After one frog's heart has been stimulated, an extract of fluid ...

[asmith134]

After one frog's heart has been stimulated, an extract of fluid from that heart can make a second frog's heart beat faster. What conclusion did Otto Loewi draw from these results?
 
  a. Transmission at synapses is a chemical event.
 b. The sympathetic and parasympathetic nervous systems are antagonistic.
  c. Transmission at heart muscle synapses is electrical.
 d. Hormones facilitate the actions of the nervous system.

Question 2

Describe how bulimia nervosa resembles drug addiction.
 
  What will be an ideal response?

[polinasid]

Answer to Question 1

a

Answer to Question 2

In important ways, bulimia resembles drug addiction. Eating tasty foods activates the same brain areas as addictive drugs, such as the nucleus accumbens. Drug addicts who cannot get drugs sometimes overeat instead, and food-deprived people or animals become more likely than others to use drugs. Researchers examined rats that were food deprived for 12 hours a day, including the first 4 hours of their wakeful period, and then offered a very sweet, syrupy sugar solution. Over several weeks on this regimen, the rats drank more and more each day, especially during the first hour of availability each day. The intake released dopamine and opioid (opiatelike) compounds in the brain, similar to the effects of highly addicting drugs. It also increased the levels of dopamine type 3 receptors in the brainagain, a trend resembling that of rats that receive morphine. If they were then deprived of this sweet liquid, they showed withdrawal symptoms, including head shaking, teeth chattering, and tremors. An injection of morphine relieved these symptoms. In short, the rats showed clear indications of an addiction to big doses of sugar. Similarly, we can regard bulimic cycles of dieting and binge eating as an addiction.