Chapter 16, Problem 3RQ

In 2003, the Nobel Prize in Physiology or Medicine was awarded to Paul C. Lauterbur and Sir Peter Mansfield for discoveries related to magnetic resonance imaging (MRI). This is a tool to see the structures of the body (not just the nervous system) that depends on magnetic fields associated with certain atomic nuclei. The utility of this technique in the nervous system is that fat tissue and water appear as different shades between black and white. Because white matter is fatty (from myelin) and gray matter is not, they can be easily distinguished in MRI images. Visit the Nobel Prize website (http://openstaxcollege.org/l/nobel_2) to play an interactive game that demonstrates the use of this technology and compares it with other types of imaging technologies. Also, the results from an MRI session are compared with images obtained from x-ray or computed tomography. How do the imaging techniques shown in this game indicate the separation of white and gray matter compared with the freshly dissected tissue shown earlier?

A patient undergoing an MRI is surrounded by a tubeshaped scanner. Watch this video (http://openstaxcollege.org/l/MRI) to learn more about MRIs. What is the function of magnets in an MRI?

Identify the four components of a negative feedback loop and explain what would happen if secretion of a body chemical controlled by a negative feedback system became too great.

What regulatory processes would your body use if you were trapped by a blizzard in an unheated, uninsulated cabin in the woods?

A satellite is launched into space, but explodes after exiting the Earth’s atmosphere. Which statement accurately reflects the observations made by an astronaut on a space walk outside the International Space Station during the explosion? The astronaut would see the explosion, but would not hear a boom The astronaut will not sense the explosion The astronaut will see the explosion, and then hear the boom The astronaut will feel the concussive force of the explosion, but will not see it.

Discuss Concepts You place a metal pan full of water on the stove and turn on the heat. After a few minutes, the handle is too hot to touch but the water is only warm. How do you explain this observation?

A common membrane-bound intermediary between the receptor and the effector protein within the plasma membrane is the __________________.

Ions or molecules tend to diffuse from a region where they are _______ (more/less) concentrated to another where they are _______ (more/less) concentrated.