Compared to arteries, veins 

• have a pleated endothelium.
  
• have thinner walls.
  
• have more smooth muscle in their tunica media. 
• hold their shape better when cut. 

Arrange the structures in the following list in the order that blood will encounter as it flows from the output side to the input side of the cardiovascular flow circuit. 
1. venules
2. arterioles
3. capillaries
4. elastic arteries
5. medium veins
6. large veins
7. muscular arteries 

• 7, 4, 2, 3, 1, 5, 6 
•  2, 7, 6, 3, 1, 5, 6 
• 5, 6, 1, 3, 2, 7, 4 
• 4, 7, 2, 3, 1, 5, 6 

As blood travels from arteries to veins, 

• pressure builds. 
• viscosity increases.
  
• pressure drops 
• diameter of the blood vessels gets progressively smaller. 

Pulmonary veins carry blood to the 

• aorta
• left atrium
• right atrium 
• lungs 

The vessel that receives blood from the head, neck, chest, shoulders, and arms is the 

• coronary sinus
• inferior vena cava
• superior vena cava
• internal jugular vein

Carry blood away from heart; mostly oxygen-rich

• Arteries
• Veins
• Capillaries

Carry blood toward heart; mostly oxygen-poor

• Arteries
• Veins
• Capillaries

Thin-walled vessels that allow for the exchange of O_{2 ,} CO₂, nutrients and wastes between blood cells or air sacs in the lungs

• Arteries
• Veins
• Capillaries

Which type of blood vessel has the thickest layer of smooth muscle in its walls?

• Arteries
• Veins
• Capillaries
• Ventricles

Structure(s) that keep the blood flowing in one direction.

• Valve(s)
• Septum(s)
• Neuron(s)
• Bronchiole(s)