Smallest cardiac veins contribute to normal physiologic shunting of blood. As a consequence of the input of these vessels, blood in the left heart is less oxygenated than the blood found at the pulmonary capillary beds, albeit to a very small degree. The "openings of smallest cardiac veins" are located in the endocardium. Here the smallest cardiac veins return blood into the heart chambers from the capillary bed in the muscular cardiac wall, enabling a form of collateral circulation unique to the heart. Not every endocardial opening connects to the thebesian veins as some connect to the vessels of Wearn, which are arteries.
Endometrial arteries body and they enrich the endometrium of the uterus. The joining of endometrial arteries and veins of the endometrium is known as arteriovenous. Endometrial arteries are also involved in the menstrual cycle. When the egg implants onto the endometrium and is not fertilized the endometrial arteries become narrow and the endometrium begins to disintegrate. This is when the endometrium sheds and results in menstruation. Endometrial arteries Arcuate arteries located in the uterus branch out and supply blood to different layers of the uterus. These arteries meet the myometrial-endometrial junction and lead to straight and endometrial arteries. The endometrium receives blood