Microvascularization of the pineal gland in the freshwater turtle, Pseudemys scripta elegans (Reptilia): A scanning electron microscopic study of vascular corrosion casts

Abstract

Gross supply, microvascular patterns, and drainage routes of the pineal gland and its vascular relations with associated structures (dorsal sac, paraphysis, choroid plexus of the third ventricle) were studied by scanning electron microscopy of microvascular corrosion casts in 10 specimens of the freshwater turtle, Pseudemys scripta elegans. Light microscopy of tissue sections (one transverse and one longitudinal series) served to attribute cast vascular territories to anatomical structures. The tubular pineal gland body is supplied bilaterally by small branches of the saccular artery, a branch of the lateral choroidal artery. Branches of the diencephalic artery supply the pineal stalk. The pineal gland microvascular bed is a two-dimensional network that embraces the tubular gland. The network is made up mainly of venules with few true capillaries. Venules draining the ventral surface of the pineal gland body join those coming from the choroid plexus of the third ventricle and drain into the sagittal sinus. The less dense vascular network embracing the dorsal surface of the pineal body drains directly into the sagittal sinus. The pineal stalk drains into the diencephalic vein or directly into the sagittal sinus. No efferent (venous) vascular connections capable as transport route for pineal secretions toward surrounding telencephalic, diencephalic, or mesencephalic areas were found.

Arterial supply of the pineal gland of Akkaraman sheep

“…In animal species arterial blood is supplied to the pineal gland mainly by the lateral choroid artery (Kleiter and Lametschwandther, 1995), the middle cerebral artery (Chunhabundit and Somona, 1991) and the caudal cerebral artery (Hodde and Veltman, 1979;Teo et al, 1993;Nasu et al, 1994;Vinos et al, 1995). In all sheep used in this study, the pineal gland was found to be supplied by vessels from the caudal cerebral artery that made anastomosis with the caudal choroid rami.…”

“…The gland has a blood vessel network which is formed by capillary anastomosis (Murakami et al, 1998). While the posteriomedial and posteriolateral arteries are known to supply blood to the gland in humans (Walter and Hendelman, 1994;Crossman and Neary, 1995;Duvernoy et al, 2000), the lateral choroid artery, middle cerebral artery, medial posterior choroidal artery and caudal cerebral arteries have been reported to carry blood to the gland in animal species (Hebel and Stromberg, 1976;Hodde and Veltman, 1979;Chunhabundit and Somana, 1991;Teo et al, 1993;Nasu et al, 1994;Kleiter and Lametschwandther, 1995;Vinos et al, 1995;Murakami et al, 1998). The pineal gland in the rat is vascularised through a network composed of several capillary arteries which arise from the caudal cerebral artery (Hodde and Veltman, 1979;Murakami et al, 1998).…”