Integumentary System

Skin. Another thing on a long list of things that amoebas don’t have – but greatly admire – because skin, which is your largest organ, is remarkable. Being the largest organ, it’s very fitting that it’s part of a system with a very long word: integumentary system. Skin - and structures associated with it – make up the integumentary system.

Why do we admire skin so much? Well, skin is critical for homeostasis because it helps maintain internal body temperature and fluid balance. As a physical barrier, it protects your internal structures and organs from being damaged. It protects from invasion of pathogens like bacteria or fungi for example. Skin is where Vitamin D is produced. Skin also

has sensory functions – for example, if a ladybug lands on your arm, you are usually aware of it. The integumentary system, which includes skin, has some depth to it: this system has layers. Layers of different tissues and cell types. And you’ll find major layers can be divided into smaller layers as well. We’re going to

take a little exploration of this – and a reminder- this is a general exploration. We’re going to start with the epidermis –first, I want to mention cells that can be found in different locations in the epidermis called keratinocytes. These are cells that make keratin. Keratin is actually a protein – a protein that helps cells be water resistant

and tough. Keratinocytes are produced at the bottom layer of the epidermis – which we’ll get to on our tour – and they get pushed upward to the top, superficial layer of the epidermis where they are considered cornified. Cornified cells are hardened , flattened, and tough – they’re also dead – they’ve lost their organelles and are just full of keratin.