Related Experiment Video
Updated: Aug 4, 2026
11:22
Three-dimensional Imaging of Nociceptive Intraepidermal Nerve Fibers in Human Skin Biopsies
Published on: April 29, 2013
Nerves and nerve endings in pigmented nevi. Part I
Archiv Fur Dermatologische Forschung
|January 1, 1975
Summary
Electron microscopy revealed unmyelinated nerve fibers in pigmented nevi, primarily showing effector-type endings. This challenges the presumed sensory function of nevus corpuscles.
Area of Science:
- Dermatology
- Neuroscience
- Histology
Background:
- Pigmented nevi are common skin lesions.
- The innervation of nevi has been previously investigated.
- The precise function of nerve fibers within nevi remains unclear.
Purpose of the Study:
- To investigate the ultrastructure of nerve fibers in pigmented nevi.
- To characterize the types of nerve endings present in nevi.
- To elucidate the functional implications of nevus innervation.
Main Methods:
- Electron microscopy was employed.
- Unmyelinated nerve fibers were identified and analyzed.
- Axon terminals were examined in relation to nevus cells and smooth muscle cells.
Main Results:
- Numerous unmyelinated nerve fibers, similar to cutaneous fibers, were observed in pigmented nevi.
- Axon terminals were frequently found between nevus cells and smooth muscle cells, identified as efferent-type free endings.
- Pure receptor-type endings were rarely observed.
Conclusions:
- The innervation of pigmented nevi predominantly features effector-type endings.
- The observed effector-type endings suggest a role in modulating nevus cell or smooth muscle activity.
- A discrepancy exists between the potential sensory structures (nevus corpuscles) and the abundant effector endings, warranting further functional studies.
Related Concept Videos
01:33Somatosensation
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
01:44Nociception
Nociception—the ability to feel pain—is essential for an organism’s survival and overall well-being. Noxious stimuli such as piercing pain from a sharp object, heat from an open flame, or contact with corrosive chemicals are first detected by sensory receptors, called nociceptors, located on nerve endings. Nociceptors express ion channels that convert noxious stimuli into electrical signals. When these signals reach the brain via sensory neurons, they are perceived as pain. Thus, pain helps the...
01:16Sensory Functions of the Skin
The skin is the largest organ of the human body and plays a crucial role in our sensory perception. It contains a vast network of sensory receptors that contribute to the skin's protective function by perceiving physical, biological, and environmental cues and generating relevant responses.
There are two main categories of receptors on the skin: capsulated and non-capsulated. The non-capsulated ones are mainly the pain receptors. The capsulated ones can be further categorized based on the...
There are two main categories of receptors on the skin: capsulated and non-capsulated. The non-capsulated ones are mainly the pain receptors. The capsulated ones can be further categorized based on the...
01:19Pigmentation
The color of the skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred to the keratinocytes via melanosomes.
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
01:24Peripheral Nervous System: Ganglia and Nerves
The Peripheral Nervous System (PNS) is a crucial component of the body's neural network, extending beyond the central nervous system (CNS) to bridge the gap between the CNS and the external environment. It encompasses nerves, ganglia, and sensory receptors.
Nerves
The nerve is a bundle of axons that serves as the communication highway in the PNS. Each nerve is ensheathed in a protective layer of connective tissue called the epineurium. This outermost layer safeguards the nerve and supports the...
Nerves
The nerve is a bundle of axons that serves as the communication highway in the PNS. Each nerve is ensheathed in a protective layer of connective tissue called the epineurium. This outermost layer safeguards the nerve and supports the...
01:19Cranial Nerves: Overview and Anatomy
The cranial nerves are an important part of the complex network of nerves in the human body. These nerves emerge directly from the brain and are responsible for transmitting essential information between the brain and various parts of the head and neck. There are 12 pairs of cranial nerves, systematically numbered using Roman numerals from I to XII, beginning from the anterior and moving to the posterior of the brain. Each cranial nerve is uniquely identified by names that reflect its function...