The layer of a blood vessel wall that contains the smooth muscle that is responsible for changing the diameter of the lumen of the vessel is called the ___________

The electrical event (action potential) that begins each heartbeat and sets the basic heart rate occurs at a region in the wall of the right atrium known as the ________________.

Lymph from the left side of the body flows through the ________ immediately before draining into the venous system at the junction of the left internal jugular vein and left subclavian vein.

Hemoglobin is a protein that is usually found dissolved in blood plasma, and it is responsible for binding and transporting oxygen in the blood.

The lymphatic vessels are an important part of the cardiovascular system.

In accordance with 14 CFR Part 107, you may operate an sUAS from a moving vehicle when no property is carried for compensation or hire: 

Capillaries in the liver and the spleen have large lumens and follow twisting paths through these organs. These capillaries also have large holes in their walls that allow large particles (such as blood cells) to exit the capillaries. What is the correct name for this type of capillary?

What type of tissue lines the oropharynx?

The hepatic portal system has two distinct capillary beds separated by the hepatic portal vein. What are the functions of these two capillary beds?

The semilunar valves are closed when: