Those with advanced training and certification, such as the CPN credential, may also receive higher compensation. RNâs that go on to become Advanced Practice Registered Nurses (APRNs), including Pediatric Nurse Practitioners (PNPs), can also expect higher salaries.
CELLS: The most common connective tissue cells are: 1  Fibroblasts, which secrete collagen and other elements of the extracellular matrix. 2  Adipocytes, which store fat. 3  Mast cells, macrophages, and lymphocytes, cells with immune function which participate in inflammation.
Answer by Mfdtwin1. Confidence votes 61. Collagen is the most abundant protein in the body as it is the main protein of connective tissue, including skin, bones, cartilage, blood vessels, and more! Collagen makes up about 25% of the average human body's protein content.