Download Connective tissue

4
PART 1
Tissues
Pages 64-73, 77-95
PowerPoint® Lecture Presentations prepared by
Leslie Hendon
University of Alabama, Birmingham
© 2014 Pearson Education, Inc.
Tissues
• Cells work together in functionally related
groups called tissues
• Tissue
• A group of closely associated cells that perform
related functions and are similar in structure
© 2014 Pearson Education, Inc.
Four Basic Tissue Types and Basic Functions
• Epithelial tissue—covering
• Connective tissue—support
• Muscle tissue—movement
• Nervous tissue—control
© 2014 Pearson Education, Inc.
Epithelial Tissue
• Covers a body surface or lines a body cavity
• Forms parts of most glands
• Functions of epithelia
• Protection
• Diffusion
• Absorption, secretion, and ion transport
• Filtration
• Forms slippery surfaces
© 2014 Pearson Education, Inc.
Special Characteristics of Epithelia
• Cellularity
• Cells separated by minimal extracellular material
• Specialized contacts
• Cells joined by special junctions
• Polarity
• Cell regions of the apical surface differ from the
basal surface
© 2014 Pearson Education, Inc.
Special Characteristics of Epithelia
• Support by connective tissue
• Avascular but innervated
• Epithelia receive nutrients from underlying
connective tissue
• Regeneration
• Lost cells are quickly replaced by cell division
© 2014 Pearson Education, Inc.
Special Characteristics of Epithelia
Cilia
Narrow
extracellular
space
Microvilli
Apical region of
an epithelial cell
Cell junctions
Tight junction
Adhesive belt
Desmosome
Gap junction
Epithelium
Nerve ending
Connective
tissue
© 2014 Pearson Education, Inc.
Basal region
Basal
lamina
Basement
Reticular
membrane
fibers
Capillary
Figure 4.1
Classifications of Epithelia
• First name of tissue indicates number of cell
layers
• Simple—one layer of cells
• Stratified—more than one layer of cells
© 2014 Pearson Education, Inc.
Classifications of Epithelia
• Last name of tissue describes shape of cells
• Squamous—cells are wider than tall (plate-like)
• Cuboidal—cells are as wide as tall, like cubes
• Columnar—cells are taller than they are wide,
like columns
© 2014 Pearson Education, Inc.
Classifications of Epithelia
Apical surface
Squamous
Simple
Basal surface
Apical surface
Cuboidal
Basal surface
Stratified
(a) Classification based on number
of cell layers
Columnar
(b) Classification based on cell shape
© 2014 Pearson Education, Inc.
Figure 4.2
Simple Squamous Epithelium
• Description—single layer; flat cells with discshaped nuclei
• Function
• Passage of materials by passive diffusion and
filtration
• Secretes lubricating substances in serosae
• Location
• Alveoli of lungs
• Lining of heart, blood, and lymphatic vessels
• Lining of ventral body cavity (serosae)
© 2014 Pearson Education, Inc.
Simple Squamous Epithelium
(a) 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
Function: Allows passage of materials
by diffusion and filtration in sites where
protection is not important; secretes
lubricating substances in serosae.
Nuclei
of squamous
epithelial
cells
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 (200).
© 2014 Pearson Education, Inc.
Figure 4.3a
Simple Cuboidal Epithelium
• Description
• Single layer of cubelike cells with large,
spherical central nuclei
• Function
• Secretion and absorption
• Location
• Kidney tubules, secretory portions of small
glands, ovary surface
© 2014 Pearson Education, Inc.
Simple Cuboidal Epithelium
(b) Simple cuboidal epithelium
Description: Single layer of
cubelike cells with large, spherical
central nuclei.
Simple
cuboidal
epithelial
cells
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 (430).
© 2014 Pearson Education, Inc.
Figure 4.3b
Simple Columnar Epithelium
• Description—single layer of column-shaped
(rectangular) cells with oval nuclei
• Some bear cilia at their apical surface
• May contain goblet cells
• Function
• Absorption; secretion of mucus, enzymes, and
other substances
• Ciliated type propels mucus or reproductive cells
by ciliary action
© 2014 Pearson Education, Inc.
Simple Columnar Epithelium
• Location
• Nonciliated form
• Lines digestive tract, gallbladder, ducts of some
glands
• Ciliated form
• Lines small bronchi, uterine tubes, and uterus
© 2014 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
Goblet
cell
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 anal canal),
gallbladder, and excretory ducts
of some glands; ciliated variety
lines small bronchi,
uterine tubes,
and some
regions of
the uterus.
© 2014 Pearson Education, Inc.
Basement
membrane
Photomicrograph: Simple columnar epithelium
of the small intestine (650).
Pseudostratified Columnar Epithelium
• Description
• All cells originate at basement membrane
• Only tall cells reach the apical surface
• Nuclei lie at varying heights within cells
• Gives false impression of stratification
© 2014 Pearson Education, Inc.
Pseudostratified Columnar Epithelium
• Function—secretion of mucus; propulsion of
mucus by cilia
• Locations
• Nonciliated type
• Ducts of male reproductive tubes
• Ducts of large glands
• Ciliated variety
• Lines trachea and most of upper respiratory tract
© 2014 Pearson Education, Inc.
Figure 4.3d Epithelial tissues.
Pseudostratified columnar epithelium
Description: Single layer of
cells of different heights, some
not reaching the free surface;
nuclei seen at different levels;
may contain mucus-secreting
goblet cells and bear cilia.
Cilia
Goblet
cell
Pseudostratified
epithelial
layer
Function: Secretion, particularly
of 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
© 2014 Pearson Education, Inc.
Basement
membrane
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea
(780).
Figure 4.4 Goblet cell (unicellular exocrine gland).
Microvilli
Secretory
vesicles
containing
mucin
Golgi
apparatus
Rough ER
Nucleus
© 2014 Pearson Education, Inc.
Stratified Epithelia
• Properties
• Contain two or more layers of cells
• Regenerate from below (basal layer)
• Major role is protection
• Named according to shape of cells at apical
layer
© 2014 Pearson Education, Inc.
Stratified Squamous Epithelium
• Description
• Many layers of cells are squamous in shape
• Deeper layers of cells appear cuboidal or
columnar
• Thickest epithelial tissue
• Adapted for protection from abrasion
© 2014 Pearson Education, Inc.
Stratified Squamous Epithelium
• Two types—keratinized and non-keratinized
• Keratinized
• Location—epidermis
• Contains the protective protein keratin
• Waterproof
• Surface cells are dead and full of keratin
• Non-keratinized
• Forms moist lining of body openings
© 2014 Pearson Education, Inc.
Stratified Squamous Epithelium
(e) 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.
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.
© 2014 Pearson Education, Inc.
Stratified
squamous
epithelium
Nuclei
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (430).
Figure 4.3e
Stratified Cuboidal Epithelium
• Description—generally two layers of
cube-shaped cells
• Function—protection
• Location
• Forms ducts of
• Mammary glands
• Salivary glands
• Largest sweat glands
© 2014 Pearson Education, Inc.
Stratified Cuboidal Epithelium
(f) Stratified cuboidal epithelium
Description: Generally two
layers of cubelike cells.
Basement
membrane
Function: Protection
Cuboidal
epithelial
cells
Location: Largest ducts of sweat
glands, mammary glands, and
salivary glands.
Duct
lumen
Photomicrograph: Stratified cuboidal epithelium forming
a salivary gland duct (285).
© 2014 Pearson Education, Inc.
Figure 4.3f
Stratified Columnar Epithelium
• Description—several layers; basal cells usually
cuboidal; superficial cells elongated
• Function—protection and secretion
• Location
• Rare tissue type
• Found in male urethra and large ducts of some
glands
© 2014 Pearson Education, Inc.
Figure 4.3g Epithelial tissues.
Stratified columnar epithelium
Description: Several cell layers;
basal cells usually cuboidal;
superficial cells elongated
and columnar.
Stratified
columnar
epithelium
Function: Protection; secretion.
Location: Rare in the body;
small amounts in male urethra
and in large ducts of some
glands.
Urethra
© 2014 Pearson Education, Inc.
Basement
membrane
Underlying
connective
tissue
Photomicrograph: Stratified columnar epithelium
lining the male urethra (360).
Transitional Epithelium
(h) Transitional epithelium
Description: Resembles both
stratified squamous and stratified
cuboidal; basal cells cuboidal or
columnar; surface cells dome shaped
or squamous-like, depending on
degree of organ stretch.
Transitional
epithelium
Function: Stretches readily and
permits distension of urinary organ
by contained urine.
Location: Lines the ureters, bladder,
and part of the urethra.
© 2014 Pearson Education, Inc.
Basement
membrane
Connective
tissue
Photomicrograph: Transitional epithelium lining the bladder,
relaxed state (390); note the bulbous, or rounded, appearance
of the cells at the surface; these cells flatten and become
elongated when the bladder is filled with urine.
Figure 4.3h
Classes of Connective Tissue
• Most diverse and abundant tissue
• Main classes
• Connective tissue proper
• Cartilage
• Bone tissue
• Blood
• Cells separated by a large amount of
extracellular matrix
• Extracellular matrix is composed of ground
substance and fibers
© 2014 Pearson Education, Inc.
Structural Elements of Connective Tissue
• Connective tissues differ in structural properties
• Differences in types of cells
• Differences in composition of extracellular matrix
• However, connective tissues all share structural
elements
© 2014 Pearson Education, Inc.
Structural Elements of Connective Tissue
• Cells—primary cell type of connective tissue
produces matrix
• Fibroblasts
• Make protein subunits
• Secrete molecules that form the ground
substance
• Chondroblasts—secrete matrix in cartilage
• Osteoblasts—secrete matrix in bone
© 2014 Pearson Education, Inc.
Structural Elements of Connective Tissue
• Cells (continued)
• Blood cells—an exception
• Do not produce matrix
• Areolar connective tissue contains
• Fat cells
• White blood cells
• Mast cells
© 2014 Pearson Education, Inc.
Structural Elements of Connective Tissue
Cell types
Macrophage
Extracellular
matrix
Ground substance
Fibers
Collagen fiber
Elastic fiber
Fibroblast
Reticular fiber
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
© 2014 Pearson Education, Inc.
Figure 4.9
Structural Elements of Connective Tissue
• Fibers—function in support
• Collagen fibers—strongest; resist tension
• Reticular fibers—bundles of special type of
collagen
• Cover and support structures
• Elastic fibers—contain elastin
• Recoil after stretching
© 2014 Pearson Education, Inc.
Structural Elements of Connective Tissue
• Ground substance
• Is produced by primary cell type of the tissue
• Is usually gel-like
• Cushions and protects body structures
• Holds tissue fluid
• Blood is an exception
• Plasma is not produced by blood cells
© 2014 Pearson Education, Inc.
Connective Tissue Proper
• Has two subclasses
• Loose connective tissue
• Areolar, adipose, and reticular
• Dense connective tissue
• Dense irregular, dense regular, and elastic
© 2014 Pearson Education, Inc.
Classes of Connective Tissue
© 2014 Pearson Education, Inc.
Table 4.2 (1 of 2)
© 2014 Pearson Education, Inc.
Areolar Connective Tissue—A Model
Connective Tissue
• Areolar connective tissue
• Underlies epithelial tissue
• Surrounds small nerves and blood vessels
• Has structures and functions shared by other CT
• Borders all other tissues in the body
© 2014 Pearson Education, Inc.
Areolar Connective Tissue
(b) 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.
Epithelium
Elastic
fibers
Collagen
fibers
Fibroblast
nuclei
Photomicrograph: Areolar connective tissue, a soft packaging
tissue of the body (360).
Lamina
propria
© 2014 Pearson Education, Inc.
Figure 4.10b
Areolar Connective Tissue
• Tissue fluid (interstitial fluid)
• Watery fluid occupying extracellular matrix
• Tissue fluid derives from blood
• Ground substance
• Viscous, spongy part of extracellular matrix
• Consists of sugar and protein molecules
• Made and secreted by fibroblasts
© 2014 Pearson Education, Inc.
Areolar Connective Tissue
• Main battlefield in fight against infection
• Defenders gather at infection sites
• Macrophages
• Mast cells
• White blood cells
• Neutrophils, lymphocytes, and eosinophils
© 2014 Pearson Education, Inc.
Adipose Tissue
(c) 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.
Location: Under skin in the hypodermis;
around kidneys and eyeballs; within
abdomen; in breasts.
Adipose
tissue
Nucleus of
fat cell
Vacuole
containing
fat droplet
Photomicrograph: Adipose tissue from the subcutaneous
layer under the skin (500).
Mammary
glands
© 2014 Pearson Education, Inc.
Figure 4.10c
Reticular Connective Tissue
(d) Connective tissue proper: loose connective tissue, reticular
Description: Network of reticular
fibers in a typical loose ground
substance; reticular cells lie on
the network.
Function: Fibers form a soft internal
skeleton (stroma) that supports other
cell types including white blood cells,
mast cells, and macrophages.
Location: Lymphoid organs (lymph
nodes, bone marrow, and spleen).
White blood cell
(lymphocyte)
Reticular
fibers
Spleen
Photomicrograph: Dark-staining network of reticular connective
tissue fibers forming the internal skeleton of the spleen (555).
© 2014 Pearson Education, Inc.
Figure 4.10d
Figure 4.10e Connective tissues.
Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily
irregularly arranged collagen
fibers; some elastic fibers;
major cell type is the fibroblast;
defense cells and fat cells are
also present.
Nuclei of
fibroblasts
Function: Able to withstand
tension exerted in many
directions; provides structural
strength.
Collagen
fibers
Location: Fibrous capsules of
organs and of joints; dermis of
the skin; submucosa of
digestive tract.
Fibrous
layer of
joint
capsule
© 2014 Pearson Education, Inc.
Photomicrograph: Dense irregular connective
tissue from the dermis of the skin (300).
Figure 4.10f 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.
Collagen
fibers
Function: Attaches muscles to
bones or to muscles; attaches
bones to bones; withstands great
tensile stress when pulling force
is applied in one direction.
Nuclei of
fibroblasts
Location: Tendons, most
ligaments, aponeuroses.
Shoulder
joint
Ligament
Tendon
© 2014 Pearson Education, Inc.
Photomicrograph: Dense regular connective
tissue from a tendon (425).
Elastic Connective Tissue
(g) Connective tissue proper: dense connective tissue, elastic
Description: Dense regular connective
tissue containing a high proportion of
elastic fibers.
Function: Allows recoil of tissue
following stretching; maintains
pulsatile flow of blood through
arteries; aids passive recoil of lungs
following inspiration.
Elastic
fibers
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within the
walls of the bronchial tubes.
Aorta
Photomicrograph: Elastic connective tissue in the wall of
the aorta (85).
Heart
© 2014 Pearson Education, Inc.
Figure 4.10g
Cartilage
• Firm, flexible tissue
• Contains no blood vessels or nerves
• Matrix contains up to 80% water
• Cell type—chondrocyte
• Hyaline cartilage
• Elastic cartilage
• Fibrocartilage
© 2014 Pearson Education, Inc.
Figure 4.10h 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.
Chondrocyte
in lacuna
Matrix
Function: Supports and
reinforces; serves as resilient
cushion; resists compressive
stress.
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
© 2014 Pearson Education, Inc.
Photomicrograph: Hyaline cartilage from a
costal cartilage of a rib (470).
Figure 4.10i Connective tissues.
Cartilage: elastic
Description: Similar to hyaline
cartilage, but more elastic
fibers in matrix.
Chondrocyte
in lacuna
Function: Maintains the shape
of a structure while allowing
great flexibility.
Matrix
Location: Supports the
external ear (pinna); epiglottis.
Photomicrograph: Elastic cartilage from the
human ear pinna; forms the flexible skeleton of
the ear (510).
© 2014 Pearson Education, Inc.
Figure 4.10j Connective tissues.
Cartilage: fibrocartilage
Description: Matrix similar
to but less firm than that in
hyaline cartilage; thick
collagen fibers predominate.
Function: Tensile strength
with the ability to absorb
compressive shock.
Collagen
fibers
Location: Intervertebral
discs; pubic symphysis;
discs of knee joint.
Chondrocytes
in lacunae
Intervertebral
discs
Photomicrograph: Fibrocartilage from an
intervertebral disc (175).
© 2014 Pearson Education, Inc.
Bone Tissue
(k) Others: bone (osseous tissue)
Description: Hard, calcified matrix
containing many collagen fibers;
osteocytes lie in lacunae. Very well
vascularized.
Function: Bone 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).
Location: Bones
Central
canal
Lacunae
Lamella
Photomicrograph: Cross-sectional view of bone (190).
© 2014 Pearson Education, Inc.
Figure 4.10k
Figure 4.10l Connective tissues.
Connective tissue: blood
Description: Red and
white blood cells in a fluid
matrix (plasma).
Red blood
cells
(erythrocytes)
White
blood cells:
• Lymphocyte
• Neutrophil
Function: Transport
respiratory gases, nutrients,
wastes, and other
substances.
Location: Contained within
blood vessels.
Plasma
Photomicrograph: Smear of human blood (1650);
shows two white blood cells surrounded by red
blood cells.
© 2014 Pearson Education, Inc.
Figure 4.11 The structure of a tissue provides clues to its location and function. (1 of 2)
© 2014 Pearson Education, Inc.
Figure 4.11 The structure of a tissue provides clues to its location and function. (2 of 2)
© 2014 Pearson Education, Inc.
Muscle Tissue
• Skeletal muscle tissue
• Cardiac muscle tissue
• Smooth muscle tissue
© 2014 Pearson Education, Inc.
Skeletal Muscle Tissue
• Description
• Long, cylindrical cells
• Multinucleate
• Obvious striations
• Function
• Voluntary movement
• Manipulation of environment
• Facial expression
• Location
• Skeletal muscles attached to bones
(occasionally
to skin)
© 2014 Pearson
Education, Inc.
Skeletal Muscle Tissue
(a) Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious striations.
Striations
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression.
Nuclei
Location: In skeletal muscles
attached to bones or occasionally
to skin.
Part of
muscle
fiber (cell)
Photomicrograph: Skeletal muscle (300).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
© 2014 Pearson Education, Inc.
Figure 4.12a
Cardiac Muscle Tissue
• Description
• Branching cells, striated
• Generally uninucleate
• Cells interdigitate at intercalated discs
• Function
• Contracts to propel blood into circulatory system
• Location
• Occurs in walls of heart
© 2014 Pearson Education, Inc.
Figure 4.13b Muscle tissues.
Cardiac muscle
Description: Branching,
striated, generally uninucleate
cells that interdigitate at
specialized junctions
(intercalated discs).
Striations
Intercalated
discs
Function: As it contracts,
it propels blood into the
circulation; involuntary
control.
Location: The walls of the
heart.
Nucleus
Photomicrograph: Cardiac muscle (355);
notice the striations, branching of cells, and
the intercalated discs.
© 2014 Pearson Education, Inc.
Smooth Muscle Tissue
• Description
• Spindle-shaped cells with central nuclei
• Arranged closely to form sheets
• No striations
• Function
• Propels substances along internal passageways
• Involuntary control
• Location
• Mostly walls of hollow organs
© 2014 Pearson Education, Inc.
Figure 4.13c Muscle tissues.
Smooth muscle
Description: Spindle-shaped cells
with central nuclei; no striations;
cells arranged closely to form
sheets.
Smooth
muscle
cell
Function: Propels substances or
objects (foodstuffs, urine, a baby)
along internal passageways;
involuntary control.
Nuclei
Location: Mostly in the walls of
hollow organs.
Photomicrograph: Sheet of smooth muscle from
the digestive tract (465).
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
Figure 4.14 Nervous tissue.
Nervous tissue
Description: Neurons are
branching cells; cell processes
that may be quite long extend from
the nucleus-containing cell body;
also contributing to nervous tissue
are nonconducting supporting
cells, neuroglia (not illustrated).
Neuron processes
Cell body
of a
neuron
Neuron
processes
Cell body
Dendrites
Axon
Function: Transmit electrical
signals from sensory receptors
and to effectors (muscles and
glands) that control the activity
of the effector organs.
Location: Brain, spinal
cord, and nerves.
© 2014 Pearson Education, Inc.
Nuclei of
neuroglia
Photomicrograph: Neurons (125).