Artistic depiction of what?

Specifically, what do you call those small sections where the tubes become small?

Update:

svgreatest informs us that ye alma mater is holding the MSRIT Quiz Fest 2010 on the 2nd and 3rd of October! Check out the link for more details. Looks like the quiz master for one of the quizzes is udupendra as well :-)

Cracked by Logik, shrik, Dibyo, Ananth, jowens, username, Manish Achuth, udupendra, raklodramA, v.chandrashekar, Treyambak Madyalkar, Sumanth Patlolla, krudebox, Rogi, Bharath, Mikey, ht, Thejas V R, Shwetha Maiya, kallukudian, dineshk and N@ngA