Interneurons: Neurons of the peripheral nervous system; send signals back and forth between the brain or spinal cord and the limbs and sense organs
Sensory neurons: Neurons that transmit messages to the brain and the spinal cord from the sense organs
Motor neurons: Neurons that carry commands from the brain and spinal cord to the muscles and glands
Chemical exchange: the means by which neurons send and receive electrical signals associated with smell and taste
Mechanical stimulus: the means by which neurons send and receive electrical signals associated with sight, sound, and touch
What best explains why someone might feel no heat when poking a hot coal with an extended finger?
Explanation
The ability to extend the finger indicates that the motor neurons reaching from the spinal cord to the finger are working properly. But the lack of any sensation of heat suggests that the sensory neurons that carry the “heat” information back to the brain via the spinal cord are malfunctioning.
Battery companies make impressive claims about how long their batteries will last. A student decided to test the running time of different batteries to determine which battery lasts the longest. The student tested 6 different batteries, 4 brand name and 2 generic, using flashlights. The results show that the battery referred to as Name Brand A lasted the longest, with 101 hours of runtime:
Flashlight | Battery | Runtime in hours |
Gearlight Super Light | Name Brand A | 101 |
SureFire | Name Brand B | 99 |
Maglight | Name Brand C | 80 |
Bright Star | Name Brand D | 75 |
SureFire | Generic A | 30 |
Bright Star | Generic B | 29 |
It could be argued that this experiment was not set up using proper experimental protocol. What would need to change in the experiment for the results to be valid?