The Connective Tissues
PREPARED BY HUGH POTTER, Ph.D
BIOLOGY DEPARTMENT
UNION COUNTY COLLEGE
All images derived from the video disk Slice of Life with the
permission of the publisher.
Connective Tissue - Introduction
The connective tissues bind, protect and support the body.
All connective tissues have three characteristics in common:
1. Cells such as fibrocytes, chondrocytes and osteocytes.
2. Three principal types of fiber found in connective tissues.
A. Collagen - abundant in tendons and bones.
B. Elastic fiber - found in the walls of arteries and in
flexible cartilage like the epiglottis.
C. Reticular fiber is the support material of soft organs
like the spleen and liver.
3. Ground substance, a complex mixture of organic and
inorganic materials, fills the spaces between the cells and
fibers.
Mesenchyme
Mesenchyme is the first connective
tissue to appear in the embryo. All
other connective tissues arise from
mesenchyme by a process known as
differentiation. The image to the right
shows a very early fetal stage. The
asterisk labels a region filled with
mesenchyme.
*
Mesenchyme cells appear to have fine
projections and are separated from one another by a
ground substance that contains delicate protein
fibers. Many adult connective tissues such as bone
and cartilage contain remnants of mesenchyme
which permit repair and growth of the adult tissues.
Connective Tissues -Types
Liquid Connective Tissue – The Blood
LOOSE CONNECTIVE TISSUES
1. ADIPOSE
2. AREOLAR
DENSE CONNECTIVE TISSUES
1. DENSE FIBROUS TISSUE - TENDON
2. SUPPORT CONNECTIVE TISSUES
A. CARTILAGE
B. BONE
Blood
Blood is considered to be a
fluid connective tissue. It
consists of formed elements or
cells and a liquid ground
substance called plasma. The
cells are primarily erythrocytes
(RBC’s) and leukocytes
(WBC’s). Fibers are only found
in the blood during the process
of clotting.
ADIPOSE TISSUE
• Adipose tissue is a loose
connective tissue. It is
located throughout the
body. It is especially
common in the
subcutaneous region
beneath the dermis where
it provides insulation
against heat loss. Fatty
tissue also stores
nutrients and vitamins
The adipocytes, the cells of
adipose tissue account for most
of the volume of fatty tissue.
Adipose cells are very active
metabolically. When we fast, the
cells deflate like spent balloons
as the oil stored in the center of
the cell is broken down for
energy. The adipocytes remain
intact and can refill with lipid
with an increase in nutrient
uptake.
Sub dermal Adipose Tissue
AREOLAR CONNECTIVE TISSUE
• Areolar connective
tissue is the most
abundant connective
tissue is the body. It is
commonly found in the
papillary region of the
dermis of skin and in
the lamina propria of
mucous membranes.
Areolar conntective tissue
contains a very fluid ground
substance. It also has a high
concentration of elastic fibers
which allow this tissue to return
to its original shape following
pressue or pinching.
Areolar tissue contains
almost all of the cell types
found in any connective tissue.
Mesenchymal cells, fibroblasts,
macrophage, adipocytes,
melanocytes and leukocytes are
found in areolar tissue.
• Tendon is a dense fibrous
tissue in which the fibers
are oriented in parallel.
The fibers are
predominantly collagen
and organized as primary
tendon bundles grouped
together as fascicles.
Blood vessels and nerves
do not enter the fascicle.
Tendons are designed to
withstand great tension
TENDON
Perichondrium
Cartilage
Cartilage is set apart from its
surrounding tissues by a dense
covering layer called the
perichondrium. The perichondrium
is divided into two layers, the fibrous
portion and the inner cellular layer.
New cartilage cells called
chondrocytes arise from the cellular
layer. These young cells produce the
gel-like ground substance of cartilage
which is rich in a polysaccharide
derivative called chondroitin sulfate.
Chondrocytes occupy
small chambers in the matrix of
cartilage called lacunae.
Cartilage is avascular.
This lack of blood vessels is due
to the production of a
compound by the chondrocytes
called anti-angiogenic factor
(AAF). This substance inhibits
the growth of blood vessels into
cartilage. AAF is being tested as
an anti-cancer drug.
lacunae
• Hyaline Cartilage
contains fiber in its outer
layer, the perichondrium.
Chondroblasts arise from
the perichondrium. As
the cartilage ages, the
cells appear in clusters of
2, 4 or 8. The matrix
consists primarily of
chondroitin sulfate.
Hyaline cartilage can be
found at the articular
ends of long bones, as
well as the trachea,
bronchi and larynx.
HYALINE
CARTILAGE
FIBROCARTILAGE
• The matrix of fibrocartilage
shows a preponderance of
coarse collagenous fibers
arranged in bundles.
Cartilage cells are arranged
between collagenous
bundles often in rows. This
cartilage lacks a
perichondrium.
It is found in the intervertebral disks, pubic symphysis
and the lining of tendon grooves. Fibrocartilage is
always found merging with neighboring hyaline cartilage
or fibrous tissue.
•
Elastic cartilage is very
similar to hyaline cartilage
except that it contains
abundant elastic fiber in
the matrix. Unstained, it
has a yellow color due to
the elastic fiber. It is
located in the auricle or
external ear and the
eustacian tube. In the
larynx, elastic cartilage
forms the epiglottis, the
corniculate, cuneiform and
the arytenoid cartilages.
ELASTIC
CARTILAGE
COMPACT BONE
• Compact bone is a dense
connective tissue. The
Haversian systems can be
seen in this view.
Osteocytes are arranged
in concentric rings around
the central Haversian
canal. Fine, thread-like
canaliculi can be seen.
Compact bone is found
around the shafts or
diaphyses of long bones
COMPACT BONE-Haversian canals
• Compact bone consists of
bone matrix laid down in
concentric layers called
lamellae. The lamellae
surround a central
Haversian canal(Hc)
which contains blood
vessels, nerves and
lymphatics. Very delicate
thread-like lines can be
seen connecting the black
osteocytes (oc)with the
Haversian canal.
Haversian Canals
oc
oc
oc
oc
In this view of a
Haversian system, the
fine thread-like
canaliculi can be seen
connecting the
osteocytes (oc) with the
Haversian canal (Hc)
Hc
oc