1. Anatomy & Physiology I Lab
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Dr. Jason Schwartz

2. Overview Human body starts with one cell
Division makes millions of cells
Each specialized for particular functions
Some are so specialized, they can create hazards
Ex. Heart cells
Groups of similar cells that are similar in structure and function: tissues

3. Tissues Histology = The study of tissues
Tissue = A collection of cells that perform related functions, and are similar in structure
The Four Primary Tissue Types
Epithelial
Connective
Muscular
Nervous

4. Classification of Tissue
1. Epithelial Tissue- lines body cavities, hollow organs and ducts. Forms skin.
2. Connective Tissue- protects and supports the body and organs.
3. Muscle- generates physical force needed for body motion.
4. Nervous Tissue- generates nerve impulses in response to internal and external changes. With the brain, helps maintain homeostatic function.

5. Epithelial Tissue -- General Features
Cover surfaces, line cavities and form glands.
Attached to underlying connective tissue by a basement membrane
Avascular---without blood vessels
nutrients diffuse in from blood vessels in underlying connective tissue
What does this mean for especially thick epithelia?
Good nerve supply
Rapid cell division; responsive to environmental stresses
Named according to the shape and arrangement of cells

6. Special Characteristics
Except for glandular, they fit closely together to form continuous sheets
Always have one free surface (apical surface): exposed to body’s exterior or the cavity of an internal organ
Lower surface rests on a basement membrane, structureless material secreted by cells
No blood supply of their own (avascular); depend on diffusion from capillaries
Regenerate themselves very easily

7. Types of Tissues Epithelium (covering) Connective (support)
Nervous (control)
Muscle (movement)
All interweave to form the fabric of the body
Tissues organized into organs
One organ can be composed of several tissue types

8. Epithelial Tissue Also called epithelium
Lining, covering, and glandular
Forms glands
Covers all free body surfaces
Versatile cells
Outer skin layer, and lining of body cavities
Every substance entering or leaving must pass through these cells

9. Classification of Epithelium
Two names
First name is for number of cells: simple (one) or stratified (more than one)
Second name describes shape: squamous (flattened), cuboidal (cube-shaped), and columnar (column-shaped)
Names are combined
*Stratified epithelia are named for the cells at the free surface of the membrane, not the those resting on the basement membrane

10. Classification of Epithelia
Simple or stratified
Figure 4.1a

12. Classification of Epithelia
Squamous, cuboidal, or columnar
Figure 4.1b

13. Simple Epithelia
Most concerned with absorption, secretion, and filtration
Simple Squamous epithelium
Single layer resting on basement membrane
Fit closely together
Usually forms membranes that use diffusion: air sacs of lungs, walls of capillaries
Also forms serous membranes or serosae: slick membranes lining ventral body cavity and cover organs in ventral cavity

14. Epithelia: Simple Squamous
Figure 4.2a

15. Lung

17. Squamous Epithelium (surface view)

19. Simple Epithelial Tissue

20. Squamous Epithelium (surface view)

21. Simple Epithelial Tissue

22. Epithelia: Stratified Squamous
Thick membrane composed of several layers of cells
Function in protection of underlying areas subjected to abrasion
Forms the external part of the skin’s epidermis (keratinized cells), and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

23. Epithelia: Stratified Squamous
Figure 4.2e

25. Simple Cuboidal & Squamous Epithelium
Cuboidal g
Squamous g

27. Fig. 5.9

28. Fig. 5.9a

29. Stratified Squamous Epithelium

30. Stratified Squamous Epithelium of the Esophagus

31. Simple Epithelia contd.
Simple Cuboidal Epi.
One layer resting on basement membrane
Common in glands and ducts: salivary glands and pancreas
Forms walls of the kidney tubules, and covers surface of the ovaries

32. Simple Cuboidal & Squamous Epithelium
Cuboidal g
Squamous g

33. Epithelia: Simple Cuboidal
Single layer of cubelike cells with large, spherical central nuclei
Function in secretion and absorption
Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface

34. Fig. 4.2b

35. Simple Cuboidal Epithelium
Thyroid Gland The layered spaces are the lumens of follicles whose walls are composed of simple cuboidal epithelium.

37. Fig. 5.5a

38. Fig. 5.5b

39. Simple Epithelia contd.
Simple Columnar Epi.
One layer of tall cells
Fit close together
Goblet cells: produce a lubricating mucus, often seen in this type of epithelium
Lines entire length of digestive tract from stomach to anus
*Epithelial membranes that line body cavities open to the exterior are called mucous membranes or mucosae

40. Epithelia: Simple Columnar

42. Fig. 4.2c

43. Goblet Cell
Figure 4.3b

44. Simple Columnar Epithelium
Gall Bladder Simple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels.

45. Simple Columnar Epithelium

46. Simple Columnar Epithelium

47. Simple Epithelia contd.
Pseudostratified Columnar Epi.
Rest on basement membrane
Cells are different heights, and nuclei appear at different heights above basement
Give false (pseudo) impression of stratified
Mainly absorption and secretion
Pseudostratified ciliated columnar epithelium
Ciliated, lines most of respiratory tract
Goblet cells produce mucus to trap dust and debris

48. Epithelia: Pseudostratified Columnar
Single layer of cells with different heights; some do not reach the free surface
Nuclei are seen at different layers
Function in secretion and propulsion of mucus
Present in the male sperm-carrying ducts (nonciliated) and trachea (ciliated)

49. Stratified Epithelia Two or more cell layers More durable than simple
Primarily for protection
Stratified Squamous Epithelium
Most common stratified
Usually several layers
Free edge are squamous, closer to basement are cuboidal or columnar
Found in “high friction” areas: esophagus, mouth, other parts of skin

50. Stratified Epithelia Stratified Cuboidal and Columnar Epithelia
Usually just two cell layers with (at least) the surface cells being cuboidal
Surface cells of stratified columnar are columnar, but its basal cells vary in size and shape
Both are fairly rare
Found mainly in the ducts or large glands

51. Stratified Epithelia Transitional Epithelium Highly modified
Stratified squamous epithelium
Forms lining of only a few organs: bladder, the ureters, and part of the urethra
All part of the urinary system and undergo considerable stretching
Basal layer are cuboidal or columnar; those at the free surface vary in appearance
Stretching changes shape, cells can flatten and become squamous-like

52. Glandular Epithelia
Gland: consists of one more cells that make and secrete a particular product
Secretion: typically contains protein molecules in an aqueous fluid
Noun and verb: glandular cells obtain needed materials from the blood and use them to make their secretion, which they then discharge
Two types:
Endocrine glands: no connection to surface (ductless), secrete hormones through diffusion
Exocrine glands: retain ducts, secretions empty to surface: sweat and oil glands, liver and pancreas, internal and external

53. Renal Corpuscle 400X
Bowman’s capsule
capsular space
glomerulus

54. Fig. 4.2g

57. Simple Columnar Epithelium
Gall Bladder Simple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels.

58. Simple Columnar Epithelium
Gall Bladder Simple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels.

59. Pseudostratified Columnar Ciliated Epithelium
Trachea The pseudostratified columnar epithelium of the trachea is ciliated and has goblet cells.

60. Pseudostratified Columnar Ciliated Epithelium

61. Epithelia: Transitional
Several cell layers, basal cells are cuboidal, surface cells are dome shaped
Stretches to permit the distension of the urinary bladder
Lines the urinary bladder, ureters, and part of the urethra

63. Transitional Epithelium (Ureter)
3 apical (free) surface

64. Transitional Epithelium
Urinary Bladder The expandable stratified epithelium of the bladder is referred to as transitional epithelium. Note that its surface cells are large rather than flattened as in stratified squamous epithelium.

65. transitional epithelium of mucosa
Ureter 100X
transitional epithelium of mucosa
lamina propria
smooth muscle
adventitia

66. * Ureter 400X
lamina propria
smooth muscle
transitional epithelium

67. detrusor muscular layer
Urinary Bladder 40X
transitional epithelium of mucosa
lamina propria
submucosa
detrusor muscular layer

68. Bladder (Empty)
White line- defines height of epithelium

69. Bladder (Full) Orange arrow - Flattened "plump" cells
White line- defines height of epithelium

70. Red arrow - Transitional Epithelium of Urethra