1. به نام خالق متعال
connective tissue
Dr. Zahiri

2. What's the main role of connective tissue?
Mechanical support
Material that connects and binds cells into tissues
Binds tissues to each other
Protection and Defense
Serving as a medium for exchange
Storage (water, ions, minerals, Growth factor)
Energy supply

3. What's the contents of connective tissue?
cells
ECM
Fibers
Ground substance
Fluid

4. Cells of connective tissue
The cells
Cells of connective tissue
Mesenchyme
Adult
Fixed Cells
Fibroblast
Macrophage
Adipose cells
Mast cells Undifferentiated mesenchyme cell
Wandering Cells
Lymphocytes
Plasma cells
Blood cells

5. Mesenchymal cells Small fusiform or stellate cells
Not easily distinguished from fibroblasts
Have delicate chromatin pattern
Pluripotential

6. Fibroblast are most common cells of C.T. Produce and secrete ECM
Active fibroblast has more cytoplasm include of developed RER, Golgi apparatus and euchromatic nucleus = activated (wound healing)
Inactive fibroblast (Fibrocyte) has flattened nuclei, sparse cytoplasm
Fibroblasts may differentiate to adipose cells or chondrocytes

8. wound healing Myofibroblast : are modified fibroblasts
They have bundle of actin similar to smooth muscle cells
Abundant in wound healing ( wound contraction)
Activated Fibrocyte = fibroblast

9. Macrophage (MPS) Origin: BM monocyte ( in blood) Macrophage in C.T.
Irregular membrane surface; nucleus may be oval and is eccentric
Size: micro
Phagocytosis of cell debris and micro organisms
Presenting antigens to lymphocytes
RBC turnover in spleen
Secretion of cytokins, enzyme
In chronic inflammation form Epitheloid cells or multinuclear giant cells

11. Mast cell
Cytoplasm full of granules containing heparin, histamine, proteases, chemotactic factors, chondroitin sulphate
Size: micro
Centeric nucleus
Originate from bone marrow stem cell

12. - Immediate hypersensitivity reaction - Slow reaction

14. Plasma cell
Common in intestinal lamina propria and glands secreting immunoglubulins such as lacrimal glands, salivary glands, and mammary gland
Oval cell with basophilic cytoplasm, clock face nucleus
Differentiate from B - lymphocytes
Life span days

16. Adipocyte

17. Others Neutrophils Eosinophils Basophils
Lymphocytes - small, heterochromatic nucleus

18. Fibers
Collagen fibers
Elastic fibers
Reticular fibers

19. Collagen fibers
Staining (Eosin - pink; Mallory’s - blue; Masson’s – green)
Physical feature

20. Chemical components
prolin
lysin
Hdroxy prolin
Hydroxy lysin

21. Biosynthesis

23. Disorders: Osteogenesis imperfecta (gene or amino acid)
Progressive systemic Sclerosis (fibrose- keloid)
Vitamin C is a co-factor for prolin hydroxylase

24. Reticular Fibers (Collagen type III)
Staining (Argylophilic- PAS)
Physical feature
Formative cell
Disorders ( ehlers-Danlos IV)

27. (a) 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.
Elastic
fibers
Function: Wraps and cushions
organs; its macrophages phagocytize
bacteria; plays important role in
inflammation; holds and conveys
tissue fluid.
Collagen
fibers
Location: Widely distributed under
epithelia of body, e.g., forms lamina
propria of mucous membranes; surrounds
capillaries.
Fibroblast
nuclei
Epithelium
Photomicrograph: Areolar connective tissue, a
soft packaging tissue of the body (300x).
Lamina
propria

28. (b) 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
fat cell
Location: Under skin in the
hypodermis; around kidneys and
eyeballs; within abdomen; in breasts.
Adipose
tissue
Vacuole
containing
fat droplet
Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (350x).
Mammary
glands

29. (c) 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.
White blood
cell
(lymphocyte)
Location: Lymphoid organs (lymph
nodes, bone marrow, and spleen).
Reticular
fibers
Spleen
Photomicrograph: Dark-staining network of reticular
connective tissue fibers forming the internal skeleton
of the spleen (350x).

30. (d) 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.
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Photomicrograph: Dense regular connective
tissue from a tendon (500x).
Tendon

31. (e) Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily
irregularly arranged collagen
fibers; some elastic fibers;
major cell type is the fibroblast.
Nuclei of
fibroblasts
Function: Able to withstand
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
Fibrous
joint
capsule
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).

32. (f) 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 (250x).
Heart

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34. Classification of connective tissue
Emberyonic (mesenchyme)
Adult ( Loose- Dense)
Dense( Regular- Irregular)

35. Elastic Fibers Staining (orsein) Chemical components:
oxytalan: GP: fibromodolin 1,2- fibrilin
Oxytalan+ elastin= elaunin
Elaunin + elastin in core= elastic
aa of elastin: Desmosin - isodesmosin
Disorders: marfan syndrom

36. Ground Substance An amorphous gel-like material
it is not visible on slides, because it is removed during the preparation process
composed of Glycosaminoglycans (GAG), Proteoglycans and multi adhesive Glycoproteins
function

37. Glycosaminoglycans (GAGs) or mucopolysaccharides
GAGs are negatively charged, long, rod-like chains of repeating disaccharides (Amino sugar + uronic acid) that have the capability of binding large quantities of water(hydrophilic)
GAGs consist of Hyaluronic acid, Dermatan sulfate, Chondroitin sulfate, Keratan sulfate, Heparan sulfate

38. Proteoglycan complex
Constitute a family of macromolecules each is composed of a protein core to which GAGs are covalently bonded
(heparin( mast cell), Agrecan(ECM), Syndecans and fibroglycan(cell surface)
They have large volume like a bottle brush
Function:
-Cell Binding to ECM .

39. Glycoproteins
They have binding site for several components of extracellular matrix as well as for:
integrin molecules of the cell membrane that facilitate the attachment of cells to the extracellular matrix
(Fibronectin, Laminin, Chondronectin, Osteonectin, Entactin, Tenascin)
Fibronectin is a v-shaped macromolecule that has binding site for
extracellular components
integrins of cell membrane,

40. Laminin is very large has three polypeptide chains, it is located in basal lamina and has binding site for:
heparan sulfate, type IV collagen, entactin and cell membrane

41. Fluid
Edeme phenomen

42. Specific connective tissue
Adipose tissue
Bone and cartilage
Blood

43. Adipose tissue (Fatty tissue)
A kind of connective tissue with many adipocytes
Forms one of the largest “organs” of body
15-20% of body weight in men
20-25% of body weight in women
Over 2 times as much stored energy as glycogen
Subcutaneous adipose shapes body
Shock absorber in soles of feet and palms
Thermal insulation
Fills space between organs

44. Two Types of Adipose Tissue
Yellow, White or unilocular
cells with one large fat droplet in cytoplasm
Brown or multilocular
cells with numerous smaller lipid droplets in cytoplasm and many mitochondria

45. Unilocular Adipose Tissue
White to dark yellow depending on diet
Most common form in adults
Cells mm diameter
Nuclei eccentric and flattened
Lipid droplet has no membrane
Heavily vascularized
Cell number constant after early postnatal period

47. Multilocular Adipose Tissue
multiple droplets
vascularization and many mitochondria,
Central nucleus
Has a lobular organization like glands
Production of body heat by many mitochondria
In human neonate, produces heat

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