insemination penile erection http://purl.bioontology.org/ontology/MESH/D010410 http://purl.obolibrary.org/obo/GO_0043084 http://purl.obolibrary.org/obo/NCIT_C25740 E1.0.0.0.0.0.8 The hardening, enlarging and rising of the penis which often occurs in the sexually aroused male and enables sexual intercourse. Achieved by increased inflow of blood into the vessels of erectile tissue, and decreased outflow. The state of the penis when the erectile tissue becomes filled or swollen (tumid) with blood and causes the penis to become rigid and elevated. It is a complex process involving central nervous system; peripheral nervous systems; hormones; smooth muscles; and vascular functions. erection penile erection, NOS penile erections penile tumescence reproductive sequence erection penis penis