Chapter 6

4. nervous system, nerves branching beyond the spinal cord into the body
7. nervous system, the part of the peripheral nervous system that controls internal biological functions
9. nervous system, the part of the peripheral nervous system that controls voluntary movement of skeletal muscles
10. the basic building blocks of heredity
11. the gap that exists between individual nerve cells
12. twins, who come from two different eggs
14. the expression of a particular trait in an organism
15. nervous system, the brain and spinal cord
18. descended from ancestors with similar genetics
20. the long, thin cells of nerve tissue along which messages travel to and from the brain
21. a machine used to record the electrical activity of large portions
23. descended from ancestors with dissimilar genetics
24. the genetic transmission of characteristics from parents to their offspring

1. the chemicals released by neurons, which determine the rate at which others neurons fire.
2. chemical substances that carry messages through the body in blood
3. resonance imaging, a measuring technique used to study brain structure and activity
5. emission tomography, an imaging technique used to see which areas are being activated while performing tasks
6. axial tomography, an imaging technique used to study the brain to pinpoint injures and brain deterioration
8. a small part of the brain above the pons the arouses the brain, integrates sensory information, and relays it upward
10. the set of genes in an organism
11. cord, nerves that run up and down the length of the back and transmit most message between the body and brain
12. a part of the brain that covers the brains central core, responisble for sensory and motor control and the processing of thinking and language
13. gland, the center of control of the endocrine system that secret a large number of hormones
16. system, a chemical communication system, using hormones, by which messages are sent through the bloodstream
17. the different regions into which the cerebral cortex is divided
19. twins, who come from one fertilized egg
22. a part of the brain located at the rear base of the skull that is involved in thbe basic processes of life