1. The study of the tissues of the body
Lab 3 – Histology
The study of the tissues of the body
Expanded Studies

2. The science of Anatomy

3. What is a tissue? Two or more cells that share a common Structure
Function
Embryological origin

4. Examples of Tissues
MACRO MICRO
Blood:
Fat:

5. Examples of Tissues MACRO MICRO Epidermis: (Stratified squamous)
Cartilage: (Hyaline)

6. Examples of Tissues MACRO MICRO Cerebral cortex: (Nervous)
Skeletal Muscle:
Tendon: (Dense irregular)

7. Understand an organ by understanding the tissue it is composed of
Goal:

8. There are four tissue categories:
Epithelial Tissue
Connective Tissue
Nerve Tissue
Muscle Tissue
Histology is the study of tissues.

9. All 4 tissue types working together to make an organ:
Example:
lining
support, bind, protect
movement
Connective
Epithelial
communication

10. In today’s lab, we’ll concentrate on these two:
Epithelial tissue
&
Connective tissue
lining
support, bind, protect
Connective
Epithelial

11. Epithelial vs. Connective Tissue
How can you tell which are Epithelial and which are Connective tissue?

12. Epithelial tissue is composed of closely packed cells,
Connective tissue is composed of a few cells surrounded by lots of extracellular matrix (fibers, fluid, minerals, etc.)
Ep;ithelial Tissue
Connective Tissue

13. Questions to ask for identifying tissues
Epithelial tissue
Connective tissue

14. Which are Epithelial and which are Connective tissue?

15. Objective 1: Epithelial Tissues

16. EPITHELIAL TISSUES - Locations
Look for the edge
Outer lining covering the body surfaces and organs
Inner linings of body cavities and organs

17. EPITHELIAL TISSUES - Functions
Diffusion
Filtration
Secretion
Absorption
Protection

18. EPITHELIAL TISSUES - Examples
Edge (apical layer)
Lung alveoli
(diffusion)
Epidermis
(protection)
Renal tubule
(filtration)
Small intestine
(secretion,
absorptoin)
Edge

19. Epithelial tissues come in 3 shapes:
Which shape is best suited for secretion &/or absorption?
Which shape is best suited for lining a tube?
Which shape is best suited for filtration?
Columnar
“Column-like”
Cuboidal
“Cubish”
Squamous
“Flat”

20. Epithelial tissues come various layers:
Single layer = Simple
2 or more layers = Stratified

21. Putting it all together:
To classify an epithelium state the number of layers then cell shape.

22. Knowing the function and location of each tissue type will help you make sense of them and aid in memorization.

23. Some specializations:
Cilia
(i.e. cells lining the trachea)
Microvilli
(i.e. cells lining the intestines)

24. Epithelial tissue is connected to the underlying Connective tissue via an extracellular matrix called basement membrane

25. A type of extracellular matrix
Basement Membrane
A type of extracellular matrix
Collagen
(protein fibers)
Nidogen
a binding glycoprotein
Perlecan
a GAG proteoglycan
Laminin
The cell adhesion molecule
Integrins
Adhesion receptors of cells
Epithelium
Read the explanation here:

26. Types of Simple Epithelia
Look for the nuclei

27. Simple Squamous Epithelia
Look for a flattened nucleus
Nucleus
Cytoplasm
Frog skin
Basement Membrane
Cytoplasm
Nucleus
Tunica interna (blood vessel)
Basement Membrane

28. Simple Cuboidal Epithelia
Look for a rounded nucleus
Nucleus Cytoplasm
Basement Membrane
Renal (kidney) duct

29. Simple Columnar Epithelia
Look for an oval nucleus
Cytoplasm
Nucleus
Intestine
Basement Membrane

30. Pseudostratified Columnar Epithelia
* Cells have a tapered appearance
Goblet Cells
Cytoplasm
Nuclei
Trachea
Basement Membrane

31. Identify this tissue type (both are the same)
Simple Squamous Epithelia
Lung alveoli
Renal corpuscle

32. Renal (kidney) tubules
Identify these Epithelial Tissues
Simple Columnar
Gall bladder
Simple Cuboidal
Renal (kidney) tubules

33. Pseudostratified Columnar
Identify these Epithelial Tissues
Pseudostratified Columnar
Trachea
Simple Columnar
Intestines

34. Identify these Epithelial Tissues
Simple Squamous
Simple Cuboidal

35. Types of Stratified Epithelia
Named according to the shape of the apical layer of cells

36. Lining esophagus, mouth & vagina
Stratified Squamous Epithelia
Lining esophagus, mouth & vagina
Keratinized: Epidermis (Skin)
Apical Cells
Basal Cells
Esophagus
Basement Membrane

37. (Ducts of large glands = sweat & mammary)
Stratified Cuboidal Epithelia
RARE
Apical Cells
Basement Membrane
Lumen
Basal Cells
Testis
(Ducts of large glands = sweat & mammary)

38. Small amounts in pharynx, male urethra & glandular duct linings
Stratified Columnar Epithelia
RARE
Basement Membrane
Basal Cells
Apical Cells
Small amounts in pharynx, male urethra & glandular duct linings

39. Lines bladder, ureters, part of urethra, uterus
Transitional Epithelia
Lines bladder, ureters, part of urethra, uterus
Apical Cells
Basal Cells
Large cells w/ Large round nuclei
“plumpy” appearance
Apical cells larger than basal cells
Basement Membrane

40. Identify the Epithelial Tissues
Stratified Cuboidal
Simple Cuboidal

41. Identify the Epithelial Tissues
Transitional
Stratified Squamous

42. Pseudostratified Columnar
Identify the Epithelial Tissues
Pseudostratified Columnar
Stratified Columnar
Tapering of cells
Nuclei uneven

43. Identify the Epithelial Tissues
Simple Squamous
Stratified Cuboidal

44. Pseudostratified Columnar
Identify the Epithelial Tissues
Simple Columnar
Pseudostratified Columnar

45. Identify the Epithelial Tissues
Transitional
Transitional

46. REVIEW

47. Objective 2: Connective Tissues

48. CONNECTIVE TISSUES – Locations
Most abundant tissue
Found everywhere except for body surfaces
What type of tissue is found on body surfaces?

49. CONNECTIVE TISSUES – Functions
Bind
Support
Protect
Insulate
Transport

50. CONNECTIVE TISSUES – Examples
Areolar
(bind, support)
Dense Irregular
(bind, support, protect)
Hyaline cartilage
(support, protect)
Bone
(support, protect)
Adipose (fat)
(protect, insulate)
Blood
(transport)

51. Connective tissue has:
Cells
Fibers
Ground substance
Areolar connective tissue The prototype of connective tissues: Other connective tissues contain variations in the amount or type of cells, ground subtance &/or fibers as found in areolar connective tissue

52. Recall Connective tissue is relatively cell poor
Contains many different
cell types
Fibroblast
Adipocytes
Mast cells
Macrophage

53. Cell types
Fibroblasts (cytes)*- secret /maintain ground substance (connective tissue proper)
Chondroblasts (cytes)*- secret /maintain ground substance (cartilage)
Mast cells – secret histamine, heparin
Macrophages – phagocytes
Adipocytes – fat storage
Blasts secrete ground substance
Cytes maintain ground substance

54. Ground substance Fibers Interstitial fluid Proteoglycans – viscosity
Collagen fibers
Elastic fibers
Reticular fibers
Thick
Thin
Hard to stain

55. “St. Ives® combines essential collagen & elastin, the proteins found in young, healthy skin, …”

56. Classes of Connective Tissue

57. Mesenchyme embryologic connective tissue
Note star-shaped cells
ground substance
cells
fibers

58. Connective Tissues Proper
Loose Connective Dense Connective
Areolar
Dense Regular
Adipose
Dense Irregular
Reticular

59. Loose Connective Tissue Areolar connective tissue
Binds other tissues together, wraps organs & vessels, underlies epithelia, forms lamina propria
cells
collagen
fibers
ground substance
elastic fibers

60. Loose Connective Tissue Adiopse tissue
extracellular matrix
Adipocytes (vacuoles)
adipocyte nucleus
Hypodermis; Omentum; Breasts; around kidneys, eyeballs, heart, lymph nodes

61. Loose Connective Tissue Reticular tissue
Lymph nodes, Spleen, Bone marrow
mast cell
reticular cell
reticular fibers

62. Dense Connective Tissue Dense regular
Tendons, most Ligaments, Aponeuroses

63. Dense Connective Tissue Dense Irregular
Dermis (skin), Submucosa (GI tract), Fibrous capsules of organs & joints
collagen fibers

64. Cartilage

65. Hyaline Cartilage matrix lacuna chondrocytes
Costal cartilage (ribs), Trachea & Bronchi, Larynx, Nose, Articular cartilage (joints)
matrix
lacuna
chondrocytes

66. External ear (pinna), Epiglottis
Elastic Cartilage
External ear (pinna), Epiglottis
elastic fibers
chondrocyte in a lacuna

67. Intervertebral discs, Pubic symphysis, Knee joint discs
Fibrocartilage
Intervertebral discs, Pubic symphysis, Knee joint discs
collagen fibers
chondrocytes in lacuna

68. Tissue Comparisons
Areolar
Mesenchyme
Reticular

69. Tissue Comparisons
Adipose
Elastic Carilage
Hyaline Cartilage

70. Tissue Comparisons
Dense Regular
Fibrocartilage
Dense Irregular

71. What questions do you need to ask to identify a connective tissue and in what order?

72. Clinical Significance: CELLULITIS
An acute inflammation of the connective tissue of the skin (dermis and hypodermis), caused by a bacterial infection, most commonly Streptococcus pyogenes and occasionally Staphylococcus aureus.
The skin tissues in the infected area become red, hot, swollen and painful.
Cellulitis can have serious consequences because of its potential to spread through the lymphatic system and into the bloodstream (bacteremia).

73. ACUTE CELLULITIS
Adipose
neutrophils
Dense Irregular
Notice the infiltration of neutrophils (white blood cells) into the dense irregular and adipose tissues of the skin.

74. Objective 3: Membranes

75. Membranes are simple organs composed of 2 tissues:
Epithelium
Connective Tissue

76. Types of Membranes Mucous Serous Cutaneous
= Moist lining of body cavities
exposed to the exterior
Serous
= Pleura, Pericardium,
Peritoneum
Cutaneous
= Skin

77. Serous Membrane Parietal peritoneum Parietal pleura Visceral
pericardium
Visceral
pericardium

78. Serous Membrane Serous Membrane Simple squamous ET Areolar CT
simple squamous epithelium
areolar connective tissue
Simple squamous ET
Areolar CT

79. Moist lining of body cavities exposed to the exterior
Mucous Membrane
Moist lining of body cavities exposed to the exterior
Mucosa of
nasal cavity
Esophagus
lining
Trachea
Mucosa of
lung bronchi
Mucosa of
digestive tract
Mucosa of
urogenital tract

80. Which type of epithelium is shown here?
Mucous Membrane
stratified squamous, pseudostratified columnar, or simple columnar epithelium
areolar connective tissue (lamina propria)
Which type of epithelium is shown here?

81. Mucous Membrane Esophagus Identify the epithelial tissue
Lamina propria
Lamina propria
Identify the epithelial tissue
Stratified squamous ET
lamina propia

82. Mucous Membrane Trachea Identify the epithelial tissue
Pseudostratified columnar ET
Identify the epithelial tissue
Lamina propria
lamina propia

83. Mucous Membrane
Intestine
Lamina propria

84. On the Practical: Identify the epithelial tissues
Identify the connective tissues
Identify the mucous membranes
Identify labeled components of each