1. Epidermis (Outer layer):
* Stratum corneum: The outermost layer, composed of dead, flattened cells filled with keratin, which provides a tough, protective barrier.
* Stratum lucidum: A thin, translucent layer found only in thick skin (palms and soles).
* Stratum granulosum: A layer containing granules that help produce keratin and lipids, contributing to the skin's barrier function.
* Stratum spinosum: A layer of prickle cells that are connected by desmosomes, providing structural support.
* Stratum basale: The innermost layer, containing melanocytes (pigment-producing cells), Merkel cells (touch receptors), and stem cells that continuously produce new cells.
2. Dermis (Inner layer):
* Papillary layer: A thin layer with finger-like projections called papillae, which interlock with the epidermis. It contains blood vessels, nerve endings, and touch receptors.
* Reticular layer: A thicker layer containing collagen and elastin fibers, giving the skin its strength and elasticity. It also contains hair follicles, sweat glands, and sebaceous glands.
Other tissues found in the skin:
* Hypodermis (Subcutaneous layer): A layer of fat and connective tissue beneath the dermis, providing insulation and cushioning.
* Blood vessels: Supply the skin with nutrients and oxygen and remove waste products.
* Nerves: Sensory nerves detect touch, pressure, temperature, and pain.
* Hair follicles: Produce hair shafts.
* Sweat glands: Produce sweat for cooling.
* Sebaceous glands: Produce sebum, an oily substance that lubricates the skin.
It's important to note that the skin is a complex organ with many different tissues working together to perform a variety of functions, including protection, regulation of body temperature, sensation, and excretion.