1. HISTOLOGY
THE STUDY OF TISSUES

2. TISSUES
Organization of similar cells embedded in a matrix (nonliving, intercellular material
Matrix can be rigid, gel, fluid or nonexistent
Specialize in performing at least one unique function essential for life

3. 1. EPITHELIAL Covers and protects body surface Lines body cavities
Secretes and absorbs substances into and out of blood
Forms glands

4. 2. CONNECTIVE Supports and connects body and its parts
Transports substances throughout the body
Protection from invading microbes
Cells spread out; lots of matrix

5. 3. MUSCLE
Produces movement by shortening complex contractile proteins

6. 4. NERVOUS
Communication between body parts and integration of their activities

7. 1. EPITHELIAL 2 types: 1. Membranous – covers and lines body
2. Glandular – exocrine and endocrine

8. FUNCTIONS
Protection
Secretion
Absorption
Excretion
Sensory

9. CHARACTERISTICS Limited amount of matrix Basement membrane Avascular
Held together by fused cell membranes
Reproduce by mitosis
Nutrients by diffusion
Polarity

10. CLASSIFICATION OF MEMBRANOUS EPITHELIUM
Based upon cell shape
Squamous (flat), cuboidal, or columnar
Based upon # of cell layers
Simple (single) or stratified (layered)

12. Simple squamous

13. Simple squamous and simple cuboidal

14. Squamous cells at surface

15. Simple squamous (endothelial lining)

16. Simple cuboidal

17. Simple cuboidal of thyroid glands

18. Simple cuboidal

20. Simple columnar

21. Simple columnar

23. Pseudostratified

24. Pseudostratified

25. Cilia on apical surface of pseudostratified epithelial tissue

26. Transitional

27. Transitional; note dome shaped cells at apical surface

28. Nonkeratinized stratified squamous

29. Nonkeratinized stratified squamous epithelium

30. Keratinized stratified squamous epithelial tissue (skin)

31. Stratified cuboidal

32. Stratified columnar

34. CLASSIFICATION OF GLANDULAR EPITHELIUM
Exocrine – discharge products into ducts
1. Apocrine
2. Holocrine
3. Merocrine
Endocrine – ductless glands

37. II. CONNECTIVE Most abundant and diverse
Connects, supports, transports and defends
Few cells, mostly matrix (nonliving extracellular material); various numbers and kinds of fibers

41. 1. AREOLAR Most common and widely distributed
Matrix is soft gel – hyaluronic acid
Matrix = collagen and elastin fibers
Fibroblasts (secrete matrix) are the predominant cells
Macrophages (phagocytosis)
Mast cells – secrete histamine

42. Areolar

44. B. ADIPOSE Mostly fat cells (adipocytes)
Protection, insulation, energy storage

45. Adipose

47. C. RETICULAR
3-D web
Defense; reticular network filters harmful substances from lymph and blood
Reticular cells phagocytic

48. Reticular

50. D. DENSE REGULAR Mainly bundles of collagen arranged in parallel rows
Few fibroblasts
Ligaments (bone to bone) and tendons (muscle to bone)

51. Dense regular

52. E. DENSE IRREGULAR Bundles of collagen arranged in various planes
Dermis of the skin
Joint capsules

53. Dense irregular

54. 6. CARTILAGE One cell type: chondrocyte
Chondrocytes produce fibers and tough gristlike material (chondroitin sulfate)
Avascular – nutrients diffuse through perichondrium which surrounds cartilage mass

55. F. HYALINE CARTILAGE Shiny Most prevalent type
Support tubes of respiratory system, ribs, tip of nose, ends of bones

56. Hyaline cartilage

57. Note glassy appearance of matrix

58. G. ELASTIC More elastic fibers Strong and flexible
External ear, epiglottis

59. Elastic cartilage

60. Note elastin fibers in matrix

61. H. FIBROCARTILAGE Strongest Shock absorbers
Found between vertebrae and knee joints
Rigid matrix filled with strong white fibers

62. Fibrocartilage

64. I. BONE Osteocytes in matrix of collagen and mineral salts (65%)
Support, protection, muscle attachment; mineral storage; hemopoiesis
Haversian system

65. Bone

66. Compact bone; note lacunae, canaliculi

67. Osteons; note lamellae (circumferential and interstitial)

68. J. BLOOD Liquid matrix (plasma) Fibers only present at clotting
Erythrocytes, leukocytes and platelets are the cells

69. Blood

71. III. MUSCLE A. Skeletal B. Cardiac C. Smooth
Multinucleate, cross striations
B. Cardiac
Heart wall; cross striations, intercalated disks, involuntary Visceral
C. Smooth
involuntary, one nucleus per cell, non striated

72. Skeletal muscle

74. Cardiac muscle

76. Smooth muscle

77. Smooth muscle

78. IV. NERVOUS Nerve cells Neuroglia Neurons
Cell body (soma), axons (away) dendrites (toward cell body)
Neuroglia
Connecting and supporting cells

79. IV. Nerve

80. Neuron smear; small dots are nuclei of glial cells (neuroglia)

81. Peripheral nerve in cross section