a simple explanation of connective tissue and its types and examples. by Dr. Asaad Abdulwahed

1. Connective tissue
What is connective tissue?
• Represent the most abundant by weight
and
• most widely distributed type of tissue in
the body

2. • Connective tissue:Connective tissue:
• Connective tissue bind and supports the otherConnective tissue bind and supports the other
functionally active tissue. Unlike the otherfunctionally active tissue. Unlike the other
tissue types ,that are formed mainly by cells,tissue types ,that are formed mainly by cells,
the constituents of connective tissue arethe constituents of connective tissue are
extracellular matrixextracellular matrix composed of (composed of (proteinprotein
fibersfibers anan amorphous ground substanceamorphous ground substance andand
tissue fluid)tissue fluid),embedded within the extracellular,embedded within the extracellular
matrix are thematrix are the connective tissue cellsconnective tissue cells..

3. • In terms of structural composition,connective tissue can be
subdivided into three classes of components;cells,fibers,and
ground substance:
• 1-Cells
• 1-fibroblasts and fibrocytes
• 2-macrophages
• 3-mast cells
• 4-plasma cells
• 5-adipose cells
• 6-pigment cells
• Extracellular Matrix
• 2-Protein fibers 3- ground substance
• ___________ _______________
• Collagen fibers
• Elastic fibers
• Reticular fibers
• The wide variety of connective tissue types in the body
represents variations in the composition and amount of these
three components.

4. • Cells of connective tissue
• __________________________________
• Fibroblast:-
• It is most commonly found in connective tissue
and it is responsible for the synthesis of fibers
and amorphous intercellular substances.
• There are two stages of activity:
• *The active form is fibroblast and the quiescent
cell is fibrocyte, the fibrocyte is smaller cell than
the fibroblast and it is spindle in shape ,and
has fewer processes than the fibroblast.

6. • Plasma cells: are few in number in connective
tissue. They are numerous in sites subject to
penetration by bacteria and foreign proteins (e.g.
intestinal mucosa) and in areas where there is
chronic inflammation.
• These cells are large, oviodal in shape contains
nucleus is spherical and eccentrically placed,
containing compact, coarse heterochromatin
alternating with lighter areas of approximately
equal size, and this resembles the face of a
clock with the heterochromatin clumps
corresponding to the numerals.
• These cells are responsible for the synthesis of
the antibodies.

8. • Mast cells: are oval to round connective
tissue cells, and wide spread in the human
body but are particularly abundant in the
dermis, digestive tract and respiratory tract.
Nucleus is small spherical and centrally
situated. Contains few small spherical
mitochondria, short cisternae of rough
endoplasmic reticulum and well-developed
Golgi complex.

9. Mast cell originate from stem
cells of bone marrow. The
principle Function of mast
cells is liberation of
pharmacologically active
substances (e.g. histamines).

10. •1-Heparin: is an anticoagulant
•2-Histamine: increase the permeability of the
vessel.
•These substances are released into the tissue
when the mast cells are rupture during
inflammation.

11. • Adipose cells
• Specialized for storage of neutral fats or for the
production of heat, also it is called (fat cell).
The fat cells found isolated or in most are found
in large aggregates ,they are oval, spherical.
Almost the whole cell is occupied by a fat
globule shifting the cytoplasm to the periphery,
have eccentric flattened nucleus, giving a
signet ring appearance. A grouping of adipose
cells form adipose tissue.

12. Adipose cell
nucleus
c
y
t
o
p
l
a
s
m

13. • Pigment cells
• Found in dermis of skin,iris.They are stellate
cell with long processes and numerous brown
to black melanin granules in the cytoplasm.

14. Collagen fibers Elastic fibers Reticular fibers
contain albuminous Protein-collagen contain a protein elastin contain an albuminous protein-
collagen. disposed as network
formation fibroblast Microfibrils appear first,synthesized by
fibroblast ,and later small clumps of
amorphous material are formed within
the groups of microfibrils
fibroblast
distribution Tendons, ligaments Blood vessels, vocal cords Along with collagen fibers also in
lymph node ,bone marrow, liver,
spleen
morphology Broad and straight or slightly wavy
fibers which do not branch
Fine thin -threads branch Very fine fibrils in a network
function Binding material Provide elasticity to blood vessels Provide yielding matrix for cells
and held them in place
*Connective tissue fibers

15. • Ground substance: It is amorphous
substance, occupying interval between cells
and fibers. It contains mucopolysaccharides,
glycoproteins, and water. It is protects and
binds the connective tissue elements and
provides medium for movements of cells and
diffusion of metabolities.

17. Derived from embryonic mesoderm or
mesenchyme

18. • Connective tissue proper:-
• ________________________________
• There are two classes of connective tissue
proper; loose and dense conn. Tissue.
• Loose conn. Tiss.:-It fills spaces between
fibers and muscle sheaths , supports epithelial
tissue ,and forms a layer that ensheathes the
lymphatic and blood vessels. This type of tissue
consists of scattered fibrous protein called
(collagen) and tissue fluid.

20. • Dense conn.tiss:- consists of the same components
found in loose con.tiss. But there is a clear
predominance of collagen fibers and fewer cells. It is
less flexible and far more resistant to stress than
loose conn. Tiss.
• Collagen that maybe in an irregular or a regular
arrangement.
• **It is known as dense irregular conn.tiss. when the
collagen fibers are arranged in bundles without a
definite orientation and form a sheaths a round the
organs.

22. **It is known as dense regular when the collagen
fibers are arranged according to a definite
pattern.
Example:
Tendons: which connect muscle to bone.
Ligaments: which conn. bones together at joints.

24. • Connective tissue with special properties:
• Adipose tissue:
• It is composed of groupings of adipose cells
within loose connective tissue. This tissue is
the large store of energy in the body (in the
form of triglycerides), the other organs that
store energy (in the form of glycogen) are the
liver and skeletal muscle.

26. • Elastic tissue: Composed of bundles of thick,
parallel elastic fibers. The space between these
fibers is occupied by thin collagen fibers, and
flattened fibroblasts, it is present in the yellow
ligaments of the vertebral column and in the
suspensory ligament of the penis.

28. • Mucous tissue: Has an abundance of
• amorphous ground substance composed
chiefly of hyaluronic acid. It is jelly like
tissue containing collagen fibers and a few
elastic or reticular fibers. The cells in this
tissue are mainly fibroblasts. It is found in
the umbilical cord and pulp of young teeth.

29. • Hematopoietic tissue
• Hematopoiesis
• Hamia=blood
• Poiesis=a making
• Hematopoiesis theories
• 1-Unitarian theory or monophyletic:-Erythrocytes
and all leukocyte cells arise from one stem cell
(hemocytoblast).
• 2-Dualistic theory or diphyletic: Lymphocyte and
monocyte derived from one stem cell (lymphoblast)
whereas the granulocyte and erythrocyte derived from
myeloblast.
• 3-Complete polyphyletic: Primitive stem cell for each
type of blood cells.

30. •Mature blood cells have short life span,
and must be replaced by the progeny of
stem cells produced in the hematopoietic
organs.
•In a healthy adult person, approximately
1011
–1012
new blood cells are produced
daily in order to maintain steady state
levels in the peripheral circulation.

31. • In the earliest stages of embryogenesis, blood
cells arise from the mesoderm sometime later,
the liver and spleen serve as temporary
hematopoietic tissues, but by the second month
the clavicle has begun to ossify and begins to
develop bone marrow in its core. After birth and
on into childhood, erythrocytes, granular
leukocytes ,monocytes, and platelets are
derived from stem cells localization in bone
marrow.

32. • The maturation of these cells are termed:
• Erythropoiesis--------- Erythrocytes
• Granulopoiesis-------- granular leukocytes
• Monocytopoiesis------- monocytes
• Megakaryocytopoiesis--- platelets

33. • All blood cells arise from a single types of stem cell in
the bone marrow (pluripotential stem cell).
• Pluripotential stem cells proliferate and form
lymphoid cells ,will become lymphocytes
• &
• another cells (myeloid cells) that develop in bone
marrow to form (granulocytes, monocytes,
erythrocytes,and megakaryocytes).
• Both these types of cells are called multipotential
cells.

34. *Lymphoid cells migrate from the bone marrow to
the lymph nodes ,spleen, and thymus, where
they differentiate into lymphocytes.
*Myeloid cells proliferate and form daughter
cells( progenitor cells) and these cells generate
precursor cells (blasts) ,producing large numbers
of differentiated mature cells.

35. Hematopoiesis

37. • Supporting conn.tissu.
• Cartilage:-Derived from mesenchymal tissue.
Consists of cells called chondrocytes and extracellular
matrix composed of (fibers and ground substances).
• Chondrocytes synthesize and secrete the extracellular
matrix. Chondrocytes surrounded by a semisolid
ground substance that imparts elastic properties to the
tissue.
• Collagen, hyaluronic acid , and small amounts of
several glycoproteins are the principal
macromolecules present in all types of cartilage
matrix.
• The variation in the composition of these matrix
components produce three types of cartilages (hyaline
,elastic, and fibro cartilage).

39. Hyaline cartilage: Most common form as
transparency mass white-bluish in color ,possesses a
matrix containing type II as the principal collagen type,
it is found at the surface of bones within movable
joints, ear ,nose, and trachea.

40. Elastic cartilage: Yellow in color, possesses in addition
to collagen type II abundance of elastic fibers within its
matrix, it is found in outer ear, larynx, eustachian
canal and epiglottis.

41. • Fibrocartilage: Possesses a dense network of
coarse type I collagen fibers it is found in
discs between the bony vertebrae of the
backbone.

42. Bone
• Composed of intercellular calcified material, the
bone matrix, and three different cell types:
• Osteocytes ,Osteoblasts ,& Osteoclasts

43. Osteocytes (osteon=bone): which are found in
cavities( lacuna) within the matrix, these cells derive
from osteoblasts, some molecular exchange between
osteocytes and blood vessels takes place through the
small amount of extracellular substance located between
osteocytes and the bone matrix.

44. •Osteoblasts: Which synthesize the organic
components of the matrix, have a cuboidal to
columnar shape. The cytoplasm is basophilic,
when they are actively in matrix synthesis.
When their synthesizing activity declines, they
flatten, and cytoplasmic basophilia declines

45. • Osteoclasts: These cells derived from the
fusion of blood-derived monocytes ,which are
multinucleated giant cells involved in the
• remodeling of bone tissue (or bone
metabolism) is a process where mature bone
tissue is removed from the skeleton(process
called bone resorption) and new bone tissue is
formed (a process called ossification or new
bone formation). These processes also control
the reshaping or replacement of bone following
injuries like fractures.
•

46. Osteoclasts secret collagenase enzymes ,these interact
with bone matrix and produce calcified ground
substance.
They are very large ,extensively branched motile cells
contain 5 to 50 or more nuclei, the branches of the cell
are quite irregular and vary in both thickness and shape.
The surface facing bone matrix contains cytoplasmic
extension.

47. • Bone matrix
• Inorganic matter represents about 50% of the
dry weight of bone matrix.
• Calcium and phosphorus are especially
abundant, but bicarbonate, citrate, magnesium,
potassium, and sodium are also found.

48. • Types of bone:
• Primary bone
• Primary or immature bone is the first bone
tissue to appear in embryonic development and
in fracture and other repair processes, it is
characterized by random disposition of fine
collagen fibers in contrast to the organized
lamellar disposition of collagen in secondary
bone. It is temporary and is replaced in adult
by secondary bone.

49. • Secondary bone
• Usually found in adults contains collagen fibers
arranged in lamellae 3-7 µm thick that are
parallel to each other or concentrically
organized around a vascular canal. The whole
complex of concentric lamella of bone
surrounding a canal containing blood vessels,
nerves,and loose connective tissue is called a
haversian system.

51. A section of bone shows dense areas without
cavities called compact bone, it is solid in nature
and contain numerous micro-spaces.

52. A section of bone shows areas with numerous
interconnecting cavities called spongy bone
(cancellous) ,consists of irregular slender plates
branched and form network.

53. • In long bones, the bulbous ends called epiphysis
are composed of spongy bone covered by a thin layer
of compact bone. The cylindrical part (diaphysis) is
almost totally composed of compact bone, with a
small component of spongy bone on its inner surface
around the bone marrow cavity.
•
epiphysis
epiphysis
diaphysis

54. The cavities of spongy bone and the marrow
cavity in the diaphysis of long bones contain
bone marrow of which there are two kinds; red
bone marrow, in which blood cells are forming,
and yellow bone marrow composed mainly of
fat cells.
Short bones usually have a core of spongy bone
completely surrounded by compact bone.

55. The flat bones that form the calvaria have two layers of
compact bone called plates separated by a layer of
spongy bone called the diploe
.

56. The hematopoietic tissue, red marrow, is
typically found within the cavities of spongy
bone of long bones and in the diploe of flat
bones
These cavities are referred to as red marrow
cavities
In infants the medullary cavity and all areas of
spongy bone contain red bone marrow

57. In the adult the medullary cavity contains fat that
extends into the epiphysis and there is little red
marrow present in spongy bone cavities
Blood cell production occurs only in the head of
the femur and humerous
Most blood cell production occurs in the diploe
areas of the sternum and hip
Yellow marrow can revert to red marrow if the
person becomes very anemic

58. Histamine is an organic
nitrogenous compound involved in
local immune responses, as well as
regulating physiological function in
the gut and acting as a
neurotransmitter for the brain,
spinal cord, and
uterus. Histamine is involved in the
inflammatory response and has a
central role as a mediator of itching

59. Once released from its granules, histamine produces
many varied effects within thebody, including the
contraction of smooth muscle tissues of the lungs,
uterus, and stomach; the dilation of blood
vessels, which increases permeability and
lowers blood pressure; the stimulation of gastric
acid secretion in the sto