Skin Anatomy and Physiology 101 - An Introduction

Antoinette Nguyen

Have a thirst for skin knowledge? Ever wonder what the commercials/ads/posts are talking about when they are referring to different parts of the skin? Want to understand the purposes of skincare products but don’t know how or where to start? Keep on reading below for our first edition of "Skin Anatomy and Physiology 101 - The Basics"!

Finding a skincare routine that can give you that glowing, dewy, soft look can be a daunting task. Trying endless amounts of products that may or may not work for you and can also be expensive. This is why it is so important to learn about your skin anatomy. By learning the basics, you will better understand what your skin is like and how to optimally incorporate the right products into your skincare regime.

Your skin is the largest organ. Its job is to protect you from environmental factors like bacteria, UV, and pollutants and prevent fluids inside your body, like water, from escaping. The skin is made up of an outer layer (called the epidermis), a middle layer (the dermis), and an inner layer (the hypodermis). Collagen and elastin, components of the skin that keep the structural integrity and elasticity intact, are found within the dermis. In order for skincare products to reach the dermis and act on cells that produce collagen and elastin, active ingredients need to penetrate the epidermis.

The epidermis is composed of 4-5 layers depending on the area. The stratum basale is the most bottom layer of the epidermis. It is where new skin cells, called keratinocytes, are produced. As the newly form cells mature, they move upwards towards the surface of your skin through another four layers until they reach the uppermost layer. Keratinocytes move from the stratum basale, to the stratum spinosum, stratum granulosa, stratum lucidum (found only in the palm and feet), and finally the stratum corneum. During this journey, the cells will die somewhat midway and are eventually sloughed off at the stratum corneum. However, they are continuously replaced by newly formed cells that were born after them roughly every 30 days. This replenishment helps maintain bright, even-textured, soft skin. As we age, this process slows such that replacement occurs approximately every 45-50 days. This lengthy skin replenishment cycle is why it can take up to three months to truly see the results of skincare products.  

The epidermis also plays a role in preventing ‘trans-epidermal water loss (TEWL)’. The cells of the stratum corneum, the outermost layer of your skin that you see, create a barrier that is glued together by lipids (fats). This is often referred to as a brick and mortar, where the keratinocytes are the bricks and the fats are the mortar. Together, they keep too much water from leaving or entering, maintaining skin hydration. Proper cell hydration helps with cell shape so it doesn’t lose its integrity and cause faulty leakage. If the outer layer is defective, water loss occurs in addition to disastrous damage by pathogens, UV, and environmental pollutants.  

So what about the dermis? As mentioned, the dermis contains elastin and collagen. Elastin helps your skin bounce back to its original shape while collagen provides structure and strength. As we age and are naturally exposed to environmental factors such as UV, our body produces less elastin and collagen. This leads to skin dullness, uneven texture, sagging, and wrinkles. Having an effective skincare regime can help maintain the vitality of your skin.

Hopefully this information has given you some of the basics of skin anatomy. By understanding the structure of your skin and how it works you will be able to choose products and ingredients that will be the most effective for you. Check out our next post on how to create a skincare regime that keeps everything we discussed in mind.



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