 Dear students, in this topic we shall discuss the arterial chemoreceptors in detail. The arterial chemoreceptors are located in the carotid and aortic bodies. They are primarily important in regulating ventilation, i.e. breathing rate, but they are also important in cardiovascular system due to its close relationship with the respiratory system. The arterial chemoreceptors monitor chemical characteristics of the blood. They respond to an increase in the concentration of carbon dioxide or decrease in the oxygen level and pH level of the blood. They help to regulate the functions of both cardiovascular and respiratory systems. Now we shall discuss the effects of stimulation of arterial chemoreceptors. The stimulation of arterial chemoreceptors due to increased carbon dioxide concentration has direct effect on heart rate and breathing rate. Heart rate and breathing rate increase when arterial chemoreceptors sense that the level of carbon dioxide is high in the blood. As a result, carbon dioxide is eliminated rapidly from the blood. Arterial chemoreceptors slow down the heart rate when the animal is breathing. This effect causes peripheral vasoconstriction while the cardiac output is reduced. Peripheral vasoconstriction results in increased arterial blood pressure which maintains blood pressure in the arteries leading to the brain so that a blood flow to the brain is ensured.