This document defines and classifies the four basic types of tissues in the body: epithelium, connective tissue, muscle tissue, and nervous tissue. It provides details on epithelium, describing its roles in protection, absorption, sensory reception and secretion. Epithelium is classified based on cell arrangement and includes simple, stratified, and transitional epithelia. The document also defines connective tissue and its subclasses, including ground substance, fibers, and cell types. It outlines the basic functions of connective tissue in support, binding, fluid holding, and defense.

1. TissuesTissues
Definition:
• a group of closely associated cells that perform related
functions and are similar in structure
• Between cells: nonliving extracellular material
• Four basic types of tissue
– Epithelium
– Connective tissue
– Muscle tissue
– Nervous tissue

2. Epithelia (plural)Epithelia (plural)
• Epithelium: sheet of cells that covers a body surface or
lines a body cavity; also forms most of the body’s glands
• Roles: interfaces and as boundaries
• Functions:
1.Protection
2.Absorption
3.Sensory reception
4.Secretion

3. Special characteristics of epitheliaSpecial characteristics of epithelia
• Cellularity
• Polarity
• Avascular but innervated
– Without vessels
– With nerve endings
• Regeneration

4. Classification of epitheliaClassification of epithelia

5. to protect
Fig: Classification based on arrangements

6. where diffusion is important
where tissues are involved in
secretion and absorption:
larger cells because of the
machinery of production,
packaging, and energy
requirements

9. “ciliated” literally =
eyelashes
(see next page)

11. Stratified: regenerate from below

12. Rare…

13. Rare…

15. EndotheliumEndothelium
A simple squamous epithelium that lines
the interior of the circulatory vessels
and heart

16.  Four basic types of tissue
Epithelium
Connective tissue
 Connective tissue proper (examples: fat
tissue, fibrous tissue of ligaments)
 Cartilage
 Bone
 Blood
Muscle tissue
Nervous tissue

17. Classes of Connective Tissue: note the cell
types and great variety of subclasses

18. Connective TissueConnective Tissue
• Originate from embryonic tissue called
mesenchyme
• Most diverse and abundant type of tissue
• Function: to protect, support and bind together
other tissues
• Cells separated from one another by large
amount of nonliving extracellular matrix

19. • Two components
1. Ground substance
 Of fluid, adhesion proteins, proteoglycans
 Liquid, semisolid, gel-like or very hard
2. Fibers:
collagen
elastic
reticular

20. Basic functions of connective tissueBasic functions of connective tissue
• Support and binding of other tissues
• Holding body fluids
• Defending the body against infection
– macrophages, plasma cells, mast cells, WBCs
• Storing nutrients as fat

21. Classes of Connective Tissue
*

26. *
Classes of Connective Tissue

29. *
Classes of Connective Tissue

33. Classes of Connective Tissue
*

35. Classes of Connective Tissue
*

37. • Four basic types of tissue
–Epithelium
–Connective tissue
–Muscle tissue
• Skeletal
• Cardiac
• Smooth
–Nervous tissue

41. • Four basic types of tissue
–Epithelium
–Connective tissue
–Muscle tissue
–Nervous tissue
• Neurons
• Supporting cells

43. Tissue response to injuryTissue response to injury
• Immune: takes longer and is highly specific
• Inflammation
– Nonspecific, local, rapid
– Inflammatory chemicals
– Signs: heat, swelling, redness, pain
• Repair – two ways
– Regeneration
– Fibrosis and scarring
• Severe injuries
• Cardiac and nervous tissue

45. Tumors: abnormal growth of cellsTumors: abnormal growth of cells
• Adenoma – neoplasm of glandular epithelium,
benign or malignant
• Carcinoma – cancer arising in an epithelium
(90% of all human cancers)
• Sarcoma – cancer arising in mesenchyme-
derived tissue (connective tissues and muscle)

46. STEM CELLS….STEM CELLS….
STEM CELLS
______
Inner cell mass becomes the baby