Skin Development - Bolender Flashcards

1
Q

What are the precursor tissues for epidermis and dermis?

A

Epidermis derived from ectoderm, dermis from mesoderm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the initial layers seen in developing epidermis.

A

A basal line of surface ectoderm is present from the start. A layer of periderm forms above these cells, and gradually sloughs off as it is replaced with intermediate layers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the vernix caseosa?

A

A white, sticky collection of periderm (and later sebum) that coats the fetal skin and separates it from the amniotic fluid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do melanocytes, merkel cells, and langerhans cells develop?

A

They migrate from basally and differentiate in the epidermis (eg neural crest cells migrate, form melanoblasts > melanocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Piebaldism

Describe its etiology & pathophysiology.

How can you distinguish it from vitiligo?

A

Piebaldism

An autosomal dominant mutation of KIT proto-oncogene. This impairs migration of melanocytes resulting in nonprogressive depigmented patches.

Look at history and progression. Vitiligo is progressive, and piebaldism generally has a familial component.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Waardenburg Syndrome

Describe its etiology.

Its symptoms include deafness, heterochromia irides, and dystopia canthorum. Why would these be true?

A

Waardenburg Syndrome

Multiple possible genes that contribute to abnormal melanocyte development.

Heterochromia irides since melanocytes provide pigment there. It is plausible that deafness & dystopia result from abnormal neural crest cell migration–not just of melanocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does immature dermis look on histology compared to mature dermis?

A

Mature dermis will have papillae.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a port-wine stain?

What is the signifiance of port-wine stain in the area of V1?

A

A port-wine stain is a collection of malformed and ectatic blood vessels which occurs in <1% of newborns.

V1 port-wine stain is a sign of Sturge-weber syndrome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the neurological and ocular findings of Sturge-Weber syndrome.

A

Neurological: Seizures, developmental delay, migraines and cortical calcifications.

Ocular: Congenital glaucoma (threatens vision) & increased choroidal vascularity (“tomato ketchup spot”).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the most common vascular tumor at birth?

Describe its progression.

A

Infantile hemangioma (4-5% incidence).

Initially a flat white patch, which grows for up to 9 months and then (incompletely) involutes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Recall the constellations of symptoms in PHACES syndrome.

A

Posterior Fossa (anomalies)

Hemangiomia

Arterial (anomalies)

Cardiac (anomalies)

Eye (anomalies)

Sternal clefting / Subraumbilical Raphe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are hair follicles formed?

A

The epidermis extends growths down into the dermis (hair buds), which form hair bulbs. Shafts/sheaths develop from there.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the two forms of sweat glands found in skin. What type of secretion do they use, and where to they secrete to?

A

Eccrine glands dump directly to the surface and use merocrine secretion.

Apocrine glands dump into the hair follicle and use apocrine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Summarize the development of nails.

A

A nail field forms at the tip of each feature, which migrates to form the nail plate. The nail grows from the proximal nail fold to fill the plate.

*Note: Fingernails precede toenails by ~4wks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hypohidriotic Ectodermal Dysplasia

What is its etiology?

What are its clinical signs?

How is it treated?

A

Hypohidrioitic Ectodermal Dysplasia

X-linked recessive mutation in the Ectodysplasin signaling pathway.

Inability to sweat, square forehead, flat nasum, low ears, thin/dry skin & hair, hypo-anodontia/”Peg Teeth”.

Avoid overheating and keep and eye on those chompers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

From what precursor are merkel cells and langerhans cells derived?

A

Neural crest.

17
Q

What condition discussed here causes deafness?

What condition discussed here causes seizures?

What conditions discussed here are essentially harmless?

A

Waardenburg syndrome.

Sturge-Weber syndrome.

Piebaldism, infantile hemangiomas.