lecture 2 Bloodtrans_notes - Immunology Lecture II...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Immunology Lecture II Lymphatic Organs: This lecture began with the lymphatic organs (except for the thymus which had been discussed in the previous lecture), beginning with the hundreds of lymph nodes found throughout the trunk of the body. The flow of the lymph fluid through the lymph node begins by the fluid entering in through the afferent lymphatic vessels. After the lymph fluid enters through the afferent lymphatic vessels it begins diffusing through the lymph node by entering an area called the cortex, which houses the B cells. Also within the cortex are the germinal centers, which are areas of rapidly dividing B cells which have been stimulated by an antigen traveling into the lymph node. After passing through the cortex, the lymph fluid enters the paracortex, which contain the T cells. The next area of the lymph node is called the medulla, which contains both B cells and T cells. After diffusing through the lymph nodes, the lymphatic fluid exits through the efferent lymphatic vessels. The organization of the lymph node is important for the interaction and communication between the B cells and the T cells. An important characteristic of the lymph node is the fact that it directly connects the circulating blood with the circulating lymphatic fluid. This is because the lymph nodes contain lymphatic arteries and veins. At the very end of the arteries are the post-capillary venules. This is where the lymphocytes circulating in the blood are able to enter the lymph node through endothelial transport. This type of cell transport is characterized by the lymphocytes passing directly into and through the endothelial cells. Larger cells must pass between the endothelial cells. After the lymph node has received the necessary lymphocytes from the blood, the rest of the blood exits out the lymphatic vein. The lymph fluid, as well as the blood will return to the circulatory system. This is accomplished the lymphatic fluid passing through the lymph nodes, entering the thoracic duct, and finally emptying into the left subclavian vein where it will then dump into the blood stream. A histological characteristic of the lymph node is the presence of a capsule surrounding the entire organ. The capsule is responsible for the swelling, which occurs during an infection. During a localized infection, only lymph nodes found in the area of infection will become swollen. On the other hand, if a systemic infection has occurred, lymph nodes throughout the body will become swollen. The spleen is another lymphatic organ, which, like the lymph nodes, contains a capsule surrounding the outer edge. This also allows for swelling to occur during infection or injury. The spleen has no direct connection with the lymphatic fluid.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern