Neurons and Neurophysiology

Front

Neuron Noun

---

[noor-on]

Back

Neuron

---

A specialized nerve cell that carries an electrical impulse, consisting of a cell body, dendrites, and an axon.

---

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

Front

Glial cells (neuroglia) Noun

---

[glee-uhl selz (noo-rog-lee-uh)]

Back

Glial cells (neuroglia)

---

Cells within nervous tissue that provide structural support, insulation, and protection for neurons in the nervous system.

---

Example: This diagram shows a glial cell (an oligodendrocyte) wrapping around a neuron's axon to form a protective layer, demonstrating its essential support role.

Front

Dendrites Noun

---

[den-dryts]

Back

Dendrites

---

Short, branch-like extensions of a neuron that receive nerve signals and chemical messages from other neurons.

---

Example: This diagram shows that dendrites are the tree-like branches of a neuron that receive electric signals from other neurons at a connection point called a synapse.

Front

Axon Noun

---

[ak-son]

Back

Axon

---

A long, slender projection of a neuron that conducts electrical impulses away from the cell body to other cells.

---

Example: This diagram shows an axon as the long part of a neuron that carries signals away from the cell body to other cells, like muscle fibers.

Front

Myelin sheath Noun

---

[my-uh-lin sheeth]

Back

Myelin sheath

---

A fatty, insulating covering on some axons that speeds up the conduction of electrical impulses along the nerve fiber.

---

Example: This diagram shows the myelin sheath as the insulating layer wrapped around the axon, helping to speed up electrical signals traveling through the neuron.

Front

Axon terminals Noun

---

[ak-son tur-min-uls]

Back

Axon terminals

---

The structures at the end of an axon that release neurotransmitters to pass a signal across a synapse.

---

Example: This image shows the axon terminal (left) releasing chemical messengers called neurotransmitters to send a signal to the next neuron's dendrite (right).

Front

Synapse Noun

---

[sin-aps]

Back

Synapse

---

The small, specialized gap between two neurons across which nerve impulses are transmitted by chemical messengers.

---

Example: This diagram shows a nerve signal traveling from one neuron to another by releasing chemical messengers (neurotransmitters) across the tiny gap (synapse) between them.

Front

Neurotransmitters Noun

---

[noor-oh-trans-mit-ers]

Back

Neurotransmitters

---

Special chemical molecules released by axon terminals to transmit a signal across a synapse to another cell.

---

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

Front

Central Nervous System (CNS) Noun

---

[sen-truhl nur-vuhs sis-tuhm]

Back

Central Nervous System (CNS)

---

The major division of the nervous system that consists of the brain and the spinal cord, processing most information.

---

Example: This diagram shows the Central Nervous System is composed of the brain and the spinal cord, which work together as the body's main control center.

Front

Peripheral Nervous System (PNS) Noun

---

[puh-rif-er-uhl nur-vuhs sis-tuhm]

Back

Peripheral Nervous System (PNS)

---

The part of the nervous system made up of all the nerves that lie outside of the brain and spinal cord.

---

Example: This diagram shows the Peripheral Nervous System (PNS) as the network of nerves and ganglia extending from the Central Nervous System (brain and spinal cord).