Crystal. When most people talk about bringing out the crystal, they are often referring to a type of glass that is made from silica, lead oxide, soda or potash, and other additives. Lead crystal is prized for its durability and decorative properties, even if it does not necessarily possess a crystalline structure.
What part of the brain controls breathing and heartbeat? The brain stem controls breathing and heart rate as well as blood pressure and alertness. Found at the top of the spinal column, the brain stem consists of three main parts, including the medulla oblongata, pons and midbrain. The medulla oblongata controls cardiac and respiratory rates.
Â­Â­ Â­ You don'Â­t have to think about breathing because your body's autonomic nervous system controls it, as it does many other functions in your body. If you try to hold your breath, your body will override your action and force you to let out that breath and start breathing again. The respiratory centers that control your rate of breathing are in the brainstem or medulla. The nerve cells that live within these centers automatically send signals to the diaphragm and intercostal muscles to contract and relax at regular intervals. However, the activity of the respiratory centers can be influenced by these factors: