Which of the following can happen as result of an open chest injury from a knife wound?

You are teaching a group of firefighters who are in class to become Emergency Medical Responders. The topic is artificial ventilation with the bag-valve mask (BVM). Which one of the following points related to using the BVM should you emphasize?

A) It is better to ventilate too quickly as opposed to too slowly. B) Maintaining a good mask-to-face seal is difficult. C) The BVM is useless unless it is hooked to supplemental oxygen. D) The bag must be fully squeezed in order to give the proper amount of volume with each breath.

Ubiquitous dendritic cells, found within mucosa and epidermis and having the function of processing foreign antigens and presenting relevant determinants to immunocompetent cells are known as:

a. Macrophages b. Langerhans cells c. Langhans giant cells d. Histiocytes e. Plasma cells