tissue and it's types
- 2. Cells are the body’s smallest functional units they are grouped together to form tissues, each of which has specialized functions,e g.blood , muscle Study of tissues is called histology.
- 3. Tissues are grouped together to form organs e.g heart,stomach ,brain. Organs are grouped together to form system,each of which performs a particular functions.eg digestive system
- 4. DEFINITION: Tissue is a collection of cells which have similar structure and perform relatively common functions.
- 7. CHARACTERISTICS Cells are closely packed without any intercellular spaces Lie on basement membrane
- 9. Found covering the body and lining cavities and tubes. Outer and inner linning of most of the body organs such as gastrointestinal tract(GIT), urinary tract , blood vessels, heart chambers uterus. Found on the entire exposed surface of the body such as skin. Also found in glands
- 10. Role of defense and protect body organs Secret gastric juice in stomach.
- 11. Absorb digested food in intestine. Removes waste as sweat in skin.
- 13. Consists of a single layer of identical cells Found on absorptive or secretary surfaces Divided into three main types.
- 17. Characteristics Consists of several layers of cells of various shapes. Continual cell divison in the lower layers pushes cells above nearer and nearer to the surface where they are shed. Basement membrane are usually absent. Main function is to protect underlying structure from mechanical wear and tear.
- 19. Found on dry surfaces subjected to wear and tear. Consists of dead epithelial cells that have lost their nuclei and contain the protein keratin. Sites Skin, hairs and nails
- 20. Protects moist surfaces subjected to wear and tear and prevents them from drying out. Sites Conjunctiva of the eyes, the lining of the mouth, the vagina.
- 21. Composed of several layers of pear shaped cells which are very elastic and have the capacity of dividing themselves. Sites Lines several parts of the urinary tract including the bladder.
- 22. It is most abundant tissue in the body Connective tissues cells are more widely separated from each other than in epithelial tissues and intercellular substance (matrix) is present in larger amount Made up of cells like fibroblast, fat cells, macrophages,leukocytes and mast cells.
- 24. Provide support Transport materials from one part of the body to another Store energy. Protection Insulation
- 25. Cells in connective tissues
- 26. FIBROBLASTS They are large cells with irregular processes Manufacture collagen and elastic fibres and a matrix of extracellular material. Functions Active in tissue repair
- 27. FAT CELLS Also known as adipocytes These cells occur singly or in groups in many types of connective tissues and are especially abundant in adipose tissue.
- 28. MACROPHAGES These are large irregular shaped cells with granules in the cytoplasm. Important part of the body defence mechanism because they are actively phagocytic, engulfing and digesting cell debris, bacteria and other foreign bodies.
- 29. LEUCOCYTES White blood cells are normally found in small numbers in healthy connective tissues. Synthesis and secret specific defensive antibodies into the blood and tissue
- 30. MAST CELLS Similar to basophilic leukocytes Found in loose connective tissues, under the fibrous capsules of some organs.eg.liver and spleen.
- 33. Most generalized type of connective tissues Matrix is semisolid with many fibroblasts and some fat cells (adipocytes), mast cells and macrophages widely separated by elastic and collagen fibres.
- 34. Found in almost part of the body, providing elasticity and tensile strength. It connects and supports other tissues,for eg. under the skin, between muscles, supporting blood vessels and and nerves, in the alimentary canal, in gland supporting secretory cells.
- 35. Consists of fat cells(adipocytes), containing large fat globules, in a matrix .
- 37. More present in obesity and in less in those who are underweight Found in between muscle fibres and under the skin, where it acts as a thermal insulator and energy store. Sites Deeper layer of skin, buttocks, breast and around kidneys
- 38. Present in the newborn Has a more extensive capillary network than white adipose tissue. Produces less energy and more heat than other fat contributing to the maintenance of body temperature.
- 39. Has a semisolid matrix with fine branching reticulin fibres. Contains reticular cells and white blood cells Found in all lymph nodes and all organs of lympatic system.
- 40. These contains more collagen fibers and fewer cells than loose connective tissues.
- 42. Made up of mainly of closely packed bundles of collagen fibres with very little matrix and few fibrocytes. Found in Ligament, tendon, fasciae
- 43. Capable of considerable extension and recoil. There are few cells and the matrix consists mainly of masses and of elastic fibres secreted by fibroblasts. Sites Large blood vessel walls, the trachea and bronchi and the lung.
- 44. Cells are sparse and lie embedded in matrix reinforced by collagen and elastic fibres.
- 46. It is a smooth bluish white tissues. The chondrocytes are arranged in small groups within cell nests and matrix is solid and smooth.
- 47. Function: Provides flexibility, support and smooth surfaces for movements at joints. Sites Ends of long bones Forming the parts of larynx, trachea and bronchi
- 48. Consists of dense masses of white collagen fibres in a matrix similar to that of hyaline cartilage with the cells widely dispersed.
- 49. It is a tough, slightly flexible, supporting tissue. Sites Pads between intervertebral disc Between pubic bones(symphysis pubis)
- 50. Contains large amount of elastin fibres in the chondrin . Elastin fibres
- 51. It’s highly flexible. Sites The pinna or lobe of ear, epiglottis
- 53. These have a diaphysis or shaft and two epiphyses or extremities. The diaphysis is composed of compact bone with a central medullary canal, containing fatty yellow bone marrow. The epiphyses consist of an outer covering of compact bone with cancellous bone inside.
- 55. Long bones are almost completely covered by a vascular membrane, the periosteum. The outer layer is fibrous and the inner layer is osteogenic containing osteoblasts (bone-forming cells) and osteoclasts (bone-destroying cells), which are involved in maintenance and remodelling of bones. Have a yellow central cavity which is filled with cells called bone marrow. Around the bone marrow cavity is layer of osteoblasts called endosteum
- 56. Types of bone: Spongy bone-spongy or fine honey comb appearance Compact bone-solid or dense appearance
- 59. A system of branched tubular structures that in the outermost region of thedbone containining blood vessels that nourish the bone is called as Haversian canals system
- 60. The outermost surface compromises dead osteocytes enclosed by tough connective tissue fibres called periosteum. Eg. Compact bones ,soft bones
- 61. They have a large number of different types of cells suspended in a fluid found substance (matrix). They are blood and lymph.
- 62. It is made up of muscle cells(muscle fibers) which unite to form muscle. It contracts and relaxes rhythmically.
- 64. Also called as skeletal, striated, striped or voluntary muscle. It is called voluntary because contraction is under conscious control. Microscopically the cells are found to be roughly cylindrical in shape and may be as long as 35 cm.
- 65. Each cell, commonly called a fibre, has several nuclei situated just under the sarcolemma or cell membrane The muscle fibres lie parallel to one another and, when viewed under the microscope, they show well-marked transverse dark and light bands, hence the name striated or striped muscle.
- 66. Sarcoplasm, the cytoplasm of muscle fibres, contains: Bundles of myofibrils Glycogen Myoglobin, a unique oxygen-binding protein molecule A myofibril has a repeating series of dark and light bands, consisting of units called sarcomeres. A sarcomere represents the smallest functional unit of a skeletal muscle fibre and consists of: thin filaments of actin • thick filaments of myosin
- 67. SMOOTH MUSCLE TISSUE
- 68. Smooth muscle may also be described as non-striated or involuntary. It is not under conscious control. It is found in the walls of hollow organs: When examined under a microscope, the cells are seen to be spindle shaped with only one central nucleus. There is no distinct sarcolemma but a very fine membrane surrounds each fiber.
- 71. Found exclusively in the wall of the heart. Cardiac muscle has cross striations formed by rotating segments of thick and thin protein filaments. Each fibre (cell) has a nucleus and one or more branches.
- 72. Microscopically these 'joints', or intercalated discs, can be seen as lines which are thicker and darker than the ordinary cross-stripes. A wave of contraction spreads from cell to cell across the intercalated discs which means that cells do not need to be stimulated individually
- 75. These types of tissues are found in nervous system. Types Excitable cells-neurones Non excitable cells- Neuroglia
- 76. Functions Irritability – the capacity to react to various physical and chemical agents. Conductivity- the ability to transmit the resulting reaction from one point to another.
- 77. Neuron also known as a neurone or nerve cell) is an electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals. It is the working unit of nervous system Consists of cell body with cytoplasmic extensions-dendrites, axon and pole Science - Structure of Neuron.mp4
- 78. Neuroglia Neuroglia form the support structure of nervous tissues, insulating and protecting neurons. They are astrocytes, oligodendrocytes, microglia and ependymal cells.
- 81. The extent to which regeneration is possible depends on the normal rate of physiological turnover of particular types of cell. Those with a rapid turnover regenerate most effectively. Types : Labile cells Stable cells Permanent cells
- 82. Labile cells : Labile cells are those in which replication is normally a continuous process. They include cells in: epithelium of e.g. skin, mucous membrane, secretory glands, ducts, uterus lining bone marrow blood spleen and lymphoid tissue.
- 83. Stable cells :Stable cells have retained the ability to replicate but do so infrequently. They include: liver, kidney and pancreatic cells fibroblasts smooth muscle cells osteoblasts and osteoclasts in bone
- 84. Permanent cells: Permanent cells are unable to replicate after normal growth is complete. They include: nerve cells (neurones) skeletal and cardiac muscle
- 85. MEMBRANE
- 86. Membranes are sheets of epithelial tissue and their supporting connective tissue that cover or line internal structures or cavities
- 87. The main membranes are: mucous serous synovial Cutaneous
- 88. Mucous membrane Moist lining of the alimentary tract, respiratory tract and genitourinary tracts and is sometimes referred to as the mucosa Membrane consists of epithelial cells, some of which produce a secretion called mucus, a slimy tenacious fluid.
- 89. The cells fill up with mucus they have the appearance of a goblet or flask and are known as goblet cells Organs lined by mucous membrane have a moist slippery surface. Mucus protects the lining membrane from mechanical and chemical injury and in the respiratory tract it traps inhaled foreign particles, preventing them from entering the alveoli of the lungs.
- 91. Serous membranes, or serosa secrete serous watery fluid. They consist of a double layer of loose areolar connective tissue lined by simple squamous epithelium. The parietal layer lines a cavity and the visceral layer surrounds organs within the cavity. The two layers are separated by serous fluid secreted by the epithelium.
- 92. There are three sites where serous membranes are found the pleura lining the thoracic cavity and surrounding the lungs the pericardium lining the pericardial cavity and surrounding the heart the peritoneum lining the abdominal cavity and surrounding abdominal organs
- 93. The serous fluid between the visceral and parietal layers enables an organ to glide freely within the cavity without being damaged by friction between it and adjacent organs. For example, the heart changes its shape and size during each beat and friction damage is prevented by the arrangement of pericardium and its serous fluid.
- 95. Synovial membrane: This membrane is found lining the joint cavities and surrounding tendons, which could be injured by rubbing against bones, e.g. over the wrist joint. Made up of a layer of fine, flattened epithelial cells on a layer of delicate connective tissue. Synovial membrane secretes clear, sticky, oily synovial fluid, which acts as a lubricant to the joints and helps to maintain their stability
- 98. Glands are groups of epithelial cells which produce specialised secretions. TYPES OF GLANDS Exocrine and endocrine gland
- 99. Exocrine glands are glands that produce and secrete substances onto an epithelial surface by way of a duct. Example: sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, and mucous.
- 102. Endocrine glands(ductless gland) are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct. E.g: the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands.
- 103. Any question
- 104. SUMMARY
Editor's Notes
- #20: Keratin (/ ˈ k ɛr ə t ɪ n /) is one of a family of fibrous structural proteins. Keratin is the protein that protects epithelial cells from damage or stress
- #22: The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits
- #27: Collagen / ˈ k ɒ l ə dʒ ɪ n / is the main structural protein in the extracellular space in the various connective tissues in animal bodies
- #29: Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells.
- #30: Leucocyte-Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses
- #31: a type of blood cell that lacks hemoglobin and is therefore colorless. Leukocytes are larger in size and fewer in number than erythrocytes Leukocytes may be classified in two main groups: the granular leukocytes are the basophils, eosinophils, and neutrophils
- #40: A reticular cell is a type of fibroblast that synthesizes collagen alpha-1(III) and uses it to produce reticular fibers A lymph node is an organized collection of lymphoid tissue, through which the lymph passes on its way back to the blood. Lymph nodes are major sites of B and T lymphocytes, and other white blood cells.
- #44: yellowish fibre composed chiefly of elastin and occurring in networks or sheets which give elasticity
- #45: Matrix-An insoluble, dynamic gel in the cytoplasm, believed to be involved in cell shape determination and locomotive mechanism, particularly across a solid substrate. It consists of polymeric microtubules, actin microfilaments and intermediate filaments interacting with a number of other proteins.
- #47: Chondrocytes-They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans
- #51: bluish-white substance that forms the matrix of cartilage
- #54: Osteoblast-a cell which secretes the substance of bone. Osteoclast-a large multinucleate bone cell which absorbs bone tissue during growth and healing. Osteocyte-a bone cell, formed when an osteoblast becomes embedded in the material it has secreted. Endosteum-a layer of vascular tissue lining the inside of some bones, e.g. the femur
- #67: Actin , myosin- protein
- #74: Striated muscle tissue is muscle tissue that features repeating functional units called sarcomeres, in contrast with smooth muscle tissue which does not. The presence of sarcomeres manifests as a series of bands visible along the muscle fibers, which is responsible for the striated appearance observed in microscopic images of this tissue Banded)
- #102: a small sac-like cavity -acinar