HISTO LEC: Module 3 - PART IV (Additional info)

DO NOT EXPLOIT.

Reticular fibers

Consist mainly of collagen type III, which forms an extensive network (reticulum) of thin fibers for the support of many different cells.

Ehlers-Danlos type IV

Collagen disorder that results in a faulty transcription or translation of collagen type III.

Ehlers-Danlos type VI

Collagen disorder that results in a faulty lysine hydroxylation

Ehlers-Danlos type VII

Collagen disorder that results in decrease in procollagen peptidase activity.

Scurvy

Collagen disorder that results in lack of vitamin C, a required cofactor for prolyl hydroxylase.

Osteogenesis imperfecta

Collagen disorder that results in change of 1 nucleotide in genes for collagen type I.

Elastic fibers

Are also 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.

Elastic lamellae

Fenestrated sheets of elastin.

Fibrillin

Composite of elastic fibers.

Elastase

Pancreatic enzyme that hydrolyze elastin that resists digestion by most proteases.

Marfan syndrome

A disease characterized by a lack of resistance in tissues rich in elastic fibers.

Aneurysms

Aortic swellings that results from the high blood pressure in the aorta from the Marfan syndrome.

Ground substance

Highly hydrated, transparent, complex mixture of three major kinds of macromolecules such as glycosaminoglycans (GAGs), proteoglycans, and multi-adhesive glycoproteins.

Glycosaminoglycans (GAGs)

Long polymers of repeating disaccharide units, usually a hexosamine and uronic acid.

Hyaluronan

The largest and most ubiquitous GAG, a very long polymer of the disaccharide glucosamine-glucuronate.

Hyaluronan synthase

Enzyme complex that synthesizes hyaluronan directly into the ECM.

Proteoglycans

Consist of core protein to which are covalently attached various numbers and combinations of the sulfated GAGs

Perlecan

The key proteoglycan in all basal laminae.

Aggrecan

A very large, having a 250 kDa core protein heavily bound with chondroitin and keratan sulfate chains.

Multi-adhesive glycoproteins

Have multiple binding site for cell surface integrins and for other matrix macromolecules.

Fibronectin

Dimer synthesized largely by fibroblasts, with binding sites for collagens and certain GAGs, and form insoluble fibrillar networks throughout connective tissue.

Integrins

Integral membrane proteins that act as matrix receptors for specific sequences on laminin, fibronectin, some collagens, and certain other ECM proteins.

Edema

The excessive accumulation of interstitial fluid in connective tissue.

Loose connective tissue

It is much common, forming a layer beneath the epithelial lining of many organs and filling the spaces between fibers of muscle and nerve.

Dense irregular connective tissue

Bundles of collagen fibers appear randomly interwoven, with no definite orientation.

Dense regular connective tissue

Consists mostly of type I collagen bundles and fibroblasts aligned in parallel for great resistance to prolonged or repeated stresses from the same direction.

Aponeuroses

Sheetlike tendons.

Ligaments

Bands or sheets that hold together components of the skeletal system

Tendonitis

The overuse of tendon-muscle units, which are characterized by inflammation of the tendons and their attachments to muscle.

Reticular tissue

Characterized by abundant fibers of type III collagen forming a delicate network that supports various types of cells.

Reticular cells

Modified fibroblasts that produces reticulin that remain associated with and partially cover the fibers.

Mucoid tissue

It is the principal component of the fetal umbilical cord, where it is referred to as Wharton’s jelly.