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Tissues A tissue is a group of similar cells that usually have a common embryonic origin & functions together to carry out specialized activities. Tissue Epithelial Tissue Connective Tissue Muscle Tissue Nervous Tissue Meghna.D.Punjabi Slide 2 Epithelial Tissue: Covers body surfaces; lines hollow organs,body cavities,and ducts;and forms glands. Meghna.D.Punjabi Slide 3 Protects & supports body and its organs, binds organs together, stores energy reserves as fats and provides immunity. Connective Tissue Meghna.D.Punjabi Slide 4 Responsible for movement and generation of force. Muscle Tissue Meghna.D.Punjabi Slide 5 Initiates and transmits action potentials (Nerve impulses) that help coordinate body activities. Nervous Tissue Meghna.D.Punjabi Slide 6 Epithelial Tissue Cells are very closely packed & intracellular substance called matrix is minimal. Cells lie on a basement membrane. Epithelial Tissue SimpleStratified Single layer of cells Several layer of cells Meghna.D.Punjabi Slide 7 Simple Epithelium Found on absorptive or secretory surfaces where single layer enhances this process. Types named on the shape of cells & more active the tissue, the taller are the cells. Squamous Cuboidal Columnar Ciliated Meghna.D.Punjabi Slide 8 Squamous (Pavement) Epithelium Single layer of flattened cells which fit closely like flat stones, forming a thin & smooth membrane. Diffusion takes place freely through this thin, smooth, inactive lining of following structures:- heart, blood vessels, lymph vessels, alveoli of the lungs. Meghna.D.Punjabi Slide 9 Cuboidal Epithelium CCube shaped cells. FForms the tubules of kidneys & some glands. IInvolved in secretion, absorption & excretion. Meghna.D.Punjabi Slide 10 Columnar Epithelium Rectangular in shape. Lining the organs of alimentary tract. Some absorb the products of digestion & some secrete mucus. Meghna.D.Punjabi Slide 11 Ciliated Epithelium Columnar cells with hair like processes called cilia. Cilia consists of microtubules. Wave like movement of many cilia propels the contents of the tubes, which they line in one direction only. Found lining the utrine tubes & respiratory passages. Meghna.D.Punjabi Slide 12 Stratified Epithelia Several layers of cells of various shapes. Basement membranes absent. Protects underlying structure from wear & tear. Stratified Epithelium Stratified Squamous epithelium Transitional epithelium Non- Keratinised Relaxed & Stretched Keratinised Meghna.D.Punjabi Slide 13 Stratified Epithelium: Meghna.D.Punjabi Slide 14 Stratified Squamous Epithelium Number of layers of cells Deepest cells are columnar & as they grow towards the surface they become flattened & are then shed. Non keratinised stratified epithelium (Wet surfaces) they are found in the conjunctiva of the eyes, lining of the mouth, pharynx, vagina, oesophagus. Keratinised stratified epithelium (Dry surfaces) they are found in the skin, hair & nails, surface layer consists of dead epithelial cells to which the protein keratin has been added, this forms a tough, relatively water proof protective layer that prevents drying of the underlying live cells. Meghna.D.Punjabi Slide 15 Transitional Epithelium: CComposed of several layers of pear-shaped cells. FFound: Lining urinary bladder. IIt allows for stretching as bladder fills. Meghna.D.Punjabi Slide 16 Glandular Epithelium: Function: Secretion,accomplished by glandular cells that often lie in clusters deep to the covering and lining epithelium. Gland may consists of one cell or a group of highly specialized epithelial cells that secrete into ducts,onto a surface or into the blood. Production of such substances always require active work by the cells and results in an expenditure of energy. Meghna.D.Punjabi Slide 17 Types of Glands: GLANDS EXOCRINE ENDOCRINE Meghna.D.Punjabi Slide 18 Exocrine Glands: SSecrete their products into ducts(tubes) that empty at the surface of covering and lining epithelium or onto a free surface. PProduct may be released at the skin surface or into lumen of hollow organs. SSecretions: Mucous,perspiration,oil,wax and digestive enzymes. EEx: Sweat glands and Salivary glands. Meghna.D.Punjabi Slide 19 Endocrine Glands: Are ductless. Secretory products enter the ECF and diffuse into blood. Secretions always HORMONES,chemicals that regulate various physiological activities. Ex: Pituitary,Thyroid snd Adrenal Glands. Meghna.D.Punjabi Slide 20 Cells forming are more widely separated from each other & intracellular substance (Matrix) is present in considerably larger amounts. Connective Tissue Meghna.D.Punjabi Slide 21 Cells of connective tissues Meghna.D.Punjabi Slide 22 Fibroblasts Large flat cells which produce collagen and elastic fibers and a matrix of extracellular material. Particularly active in tissue repair (wound healing). Meghna.D.Punjabi Slide 23 Fat Cells KKnown as adipocytes these cells occur singly or in groups. VVary in size and shape according to the amount of fat they contain. Meghna.D.Punjabi Slide 24 Macrophages Irregular shaped cells with granules in the cytoplasm. Important part of the bodys defence mechanism as they are actively phagocytic,engulfing and digesting cell debris,bacteria and other foreign bodies. Meghna.D.Punjabi Slide 25 Leukocytes WBCs found in small numbers in healthy connective tissue but migrate in significant number during infection when they play an important role in tissue defense. Meghna.D.Punjabi Slide 26 Mast cells Found in liver, spleen and around blood vessels. Produce granules containing heparin, histamine etc. which are released when cells are damaged by diseases or injury. Meghna.D.Punjabi Slide 27 Loose Connective Tissue FFound in every part of the body providing elasticity and tensile strength. CConnects and supports other tissues. EExample: Under the skin Between muscles, Supporting blood vessels and nerve cells, Alimentary canal, Glands supporting secretory cells. Meghna.D.Punjabi Slide 28 Consists of fat cells Adipose Tissue Meghna.D.Punjabi Slide 29 20 to 25% of body weight in adults. It is found supporting kidneys & the eyes, between muscle fibres & under the skin where it acts as a thermal insulator White Adipose Tissue Meghna.D.Punjabi Slide 30 Found in newborn When brown tissue is metabolized produces less energy and considerably more heat than other fat, contributing to maintenance of body temperature. Brown Adipose Tissue Meghna.D.Punjabi Slide 31 Dense Connective Tissue Meghna.D.Punjabi Slide 32 Fibrous tissue FFound forming ligaments, which binds bones together. AAs an outer protective covering for bone called periostium. OOuter protective covering of some organs eg. kidneys,brain,lymph node. FForming muscle sheaths called muscle facia which extends beyond the muscle to become the tendon that attaches muscle to bone. Meghna.D.Punjabi Slide 33 Elastic Tissue Considerable extension & recoil. Few cells & the matrix consists mainly of masses of elastic fibres secreted by fibroblasts. Found in organs where alteration of shape is required eg. Large blood vessels, epiglotis & outer ears. Meghna.D.Punjabi Slide 34 Blood Meghna.D.Punjabi Slide 35 Blood Fluid connective tissue. Consists of plasma & formed elements which include erythrocytes, leukocytes & thrombocytes. Found within blood vessels (atreries, arterioles, capillaries, venules & veins.) Transport oxygen & carbon dioxide; leukocytes carry on phagocytosis & are involved in allergic reactions & immunity, thrombocytes are essential for the clotting of blood. Meghna.D.Punjabi Slide 36 Lymphoid Tissue Found in blood & in the lymphoid tissue in the lymph nodes, spleen, palatine & pharyngeal tonsils, vermiform appendix and wall of large intestine. Meghna.D.Punjabi Slide 37 Firmer than any other connective tissue. Cells are chondrocytes and are less numerous & are reinforced by collagen& elastic fibres. Cartilage Types Hyaline Cartilage Fibro Cartilage Elastic Cartilage Meghna.D.Punjabi Slide 38 Hyaline Cartilage Appears as a smooth bluish-white tissue. Chondrocytes are in small groups within cell nests and the matrix solid and smooth. Found: On the surfaces of the parts of bones that form joints. Forming the costal cartilages,which attach ribs to sternum. Forming parts of larynx,trachea and bronchi. Meghna.D.Punjabi Slide 39 Fibro Cartilage TTough, slightly flexible tissue. FFound as follows:- 1) As pads between the bodies of the vertebrae called the intervertebral discs. 2) Between the articulating surfaces of the bones of the knee joint called semilunar cartilages. 3) On the rim of the bony sockets of the hip & shoulder joints deepening cavities without restricting movements. 4) As ligaments joining bones. Meghna.D.Punjabi Slide 40 Forms pinna or lobe of the ear, the epiglotis and part of the tunica media of blood vessel walls. Elastic Cartilage Meghna.D.Punjabi Slide 41 Connective tissue with cells (Osteocytes) surrounded by a matrix of collagen fibres that is strengthened by inorganic salts especially calcium & phosphate. Bones Meghna.D.Punjabi Slide 42 Bones Compact Bone: Solid or dense appearance Compact bone consists of osteons that contain lamellae, lacunae, osteocytes, canaliculi & central canals. Cancellous or spongy bone: Spongy of fine honeycomb appearance. Spongy bones consists of thin plates called trabeculae. Both compact & spongy bones comprise the various parts of bones of the body. Support, protection, storage, houses blood forming tissue and serves as levers that act together with muscle tissue to provide movement. Meghna.D.Punjabi Slide 43 Muscle tissue Meghna.D.Punjabi Slide 44 Skeletal Tissue: Meghna.D.Punjabi Slide 45 Skeletal Muscle Tissue: Description: Cylindrical, striated fibres with many peripheral nuclei, voluntary control. Location: Usually attached bones. Function: Motion, posture, heat production. Meghna.D.Punjabi Slide 46 Smooth Muscle Tissue: Meghna.D.Punjabi Slide 47 Smooth Muscle Tissue: Description: Spindle-shaped, nonstriated fibres with one centrally located nucleus; usually involuntary control. Location: Walls of hollow internal structures such as blood vessels, airways to the lungs, stomach, intestines, gall bladder, and urinary bladder. Function: Motion (constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract; contraction of urinary bladder and gall bladder). Meghna.D.Punjabi Slide 48 Cardiac Muscle Tissue: Meghna.D.Punjabi Slide 49 Cardiac Muscle Tissue: DDescription: Branched cylindrical, striated fibres with one or two centrally located nuclei, contains intercalated discs, mainly involuntary control. LLocation: Heart Wall. FFunction: Pumps blood to all parts of the body. Meghna.D.Punjabi Slide 50 Nervous Tissue: Meghna.D.Punjabi Slide 51 Nervous Tissue: Description: 2 Principal cells neurons and neuroglia. Neurons (nerve cells) consists of a cell body and processes extending from cell body called dendrites or axons. Dendrites are highly branched tapered processes of the cell body. Axons are single, long processes of the cell body that usually conduct impulses away from the cell body. Meghna.D.Punjabi Slide 52 Neuroglia: Neuroglia do not generate or conduct nerve impulses, but have other important functions; a) Development of brain by assisting migration of neurons. b) Link between neurons and blood vessels. c) Produce myelin sheath (multilayer lipid and protein covering); this electrically isolates axon of neuron and increases speed of nerve impulse conduction around axons of neurons in CNS Meghna.D.Punjabi Slide 53 Neuroglia Functions: d) Engulf and destroy microbes and cellular debris in the CNS. e) Assist in circulation of CSF in the areas of brain and spinal cord by providing epithelial lining for ventricles of brain and central canal of spinal cord. Meghna.D.Punjabi Slide 54 Nervous Tissue: LLocation: Nervous System. FFunction: Exhibits sensitivity to various types of stimuli; converts stimuli into nerve impulses,and conducts nerve impulses to other neurons, muscle fibres, or glands. Meghna.D.Punjabi Slide 55 MEMBRANES: Meghna.D.Punjabi EPITHELIAL MEMBRANES SEROUS MEMBRANE MUCOUS MEMBRANES CUTANEOUS MEMBRANE (SKIN) CONNECTIVE TISSUE MEMBRANE SYNOVIAL MEMBRANE Slide 56 MUCOUS MEMBRANES LLines body cavity that opens to the exterior. CConsists of a lining layer of epithelium and an underlying layer of connective tissue. LLines the entire digestive, respiratory and reproductive systems and much of urinary system. EEpithelial layer of a mucous membrane=bodys defense mechanisms. CCertain cells of mucous membranes secrete mucous, which prevent underlying structures from drying out. IIt traps particles in respiratory passageways and lubricates food as it moves through the GI tract. Meghna.D.Punjabi Slide 57 MUCOUS MEMBRANES The epithelial layer secretes enzymes needed for digestion and is a site of food absorption in the GI tract. Connective Tissue layer is called lamina propria. It binds epithelium to underlying structures and allows some flexibility of the membrane. It also holds blood vessels in place and protects underlying muscles from abrasion and puncture. Oxygen and nutrients diffuse from lamina propria to the epithelium covering it,while carbondioxide and waste diffuse in the opposite direction. Meghna.D.Punjabi Slide 58 SEROUS MEMBRANES Lines body cavity that does not open directly into the exterior, it lines organs within the cavity. Consists of thin layers of areolar connective tissue covered by mesothelium and they are composed of 2 portions. Part attached to cavity wall=Parietal Portion Part that covers and attaches to organs within the cavity=Visceral Portion. Meghna.D.Punjabi Slide 59 SEROUS MEMBRANES The serous membranes lining different organs and cavities have different names: A) Lining thoracic cavity and covering lungs=PLEURA. B) Lining the heart cavity and covering the heart=PERICARDIUM. C) Lining abdominal cavity and covering abdominal organs and some pelvic organs=PERITONIUM. Meghna.D.Punjabi Slide 60 SEROUS MEMBRANES Epithelial layer of serous membrane secrete lubricating fluid called serous fluid, that allows organs to glide easily against one another or against the walls of the cavity. The 2 layers are separated by serous fluid. For Example: The heart changes shape during each beat and friction damage is prevented by the arrangement of pericardium and its serous fluid. Meghna.D.Punjabi Slide 61 SYNOVIAL MEMBRANES Lines cavities of freely movable joints. Line structures that do not open to the exterior. Composed of areolar connective tissue with elastic fibers and varying amount of fat. Secrete synovial fluid,which lubricates the cartilage at the ends of bones during their movements and nourishes cartilage covering bones at joints. Called articular synovial membranes. Other synovial membranes line cushioning sacs,called bursae,and tendon sheaths in our hands and feet that ease the movement of muscle tendons. Meghna.D.Punjabi Slide 62