Iron is normally stored in your pancreas. Each platelet a. lives for 6 months in the blood. Cardiac muscle cells contract a. only after excitation by a neuron. The primary pacemaker of the heart is called the a. sinoatrial node. Assume that CO remains constant in the following choices.
Arteries have a. lots of smooth muscle tissue.
Parasympathetic stimulation to the heart a. increases your heart rate. Atherosclerosis, or fat deposition inside artery walls, may a. decrease vessel diameter. Gas exchange between systemic tissues and the blood is called a. external respiration. Respiratory acidosis is often a consequence of diseases like emphysema. The normal respiratory response to exposure to smoke or air pollution includes increased a. cilia activity.