Integument (Exam 3) Flashcards
What is the epidermis derived from
surface ectoderm
What are the three stages of epidermis development
Stage 1
Stage 2
Stage 3
What occurs in the first stage of epidermis development
surface ectoderm and mesoderm form
What occurs in the second stage of epidermis development
surface ectoderm proliferates and forms superficial cells
What occurs to the superficial cells produced in the first stage of epidermis development
they become keratinized
What do the keratinized cells of epidermis form
vernix caseosa
What is the function of the vernix caseosa
lubrication and protection
What does the original layer of ectoderm remain as
proliferative layer
What occurs during the third stage of ectoderm formation
definitive layers are formed
What are the definitive layers of the ectoderm
stratum germivatum stratum spinosum stratum granulosum stratum lucidum stratus corneum
What will nerural crest cells give rise to in the skin
melanocytes
What will melanocytes secrete
melanin
What is the dermis derived from
somatic mesoderm from lateral plate mesoderm
somites
How do sebaceous glands develop
buds of ectoderm down into the dermis layer
Where do the sebaceous glands form in the dermis layer
near the root of hair follicles
What is the function of sebaceous glands in the fetus
contribute to the vernix caseosa
What is the vernix caseosa
white thick, cheesy material that protects the skin
What is the vernix caseosa composed of
epithelial cells and secretions of glands
How are mammary glands formed
buds of ectoderm into the dermis (mammary buds)
follow the ectodermal ridge thickenings (milk lines) down the body
What is witch’s milk
clear or milky white fluid that is sometimes expressed from a new born’s breasts due to the influence of maternal hormones
What are the only ducts formed at birth
main lactiferous ducts
When do the remaining mammary ducts form
at puberty
How do hair follicles form
proliferation of the deepest ectoderm layer into the derms.
forms a bulb at the end which contains germinal matrix to produce the hair
as cells proliferate they are pushed to the surface and become keratizines
What is the function of the first hairs produced by the embryo
hold the vernix against the skin
Later, what occurs to the hair bulbs
melanocytes migrate into the hair bulbs and contribute melanin to the hair
How will arrector pili muscles form
mesoderm
How do nails form
epidermal thickenings (nail fields) at the tip of the digits. Migrates to the dorsal aspect with time
What is ichthyosis
excessive keratinization of the skin, producing dry and scaly skin
In a harlequin fetus, what is the skin like
abnormally thick and cracked
In a collodion infant what is the skin like
thick membrane that cracks and eventually is shed to reveal normal skin
What are angiomas
persistence or surplus of blood or lymphatic vessels
What is nevus flammeus
flat pink or red blotch that appears on the psoterior aspect of the neck
What is a hemagioma (port wine stain)
red but is found on the face
WHat causes albinism
melanocytes fail to produce melanin and the skin, hair, and retina lack pigment
What are supernumerary nipples
extra nipples or breast tissue can form anywhere along the milk lines and are fairly common
What is congenital alopecia
absence of hair
What is hypertrichosis
abnormal amount of hair growth on the body
In what condition is localized hypertrichosis found
spina bifida occulta
What is neurofibromatosis Type 1
NT1-Chromosome 17
GTPase that activates ras
common features: plexiform, cafe au lait spots, axillary frecklying
