Lymphatic Vessels (Nursing)

00:00 Welcome.

00:01 In this lecture we will be learning about the lymphatic system of the body.

00:08 The lymphatic system is going to serve to return fluids that have leaked from our blood vessels back to our blood.

00:17 The lymphatic system consists of three main parts.

00:21 You have a network of lymphatic vessels referred to as the lymphatics.

00:26 The fluid inside those vessels referred to as the lymph.

00:30 And finally we have the lymph nodes, which are going to serve to clean that fluid.

00:38 The lymphatic system is going to return interstitial fluid and leaked plasma proteins back to the blood.

00:46 Recall that interstitial fluid is that extracellular fluid formed when components of our blood plasma leak out of our blood capillaries.

00:57 and then while some of that blood plasma is reabsorbed, the rest of it is going to drain into the lymphatic vessels.

01:08 The lymphatic vessels themselves are an elaborate network of drainage vessels.

01:15 They circulate about three liters of interstitial fluid in a day.

01:21 And once the interstitial fluid enters the lymphatics, we then refer to that fluid as the lymph.

01:30 Our lymphatic vessels are going to offer a one way system, ensuring that the lymph is going to flow in only one direction and that is toward the heart.

01:41 The lymph vessels also referred to as lymphatics include lymphatic capillaries, as well as larger lymphatic vessels.

01:52 These blind ended vessels are going to weave between the tissue cells and our blood capillaries.

02:00 They are absent however, from our bones, teeth, bone marrow as well as the central nervous system.

02:07 Recall the central nervous system uses the cerebral spinal fluid for drainage instead of this lymphatic system.

02:16 The lymphatic capillaries are very similar to our blood capillaries, however, they are a bit more permeable.

02:25 Unlike our blood capillaries, the lymphatic capillaries can take up larger molecules and particles that the blood capillaries cannot.

02:34 So for example, our lymphatic vessels are able to bring in proteins, cell debris, pathogens, and even cancer cells.

02:44 And sometimes, the lymphatic vessels, or these lymphatic capillaries can act as a route for these pathogens or cancer cells to travel throughout the body.

02:58 So depicted here, you can see the very intimate association between our lymph capillaries, which are in green, and the blood capillaries.

03:12 Increased permeability of these lymphatic capillaries are due to multiple specialized structures two of those include the fact that endothelial cells overlap very loosely to form one way valves.

03:28 So just like in the veins, we have valves we also have valves in these vessels.

03:35 The many valves are going to be anchored by collagen filaments to the matrix.

03:40 So it's going to increase the extracellular fluid volume as these many valves open even more.

03:49 The decrease in the extracellular fluid will cause many valves to then close.

03:54 Also, in our GI tract in the digestive system, we have a specialized lymph called Lacteal.

04:03 These lymph capillaries are going to absorb digested fats and deliver fatty lymph or chyle to the blood.

04:14 The lymph capillaries are going to drain into increasingly large vessels.

04:19 These vessels are called collecting lymphatic vessels.

04:24 These vessels consist of: collecting vessels, trunks, and ducts.

04:31 These vessels also have structures and tunics that are very similar to that of veins.

04:37 Except that these are going to have much thinner walls and more valves.

04:43 Also, these are going to anastomose more frequently.

04:49 The collecting vessels in our skin are going to travel with our superficial veins, while the deeper vessels will usually travel with the arteries.

05:00 So these larger vessels, also known as lymphatic trunks, are formed by the union of the largest collecting vessels, and they're going to drain large areas of the body.

05:14 The lymphatic trunks are named for the part of the body that they drain.

05:19 And they include the paired lumbar which are going to drain the lymph from our lower limbs, walls of the viscera of the pelvis, the kidneys, the adrenal gland, and the abdominal wall.

05:33 The paired bronchomediastinal which are going to drain the lymph from the thoracic wall, the lungs, and the heart.

05:42 The paired sabclavian which are going to drain lymph from the upper limbs.

05:47 The paired jugular trunks which are going to join lymph from the head and the neck.

05:52 And finally, the single intestinal trunk which is going to drain lymph from our stomach, intestines, pancreas, spleen, and parts of the liver.

06:04 The lymph is then going to be delivered from these trunks into one of the two large lymphatic ducts.

06:12 We have the right lymphatic duct, which is going to drain the right upper arm and the right side of the head and the thorax.

06:21 Then we have the thoracic duct, which drains the entire rest of the body.

06:27 In some individuals, we also have this enlarged sac in the abdominal area known as Cysterna chyli.

06:36 This is where the thoracic duct is going to actually start.

06:41 Each of these ducts are going to empty the lymph into our venous circulation at the junction of the internal jugular, and subclavian veins on each side of the body.