Tissues
Chapter 5
Tissue
• Definition – an aggregation of cells in
which each cooperates with all others in the
performance of a given function
• Examples of general functions
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–
–
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Movement
Protection
Support
Production of chemicals
Principal Tissue Types
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•
•
•
Epithelial
Connective
Muscular
Nervous
Epithelial Tissue
• Functions
– Coverings and
linings
– Forms glands
• Characteristics
– Closely packed cells
– Continuous sheets
– Basement
membrane
– Avascular
• Classification
– Simple
– Stratified
Human Anatomy, 3rd edition
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Epithelia of Coverings and
Linings
Squamous Epithelium
• Simple Squamous
Epithelium
– Highly adapted to
diffusion, osmosis,
& filtration
www.stegen.k12.mo.us/.../TissueSlides.htm
Squamous Epithelium
• Stratified
Squamous
Epithelium
– Surface layer is flat
– Function protection
www.stegen.k12.mo.us/.../TissueSlides.htm
Cuboidal Epithelium
• Simple cuboidal
epithelium
– Function – secretion
and absorption
– Lines glands and
their ducts
• Stratified Cuboidal
epithelium
– Surface layer cubeshaped
– Function – protection
www.stegen.k12.mo.us/.../TissueSlides.htm
Glandular Epithelium
• Gland – 1 or more cells
• Function – secretion
• Types
– Exocrine – to surface or ducts
– Endocrine – to blood
Transitional Epithelium
• Can be stretched
• Lines hollow
structures that
expand
• Function – prevents
rupture of organ
http://www.mhhe.com/biosci/ap/histology_mh/stratepi.html
Columnar Epithelia
• Simple columnar
epithelium
– Functions
• Protection,
• Absorption or
secretion
• Stratified columnar
epithelium
– More than one layer
– Function
• Protection
www.stegen.k12.mo.us/.../TissueSlides.htm
Pseudostratified Columnar Epithelium
• Appear stratified
but all cells connect
to the basement
membrane
• Functions
– Protection
– Secretion
http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab1b/Pseudostratified_Model_1/pseudostratified_model_1.htm
Connective Tissue
• Most abundant tissue
• Functions are varied
• Characteristics
– Specialized cells, widely scattered
– Rich blood supply
– Much matrix
• Extracellular fibers
• Ground substance
Cell Types Found in Connective Tissue
• Fibroblasts
– Secrete the molecules that form the matrix
– Fixed cells
• Fibrocytes
• Macrophages
– “Big eaters”
– May be fixed or wandering
Connective Tissue Fibers
• Collagen fibers
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–
–
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Most common type
White
Strong, ropelike
Form ligaments, tendons
• Reticular fibers
– Thin
– Woven into rough, flexible network
• Elastic fibers
– Yellow
– Thin
– Stretch
• Contain elastin
Ground Substance
• Extracellular fluid in connective tissue
– Water
– Glycoproteins
Types of Connective Tissue
Loose (Areolar) Connective Tissue
• Fibers not abundant
• Contains all 3 types of fibers
• Examples of locations
– Between skin and muscles
– Around digestive tract
– Around blood vessels
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Adipose Tissue
• Most of the volume is adipocytes
• Provides padding, slows heat loss, food reserve
• Locations
– Wherever there is loose connective tissue
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Dense Connective Tissue
• Types
– Dense Regular Connective Tissue
– Dense Irregular Connective Tissue
– Elastic Connective Tissue
Dense Regular Connective Tissue
• Lots of collagen fibers in bundles
• Cells – fibroblasts in rows between bundles
• Examples
– Tendons, ligaments
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Dense Irregular Connective Tissue
• Tensions in various
directions
• Occurs in sheets
• Locations
– Periosteum
– Perichondrium
– Fibrous capsules of
some organs
– Fasciae
– Dermis
Human Anatomy, 3rd edition
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Elastic Tissue
• Lots of elastic fibers
• Fibroblasts in spaces between fibers
• Provides stretch and strength
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Cartilage
• Dense network of collagenous fibers &
elastic fibers in a gel-like substance
• Cells – chondrocytes in lacunae
– Chondroblasts
• Perichondrium – surrounds surface of
cartilage
Types of Cartilage
• Hyaline cartilage
• Fibrocartilage
• Elastic cartilage
Hyaline Cartilage
• Most common
• Provides
flexibility and
support
• Locations
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–
–
–
Ends of bones
Trachea
Larynx
Embryonic
skeleton
Human Anatomy, 3rd edition
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Fibrocartilage
• Visible collagenous fibers with scattered chondrocytes
• Provides strength and rigidity
• Locations
– Intervertebral discs
– Symphysis pubis
Human Anatomy, 3rd edition
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Elastic Cartilage
• Threadlike network of elastic fibers with chondrocytes
• Provides strength and maintains shape
• Locations
– Pinna
– Eustacian tube
Human Anatomy, 3rd edition
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Bone
• Solid matrix
• Cells
– Osteocytes in
lacunae
– Osteoblasts
– Osteoclasts
• Periosteum
surrounds surface
of bone
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Blood
• Functions
– Transport medium
– Regulation
– Protection
• Composition
– Plasma – fluid
– Formed elements –
cells & cell fragments
• Erythrocyte
• Leukocyte
• Thrombocyte
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A Red Blood Cell
Human Anatomy, 3rd edition
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SEM of RBCs
Human Anatomy, 3rd edition
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Muscular Tissue
• Specialized cells
• Function - contraction
• 3 types
– Skeletal muscle
– Cardiac muscle
– Smooth muscle
Skeletal Muscle
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•
•
•
Connected to bones
Striated
Multinucleated
Voluntary
Human Anatomy, 3rd edition
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Cardiac Muscle
•
•
•
•
Found in the heart
Striations
Intercalated discs
Involuntary
Human Anatomy, 3rd edition
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Smooth Muscle
• Found in walls of internal organs
• Nonstriated
• Involuntary
Human Anatomy, 3rd edition
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Nervous Tissue
• Specialized cells
• Function – conduction of electrical impulses
• Cells
– Neurons
– Neuroglia
Human Anatomy, 3rd edition
Prentice Hall, © 2001