Jaume was born in Barcelona in 1905, son of surgeon Antoni Raventós i Avinyò from the Hospital de la Santa Creu i Sant Pau and nephew of the historian, architect and collaborator of Enric Prat de la Riba in the Institute for Catalan Studies (IEC), Josep Pijoan i Soteras. He did his studies of Medicine at the University of Barcelona, where was internal student of Physiology with Dr. August Pi and Sunyer. It obtained the degree in 1930 and was internal doctor, later internal teacher and assistant teacher of Human Physiology of the Department of Physiology. It defended his doctoral thesis in neurotransmitters in 1934.