Editing Scurvy (section)

== Pathogenesis ==
[[File:ASM-30-325-g003.jpg|thumb|X-ray of the knee joint (arrow indicates scurvy line)]]
Vitamins are essential to the production and use of enzymes in ongoing processes throughout the human body.<ref name="Distillations"/> [[Ascorbic acid]] is needed for a variety of biosynthetic pathways, by accelerating [[hydroxylation]] and [[amidation]] reactions.

The early symptoms of [[malaise]] and [[lethargy]] may be due to either impaired [[fatty acid metabolism]] from a lack of carnitine and/or from a lack of catecholamines which are needed for the [[cAMP-dependent pathway]] in both glycogen metabolism and fatty acid metabolism.<ref name=":0" /> Impairment of either fatty acid metabolism or glycogen metabolism leads to decreased [[Adenosine triphosphate|ATP]] (energy) production. ATP is needed for cellular functions, including [[Muscle contraction#Cross-bridge cycle|muscle contraction]]. ''(For low ATP within the muscle cell, see also [[Purine nucleotide cycle]].)''

In the synthesis of [[collagen]], ascorbic acid is required as a cofactor for [[prolyl hydroxylase]] and [[lysyl hydroxylase]]. These two enzymes are responsible for the hydroxylation of the [[proline]] and [[lysine]] amino acids in collagen. [[Hydroxyproline]] and [[hydroxylysine]] are important for stabilizing collagen by cross-linking the propeptides in collagen.

Collagen is a primary structural protein in the human body, necessary for healthy blood vessels, muscle, skin, bone, cartilage, and other connective tissues. Defective connective tissue leads to fragile capillaries, resulting in abnormal bleeding, bruising, and internal hemorrhaging. Collagen is an important part of bone, so bone formation is also affected. Teeth loosen, bones break more easily, and once-healed breaks may recur.<ref name="Distillations"/> Defective collagen fibrillogenesis impairs wound healing. Untreated scurvy is invariably fatal.<ref name=Naked>{{cite web|url=http://www.thenakedscientists.com/HTML/articles/article/forgotten-knowledge/|title=Forgotten Knowledge: The Science of Scurvy|date=28 November 2010|access-date=29 April 2016|url-status=live|archive-url=https://web.archive.org/web/20160510164237/http://www.thenakedscientists.com/HTML/articles/article/forgotten-knowledge/|archive-date=10 May 2016}}</ref>