1. This slide is a cross-section through the aorta. View the slide on low magnification. In this view, you should be able to see the lumen, wall and surrounding structures of the blood vessel.
2. Identify:
   • The lumen of the blood vessel
   • Wall of the blood vessel
   • Adipose tissue surrounding the aorta
   • Vasa vasorum
   • Accompanying blood vessels

   Is this a cross or longitudinal section? What is the approximate diameter of the lumen of the blood vessel relative to the wall? What is the approximate diameter of the wall of the blood vessel relative to the lumen? Name the 3 layers and divisions of the wall of the aorta. What is characteristic of each layer and divisions of the wall of the aorta? What is characteristic of the elastic fibres in each layer? How is the outer border of the tunica intima determined? How does the inner part of elastic arteries receive nutrients? The outer part?

3. View the medium and high magnification slides of the elastic artery. In this view, cellular detail should be visible.
   • Identify the 3 layers of the elastic artery.
   • Identify the tissue components present in each layer of the elastic artery.
   • The amount and distribution of the elastic fibers
4. Make an annotated diagram of a partial section of the wall of the elastic artery, indicating the layers, divisions and tissue components. Clearly indicate the elastic elements in each layer and division.

   What are identifying features of elastic arteries? With increased age and increased blood pressure, a layer in elastic arteries increase in thickness. Name the layer and the component in the layer which cause the increased thickness. Cells in the wall of the elastic artery are involved with repair (normal) and atherosclerosis (pathological). Name the cells and the originating layer.

1. What is characteristic of the elastic fibers in each layer?
2. How does one determine the outer border of the tunica intima?
3. What are identifying features of elastic arteries?

1. Slide 49: Low magnification of the aorta
   
2. Cross section through the aorta showing all layers, surrounding tissues and accompanying lymph vessel
   
3. Cross section through the aorta showing all layers, surrounding tissues and accompanying lymph vessel
   
4. Cross section through the aorta showing the lumen, tunica intima and contact with the tunica media
   
5. Cross section through the aorta showing the tunica media and adventitia
   
6. Cross section through the aorta showing a small part of the media and the detail of the tunica adventitia

Clinical case