Which vessel (A or B) has a thick, muscular wall?

  Identify the structure indicated by the arrow C

Identify the blood vessels indicated by the arrows.

Identify the layer shown by the  arrow 

  Identify the structure indicated by arrow B  

Give the immune property of this organ

Identify the vessel at Arrow D.  

Name a specific cell found in the circled with the arrow on the above histology slide.

  Identify the region indicated by arrow B

Identify the structures at the arrows for this histological specimen.