Question

PROCEDURE Exercise 20-2 Lymphatic Organ Histology Microscopy 1 Obtain prepared slides of the spleen, a lymph node, and the small intestine (be certain that your slide is labeled the ilee) MATERIALS u Spleen section slide Light microscope J Lymph node slide 2 Use your colored pencils to draw what you see in the fiel Colored pencils of view and label your drawing with the terms below. Peyer's patch slide Spleen 1. Red pulp 2. White pulp In this exercise, you will examine the microscopic anatomy of three different lymphoid organs: the spleen, a lymph node, and a special type of MALT found in the terminal portion of the small intestine called a Peyer's patch. Following are some hints regarding what to look for on each slide 1. Spleen: Note in atlas Figure 13.10 that the spleen consists of two types of tissue: a. red pulp, which is involved in the destruction of old and worn-out red blood cells, and b. white pulp, which contains phagocytes and lymphocytes that play a role in the immune system. Lymph node 1. Capsule 2. Cortex 3. Medulla 2. Lymph nodes: Lymph nodes consist of an outer cortex that contains spherical clusters of cells (primarily B lymphocytes) called lymphatic nodules, or germinal centers (atlas Figure 13.12). Deep to the lymphatic nodules we find an area of the cortex that houses primarily T lymphocytes. The innermost region of the node, called the medulla, houses macrophages, which are highly active phagocytes. The entire lymph node is surrounded by a capsule made of dense irregular 4. Lymphatic nodule lagenous connective tissue. 3. Peyer's patch: Peyer's patches somewhat resemble lymph nodes, although their lymphatic nodules are less wel defined and their capsules are incomplete. To have the best chance of finding them, examine your section on low power and look for the epithelial lining of the small intestine. Scroll downward (deep to the epithelium) into the connective tissue, where you will note large, oval or teardrop-shaped, purplish clusters. These are Peyer's patches. There is no image of a Peyer's patch in your atlas, but they look similar to the lymphatic nodules in the appendix, shown in atlas Figure 15.37 Peyer's patch 1. Mucosa (simple columnar epithelial 2. Peyer's patch The Lymphatic SystemUnit 20 23

Answer 1

ISTOLOGICAL SECTION Capsule Trabeculae wth SpRenic (Red Pulp Trabecula whit Central Pulp auetesiole -sheathed es

Affetent lymphatic vesser sule hatic modudes Secom ymphoid tolticle Medullary Cord Me dullany Smus Gesiminal Center Effexent lymphat Vessel

  

Mucosa M c 入ㄧ一、.laynina ProPua folli Submutasa germinal ortex Peyeris Patch

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