The Integumentary System Structure and Functions
Your skin does way more than just cover your body! The integumentary system prevents water loss, excretes waste through sweat, and even helps produce vitamin D with sunlight. It provides physical protection through tough keratin cells while the "acid mantle" keeps harmful bacteria at bay.
The epidermis is your skin's outermost layer, made of epithelial cells arranged in five distinct sublayers - from the surface stratum corneum down to the stratum basale. Four specialized cell types work here keratinocytes produce protective keratin, melanocytes create skin pigment, dendritic cells defend against pathogens, and Merkel cells help with your sense of touch.
Beneath the epidermis lies the dermis, which makes up most of your skin. This vascularized layer (meaning it contains blood vessels) houses sweat glands, oil glands, hair follicles, and sensory nerves. The bottom subcutaneous layer isn't technically skin but provides crucial support with fatty and connective tissues.
Did you know? Your skin is constantly renewing itself! The cells in your epidermis completely regenerate about every 27 days, which means the skin you have today isn't the same skin you had a month ago.