Central Nervous System

Front

Neuron Noun

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[noor-on]

Back

Neuron

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The fundamental cell of the nervous system that transmits electrical and chemical signals to other cells.

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Example: This diagram shows a nerve cell (neuron), labeling its main parts: the dendrites that receive signals, the soma (cell body), and the axon.

Front

Synapse Noun

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[sin-aps]

Back

Synapse

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The specialized gap between two neurons where chemical signals are passed from one cell to the next.

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Example: This diagram shows a synapse, the gap where a signal passes from one nerve cell (axon) to another (dendrite) using chemical messengers called neurotransmitters.

Front

Neurotransmitter Noun

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[noor-oh-trans-mit-er]

Back

Neurotransmitter

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A chemical messenger used by a neuron to transmit an impulse across a synapse to another cell.

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Example: This diagram shows neurotransmitters as chemical messengers released from one neuron, crossing a tiny gap called a synapse, and binding to receptors on another neuron.

Front

Action Potential Noun

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[ak-shun poh-ten-shul]

Back

Action Potential

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A rapid, temporary change in a neuron's membrane polarity that propagates an electrical impulse along the axon.

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Example: This graph shows how a neuron's electrical charge (voltage) rapidly changes to create a nerve signal, but only if the initial stimulus crosses a threshold.

Front

Myelin Sheath Noun

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[my-uh-lin sheeth]

Back

Myelin Sheath

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An insulating layer formed by glial cells that surrounds a neuron's axon to increase impulse transmission speed.

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Example: This diagram shows the myelin sheath as a fatty layer insulating the axon of a nerve cell, helping to speed up electrical messages.

Front

Cerebrum Noun

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[suh-ree-brum]

Back

Cerebrum

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The largest part of the brain, responsible for higher thought processes like language, learning, memory, and consciousness.

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Example: This diagram shows the cerebrum is the largest, wrinkled, upper part of the brain, located within the central nervous system.

Front

Cerebellum Noun

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[ser-uh-bel-um]

Back

Cerebellum

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The brain structure located at the back of the head that controls balance, posture, and complex motor functions.

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Example: This diagram shows the cerebellum's location at the back of the brain, underneath the cerebrum and connected to the brain stem and spinal cord.

Front

Brain Stem Noun

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[breyn stem]

Back

Brain Stem

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The part of the brain connecting to the spinal cord that controls vital autonomic functions like breathing and heart rate.

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Example: This diagram shows the brain stem's location connecting the main brain to the spinal cord and identifies its three parts: midbrain, pons, and medulla.

Front

Hypothalamus Noun

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[hy-poh-thal-uh-mus]

Back

Hypothalamus

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A small brain structure that regulates body temperature, appetite, thirst, and controls the fight-or-flight response.

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Example: This diagram shows a cross-section of the human brain, highlighting the small, central location of the hypothalamus, a key part of the central nervous system.

Front

Cerebral Cortex Noun

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[suh-ree-bruhl kor-teks]

Back

Cerebral Cortex

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The wrinkly outer layer of the cerebrum, which is involved in complex brain functions like thought and language.

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Example: This diagram shows the cerebral cortex, the brain's outer layer, identifying its characteristic folds (gyri) and grooves (sulci) that increase its surface area.