Download كاربرد طبي Mast Cell “Masten” (Ger)

‫بسم هللا الرحمن الرحيم‬
Histology
Lecture 5: Connective Tissue
Connective Tissue Functions
 Mechanical support
 Material that connects and binds cells into
tissues
 Binds tissues to each other
 Serving as a medium for exchange
 Aiding in the defense and protection
 Internal support for organs/tissues
 Forming a site for storage of energy and
water
Extracellular Matrix
A complex of nonliving macromolecules in
extracellular space
It has two components: Ground Substance & Fibers
Ground
Ground Substance
Substance: An amorphous gel-like material
composed of Glycosaminoglycans, Proteoglycans and
Glycoproteins
Fibers
Fibers include of different types of Collagen fiber and
Elastic fiber
Connective Tissue Cells
Fixed cells:
* Mesenchymal cells
* Fibroblasts
* Macrophages
* Mast cells
* Adipose cells
* Pericytes
Transient cells:
* WBC of Blood
* Plasma cells
* Macrophages
Mesenchymal cells
* Small fusiform or stellate cells
* Not easily distinguished from fibroblasts
* Have coarser chromatin pattern
* Fewer mitochondria and little or no ER
• Pluripotential
• Regenerative medicine
Fibroblast and Fibrocyte
 * Most
common cells of connective
tissue
* Produce and secrete fibers and
ground substance
* Active fibroblast (wound healing)
* Inactive fibroblast (Fibrocyte)
Myofibroblast
 Modified fibroblasts
 Have bundle of actin and dense
bodies similar to smooth muscle cells
 Nucleus is also similar to the
nucleus of smooth muscle
 Have not external lamina (Basal
lamina)
Macrophage
 Character:
(Irregular membrane surface;
nucleus may be oval and is eccentric)
 Phagocytosis (Debris, microorganism
 APC
 Two categories: Resident and Elicited
 Resident M. reside normally in CT
 Elicited M. develop as a result of an
exogenous stimulus and migrate to
particular site of CT
 Epitheloid cells
Macrophage
Macrophage
Mononuclear phagocytic system
‫كاربرد طبي‬
Mast Cell
• “Masten” (Ger) = to feed/fatten
• Cytoplasm full of granules containing
heparin, histamine, proteases,
chemotactic factors
• Originate from bone marrow stem cell
• Delayed hypersensitivity (allergy)
• Mucosal mast cells are located in
alimentary tact mucosa contain
chondroitin sulfate
Mast cell,
Degranulation
‫كاربرد طبي‬
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, pale
centrosome, clockface nucleus
• Differentiate from B - lymphocytes
• Life span 10-20 days
‫كاربرد طبي‬
White Blood Cells
Attracted to areas of inflammation
Neutrophils phagocytose bacteria
Eosinophils
Basophils
Lymphocytes
– T- lymphocytes: cell-mediated immune
response
– B - lymphocytes: differentiate into
plasma cells producing antibody
Inflamation, intestine
Connective Tissue Fibers
Connective Tissue Fibers are
consists of:
 Collagen fibers
 Elastic fibers
 Reticular fibers
Collagen
 Most abundant protein, 30% dry weight
 More than 19 types
 Type I most abundant, triple helix
 Types I,II and III form fibers
 Types IV and V are amorphous
 Types VII attaches basal lamina to the
lamina reticularis
 Eosin - pink; Mallory’s - blue;
Masson’s - green
‫سازماندهي كالژن‬
‫انواع كالژن‬
‫كاربرد طبي ‪:‬جهش‬
‫(استئوژنسيس امپرفكتا)‪،‬‬
‫اسكلروسيس فيبروسيس‪،‬‬
‫كلوئيد‬
‫بيوسنتز كالژن‬
Reticular Fibers (Collagen type III)
 Bundles
are 0.5-2 mm diameter
 Stained by silver and periodic acidSchiff (PAS)
 45 nm fibrils made of collagen
 Abundant in smooth muscle, nerves,
spleen, lymph nodes, bone marrow
 Form network around cells of liver,
kidney, and endocrine organs
‫‪Mesenter‬‬
‫ميكروسكوپ‬
‫پالريزان‬
‫‪Reticular fiber‬‬
‫كاربرد طبي ‪:‬سندرم اهلرز دانلوس‬
Elastic Fibers
 Stretch and return to
original length
 Form branched fibers in
areolar spread
 Large elastic arteries
 Not stained by H & E; use
resorcin-fuchsin, aldehyde
fuchsin or orcein
Elastic Fibers
‫كاربرد طبي ‪:‬سندرم مارفان‬
Tissue fluid
 Plasma from capillaries and
venules enter the connective tissue
spaces as extracellular fluid, which
percolates through the ground
substance.
 Extracellular fluid reenters the
venules as well as lymphatic
capillaries
Extracellular Matrix
A complex of nonliving macromolecules
in extracellular space

Ground Substance
 1- Glycosaminoglycans,
 2- Proteoglycans
 3- Glycoproteins
Fibers
Glycosaminoglycans
 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, and Heparin
 Hyaluronic acid is nonsulfated and is a huge
macromolecule and may be 20 micrometer in
length
Different Types of GAGs
Proteoglycans
 Decorin, Aggrecan, Syndecans
 They have large volume like a bottle
brush
 They resist compression, retard movement
of microorganisms
 In association with basal lamina form a
molecular filters
 Posses binding sites for certain signaling
molecules
Glycoproteins
Tenacin composed of 6 chains
Entactin bind to laminin and
type IV collagen
Chondronectin and Osteonectin
are similar to fibronectin
Fibronectin
Tongue
Laminin
Integrins (Transmembrane Linkers)
 Integrins are transmembrane proteins but unlike
other cell surface receptors, they are linked to
cytoskeleton and structural member of
extracellular matrix such as collagen
 Integrins are much more numerous than usual
receptors
 they bind to extracellular component by weak
bonds
Oedema
Connective Tissue Classification
1) Embryonic Connective Tissue
Mesenchymal connective tissue
Mucous connective tissue
2) Connective Tissue Proper
Loose connective tissue (Areolar CT)
Dense connective tissue
 Dense irregular connective tissue
 Dense regular connective tissue
 1- Collagenous
 2- Elastic
Reticular connective tissue
Adipose connective tissue
Loose connective tissue (Areolar CT)
Loose connective tissue (Areolar CT)
Dense irregular connective tissue
Dense irregular connective tissue
Dense regular connective tissue
Reticular connective tissue
Mucous connective tissue
Histology