C4 - Control of breathing

• Neutral control • Chemical control

• Breathing is under involuntary control • Controlled by respiratory centres of the brain • Controlled by neurons found in the brain stem • Key area of the brain controlling involuntary functions (respiration/ breathing) is the medulla oblongata

• A passive process, as the diaphragm simply relaxes allowing air to leave the lungs

• An active process, as the diaphragm actively contracts which causes air to be drawn into the lungs

• Cells that conduct nerve impulses

• Located in the middle of the brain, essential for involuntary functions like heart beat, breathing and sneezing

• Dorsal respiratory group (DRG) • Ventral respiratory group (VRG)

• The rhythm generation that allows rhythmic and continuous breathing

• Continually changing levels of oxygen and carbon dioxide in the blood which impacts on breathing control • These are chemicals that respond to fluctuation in the gas levels known as chemoreceptors • As a result of this they will send signals to the medulla that will then regulate and make changes to the breathing rate

• Found in the medulla, the aortic arch and the carotid arteries • Detect minute changes in blood carbon dioxide levels as well as changes in blood acidity (pH levels of lactic acid)