Control and coordination in mammals — practice question

Describe the way olfactory receptor cells in the nasal cavity of dogs respond to chemicals in order to generate an action potential.

Dogs can use their sense of smell to distinguish the breath of people with lung cancer from the breath of people without lung cancer. These differences are caused by particular chemicals at very low concentrations in the breath of people with lung cancer. Dogs can be trained to sit when a person’s breath shows that lung cancer is present. Screening people for lung cancer is important for early detection and treatment. Suggest two advantages of using dogs in this way to screen people for lung cancer.