Each cerebral hemisphere is divided into four lobes; the frontal, parietal, temporal, and the occipital. The Frontal Lobe is the most anterior lobe of the brain.Its posterior boundary is the fissure of Rolando, or central sulcus, which separates it from the parietal lobe.Inferiorly, it is divided from the temporal lobe by the fissure of Sylvius which is also called the lateral fissure.he Frontal Lobe is the most anterior lobe of the brain. Its posterior boundary is the fissure of Rolando, or central sulcus, which separates it from the parietal lobe. Inferiorly, it is divided from the temporal lobe by the fissure of Sylvius which is also called the lateral fissure.
Main article: Thoracic diaphragm. The diaphragm is the major muscle responsible for breathing. It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. During inhalation, the diaphragm contracts, so that its centre moves caudally (downward) and its edges move rostrally (upward).
Ventilation facilitates respiration. Respiration refers to the uptake of oxygen and the removal of carbon dioxide. Under most conditions, the partial pressure of carbon dioxide controls the rate of respiration. The most important function of breathing is gas exchange (of oxygen and carbon dioxide). Thus the control of respiration is centered primarily on how well this is achieved by the lungs. There are four main centers in the reticular formation and other parts of the brainstem that regulate the respiration rate.