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.
The trachea is part of you resportory system and is used to breathe to get air into your lungs. It is just a fancy way of saying yo windpipe! It provides part of the open passageway through which air can reach the lungs from the outside. the trachea is the tube that connects your mouth to your lungs.