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a transitory dilation in the embryonic heart where the arterial trunk joins the ventral roots of the aortic arches.
In the embryo, the segment of the heart tube destined to be partitioned and to form the two ventricular outflow segments, to the aorta on the left and to the pulmonary trunk on the right.
See also: bulbus
pl. bulbi [L.] bulb.
the swollen, first part of the aorta, between the atria; swollen because of the sinuses above each of the three cusps of the aortic valves.
the outflow tract of the embryonic heart between the primitive ventricle and the aorta.
the bulb of the dog's penis; the proximal portion which enlarges greatly during erection and is the part responsible for preventing withdrawal during ejaculation.
see hair bulb.
a well-organized fibroadipose mass in a muscular envelope into which the retrices (tail feathers of birds) are embedded. It occupies a trough-shaped socket bounded by the caudal vertebrae and the intrinsic tail muscles.