Also, RF is a power muscle made up predominantly of type II fast-twitch fibers, while AT muscle composition is mainly made of type I slow-twitch fibers [35].
The cells are embedded in a three-dimensional network of extracellular matrix (ECM) consisting predominantly of type I collagen, other collagens (such type III and V), proteoglycans, elastin and fibronectin (Andres and Murrell 2008; Sayegh et al. 2015).
To understand cervical ripening and especially the pathophysiology of cervical insufficiency, it is important to know the cervical composition: the cervix is dominated by fibrous connective tissue, consisting predominantly of Type I collagen (70%).
This ECM is then partially mineralized, resorbed and replaced by a matrix comprised predominantly of type I collagen (Col1).
The ECM consists predominantly of type I collagen throughout, type II collagen in the inner meniscus, and proteoglycans, of which aggrecan is predominant [ 6- 8].
It consists of the peripheral annulus fibrosus (AF), a ligamentous lamellar structure composed predominantly of type I collagen fibres, and the central nucleus pulposus (NP), a highly hydrated structure, composed of the proteoglycan aggrecan, interspersed with type II collagen fibres.
Although type II collagen may be produced by this reparative tissue, it consists predominantly of type I collagen, resulting in the formation of fibrocartilage which does not have the biomechanical properties of articular cartilage [ 9].
The cells of the outer one-third are fibroblast-like, with extensive cellular processes that may stain positively for CD34 and are within a dense connective tissue, which is composed predominantly of type I collagen fibre bundles aligned in the circumferential direction of the tissue, along with smaller amounts of proteoglycans and minor collagens including types III and V [ 16, 18- 21].
The m. gastrocnemius (whole) used in this study has a high type IIB content whereas both m. rectus femoris and m. gluteus maximus are predominantly composed of types IIA and IID.
Broilers worldwide are predominantly of two types, from either one of two major international breeder companies, labelled here A and B. Birds from both genotypes are sometimes reared together within one flock.
