Trans 4 Flashcards
All constituents of the skin are derived from:
______________ and _______________
Ectoderm (10-12 days EAG)
Mesoderm (18-19 days EAG)
Epidermis and skin appendages are derived from the ______________.
Ectoderm
Melanocytes and the nerves are derived from the _______________.
Neuroectoderm
Describe the development of the epidermis in: Week 4-5 EAG Week 5-6 EAG Week 8-10 EAG Week 12 EAG
Week 4-5 EAG - Surface ectoderm develops into a single cuboidal cell layer (mitotically active)
Week 5-6 EAG - Periderm covers the single cuboidal cell layer
Week 8-10 EAG - Germinative layer gives rise to the intermediate layer; the stratified squamous epithelium begins to form
Week 12 EAG - Epidermis is almost complete by the end of the 1st trimester. The different epidermal layers are already present
In adults, keratinization occurs for _________ in a _____ environment
14-31 days, dry
In a fetus, keratinization occurs for __________ in a _____ environment
22-24 weeks, wet (amniotic fluid)
What compound is abundant in the fetal keratinocyte and serves as the main energy source?
Glycogen
Dermis is derived from the __________.
Mesoderm
These structures are derived from which germ layer?
Dermis Epidermis Fibroblasts Endothelial and Perithelial cells Myocytes Mast cells Nails Hair Fibers Glands Ground substance Melanocytes Nerves
Dermis - Mesoderm Epidermis - Ectoderm Fibroblasts - Mesoderm Endothelial and Perithelial cells - Mesoderm Myocytes - Mesoderm Mast cells - Mesoderm Nails - Ectoderm Hair - Ectoderm Fibers - Mesoderm Glands - Ectoderm Melanocytes - Neuroectoderm Nerves - Neuroectoderm Ground substance - Mesoderm
Which fiber provides tensile strength and limits extent of deformation of skin when pulled?
Collagen fibers
Which fiber imparts skin its original shape after being stretched?
Elastic fibers
True or false. The dermis is 80% collagen and 1% elastic fiber.
True
Development of the dermis:
Week 6
Week 12
Week 24
Week 6: Collagen fibers develop
Week 12: Collagen bundles develop
Week 24: Elastic fibers develop
Differentiate neonates and infants
Neonatal period: 0-30 days of life
Infant: 30 days - 12 months of life
True or false. Skin development is complete after birth.
False. It continues to undergo a process of adaptation and maturation even after birth.
True or false. Newborn skin has less hair, sebaceous and sweat glands.
True
True or false. Newborn skin has more intercellular attachments and desmosomes.
False
Condition wherein there is a grayish-white film after birth that serves as a lubricant and an antibacterial compound.
Vernix caseosa
It is the intensely erythematous skin caused by the drying up and flaking off of the vernix caseosa.
Erythema neonatorum
Blotchy or lace-like pattern of dusky erythema caused by exposure to cold environments. It reflects the vasomotor instability (immature autonomic control of cutaneous vascular plexus) of newborns.
Mottling and Cutis marmorata
Bluish discoloration on palms, soles, and mouth
Acrocyanosis
Sharp longitudinal midline demarcation of the body when placed on his/her side, observed usually in infants with low birth weight. It reflects immaturity of the hypothalamic center.
Harlequin color change
Few, white globular papules representing benign, superficial epidermal inclusion cysts commonly on the face of newborns.
Milia
Milia found inside mouth of neonates
Epstein’s pearls
