Transcript What is a Tissue? - HCC Learning Web

Chapter 4
The Tissue Level
of Organization
Lecture Presentation by
Lee Ann Frederick
University of Texas at Arlington
© 2015 Pearson Education, Inc.
An Introduction to Tissues
• Learning Outcomes
• 4-1 Identify the four major types of tissues in the
body and describe their roles.
• 4-2 Discuss the types and functions of epithelial
tissue.
• 4-3 Describe the relationship between structure
and function for each type of epithelium.
© 2015 Pearson Education, Inc.
An Introduction to Tissues
• Learning Outcomes
• 4-4 Compare the structures and functions of the
various types of connective tissue.
• 4-5 Describe how cartilage and bone function as
a supporting connective tissue.
• 4-6 Explain how epithelial and connective tissues
combine to form four types of tissue
membranes, and specify the functions of
each.
• 4-7 Describe how connective tissue establishes
the framework of the body.
© 2015 Pearson Education, Inc.
An Introduction to Tissues
• Learning Outcomes
• 4-8
Describe the three types of muscle tissue
and the special structural features of each
type.
• 4-9 Discuss the basic structure and role of
neural tissue.
• 4-10 Describe how injuries affect the tissues of
the body.
• 4-11 Describe how aging affects the tissues of
the body.
© 2015 Pearson Education, Inc.
What is a Tissue?
 A tissue collections of specialized cells and cell
products that carry out specific functions.
Common embryonic origin.
 Hard (bone), semisolid (fat), or liquid (blood)
 Histology is the science that deals with the study of
microscopic anatomy of the tissues.
 Pathologist is specialized in laboratory studies of
cells and tissue for diagnoses
 Histology is a branch of Pathology.
4 Types of Tissues
 Epithelial
Covers body surfaces and lines hollow organs, body
cavities, duct, and forms glands
 Connective
Fills internal spaces, provides structural support,
transports materials within the body, and stores energy.
 Muscular
Generates the physical force needed to make body
structures move (contraction of the muscles) and
generate body heat
 Nervous
Detects changes in body and responds by generating
nerve impulses (electrical signals)
Development of Tissues
 Tissues of the body develop from three primary germ
layers:
Ectoderm, Endoderm, and Mesoderm
 Epithelial tissues develop from all three germ
layers
 All connective tissue and most muscle tissues
drive from mesoderm
 Nervous tissue develops from ectoderm
4-2 Epithelial Tissue
• Epithelia
• Layers of cells covering internal or external
surfaces
• Glands
• Structures that produce secretions
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4-2 Epithelial Tissue
• Characteristics of Epithelia
• Cellularity (cell junctions)
• Polarity (apical and basal surfaces): cells
arranged in continuous sheets, in either single or
multiple layers
• Attachment (basement membrane or basal
lamina)
• Avascularity
• Regeneration
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Figure 4-1 The Polarity of Epithelial Cells.
Cilia
Microvilli
Apical
surface
Golgi
apparatus
Nucleus
Mitochondria
Basement membrane
Basolateral
surfaces
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4-2 Epithelial Tissue
• Functions of Epithelial Tissue
1.
2.
3.
4.
Provide Physical Protection
Control Permeability
Provide Sensation
Produce Specialized Secretions (glandular
epithelium)
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4-2 Epithelial Tissue
• Specializations of Epithelial Cells
1. Move fluids over the epithelium (protection)
2. Move fluids through the epithelium
(permeability)
3. Produce secretions (protection and
messengers)
• Polarity
1. Apical surfaces
• Microvilli increase absorption or secretion
• Cilia (ciliated epithelium) move fluid
2. Basolateral surfaces
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4-2 Epithelial Tissue
• Maintaining the Integrity of Epithelia
1. Intercellular connections
2. Attachment to the basement membrane
3. Epithelial maintenance and repair
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4-2 Epithelial Tissue
• Intercellular Connections
• Support and communication
• CAMs (cell adhesion molecules)
• Transmembrane proteins
• Intercellular cement
• Proteoglycans
• Hyaluronan (hyaluronic acid)
• Glycosaminoglycans
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4-2 Epithelial Tissue
• Intercellular Connections
• Cell junctions
• Form bonds with other cells or extracellular
material
1.
2.
3.
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Tight junctions
Gap junctions
Desmosomes
Intracellular Junctions
Interactions Animation
• Intracellular Junctions
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4-2 Epithelial Tissue
• Tight Junctions
•
•
•
•
Between two plasma membranes
Adhesion belt attaches to terminal web
Prevents passage of water and solutes
Isolates wastes in the lumen
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4-2 Epithelial Tissue
• Gap Junctions
• Allow rapid communication
• Are held together by channel proteins (junctional
proteins, connexons)
• Allow ions to pass
• Coordinate contractions in heart muscle
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4-2 Epithelial Tissue
• Desmosomes
• CAMs, dense areas, and intercellular cement
• Spot desmosomes
• Tie cells together
• Allow bending and twisting
• Hemidesmosomes
• Attach cells to the basement membrane
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4-2 Epithelial Tissue
• Attachment to the Basement Membrane
• Clear layer (lamina lucida)
• Thin layer
• Secreted by epithelia
• Barrier to proteins
• Dense layer (lamina densa)
• Thick fibers
• Produced by connective tissue
• Strength and filtration
© 2015 Pearson Education, Inc.
Figure 4-2 Cell Junctions.
Interlocking
junctional
proteins
Embedded
proteins
(connexons)
Tight junction
Tight
junction
Adhesion belt
Terminal web
Adhesion
belt
Gap junctions
b Gap junctions permit
Spot desmosome
the free diffusion of
ions and small
molecules between
two cells.
Hemidesmosome
c A tight junction is formed by the
a
This is a diagrammatic view of an
epithelial cell, showing the major
types of intercellular connections.
fusion of the outer layers of two
plasma membranes. Tight junctions
prevent the diffusion of fluids and
solutes between the cells. A
continuous adhesion belt lies deep
to the tight junction. This belt is
tied to the microfilaments of the
terminal web.
Intermediate
filaments
Clear
layer
Dense
layer
Basement
membrane
Cell adhesion
molecules
(CAMs)
Dense area
e Hemidesmosomes attach a cell
to extracellular structures, such
as the protein fibers in the
basement membrane.
Proteoglycans
d A spot desmosome ties
adjacent cells together.
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4-2 Epithelial Tissue
• Epithelial Maintenance and Repair
• Epithelia are replaced by division of germinative
cells (stem cells)
• Near basement membrane
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4-3 Classification of Epithelia
• Singular = Epithelium; Plural = Epithelia
• Classes of epithelia
1. Based on shape
• Squamous epithelia — thin and flat
• Cuboidal epithelia — square shaped
• Columnar epithelia — tall, slender rectangles
2. Based on layers
• Simple epithelium — single layer of cells
• Stratified epithelium — several layers of cells
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Table 4-1 Classifying Epithelia (Part 1 of 2).
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Table 4-1 Classifying Epithelia (Part 2 of 2).
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4-3 Classification of Epithelia
• Squamous Epithelia
• Simple squamous epithelium
• Absorption and diffusion
• Mesothelium
• Lines body cavities
• Endothelium
• Lines heart and blood vessels
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Figure 4-3a Squamous Epithelia.
Simple Squamous Epithelium
LOCATIONS: Mesothelia lining pleural, pericardial, and peritoneal cavities; endothelia
lining heart and blood vessels; portions of kidney tubules (thin sections of nephron
loops); inner lining of cornea; alveoli of lungs
FUNCTIONS: Reduces friction; controls vessel permeability; performs
absorption and secretion
Cytoplasm
Nucleus
Connective tissue
a
Lining of peritoneal cavity
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4-3 Classification of Epithelia
• Squamous Epithelia
• Stratified squamous epithelium
• Protects against attacks
• Keratin protein adds strength and water resistance
• Keratinized or Non-Keratinized
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Figure 4-3b Squamous Epithelia.
Stratified Squamous Epithelium
LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum,
anus, and vagina
FUNCTIONS: Provides physical protection against abrasion, pathogens,
and chemical attack
Squamous
superficial cells
b
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Surface of tongue
Stem cells
Basement
membrane
Connective
tissue
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4-3 Classification of Epithelia
• Cuboidal Epithelia
• Simple cuboidal epithelium
• Secretion and absorption
• Stratified cuboidal epithelia
• Sweat ducts and mammary ducts
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Figure 4-4a Cuboidal and Transitional Epithelia.
Simple Cuboidal Epithelium
LOCATIONS: Glands; ducts;
portions of kidney tubules; thyroid
gland
Connective
tissue
FUNCTIONS: Limited protection,
secretion, absorption
Nucleus
Cuboidal
cells
Basement
membrane
a Kidney tubule
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Figure 4-4b Cuboidal and Transitional Epithelia.
Stratified Cuboidal Epithelium
LOCATIONS: Lining of some ducts
(rare)
FUNCTIONS: Protection, secretion,
absorption
Lumen
of duct
Stratified
cuboidal
cells
Basement
membrane
Nucleus
Connective
tissue
b Sweat gland duct
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4-3 Classification of Epithelia
• Transitional Epithelium
• Tolerates repeated cycles of stretching and
recoiling and returns to its previous shape without
damage
• Appearance changes as stretching occurs
• Situated in regions of the urinary system (e.g.,
urinary bladder)
© 2015 Pearson Education, Inc.
Figure 4-4c Cuboidal and Transitional Epithelia.
Transitional Epithelium
LOCATIONS: Urinary
bladder; renal pelvis;
ureters
FUNCTIONS: Permits
expansion and recoil
after stretching
Epithelium
(relaxed)
Basement membrane
Empty bladder
Connective tissue and
smooth muscle layers
LM × 400
Epithelium
(stretched)
Full bladder
c Urinary bladder
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Basement membrane
Connective tissue and
smooth muscle layers
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4-3 Classification of Epithelia
• Columnar Epithelia
• Simple columnar epithelium
• Absorption and secretion
• Pseudostratified columnar epithelium
• Cilia movement
• Stratified columnar epithelium
• Protection
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Figure 4-5a Columnar Epithelia.
Simple Columnar Epithelium
LOCATIONS: Lining of
stomach, intestine, gallbladder,
uterine tubes, and collecting
ducts of kidneys
Microvilli
Cytoplasm
FUNCTIONS: Protection,
secretion, absorption
Nucleus
a
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Intestinal lining
Basement
membrane
Loose
connective tissue
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Figure 4-5b Columnar Epithelia.
Pseudostratified Ciliated Columnar Epithelium
LOCATIONS: Lining of
nasal cavity, trachea, and
bronchi; portions of male
reproductive tract
Cilia
Cytoplasm
FUNCTIONS: Protection,
secretion, move mucus
with cilia
Nuclei
Basement
membrane
Loose connective
tissue
b Trachea
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Figure 4-5c Columnar Epithelia.
Stratified Columnar Epithelium
LOCATIONS: Small areas of
the pharynx, epiglottis, anus,
mammary glands, salivary
gland ducts, and urethra
Loose
connective tissue
Deeper cells
FUNCTION: Protection
Lumen
Superficial
columnar cells
Lumen
Cytoplasm
Nuclei
c
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Salivary gland duct
Basement
membrane
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4-3 Classification of Epithelia
• Glandular Epithelia
• Endocrine glands
• Release hormones
• Into interstitial fluid and directly into the
bloodstream.
• No ducts
• Exocrine glands
• Produce secretions
• Onto epithelial surfaces
• Through ducts
• Mucus, sweat, oil, earwax, saliva, and digestive
enzymes.
© 2015 Pearson Education, Inc.
4-3 Classification of Epithelia
• Glandular Epithelia
• Modes of secretion
1. Merocrine secretion
2. Apocrine secretion
3. Holocrine secretion
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4-3 Classification of Epithelia
• Merocrine Secretion
• Produced in Golgi apparatus
• Released by vesicles (exocytosis)
• For example, sweat glands
• Apocrine Secretion
• Produced in Golgi apparatus
• Released by shedding cytoplasm
• For example, mammary glands
• Holocrine Secretion
• Released by cells bursting, killing gland cells
• Gland cells replaced by stem cells
• For example, sebaceous glands
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Figure 4-6 Modes of Glandular Secretion.
(a) Merocrine secretion
In merocrine secretion, the product is released from secretory
vesicles at the apical surface of the gland cell by exocytosis.
Secretory
vesicle
Golgi
apparatus
Nucleus
TEM × 3039
Salivary gland
(b) Apocrine secretion
Mammary
gland
Apocrine secretion involves the loss of apical cytoplasm.
Inclusions, secretory vesicles, and other cytoplasmic components
are shed in the process. The gland cell then grows and repairs itself
before it releases additional secretions.
Breaks
down
Golgi apparatus
Secretion
Hair
1
2
Regrowth
3
4
Sebaceous gland
Hair follicle
(c) Holocrine secretion
Holocrine secretion occurs as superficial gland cells burst.
Continued secretion involves the replacement of these cells
through the mitotic divisions of underlying stem cells.
3 Cells burst, releasing
cytoplasmic contents
2
Cells form secretory
products and increase
in size
1 Cell division replaces
lost cells
Stem cell
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4-3 Classification of Epithelia
• Glandular Epithelia
• Types of secretions
• Serous glands
• Watery secretions
• Mucous glands
• Secrete mucins
• Mixed exocrine glands
• Both serous and mucous
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4-3 Classification of Epithelia
• Glandular Epithelia
• Gland structure
• Unicellular glands
• Mucous (goblet) cells are the only unicellular
exocrine glands
• Scattered among epithelia
• For example, in intestinal lining
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4-3 Classification of Epithelia
• Gland Structure
• Multicellular glands
1. Structure of the duct
• Simple (undivided)
• Compound (divided)
2. Shape of secretory portion of the gland
• Tubular (tube shaped)
• Alveolar or acinar (blind pockets)
3. Relationship between ducts and glandular areas
• Branched (several secretory areas sharing one
duct)
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Figure 4-7 A Structural Classification of Exocrine Glands (Part 1 of 2).
SIMPLE GLANDS
Duct
Gland
cells
SIMPLE
TUBULAR
Examples:
•Intestinal glands
SIMPLE COILED
TUBULAR
SIMPLE BRANCHED
TUBULAR
Examples:
•Merocrine sweat
glands
Examples:
•Gastric glands
•Mucous glands
of esophagus,
tongue, duodenum
SIMPLE ALVEOLAR
(ACINAR)
Examples:
•Not found in adult; a
stage in development
of simple branched
glands
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SIMPLE BRANCHED
ALVEOLAR
Examples:
•Sebaceous (oil)
glands
Figure 4-7 A Structural Classification of Exocrine Glands (Part 2 of 2).
COMPOUND GLANDS
COMPOUND
TUBULAR
Examples:
•Mucous glands (in mouth)
•Bulbourethral glands (in
male reproductive system)
•Testes (seminiferous
tubules)
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COMPOUND ALVEOLAR
(ACINAR)
Examples:
•Mammary glands
COMPOUND
TUBULOALVEOLAR
Examples:
•Salivary glands
•Glands of respiratory
passages
•Pancreas
4-4 Connective Tissue
• Characteristics of Connective Tissue
1. Specialized cells
2. Solid extracellular protein fibers
3. Fluid extracellular ground substance
• The Extracellular Components of Connective
Tissue (Fibers and Ground Substance)
• Make up the matrix
• Majority of tissue volume
• Determines specialized function
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4-4 Connective Tissue
• Functions of Connective Tissue
•
•
•
•
Establishing a structural framework for the body
Transporting fluids and dissolved materials
Protecting delicate organs
Supporting, surrounding, and interconnecting
other types of tissue
• Storing energy reserves, especially in the form of
triglycerides
• Defending the body from invading microorganisms
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4-4 Connective Tissue
• Classification of Connective Tissues
1. Connective tissue proper
• Connect and protect
2. Fluid connective tissues
• Transport
3. Supporting connective tissues
• Structural strength
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4-4 Connective Tissue
• Categories of Connective Tissue Proper
• Loose connective tissue
• More ground substance, fewer fibers
• For example, fat (adipose tissue)
• Dense connective tissue
• More fibers, less ground substance
• For example, tendons
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4-4 Connective Tissue
Connective Tissue Proper Cell Populations
• Fibroblasts
• Mast cells
• Fibrocytes
• Lymphocytes
• Adipocytes
• Microphages
• Mesenchymal cells
• Melanocytes
• Macrophages
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4-4 Connective Tissue
• Fibroblasts
• The most abundant cell type
• Found in all connective tissue proper
• Secrete proteins and hyaluronan (cellular cement)
• Fibrocytes
• The second most abundant cell type
• Found in all connective tissue proper
• Maintain the fibers of connective tissue proper
• Adipocytes
• Fat cells
• Each cell stores a single, large fat droplet
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4-4 Connective Tissue
• Mesenchymal Cells
• Stem cells that respond to injury or infection
• Differentiate into fibroblasts, macrophages, etc.
• Macrophages
• Large, amoeba-like cells of the immune system
• Eat pathogens and damaged cells
• Fixed macrophages stay in tissue
• Free macrophages migrate
• Mast Cells
• Stimulate inflammation after injury or infection
• Release histamine and heparin
• Basophils are leukocytes (white blood cells) that also
contain histamine and heparin
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4-4 Connective Tissue
• Lymphocytes
• Specialized immune cells in lymphatic (lymphoid) system
• For example, lymphocytes may develop into plasma
cells (plasmocytes) that produce antibodies
• Microphages
• Phagocytic blood cells
• Respond to signals from macrophages and mast cells
• For example, neutrophils and eosinophils
• Melanocytes
• Synthesize and store the brown pigment melanin
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4-4 Connective Tissue
• Connective Tissue Fibers
1. Collagen fibers
2. Reticular fibers
3. Elastic fibers
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4-4 Connective Tissue
• Collagen Fibers
• Most common fibers in connective tissue proper
• Long, straight, and unbranched
• Strong and flexible
• Resist force in one direction
• For example, tendons and ligaments
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4-4 Connective Tissue
• Reticular Fibers
• Network of interwoven fibers (stroma)
• Strong and flexible
• Resist force in many directions
• Stabilize functional cells (parenchyma) and
structures
• For example, sheaths around organs
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4-4 Connective Tissue
• Elastic Fibers
•
•
•
•
Contain elastin
Branched and wavy
Return to original length after stretching
For example, elastic ligaments of vertebrae
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4-4 Connective Tissue
• Ground Substance
• Is clear, colorless, and viscous
• Fills spaces between cells and slows pathogen
movement
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Figure 4-8 The Cells and Fibers of Connective Tissue Proper.
Reticular
fibers
Melanocyte
Fixed
macrophage
Plasma cell
Mast cell
Elastic
fibers
Free
macrophage
Collagen
fibers
Blood
in vessel
Adipocytes
(fat cells)
Ground
substance
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Fibroblast
Mesenchymal
cell
Lymphocyte
4-4 Connective Tissue
• Embryonic Connective Tissues
• Are not found in adults
• Mesenchyme (embryonic stem cells)
• The first connective tissue in embryos
• Mucous connective tissue
• Loose embryonic connective tissue
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Figure 4-9a Embryonic Connective Tissues.
Blood vessel
Mesenchymal
cells
Mesenchyme
a
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This is the first connective tissue to
appear in an embryo.
Figure 4-9b Embryonic Connective Tissues.
Blood vessel
Mesenchymal
cells
Mucous connective tissue
(Wharton’s jelly)
b
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This sample was taken from the
umbilical cord of a fetus.
4-4 Connective Tissue
• Loose Connective Tissues
• The “packing materials” of the body
• Three types in adults
1. Areolar
2. Adipose
3. Reticular
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4-4 Connective Tissue
• Areolar Tissue
• Least specialized
• Open framework
• Viscous ground substance
• Elastic fibers
• Holds blood vessels and capillary beds
• For example, under skin (subcutaneous layer)
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Figure 4-10a Loose Connective Tissues.
Areolar Tissue
LOCATIONS: Within and deep to the
dermis of skin, and covered by the
epithelial lining of the digestive,
respiratory, and urinary tracts;
between muscles; around joints,
blood vessels, and nerves
Fibrocytes
Macrophage
Collagen
fibers
FUNCTIONS: Cushions organs; provides
support but permits independent
movement; phagocytic cells
provide defense against
pathogens
Areolar tissue
from pleura
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Mast cell
Elastic fibers
a
Areolar tissue
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4-4 Connective Tissue
• Adipose Tissue
• Contains many adipocytes (fat cells)
• Two types of adipose tissue
1. White fat
2. Brown fat
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4-4 Connective Tissue
• White fat
• Most common
• Stores fat
• Absorbs shocks
• Slows heat loss (insulation)
• Brown fat
• More vascularized
• Adipocytes have many mitochondria
• When stimulated by nervous system, fat breakdown
accelerates, releasing energy that will be absorbed
by surrounding tissues
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4-4 Connective Tissue
• Adipose Tissue
• Adipose cells
• Adipocytes in adults do not divide
• Expand to store fat
• Shrink as fats are released
• Mesenchymal cells divide and differentiate
• To produce more fat cells
• When more storage is needed
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Figure 4-10b Loose Connective Tissues.
Adipose Tissue
LOCATIONS: Deep to the skin,
especially at sides, buttocks,
and breasts; padding around
eyes and kidneys
FUNCTIONS: Provides
padding and cushions
shocks; insulates
(reduces heat loss);
stores energy
Adipocytes
(white adipose
cells)
b Adipose tissue
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4-4 Connective Tissue
• Reticular Tissue
• Provides support
• Complex, three-dimensional network
• Supportive fibers (stroma)
• Support functional cells (parenchyma)
• Reticular organs
• Spleen, liver, lymph nodes, and bone marrow
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Figure 4-10c Loose Connective Tissues.
Reticular Tissue
LOCATIONS: Liver, kidney, spleen,
lymph nodes, and bone marrow
FUNCTIONS: Provides supporting
framework
Reticular
fibers
Reticular tissue
from liver
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c Reticular tissue
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4-4 Connective Tissue
• Dense Connective Tissues
• Connective tissues proper, tightly packed with high
numbers of collagen or elastic fibers
• Dense regular connective tissue
• Dense irregular connective tissue
• Elastic tissue
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4-4 Connective Tissue
• Dense Regular Connective Tissue
• Tightly packed, parallel collagen fibers
• Tendons attach muscles to bones
• Ligaments connect bone to bone and stabilize
organs
• Aponeuroses attach in sheets to large, flat
muscles
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Figure 4-11a Dense Connective Tissues.
Dense Regular Connective Tissue
LOCATIONS: Between skeletal
muscles and skeleton (tendons
and aponeuroses); between
bones or stabilizing positions
of internal organs (ligaments);
covering skeletal muscles;
deep fasciae
FUNCTIONS: Provides
firm attachment; conducts
pull of muscles; reduces
friction between muscles;
stabilizes positions
of bones
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Collagen
fibers
Fibroblast
nuclei
a
Tendon
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4-4 Connective Tissue
• Dense Irregular Connective Tissue
• Interwoven networks of collagen fibers
• Layered in skin
• Around cartilages (perichondrium)
• Around bones (periosteum)
• Form capsules around some organs (e.g., liver,
kidneys)
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Figure 4-11b Dense Connective Tissues.
Dense Irregular Connective Tissue
LOCATIONS: Capsules of
visceral organs; periostea
and perichondria; nerve
and muscle sheaths; dermis
FUNCTIONS: Provides
strength to resist forces
from many directions;
helps prevent
overexpansion of
organs, such as
the urinary bladder
Collagen
fiber
bundles
b Deep dermis
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LM × 111
4-4 Connective Tissue
• Elastic Tissue
• Made of elastic fibers
• For example, elastic ligaments of spinal vertebrae
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Figure 4-11c Dense Connective Tissues.
Elastic Tissue
LOCATIONS: Between vertebrae
of the spinal column (ligamentum
flavum and ligamentum nuchae);
ligaments supporting penis;
ligaments supporting transitional
epithelia; in blood vessel walls
Elastic
fibers
FUNCTIONS: Stabilizes
positions of vertebrae and
penis; cushions shocks;
permits expansion and
contraction of organs
Fibroblast
nuclei
c Elastic ligament
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4-4 Connective Tissue
• Fluid Connective Tissues
• Blood and lymph
• Watery matrix of dissolved proteins
• Carry specific cell types (formed elements)
• Formed elements of blood
• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets
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4-4 Connective Tissue
• Fluid Elements of Connective Tissues
• Extracellular
• Plasma
• Interstitial fluid
• Lymph
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Figure 4-12 Formed Elements in the Blood (Part 1 of 3).
Red blood cells
Red blood cells, or
erythrocytes
(e-RITH-ro-sits),
are responˉ ˉ
sible for the transport of
oxygen (and, to a lesser
degree, of carbon dioxide)
in the blood.
Red blood cells
account for about
half the volume of
whole blood and
give blood its color.
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Figure 4-12 Formed Elements in the Blood (Part 2 of 3).
White blood cells
White blood cells, or leukocytes
ˉ ˉ leuko-, white), help defend the
(LOO-ko-sits;
body from infection and disease.
Neutrophil
Eosinophil
Monocytes
are phagocytes
similar to the
free macrophages in
other tissues.
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Lymphocytes are
uncommon in the blood
but they are the dominant
cell type in lymph, the
second type of fluid
connective tissue.
Basophil
Eosinophils and neutrophils are phagocytes.
Basophils promote inflammation much like mast cells
in other connective tissues.
Figure 4-12 Formed Elements in the Blood (Part 3 of 3).
Platelets
Platelets are
membrane-enclosed
packets of cytoplasm
that function in blood
clotting.
These cell fragments
are involved in the
clotting response that
seals leaks in damaged or broken blood
vessels.
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4-4 Connective Tissue
• Lymph
• Extracellular fluid
•
•
•
•
Collected from interstitial space
Monitored by immune system
Transported by lymphatic (lymphoid) system
Returned to venous system
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4-4 Connective Tissue
• Fluid Tissue Transport Systems
• Cardiovascular system (blood)
• Arteries
• Capillaries
• Veins
• Lymphatic (lymphoid) system (lymph)
• Lymphatic vessels
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4-5 Supporting Connective Tissues
• Support Soft Tissues and Body Weight
• Cartilage
• Gel-type ground substance
• For shock absorption and protection
• Bone
• Calcified (made rigid by calcium salts, minerals)
• For weight support
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4-5 Supporting Connective Tissues
• Cartilage Matrix
• Proteoglycans derived from chondroitin sulfates
• Ground substance proteins
• Chondrocytes (Cartilage Cells) surrounded by
Lacunae (Chambers)
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4-5 Supporting Connective Tissues
• Cartilage Structure
• No blood vessels
• Chondrocytes produce antiangiogenesis factor
• Perichondrium
• Outer, fibrous layer (for strength)
• Inner, cellular layer (for growth and maintenance)
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Figure 4-13a The Growth of Cartilage.
Matrix
New
matrix
Chondrocyte
Lacuna
Chondrocyte undergoes division within a
lacuna surrounded by cartilage matrix.
a Interstitial growth
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As daughter cells secrete additional matrix, they move
apart, expanding the cartilage from within.
Figure 4-13b The Growth of Cartilage.
Fibroblast
Dividing stem cell
Perichondrium
New matrix
Chondroblasts
Immature
chondrocyte
Older matrix
Mature
chondrocyte
Cells in the cellular layer of
the perichondrium differentiate
into chondroblasts.
b Appositional growth
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These immature chondroblasts
secrete new matrix.
As the matrix enlarges, more
chondroblasts are incorporated;
they are replaced by divisions of
stem cells in the perichondrium.
4-5 Supporting Connective Tissues
• Types of Cartilage
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage (fibrous cartilage)
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4-5 Supporting Connective Tissues
• Hyaline Cartilage
• Stiff, flexible support
• Reduces friction between bones
• Found in synovial joints, rib tips, sternum, and trachea
• Elastic Cartilage
• Supportive but bends easily
• Found in external ear and epiglottis
• Fibrocartilage (Fibrous Cartilage)
• Limits movement
• Prevents bone-to-bone contact
• Pads knee joints
• Found between pubic bones and intervertebral discs
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Figure 4-14a Types of Cartilage.
Hyaline Cartilage
LOCATIONS: Between tips of ribs
and bones of sternum; covering
bone surfaces at synovial joints;
supporting larynx (voice box),
trachea, and bronchi; forming part
of nasal septum
FUNCTIONS: Provides stiff but
somewhat flexible support;
reduces friction
between bony
surfaces
Chondrocytes
in lacunae
Matrix
LM × 500
a Hyaline cartilage
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Figure 4-14b Types of Cartilage.
Elastic Cartilage
LOCATIONS: Auricle of external ear;
epiglottis; auditory canal; cuneiform
cartilages of larynx
FUNCTIONS: Provides support, but
tolerates distortion without
damage and returns
to original shape
Chondrocytes
in lacunae
Elastic fibers
in matrix
b Elastic cartilage
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LM × 358
Figure 4-14c Types of Cartilage.
Fibrocartilage
LOCATIONS: Pads within knee joint;
between pubic bones of pelvis;
intervertebral discs
FUNCTIONS: Resists
compression;
prevents bone-to-bone
contact; limits
movement
Chondrocytes
in lacunae
Fibrous
matrix
LM × 400
c Fibrocartilage
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4-5 Supporting Connective Tissues
• Bone or Osseous Tissue
• Strong (calcified calcium salt deposits)
• Resists shattering (flexible collagen fibers)
• Bone Cells or Osteocytes
• Arranged around central canals within matrix
• Small channels through matrix (canaliculi) access
blood supply
• Periosteum
• Covers bone surfaces, and arranged into two layers:
• Fibrous layer
• Cellular layer
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Figure 4-15 Bone.
Canaliculi
Osteocytes
in lacunae
Matrix
Osteon
Central canal
Blood vessels
Osteon
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LM × 375
Fibrou
s
layer
Cellular
layer
Periosteum
Table 4-2 A Comparison of Cartilage and Bone.
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Connective Tissue
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Figure 4.6
4-6 Membranes
• Membranes
• Physical barriers
• Line or cover portions of the body
• Consist of:
• An epithelium
• Supported by connective tissue
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4-6 Membranes
• Four Types of Membranes
1.
2.
3.
4.
Mucous membranes
Serous membranes
Cutaneous membrane
Synovial membranes
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4-6 Membranes
• Mucous Membranes (Mucosae)
• Line passageways that have external connections
• In digestive, respiratory, urinary, and reproductive
tracts
• Epithelial surfaces must be moist
• To reduce friction
• To facilitate absorption and excretion
• Lamina propria
• Is areolar tissue
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Figure 4-16a Types of Membranes.
Mucous secretion
Epithelium
Lamina propria
(areolar tissue)
a Mucous membranes are coated with the
secretions of mucous glands. These
membranes line the digestive, respiratory,
urinary, and reproductive tracts.
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4-6 Membranes
• Serous Membranes
• Line cavities not open to the outside
• Are thin but strong
• Have fluid transudate to reduce friction
• Have a parietal portion covering the cavity
• Have a visceral portion (serosa) covering the organs
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4-6 Membranes
• Three Serous Membranes:
1. Pleura
• Lines pleural cavities
• Covers lungs
2. Peritoneum
• Lines peritoneal cavity
• Covers abdominal organs
3. Pericardium
• Lines pericardial cavity
• Covers heart
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Figure 4-16b Types of Membranes.
Transudate
Mesothelium
Areolar tissue
b Serous membranes line the ventral body
cavities (the peritoneal, pleural, and
pericardial cavities).
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4-6 Membranes
• Cutaneous Membrane
• Is skin, surface of the body
• Thick, waterproof, and dry
• Synovial Membranes
•
•
•
•
Line moving, articulating joint cavities
Produce synovial fluid (lubricant)
Protect the ends of bones
Lack a true epithelium
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Figure 4-16c Types of Membranes.
Epithelium
Areolar tissue
Dense irregular
connective tissue
c The cutaneous membrane, or skin, covers the
outer surface of the body.
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Figure 4-16d Types of Membranes.
Articular (hyaline) tissue
Synovial fluid
Capsule
Capillary
Adipocytes
Areolar
tissue
Epithelium
Synovial
membrane
Bone
d Synovial membranes line joint cavities and produce
the fluid within the joint.
© 2015 Pearson Education, Inc.
4-7 Internal Framework of the Body
• Connective Tissues
1. Provide strength and stability
2. Maintain positions of internal organs
3. Provide routes for blood vessels, lymphatic
vessels, and nerves
• Fasciae
• Singular form = fascia
• Are connective tissue layers and wrappings
that support or surround organs
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4-7 Internal Framework of the Body
• Three Types of Fasciae
1. Superficial fascia
2. Deep fascia
3. Subserous fascia
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Figure 4-17 The Fasciae.
Body wall
Connective Tissue Framework of Body
Body cavity
Superficial Fascia
• Between skin and
underlying organs
• Areolar tissue and adipose
tissue
• Also known as
subcutaneous layer
or hypodermis
Skin
Deep Fascia
• Bound to capsules, tendons,
and ligaments
• Dense connective tissue
• Forms a strong, fibrous
internal framework
Subserous Fascia
Rib
• Between serous
membranes and
deep fascia
• Areolar tissue
Serous membrane
Cutaneous membrane
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4-8 Muscle Tissue
• Muscle Tissue
• Specialized for contraction
• Produces (initiates) all body movement
• Three types of muscle tissue
1. Skeletal muscle tissue
• Large body muscles responsible for movement
2. Cardiac muscle tissue
• Found only in the heart
3. Smooth muscle tissue
• Found in walls of hollow, contracting organs
(blood vessels; urinary bladder; respiratory,
digestive, and reproductive tracts)
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4-8 Muscle Tissue
• Classification of Muscle Cells
• Striated (muscle cells with a banded appearance)
• Nonstriated (not banded; smooth)
• Muscle cells can have a single nucleus (unicellular)
• Muscle cells can be multinucleate
• Muscle cells can be controlled voluntarily
(consciously)
• Muscle cells can be controlled involuntarily
(automatically)
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4-8 Muscle Tissue
• Skeletal Muscle Cells
• Long and thin (cylindrical)
• Usually called muscle fibers
• Do not divide
• New fibers are produced by stem cells (myosatellite
cells)
• Multinucleated, cylindrical, striated, voluntary muscles
© 2015 Pearson Education, Inc.
Figure 4-18a Types of Muscle Tissue.
Skeletal Muscle Tissue
Cells are long, cylindrical,
striated, and multinucleate.
LOCATIONS: Combined
with connective tissues
and neural tissue in
skeletal muscles
FUNCTIONS: Moves or
stabilizes the position of
the skeleton; guards
entrances and exits to the
digestive, respiratory, and
urinary tracts; generates
heat; protects internal
organs
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Striations
Nuclei
Muscle
fiber
a Skeletal muscle
LM × 180
4-8 Muscle Tissue
• Cardiac Muscle Cells
• Called cardiocytes
• Form branching networks connected at intercalated
discs
• Short branched, striated, involuntary muscles
• Smooth Muscle Cells
• Small and tapered
• Can divide and regenerate
• Unicellular, spindle-shaped, nonstriated, involuntary
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Figure 4-18b Types of Muscle Tissue.
Cardiac Muscle Tissue
Cells are short, branched,
and striated, usually with a
single nucleus; cells are
interconnected by
intercalated discs.
Nuclei
Cardiac
muscle
cells
LOCATION: Heart
FUNCTIONS: Circulates
blood; maintains
blood pressure
Intercalated
discs
Striations
b Cardiac muscle
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LM × 450
Figure 4-18c Types of Muscle Tissue.
Smooth Muscle Tissue
Cells are short, spindleshaped, and nonstriated,
with a single, central
nucleus.
LOCATIONS: Found in
the walls of blood vessels
and in digestive, respiratory,
urinary, and reproductive organs
FUNCTIONS: Moves food,
urine, and reproductive
tract secretions; controls
diameter of respiratory
passageways; regulates
diameter of blood vessels
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Nuclei
Smooth
muscle
cells
c Smooth muscle
LM × 235
4-9 Neural Tissue
• Neural Tissue
• Also called nervous or nerve tissue
• Specialized for conducting electrical impulses
• Rapidly senses internal or external environment
• Processes information and controls responses
• Neural tissue is concentrated in the central nervous
system (Brain and spinal cord)
• Two Types of Neural Cells
1. Neurons: Nerve cells, perform electrical
communication
2. Neuroglia: Supporting cells, repair and supply
nutrients to neurons
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4-9 Neural Tissue
• Cell Parts of a Neuron
• Cell body
• Contains the nucleus and nucleolus
• Dendrites
• Short branches extending from the cell body
• Receive incoming signals
• Axon (nerve fiber)
• Long, thin extension of the cell body
• Carries outgoing electrical signals to their
destination
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Figure 4-19 Neural Tissue.
NEUROGLIA (supporting cells)
NEURONS
Nuclei of neuroglia
• Maintain physical structure
of tissues
• Repair tissue framework
after injury
• Perform phagocytosis
• Provide nutrients to neurons
• Regulate the composition of the
interstitial fluid surrounding neurons
Cell body
Axon
Nucleolus
Nucleus
of neuron
Dendrites
LM × 600
Dendrites
(contacted by
other neurons)
Microfibrils and
microtubules
Axon (conducts
information to
other cells)
Cell body
(contains
nucleus
and major
organelles)
Nucleus
Nucleolus
Mitochondrion
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A representative neuron
(sizes and shapes vary widely)
Contact with
other cells
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4-10 Tissue Injuries and Repair
• Tissues Respond to Injuries
• To maintain homeostasis
• Cells restore homeostasis with two processes
1.
2.
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Inflammation
Regeneration
4-10 Tissue Injuries and Repair
• Inflammation = Inflammatory Response
• The tissue’s first response to injury
• Signs and symptoms of the inflammatory response
include:
• Swelling
• Redness
• Heat
• Pain
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4-10 Tissue Injuries and Repair
• Inflammatory Response
• Can be triggered by:
• Trauma (physical injury)
• Infection (the presence of harmful pathogens)
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4-10 Tissue Injuries and Repair
• The Process of Inflammation
• Damaged cells release chemical signals into the
surrounding interstitial fluid
• Prostaglandins
• Proteins
• Potassium ions
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4-10 Tissue Injuries and Repair
• The Process of Inflammation
• As cells break down:
• Lysosomes release enzymes that destroy the
injured cell and attack surrounding tissues
• Tissue destruction is called necrosis
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4-10 Tissue Injuries and Repair
• The Process of Inflammation
• Necrotic tissues and cellular debris (pus)
accumulate in the wound
• Abscess — pus trapped in an enclosed area
• Injury stimulates mast cells to release:
• Histamine
• Heparin
• Prostaglandins
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4-10 Tissue Injuries and Repair
• The Process of Inflammation
• Dilation of blood vessels
• Increases blood circulation in the area
• Causes warmth and redness
• Brings more nutrients and oxygen to the area
• Removes wastes
• Plasma diffuses into the area
• Causes swelling and pain
• Phagocytic white blood cells
• Clean up the area
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4-10 Tissue Injuries and Repair
• Regeneration
• When the injury or infection is cleaned up
• Healing (regeneration) begins
• The Process of Regeneration
• Fibrocytes move into necrotic area
• Lay down collagen fibers
• To bind the area together (scar tissue)
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4-10 Tissue Injuries and Repair
• The Process of Regeneration
• New cells migrate into area
• Or are produced by mesenchymal stem cells
• Not all tissues can regenerate
• Epithelia and connective tissues regenerate well
• Cardiac cells and neurons do not regenerate (or
regenerate poorly)
© 2015 Pearson Education, Inc.
Figure 4-20 Inflammation and Regeneration (Part 1 of 5).
Mast Cell Activation
When an injury damages connective
tissue, mast cells release a variety of
chemicals. This process, called mast cell
activation, stimulates inflammation.
Histamine
stimulates
Exposure to Pathogens and Toxins
Injured tissue contains an abnormal
concentration of pathogens, toxins,
wastes, and the chemicals from
injured cells.
When a tissue is injured,
a general defense
mechanism is
activated.
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Mast cell
Figure 4-20 Inflammation and Regeneration (Part 2 of 5).
Mast Cell Activation
When an injury damages connective
tissue, mast cells release
a variety of
Mast
chemicals. This process, called mast cell
cell
activation, stimulates inflammation.
Mast Cell
Histamine
Heparin
Prostaglandins
INFLAMMATION
Inflammation produces several familiar indications of injury, including swelling,
redness, heat (warmth), pain, and sometimes loss of function. Inflammation may
also result from the presence of pathogens, such as harmful bacteria, within the
tissues. The presence of these pathogens constitutes an infection.
Increased Blood Flow Increased Vessel Permeability Pain
In response to the
released chemicals, blood
vessels dilate, increasing
blood flow through the
damaged tissue.
Vessel dilation is accompanied by
an increase in the permeability of
the capillary walls. Plasma now
diffuses into the injured tissue, so
the area becomes swollen.
The abnormal conditions
within the tissue and the
chemicals released by
mast cells stimulate nerve
endings that produce the
sensation of pain.
PAIN
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Figure 4-20 Inflammation and Regeneration (Part 4 of 5).
Increased Local
Temperature
Increased Oxygen
and Nutrients
Increased
Phagocytosis
Removal of Toxins
and Wastes
The increased
blood flow and
permeability
causes the tissue
to become warm
and red.
Vessel dilation,
increased blood
flow, and increased
vessel permeability
result in enhanced
delivery of oxygen
and nutrients.
Phagocytes in
the tissue are
activated, and
they begin
engulfing tissue
debris and
pathogens.
Enhanced circulation
carries away toxins
and wastes,
distributing them to the
kidneys for excretion,
or to the liver for
inactivation.
O2
Toxins
and wastes
Regeneration
Regeneration is the repair that
occurs after the damaged tissue has
been stabilized and the inflammation
has subsided. Fibroblasts move into
the area, laying down a collagenous
framework known as scar tissue.
Over time, scar tissue is usually
“remodeled” and gradually assumes
a more normal appearance.
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Inflammation Subsides
Over a period of hours to
days, the cleanup process
generally succeeds in
eliminating the
inflammatory stimuli.
4-11 Aging and Tissue
• Aging and Tissue Structure
• Speed and efficiency of tissue repair decrease
with age, due to:
• Slower rate of energy consumption (metabolism)
• Hormonal alterations
• Reduced physical activity
© 2015 Pearson Education, Inc.
4-11 Aging and Tissue
• Effects of Aging
• Chemical and structural tissue changes
•
•
•
•
•
Thinning epithelia and connective tissues
Increased bruising and bone brittleness
Joint pain and broken bones
Cardiovascular disease
Mental deterioration
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4-11 Aging and Tissue
• Aging and Cancer Incidence
• Cancer rates increase with age
• Twenty-five percent of all people in the United
States develop cancer
• Cancer is the #2 cause of death in the United
States
• Environmental chemicals and cigarette smoke
cause cancer
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