Chapter 6

3. the basic building blocks of heredity
6. the expression of a particular trait in an organism
9. descended from ancestors with dissimilar genetics
13. twins who come from one fertiliezed egg; twins having the same heredity
14. nerves that run up and down the length of the back and transmit most messages between the body and brain
16. a part of the brain that covers the brains central core, responsible for sensory and motor control
18. chemical sbstances that carry messages through the body in blood
19. the genetic transmission of characters from parents to their offspring
21. the part of the peripheral nervous system that controls internal biological functions
22. descended from ancestors with similar genetics
23. a chemical communication system using hormones, by which messages are sent through the bloodstream
24. nerves branching beyond the spinal cord into the body
25. an imaging technique used to see which brain areas are being activated while performing tasks
27. the set of genes in organism

1. the chemicals released neurons which determine the rate at which other neurons fire
2. a measuring technique used to study brain structure and activity
4. a part of the brain locate dat the rear base of the skull
5. the center of control of the endocrine system that secretes a large number of hormones
7. the part of the peripheral nervous system that controls voluntary movement of skeletal muscles
8. the ap that exists between individual nerve cells
10. the different regions into which the cerebral cortex is divided
11. twins who come from two different eggs fertilized by two different sperm
12. a small part of the brain above the pons that arouses the brain
15. an imaging technique used to study th ebrain to pinpoint injuries and brain deterioration
17. a machine used to record the electrical activity of large portions of the brain
20. the brain and spinal cord
26. the long thin cells of nerve tissue along which messages travel to and from the brain