What occurs when air is forced into the stomach instead of the lungs during rescue breathing?

Which of the following is the thickest layer of the heart, which is made up of muscle?

A. Endocardium B. Pericardial cavity C. Pericardium D. Epicardium E. Myocardium

Chemoreceptors send messages to the brain to increase respirations when:

A. arterial blood pressure falls. B. arterial oxygen levels increase. C. arterial carbon dioxide levels increase.