| the system by which oxygen is taken into the body; in mammals the system includes the nasal passages, pharynx, trachea, bronchi, and lungs |
| ductless glands above the kidneys, consisting of a cortex producing steroidal hormones, and a medulla producing epinephrine and norepinephrine |
constrictor con·stric·tor (kən-strĭk'tər)
n.
One that constricts, especially a muscle that contracts or compresses a part or organ of the body.