Wildlife of China "ciwei" or the "thorned creature". Porcupines are rodents and hedgehogs belong to a separate order. Three species of Old World porcupine are found in China: the Asiatic brush-tailed porcupine, Indian crested porcupine, and Malayan porcupine. Many parts of the porcupine including the brain, organs, fat, quills and even the feces can be used to make traditional Chinese medicine. Porcupines are raised on farms. In the early 20th century, the Eurasian beaver was hunted to near extinction for its fur and castoreum, a scent gland secretion used to make perfume and medicine. Though the global population has rebounded, the animal remains
Ground substance as hyaluronic acid, heparan sulfate, dermatan sulfate, and chondroitin sulfate, proteoglycans which GAGs are bound to, and glycoproteins. Components of the ground substance are secreted by fibroblasts. Usually it is not visible on slides, because it is lost during staining in the preparation process. Link proteins such as vinculin, spectrin and actomyosin stabilize the proteoglycans and organize elastic fibers in the ECM. Changes in the density of ground substance can allow collagen fibers to form aberrant cross-links. Loose connective tissue is characterized by few fibers and cells, and a relatively large amount of ground substance. Dense connective tissue has a