Princeton's WordNet(1.50 / 2 votes)Rate this definition: 1  cocoa, chocolate, hot chocolate, drinking chocolate(noun) a beverage made from cocoa powder and milk and sugar; usually drunk hot. 2  cocoa(noun) powder of ground roasted cacao beans with most of the fat removed.
Nerve and Muscles of the Respiratory System. When a spinal cord injury occurs, the lungs and the alveoli remain the same. However, just as the injury affects the nerves that control the muscles of the arms and legs, it also affects the nerves that activate the muscles used for breathing.
These 10 facts about space will blow your mind. The respiratory center consists of areas of the brain that are responsible for automatic control of breathing. Nerve cells in part of the lower brain stem, known as the medulla oblongata, initiate and set the rhythm of respiration. Another area of the brain stem, called the pons, contains nerve cells that affect the breathing rate. Nerve impulses travel from these areas to the respiratory muscles, causing inspiration and expiration.