Transcription
Hey guys, it's Medicos is Perfection Ellis with a new topic today. Let's talk about the lymphatic system. How do you like these lymph nodes in this guy? That looks like Tony Robbins. Just kidding.
[Music]
Many people ask me about my references, so here are the books and flashcards that I use. See the links in the description.
So here is the heart pumping blood, arteries, then arterioles. There is the capillary bed, then we have venules and big veins. And the capillary bed, exchange occurs with the cell, but some fluid is getting lost in the interstitial or the extracellular space. This fluid is picked up by the lymphatic capillaries or plexus. Then we have the afferent lymph vessels, good old lymph nodes with germinal centers, then we have the efferent lymph vessels, lymph trunk, and lymph duct, back to the big veins, back to the circulation.
So you have two kinds of beds: the capillary bed and the lymphatic bed. So when life hits you hard and you become so poor with nowhere to sleep, just remember that you have two beds. This is a joke.
Some quick bullet points: Lymph capillaries are blind-ended. The lymphatic system returns the fluid lost from the capillaries during exchange and back to that venous system. So if here we have 100% of the blood, 90% will go back in the veins, 10% go through the lymphatic and then back to the veins, so that no fluid is left behind. Big ducts go to big veins at the root of your neck.
Blood circulatory system is a closed system because it starts in the heart and ends in the heart. However, the lymphatic system is not a closed system. It starts in the interstitial and ends in big veins. Also, remember lymphatic vessels have valves like the veins because the pressure is low, but arteries do not need valves because the pressure is high. They can sustain blood movement in only one direction.
So what's in your lymph fluid? Loss from capillaries, pathogens, cells of the lymphatic system such as lymphocytes, natural killer cells, cell products such as hormones, and some nasties of debris.
Let's say that you go eat this burger, which tastes absolutely delicious. However, it contains lots of fat. Since we have two layers of cheese, we call this that double cheeseburger. It goes to your stomach, then the small intestine. Absorption will take place. We have the villi lined by columnar epithelium. Why columnar? Because any cell that will secrete needs a lot of space in order to store these secretions, so that's why these cells are columnar epithelium. Inside them, there is the lacteal. The lacteal is a special type of lymphatic vessel that will drain into lymphatic vessels to the big veins eventually. So the lymphatic system is a major route of transport for absorbed fat by the GI tract. So they are absorbed into the epithelium and packaged like the Amazon packages and forming chylomicrons, which contains the lipid droplets in the center surrounded by protein into the interstitium, lymph capillaries, lymph vessels, back to the circulation.
The lymphatic system returns the fluid lost from the capillaries back to the circulation. But why bother with all of this mess? Because the lymph nodes are interrogation rooms. They have officers or lymphocytes acting on pathogens and destroying them. So the bacteria cannot enter the blood circulation. Hashtag no bacteremia. Thanks to lymph nodes.
Quick comparison between lymph and chyle: Lymph is in most lymphatic vessels, clear and colorless. Chyle is in lacteals only in your gut. They are opaque and contain milky fluid because lacteals mean milk, lactose, lactase, you get the idea. Why milky? Due to the presence of chylomicrons.
Lymphatics are all over the place except CNS, bone, bone marrow, teeth, cartilage, and epithelium. Lymphoid organs are organs that produce lymphocytes, including all of these.
How does lymph move inside the vessels? By skeletal muscle contraction and arterial pulsation, similar to veins. We have two types of lymphatic vessels: the superficial, which are subcutaneous in the subcutaneous tissue, they accompany the veins and they will drain into the deep lymphatic vessels. These are deeper, accompany the artery and receive drainage from internal organs. Both the superficial and the deep lymphatics traverse the lymph node.
Question of the day here is my eleventh question. All of these questions and answers are on my Facebook page. So we have numbers, try to match them with the structure. Let me know down below in the comment section what you think and let's see who will answer it first. Remember, these green letters are lymphatic vessels and the blue letters are veins, just to make it easier.
Stay tuned for the next video where we will discuss anatomy of the lymph node. Don't forget to subscribe and hit the bell to get notified. The answer to today's question is on my Facebook page. Also, Twitter, SoundCloud, Instagram. Please support my channel on Patreon. Thanks to our mod for answering my previous question correctly. This is Medicos is Perfection Ellis. Be safe, stay happy, and study hard.