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prepared by
Barbara Heard,
Atlantic Cape Community
College
CHAPTER
4
Tissue: The
Living Fabric:
Part A
© Annie Leibovitz/Contact Press Images
© 2013 Pearson Education, Inc.
Tissue: The Living Fabric
• Individual body cells specialized
– Each type performs specific functions that
maintain homeostasis
• Tissues
– Groups of cells similar in structure that
perform common or related function
• Histology
– Study of tissues
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Types of Primary Tissues
• Epithelial tissue
– Covers
• Connective tissue
– Supports
• Muscle tissue
– Produces movement
• Nerve tissue
– Controls
© 2013 Pearson Education, Inc.
Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues.
Nervous tissue: Internal communication
• Brain
• Spinal cord
• Nerves
Muscle tissue: Contracts to cause movement
• Muscles attached to bones (skeletal)
• Muscles of heart (cardiac)
• Muscles of walls of hollow organs (smooth)
Epithelial tissue: Forms boundaries between different
environments, protects, secretes, absorbs, filters
• Lining of digestive tract organs and other hollow
organs
• Skin surface (epidermis)
Connective tissue: Supports, protects, binds
other tissues together
• Bones
• Tendons
• Fat and other soft padding tissue
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Studying Human Tissue: Microscopy
• Tissue is fixed
– Preserved
• Cut
– Sliced thin enough to transmit light or
electrons
• Stained
– Enhances contrast
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Epithelial Tissue (Epithelium)
• Form boundaries
• Two main types (by location)
– Covering and lining epithelia
• On external and internal surfaces
– Glandular epithelia
• Secretory tissue in glands
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Epithelial Tissue Functions
•
•
•
•
•
•
Protection
Absorption
Filtration
Excretion
Secretion
Sensory reception
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Five Characteristics of Epithelial Tissues
•
•
•
•
•
Polarity
Specialized contacts
Supported by connective tissues
Avascular, but innervated
Can regenerate
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Characteristics of Epithelial Tissue: Polarity
• Cells have polarity
– Apical surface (upper free) exposed to
exterior or cavity
– Basal surface (lower, attached)
– Both surfaces differ in structure and function
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Figure 4.2a Classification of epithelia.
Apical surface
Basal surface
Simple
Apical surface
Basal surface
Stratified
Classification based on number of cell layers.
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Apical Surface of Epithelial Tissues
• May be smooth & slick
• Most have microvilli (e.g., brush border of
intestinal lining)
– Increase surface area
• Some have cilia (e.g., lining of trachea)
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Basal Surface of Epithelial Tissues
• Noncellular basal lamina
– Glycoprotein and collagen fibers lies adjacent
to basal surface
– Adhesive sheet
– Selective filter
– Scaffolding for cell migration in wound repair
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Characteristics of Epithelial Tissue:
Specialized Contacts
• Covering and lining epithelial tissues fit
closely together
– Form continuous sheets
• Specialized contacts bind adjacent cells
– Lateral contacts
• Tight junctions
• Desmosomes
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Characteristics of Epithelial Tissue:
Connective Tissue Support
• All are supported by connective tissue
• Reticular lamina
– Deep to basal lamina
– Network of collagen fibers
• Basement membrane
– Basal lamina + reticular lamina
– Reinforces epithelial sheet
– Resists stretching and tearing
– Defines epithelial boundary
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Characteristics of Epithelial Tissue:
Avascular but Innervated
• No blood vessels in epithelial tissue
– Must be nourished by diffusion from
underlying connective tissues
• Is supplied by nerve fibers
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Characteristics of Epithelial Tissue:
Regeneration
• High regenerative capacity
• Stimulated by loss of apical-basal polarity
and lateral contacts
– Some exposed to friction
– Some exposed to hostile substances
• If adequate nutrients can replace lost cells
by cell division
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Classification of Epithelia
• All epithelial tissues have two names
– One indicates number of cell layers
• Simple epithelia = single layer of cells
• Stratified epithelia = two or more layers of cells
– Shape can change in different layers
– One indicates shape of cells
• Squamous
• Cuboidal
• Columnar
• In stratified epithelia, epithelia classified by
cell shape in apical layer
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Figure 4.2a Classification of epithelia.
Apical surface
Basal surface
Simple
Apical surface
Basal surface
Stratified
Classification based on number of cell layers.
© 2013 Pearson Education, Inc.
Cells of Epithelial Tissues
• Squamous cells
– Flattened and scalelike
– Nucleus flattened
• Cuboidal cells
– Boxlike
– Nucleus round
• Columnar cells
– Tall; column shaped
– Nucleus elongated
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Figure 4.2b Classification of epithelia.
Squamous
Cuboidal
Columnar
Classification based on cell shape.
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Classification of Epithelia:
Simple Epithelia
•
•
•
•
Absorption
Secretion
Filtration
Very thin
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Simple Squamous Epithelium
• Cells flattened laterally
• Cytoplasm sparse
• Function where rapid diffusion is priority
– i.e., kidney, lungs
• Note description, function, location on next
slide
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Figure 4.3a Epithelial tissues.
Simple squamous epithelium
Description: Single layer of
flattened cells with disc-shaped
central nuclei and sparse
cytoplasm; the simplest of the
epithelia.
Air sacs
of lung
tissue
Nuclei of
squamous
epithelial
cells
Function: Allows materials to pass
by diffusion and filtration in sites
where protection is not important;
secretes lubricating substances in
serosae.
Location: Kidney glomeruli; air
sacs of lungs; lining of heart, blood
vessels, and lymphatic vessels;
lining of ventral body cavity
(serosae).
Photomicrograph: Simple squamous
epithelium forming part of the alveolar
(air sac) walls (140x).
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Simple Squamous Epithelium
• Two other locations
– Endothelium
• The lining of lymphatic vessels, blood vessels, and
heart
– Mesothelium
• The epithelium of serous membranes in the ventral
body cavity
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Simple Cuboidal Epithelia
•
•
•
•
Single layer of cells
Secretion
Absorption
Forms walls of smallest ducts of glands
and many kidney tubules
• Note description, function, location on next
slide
© 2013 Pearson Education, Inc.
Figure 4.3b Epithelial tissues.
Simple cuboidal epithelium
Description: Single layer of
cubelike cells with large, spherical
central nuclei.
Simple
cuboidal
epithelial
cells
Nucleus
Function: Secretion and
absorption.
Basement
membrane
Location: Kidney tubules; ducts
and secretory portions of small
glands; ovary surface.
Connective
tissue
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).
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Simple Columnar Epithelium
•
•
•
•
Single layer of tall, closely packed cells
Absorption
Secretion
Note description, function, location on next
slide
© 2013 Pearson Education, Inc.
Figure 4.3c Epithelial tissues.
Simple columnar epithelium
Description: Single layer of tall
cells with round to oval nuclei;
some cells bear cilia; layer may
contain mucus-secreting
unicellular glands (goblet cells).
Microvilli
Simple
columnar
epithelial
cell
Function: Absorption; secretion
of mucus, enzymes, and other
substances; ciliated type propels
mucus (or reproductive cells) by
ciliary action.
Location: Nonciliated type lines
most of the digestive tract
(stomach to rectum), gallbladder,
and excretory ducts of some
glands; ciliated variety lines small
bronchi, uterine tubes, and some
regions of the uterus.
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Mucus of
goblet cell
Basement
membrane
Photomicrograph: Simple columnar
epithelium of the small intestine mucosa (660x).
Pseudostratified Columnar Epitheliem
• Cells vary in height
– Cell nuclei at different levels
– Appears stratified, but is not
– Secretion
– Absorption
– Note description, function, location on next
slide
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Figure 4.3d Epithelial tissues.
Pseudostratified columnar epithelium
Description: Single layer of cells
of differing heights, some not
reaching the free surface; nuclei
seen at different levels; may
contain mucus-secreting cells
and bear cilia.
Cilia
Pseudostratified
epithelial
layer
Function: Secrete substances,
particularly mucus; propulsion of
mucus by ciliary action.
Location: Nonciliated type in
male’s sperm-carrying ducts and
ducts of large glands; ciliated
variety lines the trachea, most of
the upper respiratory tract.
Trachea
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Photomicrograph: Pseudostratified
ciliated columnar epithelium lining the
human trachea (800x).
Basement
membrane
Stratified Epithelial Tissues
• Two or more cell layers
• Regenerate from below
– Basal cells divide, cells migrate to surface
• More durable than simple epithelia
• Protection is major role
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Stratified Squamous Epithelium
• Most widespread of stratified epithelia
• Free surface squamous; deeper layers
cuboidal or columnar
• Located for wear and tear
• Those farthest from basal layer (and
therefore nutrients) less viable
• Note description, function, location on next
slide
© 2013 Pearson Education, Inc.
Figure 4.3e Epithelial tissues.
Stratified squamous epithelium
Description: Thick membrane
composed of several cell layers;
basal cells are cuboidal or
columnar and metabolically active;
surface cells are flattened
(squamous); in the keratinized
type, the surface cells are full of
keratin and dead; basal cells are
active in mitosis and produce the
cells of the more superficial layers.
Stratified
squamous
epithelium
Function: Protects underlying
tissues in areas subjected to
abrasion.
Location: Nonkeratinized type
forms the moist linings of the
esophagus, mouth, and vagina;
keratinized variety forms the
epidermis of the skin, a dry
membrane.
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Nuclei
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous
epithelium lining the esophagus (285x).
Stratified Cuboidal Epithelium
• Quite rare
• Found in some sweat and mammary
glands
• Typically two cell layers thick
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Stratified Columnar Epithelium
• Limited distribution in body
• Small amounts in pharynx, male urethra,
and lining some glandular ducts
• Also occurs at transition areas between
two other types of epithelia
• Only apical layer columnar
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Transitional Epithelium
•
•
•
•
•
Forms lining of hollow urinary organs
Basal layer cells are cuboidal or columnar
Ability to change shape with stretch
Apical cells vary in appearance
Note description, function, location on next
slide
© 2013 Pearson Education, Inc.
Figure 4.3f Epithelial tissues.
Transitional epithelium
Description: Resembles both
stratified squamous and stratified
cuboidal; basal cells cuboidal or
columnar; surface cells dome
shaped or squamouslike,
depending on degree of organ
stretch.
Transitional
epithelium
Function: Stretches readily,
permits stored urine to distend
urinary organ.
Location: Lines the ureters,
bladder, and part of the urethra.
Photomicrograph: Transitional epithelium
lining the bladder, relaxed state (360x); note the
bulbous, or rounded, appearance of the cells at
the surface; these cells flatten and elongate
when the bladder fills with urine.
© 2013 Pearson Education, Inc.
Basement
membrane
Connective
tissue
Glandular Epithelia
• Gland
– One or more cells that makes and secretes an
aqueous fluid called a secretion
• Classified by
– Site of product release—endocrine or
exocrine
– Relative number of cells forming the gland
• unicellular (e.g., goblet cells) or multicellular
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Endocrine Glands
• Ductless glands
– Secretions not released into a duct
• Secrete (by exocytosis) hormones that
travel through lymph or blood to their
specific target organs
• Target organs respond in some
characteristic way
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Exocrine Glands
• Secretions released onto body surfaces
(skin) or into body cavities
• More numerous than endocrine glands
• Secrete products into ducts
• Examples include mucous, sweat, oil, and
salivary glands
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Connective Tissue
• Most abundant and widely distributed of
primary tissues
• Four main classes
– Connective tissue proper
– Cartilage
– Bone
– Blood
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Table 4.1 Comparison of Classes of Connective Tissues (1 of 2)
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Table 4.1 Comparison of Classes of Connective Tissues (2 of 2)
© 2013 Pearson Education, Inc.
Major Functions of Connective Tissue
•
•
•
•
•
Binding and support
Protecting
Insulating
Storing reserve fuel
Transporting substances (blood)
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Characteristics of Connective Tissue
• Three characteristics make connective
tissues different from other primary tissues
– Have mesenchyme (an embryonic tissue) as
their common tissue of origin
– Have varying degrees of vascularity (blood
vessels)
– Have extracellular matrix
• Connective tissue not composed mainly of cells
• Largely nonliving extracellular matrix separates
cells
– So can bear weight, withstand tension, endure abuse
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Structural Elements of Connective Tissue
• Three elements
– Ground substance
– Fibers
– Cells
• Composition and arrangement varies in
different connective tissues
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Ground Substance
• Unstructured material that fills space between
cells
– Medium through which solutes diffuse between blood
capillaries and cells
• Components
– Interstitial fluid
– Cell adhesion proteins ("glue" for attachment)
– Proteoglycans
• Protein core + large polysaccharides (chrondroitin sulfate
and hyaluronic acid)
• Trap water in varying amounts, affecting viscosity of ground
substance
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Connective Tissue Fibers
• Three types of fibers provide support
– Collagen
• Strongest and most abundant type
• Tough; provides high tensile strength
– Elastic fibers
• Networks of long, thin, elastin fibers that allow for
stretch and recoil
– Reticular
• Short, fine, highly branched collagenous fibers
(different chemistry and form than collagen fibers)
• Branch, forming networks that offer more "give"
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Cells
• "Blasts" cells
– Immature forum; mitotically active; secrete ground
substance and fibers
– Fibroblasts in connective tissue proper
– Chondroblasts in cartilage
– Osteoblasts in bone
– Hematopoietic stem cells in bone marrow
– "Cyte" cells
– Mature form; maintain matrix
– Chondrocytes in cartilage
– Osteocytes in bone
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Other Cell Types in Connective Tissues
• Fat cells
– Store nutrients
• White blood cells
– Neutrophils, eosinophils, lymphocytes
– Tissue response to injury
• Mast cells
– Initiate local inflammatory response against foreign
microorganisms they detect
• Macrophages
– Phagocytic cells that "eat" dead cells,
microorganisms; function in immune system
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Figure 4.7 Areolar connective tissue: A prototype (model) connective tissue.
Cell types
Macrophage
Fibroblast
Lymphocyte
Fat cell
Mast cell
Neutrophil
Capillary
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Extracellular
matrix
Ground substance
Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Types of Connective Tissues: Connective
Tissue Proper
• All connective tissues except bone, cartilage and
blood
• Two subclasses
– Loose connective tissues
• Areolar
• Adipose
• Reticular
– Dense connective tissues (also called fibrous
connective tissues)
• Dense regular
• Dense irregular
• Elastic
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Areolar Connective Tissue
• Support and bind other tissues
– Universal packing material between other tissues
•
•
•
•
•
•
•
•
Most widely distributed
Provide reservoir of water and salts
Defend against infection
Store nutrients as fat
Fibroblasts
Loose arrangement of fibers
Ground substance
When inflamed soaks up fluid  edema
© 2013 Pearson Education, Inc.
Figure 4.8a Connective tissues.
Connective tissue proper: loose connective tissue, areolar
Description: Gel-like matrix with
all three fiber types; cells:
fibroblasts, macrophages, mast
cells, and some white blood cells.
Function: Wraps and cushions
organs; its macrophages
phagocytize bacteria; plays
important role in inflammation;
holds and conveys tissue fluid.
Location: Widely distributed
under epithelia of body, e.g., forms
lamina propria of mucous
membranes; packages organs;
surrounds capillaries.
Elastic
fibers
Ground
substance
Fibroblast
nuclei
Collagen
fibers
Epithelium
Lamina
propria
© 2013 Pearson Education, Inc.
Photomicrograph: Areolar connective
tissue, a soft packaging tissue of the body (340x).
Adipose Tissue
• White fat
– Similar to areolar but greater nutrient storage
– Cell is adipocyte
• Stores nutrients
– Scanty matrix
– Richly vascularized
– Shock absorption, insulation, energy storage
• Brown fat
– Use lipid fuels to heat bloodstream not to
produce atp
© 2013 Pearson Education, Inc.
Figure 4.8b Connective tissues.
Connective tissue proper: loose connective tissue, adipose
Description: Matrix as in areolar,
but very sparse; closely packed
adipocytes, or fat cells, have
nucleus pushed to the side by
large fat droplet.
Function: Provides reserve food
fuel; insulates against heat loss;
supports and protects organs.
Nucleus of
adipose
(fat) cell
Location: Under skin in
subcutaneous tissue; around
kidneys and eyeballs; within
abdomen; in breasts.
Adipose
tissue
Fat droplet
Photomicrograph: Adipose tissue from
the subcutaneous layer under the skin (350x).
Mammary
glands
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Dense Regular Connective Tissue
• Closely packed bundles of collagen fibers
running parallel to direction of pull
– White structures with great resistance to
pulling
– Fibers slightly wavy so stretch a little
• Tendons/ligaments
• Few cells
• Poorly vascularized
© 2013 Pearson Education, Inc.
Figure 4.8d Connective tissues.
Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel
collagen fibers; a few elastic fibers;
major cell type is the fibroblast.
Function: Attaches muscles to
bones or to muscles; attaches
bones to bones; withstands great
tensile stress when pulling force is
applied in one direction.
Collagen
fibers
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Tendon
© 2013 Pearson Education, Inc.
Photomicrograph: Dense regular connective
tissue from a tendon (430x).
Dense Irregular Connective Tissue
• Same elements but bundles of collagen
thicker and irregularly arranged
• Found in Joints and fibrous organs
• Resists tension from many directions
– Dermis
– Fibrous joint capsules
– Fibrous coverings of some organs
© 2013 Pearson Education, Inc.
Figure 4.8e Connective tissues.
Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily irregularly
arranged collagen fibers; some
elastic fibers; fibroblast is the
major cell type.
Nuclei of
fibroblasts
Function: Withstands tension
exerted in many directions;
provides structural strength.
Location: Fibrous capsules of
organs and of joints; dermis of the
skin; submucosa of digestive tract.
Collagen
fibers
Shoulder
joint
Fibrous
joint
capsule
Photomicrograph: Dense irregular connective
tissue from the fibrous capsule of a joint (430x).
© 2013 Pearson Education, Inc.
Elastic Connective Tissue
• Some ligaments very elastic
– Those connecting adjacent vertebrae
• Many of larger arteries have in walls
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Figure 4.8f Connective tissues.
Connective tissue proper: dense connective tissue, elastic
Description: Dense regular
connective tissue containing a
high proportion of elastic fibers.
Function: Allows tissue to recoil
after stretching; maintains pulsatile
flow of blood through arteries; aids
passive recoil of lungs following
inspiration.
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within
the walls of the bronchial tubes.
Elastic
fibers
Aorta
Heart
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Photomicrograph: Elastic connective tissue
in the wall of the aorta (250x).
Cartilage
•
•
•
•
Chondroblasts and chondrocytes
Tough yet flexible
Lacks nerve fibers
Up to 80% water - can rebound after
compression
• Avascular
– Receives nutrients from membrane surrounding it
• Perichondrium
• Three types of cartilage:
– Hyaline cartilage
– Elastic cartilage
– Fibrocartilage
© 2013 Pearson Education, Inc.
Figure 4.8g Connective tissues.
Cartilage: hyaline
Description: Amorphous but firm
matrix; collagen fibers form an
imperceptible network;
chondroblasts produce the matrix
and when mature (chondrocytes)
lie in lacunae.
Function: Supports and reinforces;
serves as resilient cushion; resists
compressive stress.
Chondrocyte
in lacuna
Location: Forms most of the
embryonic skeleton; covers the
ends of long bones in joint cavities;
forms costal cartilages of the ribs;
cartilages of the nose, trachea, and
larynx.
Costal
cartilages
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Matrix
Photomicrograph: Hyaline cartilage from
a costal cartilage of a rib (470x).
Figure 4.8h Connective tissues.
Cartilage: elastic
Description: Similar to hyaline
cartilage, but more elastic fibers
in matrix.
Function: Maintains the shape of
a structure while allowing great
flexibility.
Chondrocyte
in lacuna
Matrix
Location: Supports the external
ear (pinna); epiglottis.
Photomicrograph: Elastic cartilage from
the human ear pinna; forms the flexible
skeleton of the ear (800x).
© 2013 Pearson Education, Inc.
Figure 4.8i Connective tissues.
Cartilage: fibrocartilage
Description: Matrix similar to but
less firm than that in hyaline
cartilage; thick collagen fibers
predominate.
Function: Tensile strength allows
it to absorb compressive shock.
Location: Intervertebral discs;
pubic symphysis; discs of knee
joint.
Chondrocytes
in lacunae
Intervertebral
discs
Collagen
fiber
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.
© 2013 Pearson Education, Inc.
Bone
•
•
•
•
•
•
•
•
•
Also called osseous tissue
Supports and protects body structures
Stores fat and synthesizes blood cells in cavities
More collagen than cartilage
Has inorganic calcium salts
Osteoblasts produce matrix
Osteocytes maintain the matrix
Osteons – structural units
Richly vascularized
© 2013 Pearson Education, Inc.
Figure 4.8j Connective tissues.
Others: bone (osseous tissue)
Description: Hard, calcified
matrix containing many collagen
fibers; osteocytes lie in lacunae.
Very well vascularized.
Function: Supports and protects
(by enclosing); provides levers for
the muscles to act on; stores
calcium and other minerals and
fat; marrow inside bones is the
site for blood cell formation
(hematopoiesis).
Central
canal
Lacunae
Lamella
Location: Bones
Photomicrograph: Cross-sectional view
of bone (125x).
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Blood
• Most atypical connective tissue – is a fluid
• Red blood cells most common cell type
• Also contains white blood cells and
platelets
• Fibers are soluble proteins that precipitate
during blood clotting
• Functions in transport
© 2013 Pearson Education, Inc.
Figure 4.8k Connective tissues.
Connective tissue: blood
Description: Red and white blood
cells in a fluid matrix (plasma).
Red blood
cells
(erythrocytes)
Function: Transport respiratory
gases, nutrients, wastes, and other
substances.
White blood
cells:
• Lymphocyte
• Neutrophil
Location: Contained within blood
vessels.
Plasma
Photomicrograph: Smear of human blood
(1670x); shows two white blood cells
surrounded by red blood cells.
© 2013 Pearson Education, Inc.