1. Tissues

2. Types of Tissues in the Body

3. Tissues Histology is the study of tissues Histology is the study of tissues Tissues are groups of specialized cells with limited number of functions Tissues are groups of specialized cells with limited number of functions There are 4 PRIMARY types of tissues in the human body There are 4 PRIMARY types of tissues in the human body Epithelial tissue Epithelial tissue Connective tissue Connective tissue Muscle tissue Muscle tissue Nervous tissue Nervous tissue

4. Epithelial tissue Epi- means upon Epi- means upon Epithelial tissue covers all exposed surfaces and lines body cavities Epithelial tissue covers all exposed surfaces and lines body cavities Various types of epithelial tissues each with specific functions Various types of epithelial tissues each with specific functions

5. Characteristics of Epithelial Tissue Tightly packed cells Tightly packed cells Polarity – epithelial cells have a “top” and “bottom” orientation. Surface that faces the surface of the body or internal space is the APICAL layer Polarity – epithelial cells have a “top” and “bottom” orientation. Surface that faces the surface of the body or internal space is the APICAL layer Attachment – basement membrane Attachment – basement membrane Avascularity – no blood supply Avascularity – no blood supply Regeneration Regeneration

6. Functions of Epithelial Tissue Physical protection Physical protection Control of permeability Control of permeability Sensations Sensations Secretions Secretions

7. Classification of epithelia Shape Shape Squamous = flat cells Squamous = flat cells Cuboidal = square Cuboidal = square Columnar = tall and thin Columnar = tall and thin Number Number Simple epithelial = one layer of cells Stratified epithelial = several layers of cells

8. Epithelial Tissue

10. Simple Squamous epithelium Single layer of flat cells Single layer of flat cells

11. Simple Squamous Epithelium

12. Endothelial cells Simple squamous epithelium

13. Simple cuboidal epithelium

14. Simple cuboidal epithelia Single layer of square cells Single layer of square cells

15. Simple columnar epithelium

16. Simple columnar epithelia Single layer of tall thin cells Single layer of tall thin cells

17. Stratified Squamous Epithelia Non-keratinized Several layers of flat cells Several layers of flat cells

18. Stratified squamous epithelium non-keratinized

20. Stratified Squamous Epithelia Keratinized Several layers of flat cells with a top layer of dead keratinized cells Several layers of flat cells with a top layer of dead keratinized cells

21. Transitional epithelia Several layers of cells. Apical cells rounded in shape. Several layers of cells. Apical cells rounded in shape.

22. Transitional epithelium

23. Pseudostratified ciliated columnar epithelia (PSCC) Not truly stratified Not truly stratified All cells touch the basement membrane but not all reach the surface All cells touch the basement membrane but not all reach the surface

27. Glands Epithelial tissues often have associated cells that produce secretions Two types of secretion Exocrine Endocrine

28. Exocrine secretion Secretion onto a surface via a tube or DUCT Secretion onto a surface via a tube or DUCT Unicellular and multicellular glands Unicellular and multicellular glands Unicellular exocrine gland is the GOBLET CELL Unicellular exocrine gland is the GOBLET CELL

29. Goblet cell (unicellular exocrine gland) Secrete mucus, often found in the gut and lining the trachea Secrete mucus, often found in the gut and lining the trachea

30. Goblet cell

31. Endocrine glands Secrete directly into the blood Secrete directly into the blood Ductless glands Ductless glands Hormones Hormones

32. Gland structure

33. Modes of secretion Merocrine, apocrine, holocrine

34. Connective Tissue Second major tissue type in the body

35. Connective Tissue Found throughout the body Found throughout the body NEVER exposed to the outside NEVER exposed to the outside Three basic components Three basic components Specialized cells - fibroblasts Specialized cells - fibroblasts Extracellular protein fibers Extracellular protein fibers Ground substance Ground substance MATRIX = fibers + ground substance MATRIX = fibers + ground substance

36. Functions of connective tissue Structural framework Structural framework Transport of fluids and chemicals Transport of fluids and chemicals Protection Protection Energy storage Energy storage Mineral storage Mineral storage Immunity Immunity

38. Connective Tissue Proper Two types Two types Loose CT Loose CT Dense CT Dense CT Three types of fibers Three types of fibers Collagen – long straight fibers, very strong Collagen – long straight fibers, very strong Reticular fibers – thinner fibers, branching interwoven network Reticular fibers – thinner fibers, branching interwoven network Elastic fibers – branching, wavy fibers that stretch Elastic fibers – branching, wavy fibers that stretch

39. Connective Tissue Proper

40. Areolar CT Very common CT Very common CT Open framework Open framework All three types of fibers All three types of fibers Found under the dermis of the skin, around muscles and blood vessels. Found under the dermis of the skin, around muscles and blood vessels. Distorts without damage Distorts without damage

41. Areolar CT

43. Adipose CT Adipocytes are the dominant cell type Adipocytes are the dominant cell type Collagen fibers present Collagen fibers present Found under the skin and around organs Found under the skin and around organs Protection and energy storage Protection and energy storage

44. Adipose CT

45. Reticular CT Open frame work tissue Open frame work tissue Composed primarily of reticular fibers Composed primarily of reticular fibers Structure of liver and spleen Structure of liver and spleen

47. Dense CT Tissue is composed mostly of collagen fibers Tissue is composed mostly of collagen fibers Types of dense CT Types of dense CT Dense regular CT Dense regular CT Elastic CT Elastic CT Dense irregular CT Dense irregular CT

48. Dense Regular CT Tightly packed collagen fibers running parallel to each other Tightly packed collagen fibers running parallel to each other Very strong tissue Very strong tissue Fibroblasts present Fibroblasts present Tendons and ligaments Tendons and ligaments

49. Dense Regular CT

51. Dense Irregular CT Collagen fibers in less organized fabric Collagen fibers in less organized fabric Meshwork, no consistent pattern Meshwork, no consistent pattern More elastic More elastic Strength to areas of the body that are stressed from many directions Strength to areas of the body that are stressed from many directions Found in the dermis of the skin and around many organs Found in the dermis of the skin and around many organs

52. Dense Irregular CT

53. Elastic CT Type of dense regular CT Type of dense regular CT Composed mostly of elastic fibers Composed mostly of elastic fibers Allows for stretch Allows for stretch Found between the vertebrae and walls of large blood vessels Found between the vertebrae and walls of large blood vessels

54. Elastic CT

55. Supportive CT Cartilage Cartilage Strong frame work for support Strong frame work for support Matrix contains numerous fibers Matrix contains numerous fibers Three types Three types Hyaline Hyaline Elastic Elastic Fibrocartilage (Fibrous cartilage) Fibrocartilage (Fibrous cartilage)

56. Hyaline cartilage Most common Most common Matrix of collagen fibers Matrix of collagen fibers Chondrocytes = cartilage cells Chondrocytes = cartilage cells Lacuna = chamber around the cartilage cell Lacuna = chamber around the cartilage cell Perichondrium present Perichondrium present Locations Locations End of long bones Tracheal rings Costal cartilage

57. Perichondrium of hyaline cartilage

58. Elastic cartilage Contains elastic fibers in the matrix for stretch Contains elastic fibers in the matrix for stretch Found in the pinna of the ear, and epiglottis Found in the pinna of the ear, and epiglottis Perichondrium present Perichondrium present

59. Fibrocartilage (Fibrous cartilage) Matrix of collagen fibers Matrix of collagen fibers Densely woven fibers Densely woven fibers Very tough and durable Very tough and durable No perichondrium No perichondrium Found: Found: Intervertebral discs Meniscus of the knee Pubic symphysis

60. Fibrocartilage

62. Bone Type of supportive CT Type of supportive CT Bone cells are osteocytes Bone cells are osteocytes Bone forming cells are osteoblasts Bone forming cells are osteoblasts Matrix is mineralized collagen fibers Matrix is mineralized collagen fibers

63. Bone

64. Fluid CT Blood Blood Lymph Lymph

65. Membranes Combination of epithelial tissues and CT Combination of epithelial tissues and CT Consists of epithelial sheet and underlying CT Consists of epithelial sheet and underlying CT Membranes cover and protect Membranes cover and protect Four types Four types Mucous membranes Mucous membranes Serous membranes Serous membranes Cutaneous membrane Cutaneous membrane Synovial membrane Synovial membrane

66. Mucous membranes Line passageways that communicate with the outside Line passageways that communicate with the outside Digestive, respiratory, reproductive, urinary tracts Digestive, respiratory, reproductive, urinary tracts Important barriers to prevent entry of pathogens Important barriers to prevent entry of pathogens Usually a simple epithelial lining but NOT always Usually a simple epithelial lining but NOT always

67. Serous membranes These membranes line the subdivisions of the ventral body cavity These membranes line the subdivisions of the ventral body cavity Simple squamous epithelial (mesothelium) and areolar CT Simple squamous epithelial (mesothelium) and areolar CT Very thin and attached to the body wall and organs covered Very thin and attached to the body wall and organs covered Pleura Pleura Peritoneum Peritoneum Pericardial Pericardial

68. Cutaneous membrane Skin Skin Covers the surface of the body Covers the surface of the body Keratinized stratified squamous epithelial and underlying CT Keratinized stratified squamous epithelial and underlying CT

69. Membranes

70. Other Tissue Types Muscles tissue Muscles tissue Skeletal muscle Skeletal muscle Cardiac muscle Cardiac muscle Smooth muscle Smooth muscle Nervous Tissue Nervous Tissue

71. Skeletal muscle

72. Cardiac muscle

73. Smooth muscle

74. Nervous tissue

75. Nervous Tissue