the nervous system

1. Na+ moves into the axon, raising charge to +40 mV.
7. arc A simple neural pathway producing a rapid, involuntary response to a stimulus.
11. membrane potential −70 mV; neuron is polarized with Na+ outside and K+ inside.
12. of parasympathetic system Acetylcholine.
14. potential All-or-none event where Na+ channels open and the neuron fires.
17. Affects movement and pleasure; imbalances linked to schizophrenia and Parkinson’s disease.
18. Chemical messenger released by neurons to transmit signals across a synapse.
20. potential Minimum charge needed to trigger an action potential (−55 mV).
21. callosum Bundle of white matter connecting the two cerebral hemispheres.
22. Junction between two neurons or between a neuron and an effector.
25. function Found in the CNS; link sensory and motor neurons.
26. Regulates homeostasis, hunger, thirst, temperature, and emotions.
27. Relays visual and auditory information; controls eye movement and skeletal muscles.
28. neuron function Carry information from sensory receptors to the CNS.
31. Excites muscle cells, causing contraction; broken down by cholinesterase.
32. Controls coordination, posture, reflexes, and fine motor skills.

2. Relay center between cerebrum, cerebellum, and the rest of the brain.
3. K+ moves out of the axon, returning charge toward −70 mV.
4. Regulates temperature, sensory perception, and mood; low levels linked to depression.
5. period Time after an action potential when the neuron cannot fire again.
6. Used in stress response; imbalances linked to anxiety, insomnia, hunger, and exhaustion.
8. neuron function Carry information from the CNS to muscles, glands, and organs.
9. nervous system Responsible for rest-and-digest; slows heart rate, promotes digestion and reproduction
10. Natural painkillers that also affect emotional areas of the brain.
13. released during stress Epinephrine and norepinephrine from the adrenal glands.
15. types of neurons Sensory neurons, interneurons, and motor neurons.
16. of sympathetic system Norepinephrine.
19. Major relay station for sensory information (except smell).
23. oblongata Controls involuntary functions such as breathing, heart rate, and blood pressure.
24. of a neuron A nerve cell; the structural and functional unit of the nervous system.
29. Three protective layers surrounding the brain and spinal cord.
30. Controls intellect, memory, consciousness, and language.