Skin Functions…Think Like a Barrier
This function of the skin helps regulate internal temperature through Mechanisms like perspiration and dilation or constriction of blood vessels
Thermoregulation
This is the outermost layer of the epidermis, made up of dead keratinized cells.
Stratum Corneum
These cells product melanin and live in the stratum básale
Melanocytes
Multiple Choice: Which of these factors makes a product absorb more easily into the skin? A) Larger molecule size B) High water content C) Lipid-solubility D) High pH
C) Lipid-solubility… 1. Mix with the skin’s oils 2. Pass through the oily layers more easily 3. Penetrate deeper into the skin
What are free radicals, and why are they considered harmful?
They are unstable molecules with unpaired electrons that damage healthy skin cells.
Besides acting as a barrier, the skin performs this protective function by neutralizing free radicals through naturally occurring antioxidants.
Antioxidant defense. The skin neutralizes free radicals with its natural antioxidants
This living layer is responsible for forming basal cells and is directly above the Dermis.
Stratum Basale (Basal Layer)
These immune cells reside in the skin and help fight off foreign invaders.
Langerhans cells
List two factors that affect skin penetration of topical products
molecule size, product formulation, solubility (lipid vs water), skin temp., condition of the skin barrier
These common sources contribute to the production of free radicals in the body. Name two.
UV rays, pollution, smoking, poor diet, stress, injury
True or False: Lipid-soluble products have a harder time penetrating the skin than water-soluble ones. Explain why.
False. Lipid-soluble products absorb more easily into the skin because they can pass through the skin’s lipid barrier.
Which layer of the dermis contains blood vessels, lymph vessels, sweat glands, oil glands, and hair follicles.
Reticular layer
Which protein is produced by keratinocytes and gives the skin its strength and waterproof barrier?
Keratin
The skin selectively absorbs products through these structures. Name at least two.
Hair follicles, sebaceous glands, cell membranes
Antioxidants are considered the “heroes” against free radicals. Name three types of antioxidants found in the skin.
Proteins, enzymes vitamins (C + E), and metabolites
Name two ways the skin defends the body against harmful bacteria or environmental invaders.
Acid Mantle, Sebum (Oil) , Melanocytes (UV protection), Langerhans cells (Immune defense), and tightly packed cells
Name the layer where melanocytes are found and state their primary function
These cells detect pressure and are found in the dermis–hint: They help you feel touch.
Merkel cells or Tactile corpuscles
Explain the difference between intercellular and transcellular absorption routes in your own words.
True or False: Free radicals stabilize themselves by donating an electron to healthy molecules.
False. Free radicals steal electrons from healthy molecules, damaging them
The skin uses this route to absorb very small molecules directly into the cells. Bonus: what is one factor that affects this kind of absorption?
Transcellular penetration. Factors: molecule size, solubility or product formulation
This dermal layer forms the papillae that connect the epidermis and dermis. Why is the structural connection important?
Papillary layer. It forms dermal papillae that anchor the epidermis and provide nutrients and oxygen to skin cells.
Which type of skin cell is responsible for forming new keratinocytes and where are they located
Basal cells located in the basal layer.
This type of product can pass through cell membranes more effectively because it is similar to the skin’s natural composition. Name it and explain why.
Lipid-soluble products. They resemble the skin’s own oils and penetrate more easily through the lipid barrier.
Explain the chain reaction caused by free radicals and how antioxidants help stop it. Bonus if you can name an antioxidant skincare ingredient.
Free radicals steal electrons from other molecules, starting the chain reaction of damage. Antioxidants stop the chain reaction by donating electrons to stabilize the free radicals. EX: Vitamin C. Green tea. Pomegranate.