"Desmosome (Macula adherens) - A cell-to-cell connection that provides structural support with intermediate filaments, particularly in tissues that undergo mechanical stress (e.g., skin, gastric tissue, bladder). Connects keratinocytes in the stratum spinosum of the epidermis." - AMBOSS

Stupid question, honestly just take your best guess and move on lol.

Basically asking if you know Pemphigus Vulgaris. Separation of suprabasilar epidermis, intact basal keratinocytes vs Bollous pemphigoid--> includes separation of basal layer

After some research this is why the other answers are incorrect:

1. basal keratinocyte & lamina lucida
2. Incorrect b/c lamina lucida is a component of the basement membrane which is found between the epithelium and underlying connective tissue (e.g., epidermis and dermis of the skin).
3. It is a roughly 40 nanometre wide electron-lucent zone between the plasma membrane of the basal cells and the (electron-dense) lamina densa of the basement membrane. (WIKI)

4. basal keratinocyte attaches to the basement membrane using hemidesmosome

5. Granular keratinocyte & stratum corneum

6. Stratum lucidum separates these two layers.
7. there are no desmosome that connect these two layers

8. Image for reference

9. Lamina lucida & Lamina densa -- click for image

10. both are part of the basement membrane and not the epidermis

11. Melanocyte & basal kertinocyte --- click for image

12. are both connected to eachoter via E-cadherins
13. it is probably the damage to this connection that might lead to melanoma

After some research this is why the other answers are incorrect:

Basal keratinocyte & lamina lucida

• Incorrect b/c lamina lucida is a component of the basement membrane which is found between the epithelium and underlying connective tissue (e.g., epidermis and dermis of the skin).
• It is a roughly 40 nanometre wide electron-lucent zone between the plasma membrane of the basal cells and the (electron-dense) lamina densa of the basement membrane. (WIKI)
• basal keratinocyte attaches to the basement membrane using hemidesmosome

Granular keratinocyte & stratum corneum

• Stratum lucidum separates these two layers.
• there are no desmosome that connect these two layers
• Image for reference

Lamina lucida & Lamina densa -- click for image

• both are part of the basement membrane and not the epidermis

Melanocyte & basal kertinocyte --- click for image

• are both connected to eachoter via E-cadherins
• it is probably the damage to this connection that

Blistering diseases such as pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune diseases in which auto-antibodies target desmogleins.

• PV is caused by circulating autoantibodies (IgG) that target Dsg3 (Desmoglein 3) and sometimes Dsg1.
• PV is manifested by suprabasal acantholysis, or blisters in the mucous membrane and blisters in the epidermis.
• PF patients have autoantibodies that target Dsg1 with superficial blisters on the epidermis with no mucous membrane issues.
• Both disease result in a loss of keratinocyte adhesion.
• Pemphigus can also be caused by a bacterial infection: bullous impetigo is an infection caused by a staphylococcus bacterium that releases a toxin that cleaves the Dsg1 extracellular domain.

Desomosmes by function interconnect keratinocytes in the stratum spinosum - startum spinosum is the suprabasal layer. Exclude option: a) Lucida is too high ; not in continuation with basal layer c) Corneum is even higher, Granulosum and Corneum aren't n continuation d) Lamina dens (BM) and lamina lucida not keratinocytes and not in continuation either e) Melanocyte are in the basal layer; it is not a keratinocyte

b) is the only option that makes sense based on histology and also the only option that speaks about inter-keratinocyte linkage

Desmoglein: Component of desmosomes, which connect keratinocytes in the stratum spinosum - FA 2018, p.467, Pemphigus Vulgaris

By this I can only assume that they mean that desmoglein connects keratinocytes to EACH OTHER, hence why the other options connecting keratinocytes to other structures are incorrect

Why is basal keratinocyte : suprabasal keratinocyte the cell junction that’s most likely to be affected? Is it because it’s the only answer that lists a junction between two keratinocytes?

Desomosmes by function interconnect keratinocytes in the stratum spinosum - startum spinosum is the suprabasal layer. Exclude option: a) Lucida is too high ; not in continuation with basal layer c) Corneum is even higher, Granulosum and Corneum aren't n continuation d) Lamina dens (BM) and lamina lucida not keratinocytes and not in continuation either e) Melanocyte are in the basal layer; it is not a keratinocyte

b) is the only option that makes sense based on histology and also the only option that speaks about inter-keratinocyte linkage

https://www.researchgate.net/profile/Mithun_Bhowmick5/publication/317179550/figure/fig1/AS:500004767715328@1496221834988/Cross-section-of-human-skin-Stratum-corneum-SC-and-epidermis-the-main-barrier-to.png maybe this picture can show where the desmosome exist