General Anatomy (connective Tissue) Flashcards

1
Q

What are the characteristics features of CT?

A
  • 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
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2
Q

What are the components of CT?

A

Extracellular matrix
- fibers
- ground substances
Glycosaminoglycans
Proteoglycan
Glycoprotein

Cells:permanent and wandering cells

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3
Q

What are the examples of permanent cells?

A
  • fibroblasts
  • Adipocyte
  • macrophages
  • mast cells
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4
Q

What are the examples of wandering cells?

A
  • lymphocytes
  • plasma cells
  • neutrophils
  • eosinophils
  • Basophils
  • monocytes
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5
Q

Where are fibroblasts and adipocytes found?

A

Fibroblasts and adipocytes are found in the mesenchymal cell and remain fixed in that tissue for rest of its life

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6
Q

Where are macrophages and mast cells found?

A

Are found in the haemopoitic stem cells in bone marrow, circulate in the blood and move to the connective tissue

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7
Q

Where are the wandering cells found?

A
  • 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
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8
Q

What are the characteristics features of the fibroblast?

A
  • abundant cytoplasm (basophilic) and irregularly branched
  • nucleus is ovoid, large, pale stained
  • prominent nucleolus
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9
Q

What is the functions of the fibroblast?

A
  • synthesize the fibers and ground substance
  • fibroblasts also produce growth factors
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10
Q

What are the characteristic features of macrophages?

A
  • very irregular surface
  • oval or kidney shaped nucleus
  • from bone marrow——monocyte——circulate in blood——enter in tissue as macrophage
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11
Q

What is the function of the macrophages?

A
  • defense - phagocytosis of foreign substances, bacteria, dead cellular debris
  • immunological - process the antigen from phagocytes materials and present that antigen to lymphocytes
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12
Q

What are the characteristic features of plasma cells?

A
  • large ovoid cells
  • juxtanuclear pale area - golgi complex and centrioles
  • nucleus - eccentric, clock face appearance due to heterochromatin clumps
  • derived from B-lymphocytes
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13
Q

What is the function of the plasma cells?

A
  • immunological - synthesize antibodies in response to antigen presented by macrophages
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14
Q

What are the characteristic features of mast cells?

A
  • abundant basophilic secretory granules containing chemical mediator for allergic reactions
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15
Q

What is the function of mast cells?

A
  • defense - synthesis and secretion of chemical mediators in response to allergic reactions
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16
Q

Where are adipose cells found?

A
  • originate from local mesenchymal cells
  • storage of lipids, large depot of energy and heat
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17
Q

What are the two types of adipocytes?

A
  • unilocular fat cell (white adipose tissue), signet ring appearance
  • multilocular fat cell (brown adipose tissue), common in newborns (abundant mitochondria)
18
Q

What are the CT matrix components?

A

Fibres (protein fibers)
- collagen fibers
- reticular fibers
- elastic fibers

Ground substances
- glycosaminoglycan (GAGs) - carbohydrates (repeating disaccharides units)
- proteoglycan - protein + carbohydrates
- glycoproteins - carbohydrates + proteins

19
Q

How are fibers made?

A

Fibroblast synthesizes protein molecules——protein polymerize to form fibrils——bundles of fibrils——fibers

20
Q

What are the three types of connective tissue fibers?

A
  • 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

21
Q

What is the synthesis of fibers?

A
  • alpha chain (polypeptide)
  • collagen molecule as triple helix
  • collagen molecule
  • packing of collagen molecules (polymerization)
  • fibril (shows bandings)
22
Q

What are the characteristics of collagen fiber?

A

• 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

23
Q

What are the characteristics of reticular fibers?

A

• 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.

24
Q

What are the characteristics of elastic fibers?

A

• 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.

25
How can elastin molecule stretch and recoil?
Elastin protein molecules are in extensive cross-linked network
26
What are ground substances?
• Fills the space between the cells & the fibres. • Colourless & transparent • It is highly hydrated, can imbibe a large volume of water. • It is viscous (jelly-like) & acts as both a lubricant & a barrier to the penetration of invaders like foreign bodies, bacteria.
27
What are the three major components of ground substances?
• Glycosaminoglycans (GAGs): e.g., Chondroitin sulfate, Keratan sulfate, Heparan sulfate, Dermatan sulfate, Hyaluronic acid • Proteoglycans: e.g., Aggrecan, Syndecan • Glycoproteins: e.g., Fibronectin, Laminin
28
What are GAGs?
• Glycosaminoglycans (GAGs) are polysaccharides & are formed by linear chains of disaccharide units. (unbranched polysaccharide chain made of repeating disaccharides) • Because of abundance of hydroxyl, carboxyl & sulfate groups in the chain, these are intensely hydrophilic. • Except for hyaluronic acid, these linear chains are bound to a protein core forming the proteoglycans. • Hyaluronic acid (Hyaluronan) is a slippery substance. They make linear aggregations of proteoglycan monomers & increases the viscosity. Bacteria that produce hyaluronidase enzyme have great invasive power.
29
What are proteoglycans?
(80-90% GAGs+10-20% Protein) • GAGs are bound to a protein core forming proteoglycans (Test tube brush pattern).
30
What are glycoproteins?
• These are polypeptide chain, attached with it are the branched chains of monosaccharides. • They have the multiple adhesive sites, that play the important role in the interaction between cells, adhesion of cells to their substrate.
31
What are the functions of connective tissues?
• Connects & binds cells, tissues, organs (tendon, intercellular matrix). • Structural support of organ, & body (capsule & stromal tissue, skeleton). • Defense & protection (phagocytosis, antibody) • Medium for exchange of nutrition & metabolites (matrix is the medium through which nutrition & metabolic wastes are exchanged with blood vessels). • Energy reservoir & heat production (adipose tissue) • Control the growth & differentiation: Fibroblast synthesize protein, it also produces growth factors to influence the cell growth & differentiation.
32
What are the three basic components that are needed for classification?
cells, fibers, ground substances) are constant in all types of CT. CT are classified depending on – which component is predominating. – Its functional aspect.
33
What is the CT proper?
– Loose CT (also called as areolar tissue) – Dense CT: (2 types) Regular & irregular dense CT
34
What is the specialized CT?
– Cartilage – Bone – Adipose tissue – Blood – Hemopoietic tissue – Lymphatic tissue
35
What is the embryonic CT?
– Mesenchyme – Mucous CT
36
What is loose connective tissue?
• More ground substance • Cells are mostly fibroblasts & macrophages • Supports the lining epithelium that are normally under pressure & friction (submucosal & subcutaneous CT). -Forms a layer that sheathes the blood vessels.
37
What is dense connective tissue?
• Predominance of collagen fibers & very few cells. • Less flexible & more resistant to stress
38
What are the two types of dense CT?
• Two types of dense CT Dense regular: collagen bundles are arranged in regular pattern. – They offer great resistance to stresses in longitudinal direction. – Example: tendon, ligament. Dense irregular: bundles of fibers are irregularly arranged. – Offer great resistance to stresses in all direction. – Example: dermis.
39
What is the adipose connective tissue?
• Special type in which adipose (fat) cells predominate. • Unilocular or white adipose tissue, signet ring appearance of the cells • Multilocular or brown adipose tissue, more in newborn • Storage & mobilization of lipid: large depot of energy. • Brown adipose tissue produces more heat.
40
What is embryonic connective tissue: mesenchyme?
• Found in the embryo • Abundance of thick ground substance • Reticular (collagen) fibers: Very fine & sparse. • Mesenchymal cells: Small, spindle- shaped, uniform cells with multiple processes
41
What is embryonic connective tissue: mucous connective tissue?
• Present in umbilical cord as Wharton’s jelly • Gelatin-like ground substance • Reticular (collagen) fibers: Very fine • Spindle-shaped cells are widely separated & appear like fibroblasts