The CpG PAMP is recognized by the pattern recognition receptor (PRR) Toll-Like Receptor 9 (TLR9), which is constitutively expressed only in B cells and plasmacytoid dendritic cells (pDCs) in humans and other higher primates.
The trachea is an important structure within your respiratory system, which is the organ system that delivers oxygen to your bloodstream. The trachea is a rigid tube that conducts air from your larynx to your bronchi. The trachea's rigidity is maintained by a series of cartilaginous rings arranged along its length called C-shaped cartilage rings.
Anatomy. The windpipe or trachea is a tube that passes air from the back of the throat to the smaller airways in the lungs called bronchi. This tube is composed of multiple cartilage, C-shaped rings. The open part of the C-shaped cartilage is covered with a membrane and thin muscle.