2. Tissue
• Groups of cells that share a common
structure and function.
• In adult organisms, there are four tissue
types:
• Epithelium tissue
• Connective tissue
• Muscle tissue
• Nervous tissue
3. Epithelium
• Epithelial tissues are thin sheets.
• Cover body surfaces and organs.
• Line body cavities.
•Occur at boundaries between two
environments.
4. Epithelium
• Functions include:
• protection
• sensory reception
• secretion
• absorption
• ion transport
• filtration
• formation of slippery surfaces for
substance
movement.
5. Epithelium
Special characteristics of epithelium
separate it from the other basic tissue
types:
• Specialized contacts
• Polarity
• Support by connective tissue
• Avascular but innervated
• Regeneration
• Cellularity
6. • Classification of Epithelia
• • Epithelium is given two names.
• • The first name indicates the
number of cell layers.
• • The second name identifies cell
shape.
• • Simple epithelium is a single
layer of cells.
• • Stratified epithelium
• has more than one layer.
7. Simple Squamous Epithelium
• • Single
layer of flat cells.
• • Found wherever diffusion or filtration are
important.
– Capillary linings, alveoli of lungs.
• • Endothelium:
–Special lining tissue (slippery).
–Blood vessels, heart, lymphatic vessels.
• • Mesothelium: peritoneal lining tissue
– (serosa).
9. Epithelial Tissues
• General Features
Cellular Layer + Basement Membrane
No Direct Circulation/Blood Supply
Touch Each Other
Rapid Rate of Cell Reproduction
33. Epithelium cont.
• Epithelium that lines cavities sits on lamina propria.
– Supports epithelium
– Binds epithelium to other tissue
– Provides nutrition
• Sides of cells are named
– Basal
– Apical (free)
– Lateral
34. Special Features of Epithelial Cells
• – Cell junctions
are lateral surfaces
features that
primarily bind
adjacent cells to
each other.
• – Main types:
• – tight junction
(zonula
• occludens)
• – adherens junction
• (zonula adherens)
• – desmosome
• – gap junctions
35. Avascular
• • Epithelium lacks
blood vessels
(avascular).
• • Epithelium does
have some nerve
endings that go
between cells
(innervated).
37. Intercellular
Junctions
Belts that circle
cell.
ZO (tight junction) acts as
barrier.
ZA provides for adhesion
of one cell to another
Spots
Des is like a spot welding.
Gap allows passage of
chemical for
communication.
38. Specializations of Cell Surface
• Microvilli
– Found mainly on absorptive cells
– Brush border, 1m high
• Cilia / flagella
– Cylindrical, motile structures, 5-10m high
– Contain microtubules
– Basal bodies
39. Microvilli
Apical region of an intestinal epithelial cell seen with TEM.
Filaments that constitute the core of the microvilli are clearly seen.
An extracellular cell coat (glycocalyx) is bound to the
plasmalemma of the microvilli. x45,000.
43. Glands
• • Many epithelial cells make and secrete a
product.
• • Glands are classed as exocrine (with ducts), or
• endocrine (without ducts), as well as
– • unicellular
– or multicellular.
• • One-celled exocrine gland is the goblet cell; its
product is mucin
• • Endocrine glands secrete hormones.
44. Multicellular Exocrine Glands
• • Glands have two
parts:
– –Secretory portion
– –Duct
• –Both surrounded by
fibrous capsule.
46. Special Features of Epithelial Cells
• The basal lamina
separates the
epithelium and
underlying
connective tissues.
• Apical surface
features are
microvilli and cilia.
47. Connective Tissue
Connective tissue is the most diverse and
abundant type of tissue. Cells are
separated by extracellular matrix.
Four main classes and many subclasses
• Connective tissue proper (loose and dense)
• Cartilage
• Bone tissue
• Blood
48. General Features of CT
– General structural features:
– fibroblast
– fibers (collagen, reticular, and elastic)
– ground substance
– General functional features:
– support and binding
– holding tissue fluid
– fighting infection
– storing fat
49. Connective Tissue
• Loose areolar
connective tissue
represents general structural
and functional elements of
connective tissue.
• This CT underlies epithelia
and surrounds nerves and
vessels.
• 3 types of extracellular
matrix fibers made by
fibroblasts:
– Collagen
– Reticular
– Elastic
50. Connective Tissue
• Ground substance:
jellylike materials that
hold interstitial fluid.
– Glysoaminoglycans
– Proteoglycans
54. • Connective Tissue Classification
• • Other connective tissues:
• • Cartilage (supporting rings of trachea)
• • Bone (skeleton)
• • Blood
55. Covering and Lining Membranes
– Covering and lining membranes combine
connective and epithelial tissues.
– There are three types of covering and lining
membranes:
• Cutaneous (skin)
• Serous (line body cavities)
• Mucous (line hollow organs)
– Underlying CT is lamina propria
58. References
• • Martini. 2002. Fundamental of Anatomy and Physiology. 5th edition.
• Prentice Hall International, Inc.
• • Norman, F., Gant, F. & Cunningham, G. (1993). Basic Gynecology
• and obstetrics. A Lange medical book. Appleton & Lange
• • Ganong, W.F. 2005. Review of Medical Physiology, 20th Ed,
• Appleton & Lange
• • Sherwood, L. 2001. Human Physiology – From Cells to Systems.
• 6th edition. McGraw Hill.
• • Marieb, E.N. 1998. Human Anatomy and Physiology, 4th Ed,
• Addison Wessley Longman Inc, New York.
• • Tortora, G.J. dan Grabowski, S.R. 2000. Principles of Anatomy and
• Physiology, 9th Ed., John Wiley & Sons, New York
