skin through the ages Flashcards
(100 cards)
At gastrulation, cells divide into 3 layers: what are they?
Ectoderm
Mesoderm
Endoderm
ectoderm then divides into_________(2 layers)
Ectoderm
Neuroectoderm (neural crest and neural tube)
epidermis is derived from________
Formed from Ectoderm
what are the five layers of the skin?
Stratum Basale
Stratum Spinulosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum
at week 6, what is developed in the epidermis?
Week 6
Bilayered Epidermis
Periderm
Basal Layer
at week 8, what is happening in the development of the epidermis?
Week 8
Stratification begins
Intermediate layer and Basal layer
defects at week 8 of skin development lead to which condition?
Defects at this point lead to Ectodermal Dysplasia
what defects are seen in ectodermal dysplasia?
Defects in hair, teeth, bone, skin
by mid-third trimester, describe development of the skin. which protein is expressed and what about the cell formation of the cell envelope? what do defects at mid 3rd trimester lead to?
By Mid 3rd Trimester: Terminally differentiated epidermal layers similar to adult skin
Filaggrin expressed and the cornified cell envelope formed
Defects at this point lead to some of the ichthyoses
which conditoin? mutation in what causes this?

ichythosis vulgaris
filaggrin mutation
what are the three specialized cells in the epidermis?
melanocytes (produce and distribute melanin)
langerhan cells (
merkle cells (specialized cell, neural type)
know: where do melanocytes originate?
neural crest
where do melanocytes migrate to?
ear(cochlear)
eye(choroid, iris, ciliary body, retnia)
skin(epdiermeis and hair follicles)
leptomeninges
KNOW: Origin/migration/survival- defect leads to _________________
Origin/migration/survival- defect leads to **patches of depigmentation where no migration took place (eg **Waardenburg Syndrome, Piebaldism) **
KNOW: melanin synthesis defects lead to _____________
Melanin synthesis- defect leads to **defective production of melanin (albinism) **
KNOW:Melanosome formation and movement- defect leads to ___________
Melanosome formation and movement- defect leads to pigment dilution
Chediak-Higashi, Hermansky Pudlak Syndrome
which condition?
cause?

- *disorder: Piebaldism**
- *cause: Defective melanocyte mutation leads to patches of depigmentation**
condition?
what causes it?

MOSAICISM
cause: Different gene populations in one individual
Melanocytes develop along lines of Blaschko
Pigmentary mosaicism seen as linear streaks or whorls
X-linked conditions often follow lines of blaschko due to lyonization(x-incactivation)
conditoin?
what causes it

cause: Waardenberg Syndrome
Defective survival of melanocytes leads to patches of depigmentation
Enteric ganglion cells also affected (also from neural crest)
condition?
what causes it?

Albinism
cause: Due to ineffective production of melanin
Melanocytes are present, but there is no melanin
Different genes lead to different phenotypes
conditoin?
cause?

condition: Hermansky Pudlak and Chediak Higashi Syndrome
cause: Ineffective transfer of melanosomes to keratinocytes lead to pigmentary dilution (silver hue).
what is affected: May affect other cells where lysosomal trafficking is important (Neutrophils, Neurons, Platelets)
which condtion?
mode of inheritance?
progression of disease?
which three defects are present?
which gender is it fatal in utero in?

condition: incontientia pigmenti
XLD: x-linked dominant
progression of disease: blaschkoid vesicles–>verrucous–>hyperpigmented–>hypopigmented lesions
defects: ocular, dental, CNS
FATAL in utero in males (females can survie b/c of lyonization)
______ lines

blaschko lines
KNOW: dermis is dervied from _________
Derived from both ectoderm and **mesoderm **



































