Which cell acts as receptor for touch sensation?

UP NHM CHO 7 Sept 2022 (Shift-2)

Applied Anatomy

Easy

Appeared in: UP NHM CHO 7 Sept 2022 (Shift-2)

Explanation

Merkel cells are specialized neuroendocrine cells located in the basal layer of the epidermis.
They function as slowly adapting mechanoreceptors, making them highly sensitive to sustained pressure, light touch, and tactile discrimination.
Each Merkel cell is closely associated with a nerve ending, forming a Merkel cell-neurite complex, which is the functional unit for touch sensation.
These receptors are most concentrated in areas requiring fine touch perception, such as the fingertips, lips, and external genitalia.

Option A: Langerhans cells are part of the skin's immune system, functioning as antigen-presenting cells. They detect and process pathogens, not mechanical stimuli like touch.
Option C: Basal cells are undifferentiated keratinocytes (stem cells) in the stratum basale. Their primary role is epidermal regeneration through cell division, not sensory perception.
Option D: This is a very general term. While Merkel cells are a type of specialized epithelial cell, this answer is not specific enough. The question asks for the specific cell that acts as a receptor.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular components of the epidermis and their specific functions, particularly sensory reception as background academic context rather than a clinical decision trigger.
A nurse's assessment of tactile sensation is a critical component of a neurological examination. Deficits can indicate peripheral neuropathy (common in diabetes), nerve compression, or central nervous system disorders.
Patients with impaired Merkel cell function or nerve damage have a reduced ability to feel light touch, pressure, and texture, increasing their risk for skin breakdown and injury.
Nursing care for patients with sensory deficits includes meticulous skin inspection, pressure redistribution, and patient education on avoiding thermal and mechanical injuries.

How to Approach the Question

First, identify the key concepts in the question: 'receptor' and 'touch sensation'. This directs you to look for a cell with a sensory function.
Next, evaluate each option based on its known primary function in the skin.
Recall that Langerhans cells are for immunity and Basal cells are for regeneration. This allows you to eliminate these two options.
Compare 'Merkel cell' and 'Epithelial cell'. 'Epithelial cell' is a broad category, while 'Merkel cell' is a specific type of cell known to be a mechanoreceptor.
Select the most specific and functionally accurate option. Merkel cells are the specialized receptors for touch, making this the best answer.

Concept Tested & Keywords

Concept Tested: Cellular components of the epidermis and their specific functions, particularly sensory reception.
Stem keywords: cell, receptor, touch sensation
Lead-in keywords: Which

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