General Anatomy (connective Tissue) Flashcards
What are the characteristics features of CT?
- large amount of extracellular matrix
- cells are widely separated
- connect the cells or the tissues or the organs together
- provides support to the organ and body
What are the components of CT?
Extracellular matrix
- fibers
- ground substances
Glycosaminoglycans
Proteoglycan
Glycoprotein
Cells:permanent and wandering cells
What are the examples of permanent cells?
- fibroblasts
- Adipocyte
- macrophages
- mast cells
What are the examples of wandering cells?
- lymphocytes
- plasma cells
- neutrophils
- eosinophils
- Basophils
- monocytes
Where are fibroblasts and adipocytes found?
Fibroblasts and adipocytes are found in the mesenchymal cell and remain fixed in that tissue for rest of its life
Where are macrophages and mast cells found?
Are found in the haemopoitic stem cells in bone marrow, circulate in the blood and move to the connective tissue
Where are the wandering cells found?
- originate from hemopoietic stem cell in bone marrow
- circulate in the blood
- they migrate from blood into connective tissue in response to specific stimuli
- later come back to the circulation
What are the characteristics features of the fibroblast?
- abundant cytoplasm (basophilic) and irregularly branched
- nucleus is ovoid, large, pale stained
- prominent nucleolus
What is the functions of the fibroblast?
- synthesize the fibers and ground substance
- fibroblasts also produce growth factors
What are the characteristic features of macrophages?
- very irregular surface
- oval or kidney shaped nucleus
- from bone marrow——monocyte——circulate in blood——enter in tissue as macrophage
What is the function of the macrophages?
- defense - phagocytosis of foreign substances, bacteria, dead cellular debris
- immunological - process the antigen from phagocytes materials and present that antigen to lymphocytes
What are the characteristic features of plasma cells?
- large ovoid cells
- juxtanuclear pale area - golgi complex and centrioles
- nucleus - eccentric, clock face appearance due to heterochromatin clumps
- derived from B-lymphocytes
What is the function of the plasma cells?
- immunological - synthesize antibodies in response to antigen presented by macrophages
What are the characteristic features of mast cells?
- abundant basophilic secretory granules containing chemical mediator for allergic reactions
What is the function of mast cells?
- defense - synthesis and secretion of chemical mediators in response to allergic reactions
Where are adipose cells found?
- originate from local mesenchymal cells
- storage of lipids, large depot of energy and heat
What are the two types of adipocytes?
- unilocular fat cell (white adipose tissue), signet ring appearance
- multilocular fat cell (brown adipose tissue), common in newborns (abundant mitochondria)
What are the CT matrix components?
Fibres (protein fibers)
- collagen fibers
- reticular fibers
- elastic fibers
Ground substances
- glycosaminoglycan (GAGs) - carbohydrates (repeating disaccharides units)
- proteoglycan - protein + carbohydrates
- glycoproteins - carbohydrates + proteins
How are fibers made?
Fibroblast synthesizes protein molecules——protein polymerize to form fibrils——bundles of fibrils——fibers
What are the three types of connective tissue fibers?
- collagen fibers - polymerization of collagen 1 and collagen 2 proteins
- reticular fibers - polymerization of collagen 3 proteins
- elastic fibers - composed mainly of elastin protein
Importance - the predominant fiber is responsible for the specific functional properties of that connective tissue
What is the synthesis of fibers?
- alpha chain (polypeptide)
- collagen molecule as triple helix
- collagen molecule
- packing of collagen molecules (polymerization)
- fibril (shows bandings)
What are the characteristics of collagen fiber?
• Collagen is the most abundant protein in human body.
• Collagen fibres are the bundles of collagen fibrils.
• Collagen-I protein fibres are widely distributed & is the strongest one, present in bones, tendons, capsules of organs, dermis.
• Collagen-II protein fibres are present in cartilage.
• Collagen fibres are not branching like reticular or elastic fibres.
• White in appearance (macroscopic)
• Acidophilic stain
• In dense CT, collagen bundles appear as
wavy structure
What are the characteristics of reticular fibers?
• These are collagen-III fibrils.
• Common in haemopoitic & lymphatic tissue.
• Fibrils are thin, branching & extensive network.
• Typically, collagen-III do not bundle to form thick fibres.
• Argyrophilic: Stains black with silver salt stain.
• In H&E stain it is not visualized.
➢ Reticular cells partially cover the fibres & ground substances.
➢ The resulting cell-lined trabecular system creates a sponge-
like structure within which other cells & fluid are freely mobile.
What are the characteristics of elastic fibers?
• Elastic fibres predominate in dermis, elastic cartilage, lung, large artery.
• Major component is elastin protein. (produced by fibroblasts, endothelium, smooth muscle, and airway epithelial cells)
• Macroscopically yellowish in color.
• Thinner than collagen fibres & arranged in branching
pattern.
• Elastic fibres allow the tissues to respond to stretch &
distension.
• Elastic fibres are poorly stained with eosin in H&E stain & appear somewhat refractive.
• Special dye, orcein or resorcin-fuchsin stain elastic fibres
selectively.