BIOL&242
Lab 35A
Hand in labeled sketches, and answers to questions below with Lab 35. For all of these slides, I
recommend using the scanning (low) power objective, unless noted otherwise. Remember to include a
TITLE above all sketches and the total magnification of your sketch. Please label all items asked for in
instructions. This lab requires 3 sketches.
Activity 2- Tissues of the Lymphatic System
1. Lymph Nodules- Peyer’s Patches (of the ileum of the small intestine)- First, hold up the slide up,
and LOOK at it. What do you see? This is a cross-section of the small intestine. So the tissue on the
slide is a piece of a tube, with a lumen at the center. Remember that epithelial cells face a lumen (here,
these are arranged atop finger-like projections of the intestinal wall). Deep to the epithelia is the basal
lamina, and then connective tissue (CT), can you see all of this, with the microscope? Peyer’s Patches
are a feature of the small intestinal wall, they are a collection of large lymph nodules surrounded by CT.
Draw and clearly label Peyer’s Patches, seen beneath the digestive mucosa layer (a mucosa is a mucous
membrane). In your sketch, label: the lumen of the digestive tract, epithelial tissue, lymphoid tissue, and
any smooth muscle present. You may find it helpful to refer to Lab 38, page 584, Figure 38.9 (b), or
Plate 35 in the Histo atlas for additional help with this slide!
Q1: What comprises a mucous membrane?
Q2: What is the name of the lymphoid nodules in the pharynx (throat)?
2. Lymph Node- Draw and clearly label a lymph node. Our slides show a PIECE of a lymph node, not
the whole thing. Label: capsule, trabeculae, follicles within the lymph node, germinal centers, and any
visible blood vessels. Using a higher power objective, examine (look at, but don’t draw) a germinal
center. What do the cells look like here?
Q3: What type of cells would you expect to find at a germinal center of a lymph node?
Q4: Name three regions of the body that have large clusters of lymph nodes.
3. Thymus
Be sure to use low power! Draw and clearly label the thymus. Label: capsule, medulla, cortex, and any
blood vessels. You may find it helpful to refer to page 781 of the text or use the Zhang book!
Q5: Which type of lymphocytes mature here (at the thymus)?
Q6: On your sketch, indicate which region of the tissue you would expect to find high
rates of mitosis to occurring.
Q7: Which region of the thymus is primarily composed of epithelial cells? What hormone
do these epithelial cells make and release? What is believed to be the function of this
hormone?
See next page for online resources.
Written
by Heidi Iverson, Ph.D.
Helpful Links:
Peyer’s patches in the ileum:
http://www.bu.edu/histology/p/12001oba.htm (remember, to zoom in on this image, click within the
black, outlined box.
http://education.vetmed.vt.edu/curriculum/vm8054/labs/Lab13/IMAGES/PEYERS.JPG
http://kobiljak.msu.edu/CAI/Histology/Hist03_01.htm
Lymph node:
http://www.bu.edu/histology/p/07101ooa.htm
Shotgun histology-lymph node: http://www.youtube.com/watch?v=8ngnKIyBA20
http://faculty.une.edu/com/abell/histo/lymnode2.jpg
http://www.pathpedia.com/education/eatlas/histology/lymph_node/Images.aspx
Thymus:
http://www.bu.edu/histology/p/07401ooa.htm
Shotgun histology- Thymus http://www.youtube.com/watch?v=38hwl88Gb44
http://i27.photobucket.com/albums/c190/lovesthesunset/anatomy%20and%20physiology/thymus.jpg