Unit 5: Hemoglobin Testing 6 Original: October 1999 Revision: September 2010 Before you learn about how to use the HemoCue machine and take blood from clients, you need to learn about anemia and the causes of anemia.
Skin has three layers: 1  The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. 2  The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. 3  The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.
Skin is composed of two regions: the epidermis and the dermis. The hypodermis, or subcutaneous layer, is located beneath the skin. Langerhans cells are macrophages found deep in the epidermis. Macrophages are related to monocytes, white blood cells produced in red bone marrow.