Duplicate
Export
Register
Connective Tissue Overview
1 Flashcard Deck
Connective Tissue Overview
Study
What are the fibers of connective tissue?
1. Collagen 2. Procollagen 3. Collagen Fibrils 4. Crossbanding 5. Collagen Bundles 6. Matrix Metalloproteinases (MMPs) 7. Reticular Fiber 8. Elastic Fibers
What are the 3 main types of fibers in connective tissue?
1. Collagen Fibers 2. Reticular Fibers 3. Elastic Fibers, which are mainly formed by Elastin.
What is collagen?
Collagen constitutes a family of proteins selected during evolution for their ability to form various extracellular fibers, sheets, and networks, all of which are extremely strong and resistant to normal shearing and tearing forces.
What is the role of collagen in connective tissues?
Collagen is a key element of all connective tissues as well as epithelial basement membranes and the external laminae of muscle and nerve cells.
What cell type primarily produces collagen?
Collagen is a major product of fibroblasts, but it is also secreted by several other cell types.
How many types of collagen exist in vertebrates?
A family of 28 collagens exists in vertebrates, numbered in the order they were identified.
What are fibrillar collagens?
Fibrillar collagens have polypeptide subunits that aggregate to form large fibrils.
Which type of collagen is the most abundant?
Collagen type I is the most abundant and widely distributed, forming collagen fibers.
What are collagen fibers?
Collagen fibers are large, eosinophilic bundles that densely fill the connective tissue, forming structures such as tendons, organ capsules, and dermis.
What are network or sheet-forming collagens?
These collagens have subunits produced by epithelial cells and are major structural proteins of external laminae and all epithelial basal laminae.
What are linking and anchoring collagens?
Linking and anchoring collagens are short collagens that link fibrillar collagens to one another, forming a larger fiber.
What is the role of type VII collagen?
Type VII collagen binds type IV collagen and anchors the basal lamina to the underlying reticular lamina in basement membranes.
Where does collagen synthesis occur?
Collagen synthesis occurs in many cell types but is a specialty of fibroblasts.
What are procollagen chains?
Procollagen chains are polypeptides made in the Rough Endoplasmic Reticulum (RER) with different chains of variable lengths and sequences synthesized from collagen genes.
How are procollagen chains aligned in the ER?
In the ER, three chains are selected, aligned, and stabilized by disulfide bonds at their carboxyl terminals, and folded into a triple helix.
What happens to the procollagen molecule after exocytosis?
The procollagen molecule undergoes cleavage to become a rod-like collagen molecule, which is the basic subunit from which fibers or sheets are assembled.
What is the difference between homotrimeric and heterotrimeric procollagen?
Homotrimeric has all three chains identical, while heterotrimeric has two or all three chains having different sequences.
What is required for collagen synthesis?
An unusually large number of posttranslational processing steps are required to prepare collagen for its final assembly in the ECM.
What role do hydroxylase enzymes play in collagen synthesis?
Hydroxylase enzymes in the ER add hydroxyl groups to amino acids, requiring oxygen, ferrous sulfate, and ascorbic acid.
What are procollagen peptidases?
Procollagen peptidases are specific proteases outside a fibroblast that remove terminal globular peptides, converting procollagen molecules to collagen molecules.
What is the function of lysyl oxidase?
Lysyl oxidase catalyzes the process that allows collagen to withstand forces and remain secured outside of the cell.
What is collagen cross-linking?
A process where the fibrillar structure is reinforced, and disassembly is prevented by the formation of covalent cross-links between collagen molecules.
What happens to collagen fibrils after exocytosis?
The nonhelical ends of procollagen subunits are removed, forming trimeric collagen molecules that aggregate and become covalently bound in large collagen fibrils.
What is crossbanding in collagen?
The highly regular assembly of collagens in the fibrils produces a characteristic pattern of crossbanding visible ultra structurally along some collagen types.
What is the stability of collagen in different organs?
In some organs, such as tendons and ligaments, collagen is very stable, whereas in others, like the periodontal ligament surrounding teeth, the collagen turnover rate is high.
What are collagenases?
Collagenases are enzymes that initiate collagen degradation and are members of the matrix metalloproteinases (MMPs).
What is a keloid?
A keloid is a local swelling caused by abnormally large amounts of collagen that form in scars of the skin.
Who is most at risk for keloids?
Keloids occur most often in individuals of African descent and can be a troublesome clinical problem to manage.
What is the difference between hypertrophic scars and keloids?
Hypertrophic scars remain confined to the original wound boundary, while keloids extend beyond the original wound area, growing into surrounding healthy skin.
What are reticular fibers?
Reticular fibers consist mainly of type III collagen and are found in delicate connective tissue of many organs, notably in the immune system.
How do reticular fibers stain in histological preparations?
Reticular fibers are seldom visible in hematoxylin and eosin (HE) preparations but are characteristically stained black after impregnation with silver salts.
What is the main property of elastic fibers?
Elastic fibers exist in a stretchable conformation that provides elastic properties to connective tissues.
What are elastic lamellae?
Elastic lamellae are fenestrated sheets of elastin in the wall of large blood vessels, especially arteries.
What proteins make up elastic fibers?
Elastin and microfibrils are the main proteins of elastic fibers.
What is Marfan syndrome?
Marfan syndrome is characterized by mutations in the fibrillin genes and is a disease characterized by a lack of resistance in tissues rich in elastic fibers.
What is ground substance?
Ground substance is a complex of anionic, hydrophilic proteoglycans, glycosaminoglycans (GAGs), and multi-adhesive glycoproteins.
How do laminin and fibronectin function in the basal lamina?
In the basal lamina, glycoproteins like laminin and fibronectin help stabilize the ECM by binding to other matrix components and integrins in cell membranes.
What role does ground substance play in cells?
Ground substance allows the exchange of nutrients and metabolic wastes between cells and the blood supply.
What is the composition of ground substance in connective tissue?
Ground substance is rich in hydrated glycosaminoglycans (GAGs), proteoglycans, and multi-adhesive glycoproteins.
What are sulfated GAGs?
Sulfated GAGs, such as chondroitin sulfate and keratan sulfate, are composed of various sizes and disaccharide polymers.
Where are linker proteins found?
Linker proteins are where proteoglycans attach to polymers of hyaluronic acid (HA) in ground substance.
What types of connective tissues exist?
1. Connective Tissue Proper 2. Loose Connective Tissues 3. Dense Irregular Connective Tissues 4. Dense Regular Connective Tissues 5. Reticular Tissue 6. Mucoid Tissue.
What is loose connective tissue?
Loose connective tissue or areolar tissue has relatively more ground substance than collagen and typically surrounds small blood vessels and occupies areas adjacent to other types of epithelia.
What is dense irregular connective tissue?
Dense irregular connective tissue is filled primarily with randomly distributed bundles of type I collagen, providing resistance to tearing from all directions as well as some elasticity.
What is dense regular connective tissue?
Dense regular connective tissue, prominent in tendons and ligaments, features bundles of essentially parallel type I collagen, providing great strength but little stretch.
What does reticular tissue consist of?
Reticular tissue consists of delicate networks of type III collagen and is most abundant in certain lymphoid organs.
What is mucoid tissue?
Mucoid tissue is a gel-like connective tissue with few cells found most abundantly around blood vessels in the umbilical cord.
Scholarly Assistant's Insights
Explore the structure and types of connective tissues, their functions, and collagen details.
Biology
Anatomy
Physiology
Medical Science
Connective Tissue
+5 more
Ask Scholarly Assistant
Similar Pages
Login to Leave a Comment
Give your feedback, or leave a comment on a page to share your thoughts with the community.
Login