Peripheral Nerve – Tutorial
Please read Unit 5 – Introduction to Nervous System Tissues prior to completing the activities in this chapter.
Introduction to Peripheral Nerves
Peripheral nerves are cable-like bundles of axons surrounded by several layers of connective tissue found outside the brain and spinal cord. The images of peripheral nerves seen in the tutorials that follow are from distal branches of spinal nerves consisting of bundles of mixed (both motor and sensory) myelinated axons. It will not be possible to differentiate between the axons of motor and sensory neurons in the images of peripheral nerves used in this chapter.
The tutorials found below will focus on the organization of the connective tissue layers associated with nerves known as epineurium, perineurium, and endoneurium. These connective tissue wrappings are composed primarily of collagen fibers of various consistencies and extend continuously along the entire length of a nerve. The epineurium is the outermost connective tissue layer of a nerve consisting of interwoven layers of collagen fibers that surround hundreds or even thousands of individual axons. Smaller bundles of axons known as fascicles within the nerve are separated from each other by a connective tissue layer known as the perineurium which surrounds each fascicle. Individual axons within a fascicle are surrounded by the innermost connective tissue layer known as the endoneurium. Collectively, these three connective tissue wrappings provide strength and protection for a nerve and help isolate nerves from surrounding tissues.
Tutorial: Use the image slider below to learn more about peripheral nerves.
Microscopy: Use the image slider below to learn how to use a microscope to study peripheral nerves.
Tutorial: Use the hotspot image below to learn more about peripheral nerves cut in cross-section.
Tutorial: Use the hotspot image below to learn more about peripheral nerves cut in longitudinal-section.
Tutorial: Use the image slider below to study numerous examples of peripheral nerves.
