Platelets are produced from cells called ______.

The inhaled air enters each lung lobe through a ______.

Quiet expiration requires the ______.

___________ play an important role in regulating the airflow through the air passageways.

The respiratory centers are located in the ______.

The systemic circuit carries _________ blood from the _________ to all parts of the body except the lungs and returns _________ blood to the _________.

When _____________, blood pressure within the ventricles increases, which causes the AV valves to close and the semilunar valves to open.

________ are leukocytes that migrate into tissues and become macrophages.

Microorganisms inhaled into the air passageways are most likely to be destroyed by ______.

Disorders in which the lymphoid system attacks self antigens are called ______.