Which of the following respiratory volumes measures the amount of air that always remains in the lungs to prevent the lungs from collapsing?
(a) residual volume
(b) expiratory reserve volume
(c) inspiratory reserve volume
(d) tidal volume

Ms. b is a 40-year-old woman who is the ceo of a struggling company. lately she has been experiencing headaches that are so severe that she gets dizzy and nauseated, and she is unable to carry out her usual daily routines. she reports that they usually begin as a throbbing pain in the left temple and then seem to spread throughout her head. a diagnosis of migraine headache is made after several tests. based on the patient history and signs and symptoms, discuss this type of headache and its physiological causes. discuss the available treatments to prevent and/or relieve the patient’s migraine.