An agent that is smaller than a virus causes scrapie. It is either a protein called a prion or it is another substance closely associated with the prion protein. Scientists still have a lot to learn about the scrapie agent and exactly how it works.
Tissue valves are made with tissues from porcine (pig) heart valves or bovine (cow) cardiac tissue because they function like human heart valves. Once the tissue is removed from the animal, it is chemically treated to preserve the tissue and prevent immulogic reactions once it is placed in a patient.
Cardiac muscle tissue is the third type of muscle tissue. Cardiac muscle tissue makes our hearts. Organs are groups of tissues that work together to do a job. Our skin is made of hair tissue, oil and sweat gland tissues, nerve tissue, blood tissue, and many other tissues to make the organ called skin.rgans are groups of tissues that work together to do a job. Our skin is made of hair tissue, oil and sweat gland tissues, nerve tissue, blood tissue, and many other tissues to make the organ called skin.