Arteries and Arterioles (Nursing)

00:01 So if we take a closer look into the structure of our arteries, we find that they're divided into three different types.

00:10 We have the elastic arteries, which are going to have a large amount of elastin in their walls.

00:17 The muscular arteries, which are going to have a larger amount of smooth muscle in their walls.

00:22 And then we have the smaller arterioles.

00:26 Starting with the elastic arteries, these are going to be thick walled with large low-resistance lumens.

00:34 Examples include the aorta and its major branches.

00:39 It is also called conducting arteries because elastic arteries are going to conduct blood from the heart to the medium size vessels.

00:49 Elastin is going to be found in all three tunics of the elastic arteries, but most of the elastin is going to be found in that middle layer or the tunica media.

01:03 This is going to contain a substantial amount of smooth muscle, but this smooth muscle is actually inactive during vasoconstriction.

01:14 The elastic fibers act as pressure reservoirs that expand and recoil as blood is ejected from the heart, which allows for continuous blood flow downstream even between heartbeats.

01:31 Next, we have the muscular arteries.

01:34 Elastic arteries are going to give rise to this second type of artery.

01:40 These are sometimes also called distributing arteries because they deliver blood to the body organs.

01:48 The diameters of our muscular arteries are going to range in size from the size of your pinky finger to a very small size like the size of pencil lead.

02:00 They can account for most of the named arteries in our bodies.

02:06 Muscular arteries have the thickest tunica media, but this tunica media is going to have more smooth muscles than it does elastic tissue.

02:17 The tunica media is usually sandwiched between an elastic membrane.

02:22 And it is very active in vasoconstriction.

02:28 The last type of artery and the smallest of our arteries are going to be our arterioles.

02:34 Our larger arterioles contain all three tunics, but as they get smaller in size and diameter, they end up being mostly a single layer of smooth muscle surrounding endothelial cells.

02:50 The arterioles are going to control flow of blood into our capillary beds via vasodilation and vasoconstriction of their smooth muscle.

03:02 Because of this they are also sometimes called resistance arteries because they change diameters in order to change the resistance to blood flow.

03:12 Arterioles lead into our capillary beds.