A&P Honors: Dev. Aspects of the Integumentary System

Wha does the epidermis develop from?

Embryonic ectoderm.

What does the dermis and subcutaneous tissue develop from?

The mesoderm

By the fourth month of development, what has happened?

The skin is fairly well formed, the epidermis has all its strata, dermal papillae are obvious, fingerprints have developed, and rudimentary epidermal appendages have formed by downward projections of cells form the basal layer.

By the fifth and sixth month, the fetus is covered in a lanugo coat. What is it? When is it shed?

A downy coat of delicate colorless hairs. Shed by the seventh month.

When a baby is born, what is it’s skin covered in?

Vernix caseosa

What is vernix caseosa?

A white, cheesy-looking substance produced by the sebaceous glands that protect the fetus’s skin within the water-filled amnion.

What are milia?

Accumulations in the sebaceous glands on the forehead and nose that appear as small white spots.

What is dermatitis?

Inflammation of the skin or scaling.

As old age approaches, what happens concerning the skin?

The rate of epidermal cell replacement slows, the skin thins, and its susceptibility to bruises and other injuries increases. The lubricating substances produced by the skin glands that make young skin so soft become deficient.