1. Introduction and Epithelium
Histology
Introduction and Epithelium

2. HISTOLOGY
HISTOLOGY: the study of tissues - the branch of anatomy that deals with the microscopic structure of tissues

3. HISTOLOGY
tissues: groups of cells that are similar in structure & function

5. 4 main types of tissue
1) Epithelial 2) Connective 3) Muscle 4) Nervous

6. All tissues are interconnected!

7. Epithelial Tissue

8. EPITHELIAL TISSUE Also known as EPITHELIUM
Is the lining, covering, and glandular tissue of the body

9. FUNCTIONS OF EPITHELIUM
Protection
Absorption
Filtration
Secretion

10. Characteristics of Epithelium
Cells fit closely together to form continuous sheets
2) Always one unattached (free) surface or edge
* called the apical surface

12. Characteristics of Epithelium
Lower surface of epithelial tissue rests on a basement membrane
* thin layer of extracellular material to which epithelial cells are attached

13. Characteristics of Epithelium
Epithelium is avascular = no blood supply of own
 blood gets to these cells by diffusion from capillaries
5) Epithelial cells can regenerate easily (if well nourished)

14. Classification of Epithelium:
Each type of epithelium has 2 names:
First part of name = # of CELL LAYERS
Second part of name = SHAPE

15. Classification of Epithelium:
First name:
Simple = one layer of cells, very thin
Functions: absorption, secretion, filtration
Stratified = two or more layers of cells, more durable
Functions: protection

16. Classification of Epithelium:
First name:
Pseudostratified = “false” stratified, cells are different heights but still one layer

17. Classification of Epithelium:
Second name:
Squamous = flattened, like fish scales or floor tiles
Cuboidal = cube-shaped, like dice
Columnar = column-shaped, thinner

18. Classification of Epithelium:
Simple vs. Stratified
Stratified epithelia named for the cells at the free surface of the epithelial membrane

19. Simple Squamous Epithelium
Single layer of flat cells resting on a basement membrane
Location: lines air sacs of lungs, blood vessels, lines ventral body cavity
Function: exchange of substances by rapid diffusion, filtration, secretion

20. Simple Squamous Epithelium

21. Simple Cuboidal Epithelium
Single layer of cube-shaped cells resting on a basement membrane
Location: salivary glands; kidney; ovaries
Functions: Secretion and absorption

22. Simple Cuboidal Epithelium

23. Nonciliated Simple Columnar Epithelium
Single layer of nonciliated rectangular cells resting on a basement membrane
Location: lines digestive, respiratory, urinary tracts
Function: Secretion and absorption

24. Nonciliated Simple Columnar Epithelium
Contain absorptive and goblet cells
Absorptive cells- columnar epithelial cells with microvilli (fingerlike projections that increase surface area, therefore increasing the rate of absorption)
Goblet cells- modified columnar cells that secrete mucus
Before mucus is released, it accumulates in the upper portion of the cell, causing that area to bulge out and resemble a goblet or wine glass

25. Simple Columnar Epithelium
Epithelial membranes that line body cavities which open to the body exterior are called mucous membranes

26. Ciliated Simple Columnar Epithelium
Single layer of ciliated columnar cells resting on a basement membrane
Location: Upper respiratory tract
Function: Moves mucus and other substances by ciliary action

27. Ciliated Simple Columnar Epithelium

28. Stratified Squamous Epithelium
Multiple layers of cells, with squamous at the apical surface and cuboidal or columnar lining the basement membrane
Location: Skin, mouth, throat
Function: protection

29. Stratified Squamous Epithelium

30. Stratified Cuboidal Epithelium
Two or more layers, with cube-shaped cells at the apical surface
Location: large glands (sweat glands)
Function: secretion

31. Stratified Cuboidal Epithelium

32. Stratified Columnar Epithelium
Two or more layers of cells with columnar shaped cells at the apical surface
Location: large glands
Function: secretion

33. Stratified Columnar Epithelium

34. Transitional Epithelium
Modified stratified squamous epithelium
Basal layer: cuboidal/columnar
Apical surface: vary in shape
Location: urinary tract (bladder, ureters, urethra)
Function: Cells can slide over each other to accommodate change in organ size
Organs can stretch without rupturing

35. Transitional Epithelium

36. Pseudostratified Columnar Epithelium
Single layer of ciliated columnar cells of varying heights resting on a basement membrane
Location: lines respiratory tract
Function: Secretion and movement of mucus by ciliary action

37. Pseudostratified Columnar Epithelium

39. 1: simple squamous

41. 2: simple cuboidal - kidney

43. 3: simple columnar – small intestine

45. 4: ciliated pseudostratified columnar - trachea

46. 5. Stratified squamous epithelium – tongue

47. 47

48. Glandular Epithelium Function: secretion
Glandular cells often lie in clusters deep to the covering and lining epithelium
A gland may consist of one cell, or a group of highly specialized cells
They secrete substances into ducts, onto a surface, or into the blood

49. Glandular Epithelium Endocrine glands
Secretions enter extracellular fluid, then diffuse into the bloodstream without flowing through a duct
Secretions are hormones (regulate metabolic and physiological activities to maintain homeostasis)
Ex: pituitary, thyroid, adrenal glands

50. Glandular epithelium Exocrine glands
Secrete into ducts that empty at the surface of covering/lining epithelium or directly onto a free surface
Skin or interior space (lumen) of a hollow organ
Secrete mucus, sweat, oil, earwax, milk, saliva, digestive enzymes
Ex: sweat glands, salivary glands

51. Epithelium Review

52. 1 2 3 4 5 6

53. Histology
What is a tissue?

54. Histology
tissues: groups of cells that are similar in structure & function

55. Epithelial Tissue
Is the lining, covering, and glandular tissue of the body

56. Functions of Epithelium
Protection
Absorption
Filtration
Secretion
Pigeons Always Fly Straight

57. Characteristics of Epithelium
Abut
Apical surface
Basement membrane
Avascular
Regenerate
Another Awesome Byrne Anatomy Review! 

58. Characteristics of Epithelium
Abut: Cells fit closely together to form continuous sheets
2) Apical Surface: Always one unattached (free) surface or edge

59. Characteristics of Epithelium
Basement Membrane: Lower surface of epithelial tissue rests on
* thin layer of extracellular material to which epithelial cells are attached

60. Characteristics of Epithelium
Avascular: no blood supply of own
 blood gets to these cells by diffusion from capillaries
5) Regenerate: Epithelial cells can regenerate easily (if well nourished)

61. Simple Squamous Specimen: artery Label: apical surface,
nucleus of squamous cell

62. Simple Cuboidal
Specimen: Kidney
Label: cuboidal cell, nucleus

63. Simple Columnar
Specimen: Small Intestine
Label: goblet cells

64. Pseudostrified ciliated columnar
Specimen: Trachea
Label: apical surface, cilia

65. Stratified Squamous Specimen: Skin
Label: squamous cell, apical surface

66. Transitional
Specimen: Urinary bladder
Label: apical surface