PRELIM: CONNECTIVE TISSUE Flashcards
Caused by deletions of a copy of 25-27 genes on chromosome 7 affecting the elastin gene among others
WILLIAMS-BEUREN SYNDROME (WBS)
-Most common in all connective tissue
-Synthesize and secretes collagen and elastin, large fibers, GAG’s, Proteoglycans and multiadhesive glycoproteins comprise the Ground substance
FIBROBLASTS
Involves in wound healing
FIBROBLASTS
Fibroblasts synthesize and secretes __________
collagen and elastin
Fibroblast target many families of proteins called
Growth factor
well-developed contractile function and are enriched with a form of actin also found in smooth muscle cells.
Myofibroblast
Found in the connective tissue of many organs.
Specialized for cytoplasmic storage of lipid as neutral fats, or less commonly for the production of heat.
Adipocytes
Tissue with a large population of adipocyte.
ADIPOSE CONNECTIVE TISSUE
have highly developed phagocytic ability and specialize in turnover of protein fibers and removal of apoptotic cells, tissue debris, or other particulate materials.
Macrophages
Present in connective tissue of most organs and Pathologist called it as
Histiocytes
formed in the yolk sac during early embryonic development circulate and become resident in developing organs.
MONOCYTE
group of related cells
MONONUCLEAR PHAGOCYTE SYSTEM
Blood
Monocyte
Connective tissue, lymphoid organs, lungs bone manow, pleural and peritoneal cavities
Macrophage
Liver (perisinusoidal)
Kupffer cell
Central nervous system
Microglial cell
Epidermes of skin
Langerhans cell
Lymph nodes, spleen
Dendritic cell
Bone
Osteoclast (from fusion of several macrophages)
In connective tisue under various pathological conditions
Multinuclear giant cell (several fused macrophages)
Oval irregular shaped cells of connective tissue between 7 and 20 um
Mast cell
Mast cell granules display _______. Can change colors of some basic dyes (e.g Toluidine blue) from blue to purple or red
METACHROMASIA
Localized release of many bioactive substances important in the local inflammatory response, innate immunity and tissue repair.
Mast cell
act as an anticoagulant
Heparin
promotes increased vascular permeability and smooth muscle contraction
HISTAMINE
activates various mediators of inflammation
SERINE PROTEASE
attracts leukocytes
EOSINOPHIL AND NEUTROPHIL CHEMOTACTIC FACTORS
directing activities of leukocytes and other immune cells
CYTOKINES
can be converted into lipid mediators of inflammatory response
PHOSPHOLIPID PRECURSORS
small blood vessels in the skin and mesenteries
PERIVASCULAR MAST CELLS
tissue that lines of digestive tract and respiratory tracts
MUCOSAL MAST CELLS
originates from the progenitor cells in the bone marrow.
Mast Cell
Lymphocyte-derived, antibody-producing cells
PLASMA CELLS
PLASMA CELLS
Average life span:_____
10-20 days
rare genetic disorder characterized by the absence/extremely low levels of immunoglobulins (antibodies)
Agammaglobulinemia
Derived from circulating blood cells
Leave body by migrating between the endothelial cells of venules to enter connective tissue
Increases greatly during inflammation.
Leukocytes
Key element of all connective tissues as well as epithelial basement membranes and the external laminae of muscle and nerve cell
Most abundant protein in human body
Major product of fibroblast
Collagen
have polypeptide subunits that aggregate to large fibrils clearly visible in light electron microscope
FIBRILLAR COLLAGEN (collagen type I, II, and III)
network sheet-forming, have subunits produced by epithelial cells and are major structural proteins of external laminae and all epithelial basal laminae
NETWORK-FORMING COLLAGENS - (collagen type IV)
are short collages that link fibrillar collagens to one another (forming larger fibers) and other
LINKING/ANCHORING COLLAGENS
Found in delicate connective tissue of many organs, notably in the immune system.
Consist mainly of collagen type III which forms an extensive network (reticulum) of thin (0.5-2 um) fibers for the support of many different cells.
Seldom visible in Hematoxylin and Eosin but are characteristically stained black after impregnation with silver salts thus termed argyrophilic
Reticular fibers
PERIODIC ACID-SCHIFF (PAS)
Positive
→high content of sugar chains bound to type III collagen of alpha chains.
PERIODIC ACID-SCHIFF (PAS)
Produced by fibroblast occurs in reticular lamina of basement membranes and typically surrounds adipocytes, smooth muscle and nerve fibers and small blood vessels.
Abundant reticular fibers also characterize in the stroma of HEMATOPOIETIC TISSUE (bone marrow), the spleen, and lymph nodes.
→ Support rapidly changing populations of proliferating cells and phagocytic cells
Reticular fibers
Thinner than the type I collagen fibers and form sparse networks interspersed with collagen bundles in many organs, particularly those subject to regular stretching or bending
Rubberlike properties such as the stroma of the lungs
In the wall of large blood vessels, e.g arteries.
Elastic fibers
fenestrated sheets
Elastic lamellae
are not strongly acidophilic and stained poorly with H&E
ELASTIC FIBERS AND LAMELLAE
Elastic fibers stained with______
ORCEIN AND ALDEHYDE FUCHSIN
Highly hydrated, transparent, complex mixtures of 3 major kinds of macromolecules: GLYCOSAMINOGLYCANS (GAGs), PROTEOGLYCANS, and MULTIADHESIVE GLYCOPROTEINS.
Ground substance
forms a viscous, pericellular network which binds a considerable amount of water, giving it an important role in allowing molecular diffusion through connective tissue and in lubricating various organs and joints.
Hyaluronan
Four major GAGs found in proteoglycans are
dermatan sulfate, chondroitin sulfates, keratan sulfate, and heparan sulfate
synthesized on RER, mature in the Golgi apparatus, where the GAG side-chains are added, and secreted from cells by exocytosis
GLYCOPROTEINS
one of the best studied proteoglycans. Abundant in cartilage
AGGRECAN
water in the ground substance of connective tissue, has an ion composition similar to blood plasma.
Intestinal fluid
is common, forming a layer beneath the epithelial lining of many organs and filling the spaces between fibers of muscle and nerve.
Loose connective tissue
Loose connective tissue is also called
AREOLAR TISSUE
Contains CELLS, FIBERS and GROUND SUBSTANCE.
Loose connective tissue
most numerous cells
Fibroblasts
predominates but elastic and reticular fibers also present.
collagen fibers