General anatomy and histology: epidermal water barrier: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · General anatomy and histology: epidermal water barrier

Sample item

A dermatology student studies why skin is waterproof. Lipid-filled lamellar bodies fuse with the plasma membrane and discharge into the intercellular space at which level of the epidermis?

AAround melanocytes of the basal layerBAt the junction of the granular and cornified layersCBetween the basal cells and the basement membraneDWithin the dermal papillary layer

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. At the junction of the granular and cornified layers

Lamellar (Odland) bodies release lipid at the transition from the granular layer to the stratum corneum. This lipid seals the extracellular spaces and forms the water barrier of the skin. Defects in this barrier occur in ichthyoses and atopic dermatitis.

Option by option

A. Around melanocytes of the basal layer
Melanocytes transfer pigment to keratinocytes and do not form the lipid barrier.
B. At the junction of the granular and cornified layers (correct)
Correct. Lipid released at the granular-cornified junction forms the permeability barrier.
C. Between the basal cells and the basement membrane
The basal layer sits on the basement membrane and is not where barrier lipid is released.
D. Within the dermal papillary layer
The papillary dermis lies below the epidermis and has no lamellar bodies.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, At the junction of the granular and cornified layers. Lamellar (Odland) bodies release lipid at the transition from the granular layer to the stratum corneum.

Why is "Around melanocytes of the basal layer" not the answer?

Melanocytes transfer pigment to keratinocytes and do not form the lipid barrier.

Why is "Between the basal cells and the basement membrane" not the answer?

The basal layer sits on the basement membrane and is not where barrier lipid is released.

Why is "Within the dermal papillary layer" not the answer?

The papillary dermis lies below the epidermis and has no lamellar bodies.

What concept does this question test?

It tests General anatomy and histology: epidermal water barrier in Anatomy. This lipid seals the extracellular spaces and forms the water barrier of the skin. Defects in this barrier occur in ichthyoses and atopic dermatitis.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study General anatomy and histology: epidermal water barrier?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.