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.
The epidermis consists of the upper and lower epidermis; it aids in the regulation of gas exchange via stomata. The epidermis is one layer thick, but may have more layers to prevent transpiration. The cuticle is located outside the epidermis and protects against water loss; trichomes discourage predation. The mesophyll is found between the upper and lower epidermis; it aids in gas exchange and photosynthesis via chloroplasts.