Neurons and Myelin Sheath

Flashcards covering key terms and concepts related to neurons, myelin sheath, and their classifications.

Myelin Sheath

A fatty protein layer that electrically insulates axons, increasing the speed of nerve impulse transmission.

Schwann Cells

Cells that wrap around axons to form the myelin sheath.

Node of Ranvier

A gap between adjacent Schwann cells on a myelinated axon.

Multipolar Neuron

A neuron type with numerous dendrites and three or more processes, making up 99% of neurons.

Bipolar Neuron

Neuron with two processes (an axon and a fused dendrite), found in rare cases such as sense organs.

Unipolar Neuron

A neuron with one process emerging from the cell body, mostly sensory neurons in the PNS.

Gray Matter

Composed of unmyelinated fibers and cell bodies.

White Matter

Composed of myelinated fibers in the CNS.

Receptive Region

Part of a neuron that receives stimuli, typically the dendrites.

Conducting Region

Part of a neuron that generates and transmits action potentials, generally the axon.

Secretory Region

Part of a neuron that releases neurotransmitters, usually located at axon terminals.

Interneuron

Multipolar neurons that conduct impulses within the CNS, integrating sensory input or motor output.

Motor Neuron

A type of neuron that conducts impulses along efferent pathways to effectors.

Sensory Neuron

Neurons that carry impulses along afferent pathways to the CNS for interpretation.