Nervous systems

1. Nets: the simplest type of nervous system; found in cnidarians.
2. Ganglia: small clusters of nerve cells outside the brain or spinal cord.
3. Cephalization: a concentration of nerve cells at the anterior end of an animal.
4. Nerve Ring: clusters of nerves shaped into an encircling ring; found in echinoderms.
5. Cerebrum: the most prominent region of the forebrain.
6. Cerebral Cortex: the wrinkled, outer region of the cerebrum.
7. Central Nervous System (CNS): the brain and spinal cord.
8. Peripheral Nervous System (PNS): all nervous structures outside of the brain and spinal cord; composed of the sensory and motor
(autonomic and somatic) divisions; includes the cranial and spinal nerves.
9. Meninges: three tough layers of connective tissue that surround and protect the brain.
10. Cerebrospinal Fluid: a pressurized, shock-absorbing fluid that fills the spaces between the 3 meninges layers and some open
spaces within the brain itself.
11. Circle of Willis: a circle of arteries at the base of the brain formed by those that carry blood to the brain.
12. Blood-Brain Barrier: barrier that protects the brain by first filtering and examining all substances before they enter the brain.
13. Astrocytes: specialized, selective cells that are part of the blood-brain barrier; function to screen all substances in the blood
before the blood enters neurons.
14. Microglia: other cells of the blood-brain barrier; they are phagocytic and function to screen and clean up debris that may be
present in the brain and spinal cord.
15. Aphasia: the inability to speak or understand written language.
16. Language Centers: three regions of the cerebrum that are responsible for our ability to speak and understand language (verbal
and written); include Broca’s area, Wernicke’s area, and the angular gyrus.
17. Nerve roots: major nerve cords running throughout the spinal cord.
18. Electroencephalograph (EEG): instrument used to monitor and record the electrical activity of the brain; data is recorded as an
electroencephalogram; normal brain activity can be recorded as alpha, beta, theta, or delta brain waves.
19. Positron Emission Tomography (PET): device and method used to monitor and record specific brain electrical activity; PET
scans can pinpoint the specific regions in the brain where nerve cells are working during a particular mental task.
20. Sympathetic Division: division of the autonomic nervous system that generally increases an action or response.
21. Parasympathetic Division: division of the autonomic nervous system that generally decreases an action or response.