Veterinary Physiology-III

VASCULAR SUPPLY TO PITUITARY GLAND

• In general the inferior or posterior hypophyseal arteries supply the neural lobe.
• The superior or anterior hypophyseal arter­ies from the internal carotid supply the anterior lobe of the pitui­tary.
• The vessels go to the median eminence of hypothalamus and break into primary plexus in the infundibulum near the lower portion of the hypothala­mus. Venous blood from these plexus is collected in two series of parallel veins which pass through the pituitary stalk ending in pars distalis. This constitutes the hypothalamo‑ hypophyseal portal sys­tem.
• Regulating factors from the hypothalamus enter into these portal system and goes to adeno-hypophysis
• The hormones of the adenohypophysis diffuse into veins and reach the target cells.