Objective 29, & 33: Heart and Blood vessels

Objective 29:Compare the structure and function of arteries, arterioles, capillaries, venules, and veins Objective 33: Describe the role of skeletal muscle contractions and venous valves in returning blood to the heart


When I was trying to understand the structure and functions of the arteries, arterioles, capillaries, venules, and veins , it almost overwhelmed me. I never realized how much there was to our bodies amazing system. My thought taking anatomy was that our body just had these set of veins and arteries that helped moved oxygen and carbon dioxide through our blood, but I never realized how much they branched off and how each one functions differently. I found a chart in Chapter 18 page 608 that summarized the structure of all of these vessels and it gave me a better understand on what they look like in our body, and I was also able to understand better on how each one functions. Another diagram that really broke down the structure of veins and arteries was found on page 606, and it helped to see the differents layers they consisted of. Along with the diagrams from our textbook, the lecture outlines were a great help in summarizing the functions on all 5 of the vessels. Arteries carry oxygenated (oxygen rich) blood away from the heart to the rest of the body. Veins do the opposite it seems, and carries deoxgenated (oxygen-poor) blood from the tissues to the heart and sends the blood through the pulmonary system to be oxygenated again. Arterioles lead to capillary beds and control the flow into the capillary beds via vasodilation and vasoconstriction. Capillaries are responsible for the exchange of gases, hormones, nutrients, wastes, etc.. Venules drain blood from capillaries into veins for the return to the heart.

When I was trying to understand what the role of skeletal muscle contractions and venous valves had to do with returning blood back to the heart, I came up with a blank. When I came across the diagram in chapter 18 page 614, it was like a light bulb came on and I felt really stupid for thinking that the concept was hard. I made it alot harder than it really was. The picture was extremely helpful and allowed me to see how the skeletal muscle effects the venous valves. Basically, the contracting skeletal muscle presses against a vein which causes the valves near the area to be forced open. Blood then goes toward the heart and the valves distal to the contracted area are closed by backflow blood. The concept was so easy, and it is also a very important adaptation of veins.