[Syndromes 11. Treacher collins syndrome]

Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by a...

The Notch signaling pathway is a major intracellular signaling pathway that is highly conserved over a broad spectrum of metazoan species. It stands unique from other intracellular signaling mechanisms in animals because notch protein itself acts as the receptor as well as the primary signaling molecule.
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...

Fibril-associated collagens are a type of collagens present in the extracellular matrix with interrupted triple helices or FACIT (Fibril-associated collagens interrupted triple-helices). FACIT help connect and attach the collagen fibrils with each other as well as with other proteins of the extracellular matrix.
For example, the type II collagen fibrils in cartilage have covalently bound type IX fibril-associated collagens at regular intervals. Other types of fibril-associated collagens are...

Type IV collagen is a 400 nm long, network-forming collagen that acts as a barrier between the epithelial and endothelial cells. Type IV collagen  forms the backbone of the basement membrane by scaffolding with laminin, entactin, proteoglycans, and fibronectin. Apart from rendering structural support to the basement membrane, it also helps entail signaling potentials necessary for both pathological and physiological functions.
A type IV collagen molecule has six alpha chains which can exist in...

The trachea, commonly known as the windpipe, is a vital part of the human respiratory system. It serves as a passageway for air to travel between the larynx and the bronchi, allowing oxygen to reach the lungs. Let's explore its anatomical features, dimensions, layers of the tracheal wall, associated muscles, and the functions of its parts.
Anatomical Features:
Location: About half of the trachea is situated in the neck, anterior to the esophagus, and extends from the larynx (at the level of the...

Complications during healing arise when tissue repair is altered by local or systemic factors. These changes involve abnormal collagen deposition, altered biomechanics, and reduced vascular supply, impairing restoration of normal structure and function.Loss of FunctionScar tissue differs significantly from the original tissue it replaces. In the skin, fibrosis lacks adnexal structures such as hair follicles, sebaceous glands, and sweat glands. Their absence reduces tactile sensitivity, impairs...