<P> Mesenchyme is a type of connective tissue found in developing organs of embryos that is capable of differentiation into all types of mature connective tissue . Another type of relatively undifferentiated connective tissue is mucous connective tissue, found inside the umbilical cord . </P> <P> Various types of specialized tissues and cells are classified under the spectrum of connective tissue, and are as diverse as brown and white adipose tissue, blood, cartilage and bone . Cells of the immune system, such as macrophages, mast cells, plasma cells and eosinophils are found scattered in loose connective tissue, providing the ground for starting inflammatory and immune responses upon the detection of antigens . </P> <P> There are many types of connective tissue disorders, such as: </P> <Ul> <Li> Connective tissue neoplasms including sarcomas such as hemangiopericytoma and malignant peripheral nerve sheath tumor in nervous tissue . </Li> <Li> Congenital diseases include Marfan syndrome and Ehlers - Danlos Syndrome . </Li> <Li> Myxomatous degeneration--a pathological weakening of connective tissue . </Li> <Li> Mixed connective tissue disease--a disease of the autoimmune system, also undifferentiated connective tissue disease . </Li> <Li> Systemic lupus erythematosus (SLE)--a major autoimmune disease of connective tissue </Li> <Li> Scurvy, caused by a deficiency of vitamin C which is necessary for the synthesis of collagen . </Li> </Ul>

Two principle types of connective tissue in a muscle are