What is the role of the phrenic nerve?

The phrenic nerve plays a crucial role in respiratory function by controlling the diaphragm, which is the primary muscle involved in breathing. When the phrenic nerve sends signals to the diaphragm, it causes the diaphragm to contract and flatten, increasing the volume of the thoracic cavity and allowing air to be drawn into the lungs. This process is essential for ventilation and is vital for adequate oxygen supply to the body.

The other choices refer to functions handled by different nerves or systems. For example, controlling the heart rate is primarily the role of the autonomic nervous system, while sensory information is transmitted through other sensory nerves. Blood pressure is regulated by various mechanisms involving the autonomic nervous system and specific reflex arcs, not by the phrenic nerve directly. Thus, the role of the phrenic nerve is specifically linked to the control of the diaphragm and the facilitation of breathing.