rectal muscles (NEMATA) Specialized muscles that function to open and close the anal opening.
rectal pad (ARTHRO: Insecta) Columnar epithelium (usually 6) extending longitudinally along the rectum, important in the reabsorption of water, salts and amino acids from the urine.
rectal papillae (ARTHRO: Insecta) In some Diptera, a papilli-form modification of the rectal pads projecting into the rectum enclosing intercellular sinuses separated from the gut lumen by cell junctions and connected indirectly with the hemocoel.
rectal pouch 1. (ARTHRO: Insecta) a. In some Coleoptera, an enlarged anterior part of the rectum opening into the hind-
gut; function unknown. b. In Isoptera, an enlargement of the colonic region of the hind gut that acts as a repository for symbiotic protozoa. 2. (BRYO) That part of the digestive tract between the pylorus and anus.
rectal tracheal gills (ARTHRO: Insecta) In some nymphs of Odonata, lamellate structures in the rectum supplied with tracheae and tracheoles.
rectal valve (ARTHRO: Insecta) A circular or lobate fold of the hind intestine separating the distal intestine and rectum.
rectate a. [L. rectus, straight] Straight.
rectification n. [L. rectus, straight; facare, to make] A property of some cell membranes that allow impulses to pass more easily in one direction that in the opposite direction, resulting in polarized transmission of nervous impulses.
rectigrade a. [L. rectus, straight; gradus, step] 1. Walking in a straight line. 2. (ARTHRO: Insecta) Pertaining to larvae with 16 legs that progress with a straight body, as opposed to geometrid.
rectilinear a. [L. rectus, straight; linea, line] Straight; formed in or bound by straight lines.
rectimarginate a. [L. rectus, straight; margo, edge] (BRACHIO) Having a straight anterior commissure.
rectum n. [L. rectus, straight] The posterior ectodermal portion of the enteron ending at the anus, in some groups this includes the entire proctodeum. rectal a. see proctodeum, hind-gut.
recumbent a. [L. recumbere, to lie down] Reclining.
recumbent spines (BRACHIO) Curved spines laying at an angle of less than 45° to the surface of the shell.
recurrent n. [L. recurrere, run again] Returning; reappearing at intervals; recurrent species.
recurrent collateral A collateral axon that turns back to end near the cell body or a similar one.
recurrent nerve (ARTHRO: Insecta) A nerve extending posteriorly from the frontal ganglion along the mid-dorsal line of the esophagus, passing under the brain and then expanding into a hypocerebral ganglion.
recurrent vein (ARTHRO: Insecta) 1. In Hymenoptera, one of two transverse veins immediately posterior to the cubital vein. 2. In Neuroptera, A vein at the base of the wing between costa and subcosta, extending obliquely from the subcosta to the costa.
recurved a. [L. re, back; curvus, bent] 1. Bent upward or backward; curved or bent back or down. 2. (ARTHRO: Cheli-cerata) In Arachnida, lateral eyes farther back than the median eyes. see procured.
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