rod

(rod). A straight, slim piece of matter: specifically, one of the rod-like bodies of the retina. r. 835 ROLLER bipolars, bipolar nerve-cells of the inner muscular layer of the retina which are specially connected with the rod visual cells. The bipolar cells connected with the cone element are called cone bipolars. Corti’s r’s, rod-like bodies in a double row which form the arches of Corti. r. ellipsoid, the outer longitudinally striated portion of the inner rod section. Sometimes called lenticulal body. enamel-r’s, the parallel hexagonal risms forming the enamel of teeth. r. epithelum, epithelium the cells of which exhibit a peculiar rod-like striation. r.-fibers, the attenuated fiber-like bodies of the rod visual cells which unite the nuclei of the latter, within the outer nuclear layer of the retina, with the retinal rods. germinal r., a sporozoite. r.-granules. See under granule. r’s of Heidenhain, the rod-like cells of the renal tubules. Kinig's r’s, a series of steel bars each of which gives a note of certain pitch when struck. ‘Maddox r’s, a set of parallel cylindric gla rods used in testing for hetero pho ria. Reichmann’s ¥., a short ivory rod with circular grooves and intervening projections, like the handle of an ivory knitting needle. It is used in auscultatory percu ion of the stomach. The rod is firmly pushed down over the stomach at a right angle to its surface, and is gently stroked with the fingers. The stethoscope is applied over the organ and the itch observed. When the rod pa es beyond the limits of the stomach, a change in pitch occurs. re r’s, highly specialized cylindric neuroepithelial cells containing rhodopsin; with the visual cones they form one of the layers of the retina. r.-segments. See under segment. rodagen (ro’daj-en). A preparation of the milk of goats from which the thyroids have been removed: used in exophthalmic goiter.