1. View the slide on low magnification. In this view, you should be able to see the complete blood vessel, and some of the surrounding tissues. Slide 109 shows only part of the wall of the vessel.
2. Identify:
   • The lumen of the blood vessel.
   • Wall of the blood vessel.
   • Smaller blood vessels in the surrounding tissues.

   What is characteristic of the lumen of the vena cava as seen on slide 92? Are there any clearly defined layers or structures visible at low magnification?

3. View the medium and high magnification slides of the large vein. In this view, cellular detail should be visible.

   What are the layers seen in the wall of the vena cava? Does the layers in the wall of the vena cava show further divisions? Name the divisions. What are characteristic of each of the layers and divisions seen in the wall of the vena cava?

4. Make and annotated diagram of the complete vein, including surrounding structures. For a partial section of the wall of the vein, make a detailed drawing showing cellular detail and distribution of fibres. Indicate cross, oblique or longitudinal sections as appropriate. Add the function of each structure.

   What is the relationship of the three layers with respect to each other? How are elastic fibres distributed in each layer?

1. What is the relationship of the three layers with respect to each other?
2. What is characteristic of each layer?

Microscope

Medium magnification

Clinical case