In your body, you have only two types of bone tissue: cortical and cancellous bone. In this lesson, we will learn about the structure and function of cancellous bone, which plays a crucial role in producing blood cells and stem cells and is the primary tissue affected by osteoporosis.
balaclava (plural balaclavas) 1  A warm cap shielding the neck and head, often made out of wool. ( 2 chiefly Canada) A ski mask with holes for the eyes and, sometimes, the nose and mouth, which may be rolled up and worn like a toque or pulled over the face for greater protection.
Individual Protective Equipment. MCU-2A/P Mask. The MCU-2A/P series mask (Air Force Technical Order 14P4-15-. 1) is designed to protect the face, eyes, and respiratory tract of. the user from tactical concentrations of chemical and biological. agents, toxins, and radioactive fallout particles.