Codex @codex  0

The +2 oxidation state of iron; the aqueous cation is commonly represented by $\mathrm{F}{\mathrm{e}}^{2+}$.

The +3 oxidation state of iron; the aqueous cation is commonly represented by $\mathrm{F}{\mathrm{e}}^{3+}$.

A family of iron hydroxide materials. Their precipitation can obscure colour tests unless the analytical sequence controls the pH.

A chemical compound containing iron; the oxidation state and associated ligands distinguish medicinal preparations.

The sulfide represented by $\mathrm{FeS}$, used historically to generate hydrogen sulfide with dilute nonoxidizing chemical acids.

The ferrous hydroxide material represented by $\mathrm{Fe}(\mathrm{OH}{)}_2$, which oxidizes on exposure to air.

The hydrated ferric precipitate conventionally represented as $\mathrm{Fe}(\mathrm{OH}{)}_3$ in qualitative analysis; real precipitates need not consist of one uniquely defined pure hydroxide phase.

Iron wire is iron-containing material drawn into a slender form with a large length-to-cross-section ratio. Its behavior depends on purity, alloy composition, surface oxide, and mechanical history.

The geometry gives a high exposed area relative to bulk pieces and determines electrical resistance and heat transfer. An experiment using iron wire therefore needs both material identity and dimensions; the word iron alone does not specify the whole experimental object.

The sphincter pupillae muscle is the circular smooth muscle of the iris that constricts the pupil. Its activation produces miosis. It differs from the radial dilator both in fiber arrangement and in its autonomic control pathway.

The opening in the iris through which light enters the eye. Its aperture affects admitted pencils of rays; the cornea and crystalline lens provide focusing power.

The iris dilator muscle has a roughly radial arrangement that enlarges the pupil when activated. Its action opposes that of the sphincter pupillae muscle. Autonomic control links the size of the optical opening to physiological state.

Bowel is a common anatomical term for the intestine. Context should specify small or large bowel when their different functions matter. The broad word does not identify one single segment or uniform mucosal structure.

The colon is the main elongated portion of the large intestine between the cecal region and rectum. Its segments support water and electrolyte handling, microbial processing and movement of contents. Anatomical position and transit behavior vary along its length.

Intestinal obstruction is impairment of onward passage through the intestine. Mechanical blockage and failure of coordinated propulsion are different routes to impaired transit. Distension and upstream accumulation describe consequences, not a unique cause.

A Peyer's patch is an organized lymphoid aggregation in the intestinal wall, particularly prominent in the ileum. It supports sampling and immune responses associated with gut contents. Its local position distinguishes it from a draining mesenteric lymph node.

The lamina propria is the connective-tissue layer beneath the epithelium of a mucosa. It contains supporting cells, vessels and immune components. Its position links epithelial exchange with the deeper tissue environment while remaining distinct from the lumen.

The muscularis mucosae is a thin smooth-muscle layer associated with the gastrointestinal mucosa. It supports local movements of the mucosal region. It is distinct from the larger outer muscle layers generating much of whole-segment mixing and propulsion.

The rectum is the terminal large-intestinal region before the anal canal. Its storage and sensory properties contribute to controlled defecation. Distension, muscular activity and outlet coordination are different components of the resulting behavior.

The intestinal lumen is the internal space through which gut contents pass. It is separated from underlying tissues and circulation by the intestinal epithelium. Material within the lumen has therefore entered the digestive tract without necessarily being absorbed into the body.

IP multicast sends an Internet Protocol datagram to a group identified by a multicast IP address. Delivery retains the underlying best-effort nature of Internet Protocol.