Chemoreceptors
- receptors in the medulla oblongata detect changes in the pH levels of the blood.
- If not enough oxygen is being taken in, the CO2 level of the blood rise, and the blood becomes more acidic.
- This triggers an increase in nerve impulses that stimulate the intercostal muscles and the diaphragm, which in turn increases lung ventilation and brings the CO2 blood levels to normal.
Adrenaline
- a hormone made in the medulla oblongata of the adrenal gland in the brain. It increases heart rate and respiration rate.