Which structure contains deoxygenated blood?
Left atrium
Pulmonary veins
Aorta
Left ventricle
Pulmonary arteries
Which of the following is true of arteries?
The walls of arteries and veins are about the same thickness in a given tissue
Their thick walls are due entirely to the bulk of elastic fibers in the middle layer
Their walls are thick and muscular compared with veins
Vein walls are thicker than arteries because veins must pump blood up from the lower body
Arteries lack an endothelial layer
