Nervous systems

Nets

Simplest nervous system in cnidarians.

Ganglia

Small clusters of nerve cells outside the brain or spinal cord.

Cephalization

Concentration of nerve cells at the anterior end of an animal.

Nerve Ring

Clusters of nerves in an encircling ring in echinoderms.

Cerebrum

Prominent region of the forebrain.

Cerebral Cortex

Outer region of the cerebrum.

Central Nervous System (CNS)

Brain and spinal cord.

Peripheral Nervous System (PNS)

Nervous structures outside the brain and spinal cord.

Meninges

Three layers of connective tissue protecting the brain.

Cerebrospinal Fluid

Fluid filling spaces in the brain and meninges.

Circle of Willis

Arterial circle at the base of the brain.

Blood-Brain Barrier

Filters substances before entering the brain.

Astrocytes

Cells part of the blood-brain barrier.

Microglia

Cells cleaning up debris in the brain and spinal cord.

Aphasia

Inability to speak or understand written language.

Language Centers

Responsible for language in the cerebrum.

Nerve roots

Major nerve cords in the spinal cord.

Electroencephalograph (EEG)

Monitors brain electrical activity.

Positron Emission Tomography (PET)

Records brain electrical activity.

Sympathetic Division

Increases an action or response.

Parasympathetic Division

Decreases an action or response.