TISSUE-GLANDS

TISSUE GLANDS

1. DR NILESH KATE MBBS,MD PROFESSOR DEPT. OF PHYSIOLOGY TISSUE & GLANDS

2. What is a Tissue? A Tissue is a group of similar cells that usually has a common embryonic origin and functions together to carry out specialized activities.

3. A Tissue may he defined as an aggregate of same type of cells combined subserving the same general function independently and united by varying amounts of intercellular substance (e.g., blood, bones, cartilage, muscle, nervous tissues, etc.). An Organ is a group of two or more tissues, which basically function independently in some instances, in particular patterns to form larger functional units (e.g., blood vessels, kidney, skin, glands, ‘etc.).

4. ELEMENTARY TISSUES OF THE HUMAN BODY The human body is composed of the following elementary tissues: Epithelial tissue. Connective (Mesenchymal) tissue. Muscular tissue. Nervous tissue.

5. EPITHELIAL TISSUE It Forms a limiting and a lining membrane . The cells remain close together with a minimum amount of intercellular cement substance. There is generally a basement membrane upon which the epithelial cells are set. The cementing substance, here, is a Mucoprotein containing Hyaluronic acid and Calcium salts. Functions : 1.Protection 2. Absorption 3. Secretion 4. Excretion

6. EPITHELIAL TISSUE CLASSIFICATION

7. EPITHELIAL TISSUE An epithelial tissue consist of cells arranged in continuous sheets, in either single or multiple layers. Epithelial tissue is a avascular. The various surface of epithelial cells often differ in structure and have specialized functions.

8. Types of epithelium Covering and lining epithelium Glandular epithelium Types of Covering and lining epithelium Simple epithelium a. Simple squamous epithelium b. Simple cuboidal epithelium c. Simple columnar epithelium (non ciliated & ciliated) 2. Stratified epithelium a. Stratified squamous epithelium (keratinized & non keratinized). b. Stratified cuboidal epithelium c. Stratified columnar epithelium d. Transitional epithelium 3. Psuedostratified columnar epithelium (non ciliated & ciliated)

9. Covering and lining epithelium A. Simple squamous epithelium Description: single layer of flat cells, centrally located nucleus. Location: lines heart, blood vessels, lymphatic vessels, air sacs of lungs, glomerular capsule of kidneys, and inner surface of the tympanic membrane, Function: filtration, diffusion, osmosis, and secretion in serous membranes.

10. B. Simple cuboidal epithelium Description: single layer of cube-shaped cells, centrally located nucleus. Location: covers the surface of ovary, lines the anterior surface of the lens of eye, lines kidney tubules and smaller ducts of many glands, and secreting ducts of some glands such as pancreas. Function: secretion and absorption.

11. C. Non ciliated simple columnar epithelium Description: single layer of nonciliated rectangular cells with nuclei near base of cells, contains goblet cells and cells with microvilli in some locations. Location lines the gastrointestinal tract from the stomach to the anus, ducts of many glands, and gallbladder. Function: secretion and absorption.

12. D. Ciliated simple columnar epithelium. Description: single layer of ciliated rectangular cells with nuclei near base of cells, contains goblet cells in some locations. Location: lines a few portions of upper respiratory tract, uterine tubes (fallopian tubes), uterus, some paranasal sinuses, and central canal of spinal cord. Function: moves mucus and other substances by ciliary action.

13. E. STRATIFIED SQUAMOUS EPITHELIUM. Description: several layers of cells, cuboidal columnar shape in deep layers, squamous cells form the apical layer and several layers deep to it, cells from the basal layer replace surface cells as they are lost . Location: keratinized variety forms superficial layer of skin, non keratinized variety lines wet surfaces, such as lining of mouth, oesophagus part of epiglottis, and vagina and covers the toungue. Function: protection.

14. PAPANICOLAOU TEST A Papanicolaou test, Pap test , or pap smear involves collecting and microscopically examination of epithelial cells that have sloughed off the apical layer of a tissue. A very common type of pap test involves examination the cells from the nonkeratinized stratified squamous epithelium of the cervix and vagina. This type of Pap test is performed mainly to detect early changes in the cells of the female reproductive system that may indicate cancer or a precancerous condition .

15. F. STRATIFIED CUBOIDAL EPITHELIUM. Description: two or more layers of cells in which the cells in the apical layer are cube-shaped. Location: Ducts of adult sweat glands and esophageal glands and part of male urethra. Functions: Protection and limited secretion and absorption.

16. G. STRATIFIED COLUMNAR EPITHELIUM Description: several layers of irregularly shaped cells, columnar cells are only in the apical layer. Location: Lines part of urethra, large excretory ducts of some glands, such as esophageal glands, small areas in anal mucous membrane, and part of the conjunctiva of the eye. Function: Protection and Secretion.

17. H. TRANSITIONAL EPITHELIUM. Description: appearance is variable, shape of cells in apical layer ranges from squamous (when stretched) to cuboidal (when relaxed). Location: Lines urinary bladder and portions of ureters and urethra. Function: permits distention.

18. I. PSEUDOSTRATIFIED COLUMNAR EPITHELIUM. Description: Not a true stratified tissue, nuclei of cells are at different levels, all cells are attached to basement membrane, but not all reach the surface. Location: pseudostratified ciliated columnar epithelium lines the airways of most of upper respiratory tract, pseusostratified nonciliated columnar epithelium lines larger ducts of any glands, epididymis, and part of male urethra. Function: secretion and movement of mucus by ciliary action.

19. GLANDULAR EPITHELIUM J. ENDOCRINE GLANDS. Description: secretory products (hormones) diffuse into blood after passing through interstitial fluid. Location: Include pituitary gland at the base of brain, pineal gland in brain, thyroid and parathyroid glands near larynx, adrenal glands superior to kidneys, pancreas near stomach, ovaries in pelvic cavity, testes in scrotum, and thymus in thoracic cavity. Function: Produce hormones that regulate various body activities.

20. GLANDULAR The holocrine type-Here the secretion collects inside the whole of the cell. The cell ultimately dies and disintegrates and thus the secretion is discharged. The adjoining younger cells multiply and replace the lost one, e.g., sebaceous glands..

21. GLANDULAR (2’) The apocrine type— Here the secretion collects in the outer portion of the cell only, which gradually swells up and bursts. The rest of the cell remains intact and alive, and repeats the process again, e.g.. mammary glands and possibly the goblet. cells

22. GLANDULAR 3) The MEROCRINE (or epicrine) type—Here no gross histological change is visible in the cell. The secretion is quietly liberated through the cell membrane. e.g., digestive- glands, endocrine glands, etc.

23. K. EXOCRINE GLANDS Description: Secretory products released into ducts. Location: Sweat, oil, and earwax glands of the skin, digestive glands such as salivary glands, which secrete into mouth cavity, and pancreas, which secretes into the small intestine. Function: Produce mucus, sweat, oil, earwax, saliva, or digestive enzymes.

24. MULTICELLULAR EXOCRINE GLANDS

25. CONNECTIVE (MESENCHYMAL) TISSUE General character. They are all developed from the Mesoderm. The intercellular substance is prominent and may be considerable in amount. This is a great contrast with the epithelial tissues. The intercellular ground substance may contain different types of fibrous elements.

26. CONNECTIVE TISSUE Most abundant and most widely distributed. Binds,supports & strengthens other body tissues. Protects & insulates internal organs. Compartmentalizes structure like skeletal muscle. Eg – Blood, Adipose tissue

27. CONNECTIVE TISSUE CELLS Mesodermal embryonic cells called mesenchymal cells give rise to these cells. Each major type of connective tissue contain an immature class of cells (-blast) Immature cells in connective tissue - fibroblast cartilage - chondroblasts bone - osteoblast Blast cells retain the capacity for cell division & secrete the matrix. Mature cells have reduced capacity for cell division & matrix formation .

28. Classification I . Embryonic connective tissue. a) Mesenchyme. b) Mucous connective tissue. II. Mature connective tissue. a) Loose connective tissue. 1. Areolar connective tissue. 2. Adipose tissue. 3. Reticular connective tissue. b) Dense connective tissue 1. Dense regular connective tissue 2. Dense irregular connective tissue 3. Elastic connective tissue.

29. C. Cartilage. 1. Hyaline cartilage. 2. Fibrocartilage. 3. Elastic cartilage. D. Bone tissue. E. Blood tissue. F. Lymph.

30. Representative cells and fibers in connective tissue

31. TYPES OF CELLS FIBROBLAST Large,flat cells with branching. Present in several connective tissue. They migrate through the con.tissue, secreting the fibres &ground substance of the matrix.

32. 2.MACROPHAGE Develop from Monocyte. Have irregular shape with short branches. Capable of engulfing bacteria & Cellular debris by Phagocytosis. Some are fixed Macrophages. Eg., Alveolar Macrophage – Lungs. Spleen Macrophage – Spleen.

33. PLASMA CELLS Small cells that develop from a type of WBC called B Lymphocyte. Secrete antibodies, proteins that attack or neutralize foreign substance. Important for bodies immune system. Reside mostly in connective tissue in GIT and Respiratory tract. Also seen in salivary gland, Lymph node & Bonemarrow

34. Mast cells Are abundant along the side of the blood vessels. They produce histamine, which dilates small blood vessels as a part of the inflammatory response.

35. ADIPOCYTE Also called fat cell are adipose cell They store triglycerides. They are found below the skin and around organs such as heart and kidneys.

36. White Blood Cell Are not found in normal connective tissue. But in response to certain condition they migrate from blood to connective tissue. Eg., Neutrophils and Eosinophils.

37. Connective Tissue Matrix GROUND SUBSTANCE: Is a component between cells & fibres Supports cells, binds & provides a medium for exchange between the blood and cells. Contains water and large molecules (complex combinations of polysaccharid and protein) Polysaccharid include hyaluronic acid, chondrotin sulfate, dermatan sulfate and keratan sulfate – referred to as glycosaminoglycans or GAGs . Most important property of GAGs is that they trap water making ground substance more jellylike.

38. Fibres Three types of fibres are embedded in the matrix between the cells. Collagen fibres Elastic fibres Reticular fibres

39. COLLAGEN FIBRES Are very strong & resist pulling forces and promotes tissue flexibility Different types of collagen fibres in various tissues have slightly different properties Eg., Collagen in cartilage and collagen in bone They occur in bundles parallel to one another Collagen fibres consist of protein; collagen Are found in bone, cartilage tendon and ligaments .

40. ELASTIC FIBRES Are smaller in diameter then collagen fibres. Branch and join together to form a network within a tissue. Consist of molecule of the protein, elastin surrounded by a glycoprotein fibrillin which strengthens and stabilzes. Because of their unique molecular structure elastic fibres are strong but can be stretched up to 150% of their relaxed length (elasticity). Present in skin, blood vessels walls and lung tissues.

41. RETICULAR FIBRES Consists of collagen arranged in fine bundles and a coating of glycoprotein. Eg., Areolar tissue, Adipose tissue and smooth muscle tissue. They are produced by fibroblasts . Are much thinner than collagen fibres and form branching networks Provide strength and support Are plenty in reticular connective tissue which form the stroma of soft organs like spleen and lymph nodes .

42. MARFAN SYNDROME Inherited disorder caused by a defective fibrillin gene. Tissues rich in fibrillin is malformed or weakened. Most affected are the covering layer of the bone,the ligament that suspends the lens,walls of large arteries.

43. B. ADIPOSE TISSUE Description: consists of adipocytes, cells specialized to store triglycerides (fats) as a large centrally located droplet, nucleus and cytoplasm are peripherally located. Location: Subcutaneous layer deep to skin, around heart and kidneys, padding around joints. Function: Reduces heat loss through skin, serves as energy reserve, supports and protects. In newborns it generates considerable heat to maintain proper body temperature.

44. C. RETICULAR CONNECTIVE TISSUE Description: Consists of a network of interlacing reticular fibers and reticular cells . Location: Stroma(supporting framework) of liver, spleen, lymph nodes, red bone marrow and around blood vessels and muscles. Function: Forms stroma of organs, binds together smooth muscle tissue cells, filters and removes worn out blood cells and microbes in lymph nodes and spleen.

45. Dense Connective Tissue D. Dense regular connective tissue. Description: Matrix looks shiny white, consists mainly of collagen fibers arranged in bundles, fibroblasts present in rows between bundles. Location: Forms tendons (attach muscle to bones), most ligaments (attach bone to bone) and aponeuroses (sheet like tendons that attach muscle to muscle or muscle to bone). Function: Provides strong attachment between various structures.

46. F. ELASTIC CONNECTIVE TISSUE . Description: Consists of predominantly freely branching elastic fibers, fibroblasts present in spaces between fibers. Location: Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspensory ligament of penis, and ligaments between vertebrae . Function: Allows stretching of various organs .

47. G. Hyaline Cartilage. Description: Consists of a bluish-white, shiny ground substance with fine collagen fibers and many chondrocytes, most abundant type of cartilage. Location: Ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic and fetal skeleton. Function: Provides smooth surfaces for movement at joints, as well as flexibility and support.

48. BONE TISSUE J. COMPACT BONE Description: Compact bone tissue consists of osteons (Haversian systems) that contain lamellae, lacunae, osteocytes, canaliculi and central (Haversian) canals. By contrast, spongy bone tissue consists of thin columns called trabeculae, spaces between trabeculae are filled with red bone marrow. Location: Both compact and spongy bone tissue make up the various parts of bones of body. Function: Support, protection, storage, housses blood forming tissue, serves as levers that act together with muscle tissue to enable movement .

49. Blood tissue K. Blood Description: Consists of blood plasma and formed elements; red blood cells (erythrocytes), white blood cells (leukocytes), and platelets ( thrombocytes ). Location: Within blood vessels (arteries, arterioles, capillaries, venules , and veins) and within the chambers of the heart. Function: RBCs transport oxygen and carbon dioxide: WBCs carry on phagocytosis and are involved in allergic reactions and immune system responses, platelets are essential for the clotting of blood.

50. MUSCULAR TISSUES The characteristics property of muscular tissue is its ability to contract when exited . there are different types of muscular tissues. These can be classified according to (a) the presence of cross-striation (i) striated and (ii) non striated (plain or smooth); (b) nature of control (i) voluntary; (controlled by volition), (ii) involuntary ay (not controlled by volition); and lastly

51. (c) distribution (i) skeletal, (ii) cardiac, (iii) visceral. These different types of classifications can be summarised in the following way: 1. Skeletal—striated voluntary (Fin. 59). 2. Cardiac—striated involuntary (Fin. 60). 3. Visceral—non-striated (plain or smooth) involuntary

52. MUSCLE TISSUE (THREE TYPES) Skeletal muscle Smooth muscle Cardiac muscle FUNCTIONS OF MUSCLE TISSUE: Muscle functions alternate by phases of contraction and relextation When fibres contract they become thicker and shorter. Skeletal muscle fibres are stimulated by motor nerve impulses originating from brain and spinal cord. Smooth and cardiac muscle have the intrinsic ability to initiate contraction. In addition ANS Hormones Local metabolites also stimulate

53. MUSCLE TONE This is the partial contraction of muscle. Skeletal muscle tone is essential for maintenance of posture – sitting and standing MUSCLE FATIGUE If a muscle is stimulated to contract at a very frequent intervals its response gradually becomes depressed and will in time cease.

54. ENERGY SOURCE FOR MUSCLE CONTRACTION : The chemical energy (ATP) which muscle require is derived from the breakdown of carbohydrate & fat (catabolism). Protein molecules inside the fibres are used to provide energy when carbohydrate and fat are deficient. For them oxygen is required. When the breakdown process and the release of energy is complete, the waste products are co2 and water.

55. ISOTONIC CONTRACTION:- Tension remains same. Changes occur in the length. Eg., Flexion of arm. ISOMETRIC CONTRACTION: Length same . Tension increased Eg., Pulling any heavy object. TISSUE REGENERATION By mitosis tissue regeneration occur.

56. MEMBRANES : ar e sheets of epithelial tissue and their supporting connective tissue that cover or line internal structures (or) cavities. Eg.,mucous , serous, synovial MUCOUS : GIT, respiratory system, urinary tracts. SEROUS: secrete serous watery fluid. They consists of double layer of loose areolar connective tissue (parietal and visceral layer) eg ., Pleura, pericardium.

57. SYNOVIAL MEMBRANE: membrane lining the joint cavities and surrounding tendons. Synovial membrane secrets clear, sticky, oily synovial fluid, act as lubricants to the joints. GLANDS: Glands are group of epithelial cells which produce specialized secretions Exocrine glands & endocrine glands

58. NERVOUS TISSUE This is a highly specialised tissue for reception, discharge of stimuli. and transmission. It is made up of nerve cells and their processes, called the nerve fibres .

59. APPLIED ASPECT 1. When the motor nerve to a skeletal muscle is cut it causes: i ) ‘atrophy’ of the muscle i.e., shrinkage of muscle fibers, which finally gets replaced by fibrous tissue (fibrous muscle) ii) Complete paralysis of the muscle called flaccid paralysis iii) appearance of fine, irregular contractions of individual fibers called fibrillations. iv) abnormal excitability of the muscle and increases its sensitivity in circulating A- ch ( Denervation hypersensitivity )

60. RELATION OF THYMUS TO Myasthenia gravis Myasthenia gravis is a disorder of neuromuscular transmission characterized by attacks of severe muscular weakness, fatigability specially affecting eyelids, deglutition, speech and is relieved by anticholinesterase, (eg.,neostigmine)

61. MUSCULAR DYSTROPHY It is a syndrome characterized by progressive muscle weakness due to mutation in dysrophin gene, which results in congenital defect in dystrophin-glycoprotein complex. MYOTONIA A condition characterized by difficulty and slowness in relaxing muscle after voluntary effort. When muscle fibers are completely depleted of ATP and phosphocreatine, they develop a state of extreme rigidity called rigor. When this occurs after death, the condition is called rigor mortis. In rigor, almost all of the myosin heads attach to actin but in an abnormal, fixed and resistant way.

62. Thank You