Neurons and Glia Lecture 2

What are the two major divisions of the nervous system?

The Central Nervous System (CNS), which includes the brain and spinal cord, and the Peripheral Nervous System (PNS), which consists of the nerves that extend throughout the body.

What is the difference between gray matter and white matter?

Gray matter is composed of neurons and glia, while white matter is primarily made of myelinated axons, which appear white due to the fatty myelin sheath.

What are efferent and afferent nerves?

Efferent nerves are motor nerves that carry signals away from the CNS to the rest of the body. Afferent nerves are sensory nerves that carry signals toward the CNS.

What is the primary function of a neuron?

they sense environmental changes, process information, communicate changes to other neurons, and command the body's responses.

What are the three main parts of a neuron?

consists of a soma (cell body), dendrites (which receive signals), and an axon (which transmits signals).

What is the axon hillock?

It is the region where the axon originates from the soma. It's the site where nerve impulses are generated.

What is a synapse?

Is the junction where a neuron communicates with another cell, typically through the release of neurotransmitters.

What is axoplasmic transport?

It is the active process by which substances are transported along the axon, essential for maintaining the axon and its communication function.

How are neurons classified based on their structure?

classified by the number of neurites (axons and dendrites) extending from the soma: Unipolar: One neurite. Bipolar: Two neurites. Multipolar: More than two neurites (most common in the brain).

How are neurons classified based on connections within the CNS?

They can be classified as sensory neurons (afferent), motor neurons (efferent), or interneurons (which connect to other neurons).

What is the primary function of glia?

(from the Greek word for "glue") provide support, insulation, and nourishment for neurons.

What is the function of an astrocyte?

are the most numerous glial cells in the brain. They regulate the extracellular environment (neurotransmitters, ions), influence neurite growth, and form the blood

What are the two types of myelinating glia and where are they found?

are in the CNS and can myelinate multiple axons. Schwann cells are in the PNS and myelinate only a single axon.

What is the function of the myelin sheath?

is a fatty insulation around the axon that allows for faster electrical signal conduction.

What is a Node of Ranvier?

is the region of the axonal membrane that is uninsulated and exposed, located between segments of myelin.

What is the function of microglia?

act as phagocytes to clean up debris from dead or dying neurons and glia, essentially acting as the immune cells of the CNS.

What is the function of ependymal cells?

they line the brain's ventricular system, which are the fluid