1. Tissue
Chapter 4
Link

2. Tissues Tissue: 4 Primary Tissue Types Epithelial Connective Muscle
Nervous

3. Match Tissue Type to Function
Epithelial
Connective
Nervous
Muscle
Supports, protects, binds other tissues together
Internal communication
Contracts to cause movement
Forms boundaries between different environments, protects, secretes, absorbs, filters

4. Epithelial Tissue (Epithelium)
Two main types (by location):
Covering and lining epithelium
Glandular epithelium
Forms boundaries b/w different environments

5. Functions of Epithelial Tissue
Protection
Absorption
Filtration
Excretion
Secretion
Sensory reception

6. Characteristics of Epithelial Tissue
Cells have polarity
Are composed of closely packed cells
Supported by a connective tissue reticular lamina (under the basal lamina)
Avascular but innervated
High rate of regeneration

7. Classification of Epithelia
Ask two questions:
How many layers?
1 = simple epithelium
>1 = stratified epithelium

8. Classification of Epithelia
What type of cell?
Squamous
Cuboidal
Columnar
Note: if stratified, name according to apical layer of cells!

9. Overview of Epithelial Tissues
For each of the following types of epithelia, note:
Description
Function
Location

10. Simple Epithelia Single cell layer (usually very thin) Concerned with:
Absorption
Secretion
Filtration
NOT concerned with: protection
Simple squamous, simple cuboidal, simple columnar, pseudo stratified columnar

11. Simple Squamous Epithelium
Description
Function
Location
Photomicrograph: Simple squamous epithelium
forming part of the alveolar (air sac) walls (125x).
Note: ENDOTHELIUM AND MESOTHELIUM

12. Simple Cuboidal Epithelium
(b) Simple cuboidal epithelium
Description
Function
Location
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).

13. Simple Columnar Epithelium
(c) Simple columnar epithelium
Description
Function
Location
Photomicrograph: Simple columnar epithelium
of the stomach mucosa (860X).

14. Pseudostratified Columnar Epithelium
(c) Simple columnar epithelium
Description
Function
Location
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (570x).

15. Stratified Epithelium
2+ cell layers
Regenerate from below
More durable than simple epithelia
Major role: Protection

16. Stratified Squamous Epithelium
Description
Function
Location
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).

17. Stratified Cuboidal Epithelium
Description
Function
Location

18. Stratified Columnar Epithelium
Description
Function
Location

19. Transitional Epithelium
Description
Function
Location
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (360X); note the bulbous, or rounded,
appearance of the cells at the surface; these cells flatten and
become elongated when the bladder is filled with urine.

20. Glandular Epithelia
Gland: one or more cells that secretes and aqueous fluid
Classified by:
Site of product release
Endocrine
Exocrine
Relative number of cells forming the gland
Unicellular
Multicellular

21. Glands Endocrine Exocrine Ductless glands
More numerous!
Glands
Endocrine
Exocrine
Ductless glands
Secrete hormones that travel through lymph or blood to target organs
Examples: Thyroid Gland, Pituitary Gland
Covered in Ch. 16
Secrete products into ducts
Secretions released onto body surfaces (skin) or into body cavities
Examples: mucous, sweat, oil, and salivary glands

22. Unicellular Exocrine Glands
Goblet cell and Mucous cell
Mucin -> mucous

23. Multicellular Exocrine Glands
Composed of a duct and a secretory unit
Classified according to:
Duct type
Simple
Compound
Structure of secretory units
tubular
alveolar
tubuloalveolar

24. Compound duct structure
Simple duct structure
(duct does not branch)
Compound duct structure
(duct branches)
Tubular
secretory
structure
Simple tubular
Simple branched
tubular
Compound tubular
Example
Intestinal glands
Example
Stomach (gastric)
glands
Example
Duodenal glands of small intestine
Alveolar
secretory
structure
Simple
alveolar
Simple branched
alveolar
Compound alveolar
Compound
tubuloalveolar
Example
No important
example in humans
Example
Sebaceous (oil)
glands
Example
Mammary glands
Example
Salivary glands
Surface epithelium
Duct
Secretory epithelium
Figure 4.5

25. Modes of Secretion Merocrine Holocrine
Products are secreted by exocytosis
pancreas, sweat and salivary glands
Products are secreted by rupture of gland cells
sebaceous (oil) glands

26. Connective Tissue Most abundant and widely distributed tissue type
Four main classes
Connective Tissue Proper
Cartilage
Bone Tissue
Blood
See Table 4.1

27. Major Functions of Connective Tissue
Binding and Support
Protection
Insulation
Stores reserve fuel
Transports

28. Characteristics of Connective Tissue
Connective tissues have:
Mesenchyme as their common tissue of origin
Varying degrees of vascularity
Cells separated by nonliving extracellular matrix (ground substance and fibers)
3 Structural Elements
Ground substance
Fibers
Cells

29. Structural Elements of Connective Tissue
Ground substance
Medium through which solutes diffuse between blood capillaries and cells
Components:
Interstitial fluid
Adhesion proteins (“glue”)
Proteoglycans
Protein core + large polysaccharides
Trap water -> viscosity

30. Structural Elements of Connective Tissue
Connective Tissue Fibers
Collagen (white fibers)
Strongest and most abundant type
Provides high tensile strength
Elastic (yellow fibers)
Networks of long, thin, elastin fibers that allow for stretch/recoil
Reticular
Short, fine, highly branched collagenous fibers

31. Structural Elements of Connective Tissue
Cells (see table 4.1)
Mitotically active and secretory cells = “blasts”
Fibroblasts, chondroblasts, osteoblasts, hematopoietic stem cells
Mature cells = “cytes”
Chondrocytes, osteocytes
Other cell types
Fat cells, white blood cells, mast cells, and macrophages

32. Cell types Extracellular matrix Ground substance Macrophage Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
Figure 4.7

33. Connective Tissue: Embryonic
Mesenchyme—embryonic connective tissue
Gives rise to all other connective tissues
Gel-like ground substance with fibers and star-shaped mesenchymal cells

34. Connective Tissue Proper
Types:
Loose connective tissue
Areolar
Adipose
Reticular
Dense connective tissue
Dense regular
Dense irregular
Elastic

35. Loose Connective: Areolar
CONNECTIVE TISSUE PROPER
Loose Connective: Areolar
Description
Function
Location
Photomicrograph: Areolar connective tissue, a
soft packaging tissue of the body (300x).

36. Loose Connective: Adipose
CONNECTIVE TISSUE PROPER
Loose Connective: Adipose
Description
Function
Location
Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (350x).

37. Loose Connective: Reticular
CONNECTIVE TISSUE PROPER
Loose Connective: Reticular
Description
Function
Location
Photomicrograph: Dark-staining network of reticular
connective tissue fibers forming the internal skeleton
of the spleen (350x).

38. Dense Connective: Dense Regular
CONNECTIVE TISSUE PROPER
Dense Connective: Dense Regular
Description
Function
Location
Photomicrograph: Dense regular connective
tissue from a tendon (500x).

39. Dense Connective: Dense Irregular
CONNECTIVE TISSUE PROPER
Dense Connective: Dense Irregular
Description
Function
Location
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).

40. Dense Connective: Elastic
CONNECTIVE TISSUE PROPER
Dense Connective: Elastic
Description
Function
Location
Photomicrograph: Elastic connective tissue in
the wall of the aorta (250x).

41. Connective Tissue: Cartilage
Stands up to both compression and tension
No nerve fibers, avascular
80% water
Chondroblasts – produce new matrix
Chondrocytes – mature cartilage cells
Found in small groups in lacunae

42. Hyaline Cartilage Description Function Location CARTILAGE
Photomicrograph: Hyaline cartilage from the trachea (750x).

43. Elastic Cartilage Description Function Location CARTILAGE
Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (800x).

44. Fibrocartilage Description Function Location CARTILAGE
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.

45. Connective Tissue: Bone
Description
Function
Location
Photomicrograph: Cross-sectional view of bone (125x).

46. Connective Tissue: Blood
Description
Function
Location .
Photomicrograph: Smear of human blood (1860x); two white blood cells (neutrophil in upper left and lymphocyte in lower right) are seen surrounded by red blood cells.

47. Nervous Tissue Description Function Location
Photomicrograph: Neurons (350x)

48. Muscle Tissue Highly cellular, well vascularized Movement Types
Skeletal
Cardiac
Smooth

49. Skeletal Muscle Description Function Location MUSCLE TISSUE
Photomicrograph: Skeletal muscle (approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.

50. Cardiac Muscle Description Function Location MUSCLE TISSUE
Photomicrograph: Cardiac muscle (500X); notice the striations, branching of cells, and the intercalated discs.

51. Smooth Muscle Description Function Location MUSCLE TISSUE
Photomicrograph: Sheet of smooth muscle (200x).

52. Epithelial Membranes Cutaneous membrane (skin) Mucous membranes
Mucosae
Line body cavities open to the exterior (e.g., digestive and respiratory tracts)
Serous Membranes
Serosae—membranes (mesothelium + areolar tissue) in a closed ventral body cavity
Parietal serosae line internal body walls
Visceral serosae cover internal organs

53. (b) Mucous membranes line body cavities open to the exterior.
Mucosa of
nasal cavity
Mucosa of
mouth
Esophagus
lining
Mucosa of
lung bronchi
(b) Mucous membranes line body cavities open to the exterior.
Figure 4.11b

54. (c) Serous membranes line body cavities closed to the exterior.
Parietal
peritoneum
Parietal
pleura
Visceral
pleura
Visceral
peritoneum
Parietal
pericardium
Visceral
pericardium
(c) Serous membranes line body cavities closed to the exterior.
Figure 4.11c

55. Steps in Tissue Repair Inflammation
Organization and Restored Blood Supply
Regeneration and Fibrosis

56. Blood clot in incised wound Vein
Scab
Epidermis
Blood clot in incised wound
Vein
Migrating white blood cell
Inflammatory chemicals
Artery 1
Inflammation sets the stage:
• Severed blood vessels bleed and inflammatory chemicals are released.
• Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area.
• Clotting occurs; surface dries and forms a scab.
Figure 4.12, step 1

57. Regenerating epithelium
Area of granulation tissue ingrowth
Fibroblast
Macrophage 2
Organization restores the blood supply:
• The clot is replaced by granulation tissue, which restores the vascular supply.
• Fibroblasts produce collagen fibers that bridge the gap.
• Macrophages phagocytize cell debris.
• Surface epithelial cells multiply and migrate over the granulation tissue.
Figure 4.12, step 2

58. Regenerated epithelium
Fibrosed area 3
Regeneration and fibrosis effect permanent repair:
• The fibrosed area matures and contracts; the epithelium thickens.
• A fully regenerated epithelium with an underlying area of scar tissue results.
Figure 4.12, step 3

59. Developmental Aspects
Primary germ layers: ectoderm, mesoderm, and endoderm
Formed early in embryonic development
Specialize to form the four primary tissues
Nerve tissue arises from ectoderm
Muscle and connective tissues arise from mesoderm
Epithelial tissues arise from all three germ layers