Moroccan riad Moroccan riad A riad () is a type of traditional Moroccan house or palace with an interior garden or courtyard. The word riad originates from the Arabian term for garden, , ryad. The ancient Roman city of Volubilis provided a reference for the beginnings of riad architecture during the Idrisid Dynasty. When the Almoravids conquered Spain in the 11th century they sent Muslim, Christian and Jewish artisans from Spain to Morocco to work on monuments. The Riad is the Moroccan traditional house, normally with two or more stories around an Andalusian-style courtyard that contained a fountain. Riads were the stately
Atrium (heart) similar function. Some animals (amphibians and reptiles) have a three-chambered heart, in which the blood from each atrium is mixed in the single ventricle before being pumped to the aorta. In these animals, the left atrium still serves the purpose of collecting blood from the pulmonary veins. In some fish, the circulatory system is very simple: a two-chambered heart including one atrium and one ventricle. Among sharks, the heart consists of four chambers arranged serially (and therefore called a serial heart): blood flows into the most posterior chamber, the sinus venosus, and then to the atrium which moves it to