, GH, LH, ACTH, These help in memory process FSH and Prolactin. These insulate the adjoining neurons. 128