Final answer:
Biological 3D printing currently includes components like skin, organs, muscles, bones, blood vessels, and nerves, but does not generally involve hair and nails. Hair and nails are composed of keratin, with hair providing sensory and protective roles, while nails offer protection and dexterity.
Step-by-step explanation:
Biological 3D printing includes a variety of components, notably skin and organs, muscles and bones, blood vessels and nerves, but typically does not incorporate structures like hair and nails in the current scope of the technology. Hair and nails are formed from the protein keratin, which provides toughness and resilience. Hair serves physiological roles such as protection from the elements, sensory input, and regulation of body temperature. Nails protect the fingertip, increase the sensitivity of the finger by acting as a counterforce when the pulp of the finger touches an object, and aid in picking up small objects or scratching an itch.
Muscles constitute a significant part of our body and are crucial for movement, while bones are living tissues that support and protect various organs, store minerals, produce blood cells, and enable mobility. Blood vessels are essential for delivering nutrients and oxygen to cells, and nerves control the activities of the body and require a significant amount of energy to function.