Name of the receptor on epidermis that transmits stimuli to the axon through a chemical synapse?

Chitranjjan National Cancer Institute Kolkata - 2021

Applied Anatomy

Easy

Appeared in: Chitranjjan National Cancer Institute Kolkata - 2021

Explanation

Merkel cells are specialized epithelial cells located in the stratum basale of the epidermis.
They function as slow-adapting mechanoreceptors, which means they respond to continuous pressure and texture.
Crucially, each Merkel cell forms a synapse with a sensory nerve ending (an Aβ afferent fiber) to create a 'Merkel cell-neurite complex'.
This complex allows the Merkel cell to release neurotransmitters that excite the nerve fiber, transmitting the sensory stimulus to the central nervous system.

Option A: Langerhans's cells are not involved in sensory perception. They are dendritic cells that act as antigen-presenting cells, playing a key role in the skin's immune response.
Option C: Woodzer cells are not a recognized or scientifically validated type of cell in human skin histology. This term is fictitious and serves as a distractor.
Option D: Similar to Woodzer cells, Berger cells are not a known cell type in the epidermis or any other human tissue. This is a fictitious name used as an incorrect option.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Sensory Receptors of the Epidermis as background academic context rather than a clinical decision trigger.
A rare but highly aggressive form of skin cancer, Merkel cell carcinoma, arises from these cells. Nurses play a role in skin cancer screening and patient education.
Assessing a patient's ability to perceive light touch and pressure is a fundamental part of a neurological examination, which evaluates the integrity of pathways involving receptors like Merkel cells.
What if? If a patient has peripheral neuropathy (e.g., from diabetes), the function of the sensory nerves connected to Merkel cells can be impaired, leading to a loss of sensation in the fingertips and feet, increasing the risk of injury.

How to Approach the Question

First, identify the key terms in the question: 'receptor', 'epidermis', 'axon', and 'chemical synapse'. This points to a question about sensory neurophysiology in the skin.
Recall the different cell types found in the epidermis. These include keratinocytes, melanocytes, Langerhans cells, and Merkel cells.
Evaluate each option based on its known function. Langerhans's cells are for immunity. 'Woodzer' and 'Berger' cells are unfamiliar and likely distractors.
Focus on Merkel cells. Recall or deduce that they are the primary touch receptors within the epidermis itself that directly communicate with nerve endings.
Confirm that Merkel cells are the only option that fits the description of an epidermal cell forming a synapse with a sensory axon to transmit touch stimuli.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 3 p. 96-98

E6 Anatomy Grays 43e Vol 1 Part 2 p. 101-103