Which of the following cells is responsible for stimulating the sensory nerves of the part of the skin that senses touch and acts as a dome?

1. A

   Langerhans cell

2. B

   Merkel cell

3. C

   Basal cell

4. D

   Epithelial cell

Appeared in: UP CHO - 2018

Explanation

• Merkel cells are specialized mechanoreceptors located in the stratum basale of the epidermis, the deepest layer.
• They are responsible for sensing fine details, such as texture and sustained light pressure.
• Merkel cells are grouped with sensory nerve endings to form structures called Merkel cell-neurite complexes or tactile domes (Iggo dome receptors).
• This unique structure, which protrudes upward, makes the area extremely sensitive to touch, matching the description in the question.

Why Other Options Were Wrong

• Option A: Langerhans cells are not sensory cells; they are part of the immune system. They function as antigen-presenting cells, identifying pathogens and initiating an immune response in the skin.
• Option C: Basal cells are undifferentiated keratinocytes (stem cells) in the stratum basale. Their primary function is mitosis, continuously dividing to produce new cells that migrate upwards to replenish the epidermis. They do not have a sensory role.
• Option D: Epithelial cell is a very broad and general term. While Merkel cells are a type of specialized epithelial cell, this option is not the best or most specific answer. The majority of epithelial cells in the skin (keratinocytes) primarily form a protective barrier and are not specialized sensory receptors.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Functions of specialized cells within the epidermis of the skin as background academic context rather than a clinical decision trigger.
• A nurse's assessment of a patient's sensory function (e.g., using a monofilament test) directly evaluates the integrity of receptors like Merkel cells and their associated nerves.
• Conditions like peripheral neuropathy, common in diabetes mellitus, damage these sensory structures, leading to a loss of protective sensation and increasing the risk for foot ulcers and injuries.
• What if? If a patient has a spinal cord injury, the pathway transmitting signals from Merkel cells to the brain (the dorsal column-medial lemniscal system) may be disrupted, resulting in loss of fine touch and pressure sensation below the level of the injury, even if the skin receptors are intact.

How to Approach the Question

• First, identify the key terms in the question: 'sensory nerves,' 'senses touch,' and 'dome.' This points to a specialized sensory function.
• Next, review the options and recall the primary function of each cell type in the epidermis.
• Eliminate Langerhans cells, as their role is immunological, not sensory.
• Eliminate Basal cells, as their role is regenerative (mitosis), not sensory.
• Compare Merkel cell and Epithelial cell. 'Epithelial cell' is a general category, while 'Merkel cell' describes a specific, specialized sensory receptor.
• Recall or deduce that Merkel cells form 'tactile domes' with nerve endings to sense touch. This directly matches all keywords in the question, making it the most accurate answer.

Concept Tested & Keywords

• Concept Tested: Functions of specialized cells within the epidermis of the skin.
• Stem keywords: cells, sensory nerves, skin, senses touch, dome
• Lead-in keywords: Which

Question ID

Q19tWFwuLewCnWj5Vt4qt5

Copy ID

Reference Book

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

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