Defensive Nerves (IMAGE) University of South Florida Caption A slice of the brainstem showing central projections of defensive nerves (red) into the medulla, where the nerves transmit signals to brainstem networks to control various involuntary functions like breathing, cough, swallowing, heart rate and blood pressure. Credit University of South Florida Usage Restrictions Please use image with appropriate caption. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.