TISSUES - TYPES characteristics classification and location

The four basic types of tissue in the human body are:
Connective tissue: Supports and binds tissues together, and includes blood, bone, and lymph tissues
Epithelial tissue: Covers and protects the body, and controls the movement of materials across its surface
Muscle tissue: Allows the body to move
Nervous tissue: Functions in communication
Tissues are like the fabric of the body, and when two or more tissues combine, they form organs. The function of a certain part of an organ depends on the type of tissue it's made of.
Membranes are layers of connective and epithelial tissues that line the body's internal and external cavities. For example, synovial membranes are connective tissue membranes that protect and line joints.here are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). Epithelial tissue provides a covering (skin, the linings of the various passages inside the body). Muscle tissue includes striated (also called voluntary) muscles that move the skeleton, and smooth muscle, such as the muscles that surround the stomach. Nerve tissue is made up of nerve cells (neurons) and is used to carry "messages" to and from various parts of the body.

1. Tissues DEFINITION, TYPES, CHARACTERISTICS, CLASSIFICATION & LOCATION PROF.CHITHRAVEL.V PRINCIPAL MMNC RANCHI

2. Tissues Definition: A tissue is a group of cells that usually have a common embryonic origin and function together to carry out specialized activities. Histology : is the science that deals with the study of tissues. Pathologist : Is a physician who specializes in laboratory studies of cells and tissues to help other physicians make accurate diagnosis.

3. Classification of body tissues Epithelial tissue Connective tissue Muscular tissue Nervous tissue

4. Epithelial tissue Covers the body surfaces and lines hollow organs, body cavities and ducts. It also forms glands.

5. Connective tissue Protects and supports the body and its organs. Various types of connective tissue bind organs together. Store energy reserves as fat and help provide immunity to disease causing organisims .

6. Muscular tissues Generates the physical force needed to make body structures move and generates body heat.

7. Nervous tissue Detects changes in a variety of conditions inside and outside the body and responds to generating action potential (nerve impulse) the activate muscular contractions.

8. An Orientation to the Tissues of the Body

9. How are cells tissues held together There are two major ways in which cells in tissues can be held together: An extracellular matrix of macromolecules can form a lattice-work that can then be used by the associated cells to move, change position and a framework in which cells can interact with one another Cell junctions can create firm, direct, specialized points of fusion between two cells in direct physical contact.

10. ECM- Extracellular Matrix The extracellular matrix provides the physical microenvironment in which cells exist. It provides a substrate for cell anchorage, serves as a tissue scaffold, guides cell migration during embryonic development and wound repair, and has a key roles in tissue morphogenesis. The extracellular matrix is also responsible for transmitting environmental signals to cells, which ultimately affects cell proliferation, differentiation and death.

11. Extracellular Matrix Components The extracellular matrix has three major components: Highly viscous proteoglycans ( heparan sulfate , keratan sulfate , chondroitin sulfate ), which cushion cells Insoluble collagen fibers , which provide strength and resilience Soluble multi-adhesive extracellular matrix proteins ( fibronectin , laminin ), which bind proteoglycans and collagen fibers to receptors on the cell surface

12. Cell junctions Definition : Cell junctions are contact points between the plasma membrane of tissue cells. Types: Tight junctions Adherens junctions Desmosomes Hemi-desmosomes Gap junctions

13. Epithelial tissue General features : Consists of cells arranged in continuous sheets. In either single layer or multiple layers. Structure: Apical surface : Most superficial layer of cells Faces the body surface, the body cavity, lumen of integral organs, tubular ducts that receive cellular secretions. Basal surface : Opposite to apical surface Deepest layer of epithelial cells Adhere to the extracellular material.

14. Basement membrane : Is a thin extracellular layer that commonly consists of two layers: The basal lamina The reticular lamina Point of attachment and support for the overlying epithelial tissue The basal lamina : Thin layer Is closer to and is secreted by epithelial cells Contains proteins such as laminin and collagen, glycoproteins, proteoglycans. The reticular lamina: Closer to underlying connective tissue. Contains proteins such as fibroblasts

15. Combination of both characteristics of covering and lining epithelium Simple epithelium: Simple squamous epithelium Simple cuboidal epithelium Simple columnar epithelium(non-ciliated and ciliated) Pseudostratified columnar (non-ciliated and ciliated) II. Stratified epithelium : Stratified squamous epithelium Stratified cuboidal epithelium Stratified columnar epithelium Transitional epithelium

16. Simple epithelium Single layer of cells. Functions: Diffusion, osmosis, filtration, secretion, absorption. Secretion: productions and release of substances such as mucus, sweat or enzymes. Absorption : is the intake of fluids or other substances such as digested food from the intestinal tract.

17. Pseudo-stratified epithelium Appears to have multiple layer of cells, because the cell nuclei lie at different levels and not all cells reach the apical surface. Cells that do not extend to the apical surface may have cilia, goblet cells( produce mucus).

18. Stratified epithelium Consists of two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear.

19. Cell shape: Squamous cells : arranged like floor tiles, are thin, allow rapid passage of substances. Cuboidal cells : Are as tall as they are wide Shaped like tubes or hexagons May have microvilli at their apical surfaces. Function in secretion and absorption

20. Columnar cells: Are much taller than they are wide , like columns. Protect underlying tissues. Apical surfaces have many cilia and microvilli. Often are specialized for secretion and absorption. Transitional cells: Cells change shape from flat to cuboidal and back. Eg ; urinary bladder cells

21. Simple squamous epithelium The tissue consists of single layer of flat cells. Resemble tiles floor Nucleus: flattened oval or sphere, centrally located. Location: lines heart, blood vessels, lymphatic vessels, air sacs of lungs, glomerular capsule of kidneys, inner surface of tympanic membrane (eardrum), forms epithelial layer of serous membranes, such as peritoneum, pericardium and pleura Function : filtration, diffusion, osmosis and secretion in serous membranes.

22. Simple cuboidal epithelium Description: single layer of cube shaped cells, centrally located nucleus. Location: covers surface of ovary, lines anterior surface of capsule of lens of the e yes, forms pigmented epithelium at the posterior surface of the eye, lines kidney tubules and smaller ducts of many glands, makes up secretory portion of some glands such as the thyroid gland and ducts of some glands such as pancreas. Function: secretion and absorption.

23. Simple columnar epithelium Types: Non ciliated Simple columnar epithelium Ciliated Simple columnar epithelium

24. Non ciliated Simple columnar epithelium Contains two type of cells: Columnar epithelial cells with microvilli at their apical surface. Goblet cells Columnar epithelial cells with microvilli at their apical surface . Microvilli, fingerlike cytoplasmic projections, increase the surface area of plasma membrane, thus increasing the rate of absorption of the cell.

25. Ciliated columnar epithelium Contains columnar epithelial cells with cilia at their apical surfaces. In respiratory tract mucus secreted by the goblet cells forms a film over the airways surface that traps inhaled foreign particles. The cilia beats moving the mucus and any foreign particles toward throat, where they can be coughed up and swallowed or spit out. Coughing and sneezing speed up the movement of cilia and mucus. Location : lines some bronchioles in respiratory tract, uterine tubes, uterus, efferent ducts of testes, Para nasal sinuses, central canal of spinal cord, ventricles of brain.

26. Pseudo stratified columnar epithelium Description: Not a true stratified tissue. Nuclei of cells are at different levels. All cells are attached to basement membrane, but all do not reach the apical surface. Location: Lines the airways of most of the upper respiratory tract, epididymis, and part of male urethra. Function : Secretion and movement of mucus by ciliary action.

27. Stratified epithelium: Stratified squamous epithelium Has two or more layers of cells. Description: Several layers of cells, cuboidal to columnar in shape in deep layers, squamous cells from the apical layer. Types: Keratinized stratified squamous epithelium Non-keratinized stratified squamous epithelium

28. Keratinized stratified squamous epithelium : The apical layer and several layers deep to it are partially dehydrated and contain a layer of keratin, (a tough fibrous protein that helps protect the skin and underlying tissues from heat, microbes and chemicals). Forms superficial layer of the skin . Non-keratinized stratified squamous epithelium : Location: Lines the mouth and esophagus, part of larynx, part of pharynx, vagina, covers the tongue(wet surfaces). Does not contain keratin in apical layer. Function : Protection (first line of defense against the microbes).

29. Stratified cuboidal epithelium Description: Two or more layers of the cells in which the cells in the apical layer are cube shaped. Location: Ducts of the adult sweat glands and esophagus glands and part of the male urethra. Function: Protections and limited secretion and absorption.

30. Stratified columnar epithelium Description: Several layers of irregular shaped cells. Only the apical layer has columnar cells. Location: Lines part of the urethra, large excretory ducts of some glands, such as esophageal glands, small areas in anal mucous membranes, and part of the conjunctiva of the eye. Function: Protection and secretion

31. Transitional epithelium Description: Appearance is variable (transitional). Shape of the cells in apical layer ranges from squamous (when stretched) to cuboidal (when relaxed). Location: Lines urinary bladder and portions of the ureters and the urethra. Function: Permits distension

32. Connective tissue

33. Connective tissue Connective tissue is one of the most abundant and widely distributed tissues in the body. Functions: Binds body tissues Supports the body tissues Protects and insulates internal organs Serves major transport system within the body(blood). Is primary location of stored energy reserves (adipose, or fat tissue) Is the main source of immune response.

34. General features of connective tissues Consists of two basic elements: Extracellular matrix Cells Extracellular matrix: is the material located between its widely spaced cell.

35. Connective tissue cells The types of connective tissue cells vary according to the type of tissue and include the following: Fibroblasts Adipocytes Mast cells White blood cells Macrophages Plasma cells

36. Fibroblasts Large flat cells with branching process. Most numerous. Secrete fibers and certain components of ground substance of extracellular matrix.

37. Adipocytes Also called fat cells/adipose cells. Are connective tissue cells that stores triglycerides (fats). Found deep in skin and around organs such as heart and kidneys.

38. White blood cells Not found in significant number in normal connective tissue. Gather at site of infection. Migrate to sites of parasitic invasion and allergic responses. E.g. neutrophils, eosinophil

39. Macrophages Also called large eaters. Develop from monocytes (type of WBC) Have irregular shape with short branching projections Process: phagocytosis Types: Fixed macrophages : reside in particular tissue; examples include alveolar macrophages in lungs or splenic macrophages in spleen. Wandering macrophages : have the ability to move throughout the tissue and gather at sites of infection and inflammation.

40. Macrophage

41. Microphages Microphage plays an important role in our immune system. Moreover, microphage can be a small  neutrophil  or an  eosinophil . They are cable of eating or ingesting small infectious particles such as bacteria.

42. Mast cells A type of white blood cell that is found in connective tissues all through the body, especially under the skin, near blood vessels and lymph vessels, in nerves, and in the lungs and intestines. Mast cells play an important role in how the immune system responds to certain bacteria and parasites and they help control other types of immune responses. They contain chemicals such as histamine, heparin, cytokines, and growth factors. They release these chemicals during allergic reactions and certain immune responses. During an allergic response, they can cause flushing (a hot, red face) and itching. In large amounts, they can also cause abdominal cramps, muscle pain, nausea, vomiting, diarrhea, low blood pressure, and shock.

43. Plasma cells Small cell that develop from a type of white blood cells called B lymphocytes. Plasma cells secrete antibodies, proteins that attack and neutralize the foreign substances. Found in gastrointestinal and respiratory tract. Abundant in salivary glands, lymph nodes, spleen and bone marrow.

44. Collagen fibers Are v ery strong Resist pulling forces, are not stiff, this property allows tissue flexibility. Occurs in parallel bundles. Composition of collagen fibers: Collagen protein Location: collagen fibers are found in bone, cartilage, tendons and ligaments.

45. Elastic fibers Smaller in diameter than collagen fibers. Branch and join together to form a network within tissue. Consists of: Elastin protein

46. Reticular fibers Consists of collagen arranged in fine bundles with a coating of glycoprotein. Support in the walls of blood vessels and form a network around the cells in some tissues, such as areolar connective tissue, adipose tissue and smooth muscle tissue.

47. Mature Connective Tissue Loose connective tissue Areolar connective tissue Adipose tissue Reticular connective tissue b . Dense connective tissue: Dense regular connective tissue Dense irregular connective tissue Elastic connective tissue

48. c. Cartilage: Hyaline cartilage Fibro cartilage Elastic cartilage d. Bone tissue e. Liquid connective tissue Blood tissue lymph

49. Loose connective tissue

50. Areolar connective tissue Cells in the tissue are: Fibroblasts Macrophages Plasma cells Mast cells Adipocytes Fibers present: Collagen fibers Elastic fibers Reticular fibers Ground substance contains: Hyaluronic acid Chondroitin sulfate Dermatan sulfate Location: Subcutaneous layer deep to the skin, papillary(superficial) region of dermis of the skin, lamina propria of mucus membrane, around blood vessels, nerves and body organs . Functions: Strength, elasticity, suppor t

51. Adipose connective tissue Cells: Adipocytes: specialized for storage of fats(triglycerides). Found wherever areolar connective tissue is present.. Is a good insulator, and reduces heat lose through the skin.. Major energy reserve and protects and supports various organs.

52. Location: Subcutaneous layer of deep skin, around heart and kidneys, yellow bone marrow, padding around joints and behind eyeballs in socket. Functions: Reduce heat through the skin Serves as an energy reserve Supports and protects the body organs In new born BAT generates considerable heat that helps maintain proper body temperature.

53. Reticular connective tissue Description: A network of interlacing reticular fibers and reticular cells Location: Stroma of liver, spleen, lymph nodes, red bone marrow, which gives rise to blood cells, reticular lamina of the basement membrane, and around blood vessels and muscles.

54. Dense connective tissue

55. Description Dense connective tissue” Contains more numerous, thicker and dense fibers (packed more closely). Has fewer cells than connective tissue. Types: Dense regular connective tissue Dense irregular connective tissue Elastic connective tissue

56. Dense regular connective tissue Description : extracellular matrix looks shiny white. Fibers : Collagen fibers, arranged in bundles Cells: Fibroblasts (present in rows between bundles). Location : forms tendons (attach muscle to bone), most ligaments (attach bone to bone), and Apo-neuroses (sheet like tendons that attach muscle to muscle or muscle to bone). Function : provide strong attachment between various structures.

57. Dense irregular connective tissue Description: Found in parts of the body where pulling forces are exerted in various directions, the tissue often occurs in sheets. Fibers: collagen fibers Cells: few fibroblasts Location: fasciae (tissue beneath skin and around muscles and other organs, reticular (deeper) region of dermis of skin, periosteum of bone, perichondrium(tissue surrounding cartilage) of cartilage, joint capsules, membrane capsule around various organs(kidney, liver, testes, lymph nodes) pericardium of heart and heart valves. Function : provides strength

58. Elastic connective tissue Description: yellowish color due to presence of elastic fibers. Fibers: Elastic fibers Cells: Fibroblasts Location : Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspensory ligament of penis, some ligaments between vertebrae.

59. PERICHONDRIUM contains two layers: Outer fibrous layer : consists of collagen fibers, blood vessels and fibroblasts. Inner cellular layer : consists of cells involved in the growth of cartilage. Cartilage does not have any blood supply, because it secretes an ant angiogenesis factor, a substance that prevents blood vessels growth.

60. Fluid/liquid connective tissue It contains of: Blood and lymph Watery matrix of dissolved proteins Carry specific cell types (formed elements )

61. Liquid connective tissue It includes: Blood & Lymph Blood: has: Liquid extracellular matrix : pale yellow fluid that consist mostly of water with a wide variety of dissolved substances- nutrients, wastes, enzymes, plasma proteins, hormones, respiratory gases and ions. Other elements : RBC’s (erythrocytes), WBC’s (leukocytes), platelets (thrombocytes).

62. Red blood cells : transport oxygen to body cells and remove some carbon dioxide from them. White blood cells : are involved in phagocytosis, immunity and allergic reactions. White blood cells include the phagocytic microphages ( neutrophils and eosinophils ), basophils, lymphocytes , and monocytes. White blood cells are important components of the immune system, which protects the body from infection and disease. Platelets: Tiny membrane–enclosed packets of cytoplasm Participate in blood clotting. These cell fragments, which contain enzymes and special proteins, function in the clotting response that seals breaks in the endothelial lining

63. Extracellular fluid Extracellular fluid includes three major subdivisions: Plasma Interstitial fluid Lymph Plasma is normally confined to the vessels of the circulatory system, and contractions of the heart keep it in motion.

64. The major difference between plasma and interstitial fluid is that plasma contains numerous suspended proteins that are too large to pass into the interstitial fluid.

65. Lymph: Is the extracellular fluid that flows in lymphatic vessels. Consist of several types of cells in clear liquid extracellular matrix that is similar to blood plasma but with much less protein. As fluid passes along the lymphatic vessels, cells of the immune system monitor the composition of the lymph and respond to signs of injury or infection. The number of cells in lymph may vary, but ordinarily 99 percent of them are lymphocytes. The rest are primarily macrophages or microphages

66. MUSCLE TISSUE Consists of elongated cells called muscle fibers or monocytes that can use ATP to generate force.

67. There are three types of muscle tissue: Skeletal muscle , which forms the large skeletal muscles responsible for gross body movements and locomotion; Cardiac muscle , found only in the heart and responsible for the circulation of blood; and Smooth muscle , found in the walls of visceral organs and a variety of other locations, where it provides elasticity, contractility, and support.

68. NEURAL TISSUE Neural tissue , which is also known as nervous tissue or nerve tissue , is specialized for the conduction of electrical impulses from one region of the body to another. Cells of the nervous system include: Non-neural cells Neurons. Non-neural cells are neuroglia (meaning nerve glue), or glial cells, which support and protect neurons and perform other functions Neurons receive stimuli and conduct action potentials.

69. Types of Neuraglia Astrocyte processes form feet that cover the surfaces of neurons and blood vessels. The astrocytes provide structural support and help form the blood brain barrier, thus playing a role in regulating what substances from the blood reach the neurons. Ciliated ependymal cells lining the ventricles of the brain help to move cerebrospinal fluid. (CSF) Ependymal cells on the surface of the choroid plexus secrete cerebrospinal fluid.