Excitable Cells

1. potential the potential energy created by the difference in charge between two environments
4. must be great enough to reach the threshold to initiate an AP
6. Regulated by changes in charge in the surrounding environment
8. regulated by chemical messengers called ligands
10. sodium channels close, potassium (K+) channels open and potassium begins moving out of the cell, making it more negative
11. potassium channels close slowly so potassium ions continue to move out of the cell
14. a type of excitable cell
17. the change in electrical potential associated with the passage of an impulse along the membrane of a muscle or nerve cell
18. for ion concentration this moves into the cell
19. sodium (Na+) channels open and sodium begins moving into cell, making it more positive

2. of the nervous system that transmit signals to the rest of the body in the form of electrical signals
3. state resting membrane potential is approximately -70 mV
5. Ions can move __________ through the membrane with a larger concentration gradient
7. channels two types both are passive transport and require no ATP
9. negatively charged molecules
12. for ion concentration this moves out of the cell
13. Action potentials follow an _________ principle
15. positively charged molecules
16. is released into the synaptic cleft to produce an action potential