Did you know your skin is made of several different layers? In this lesson we’ll discuss the definition and function of the basal lamina, which is also known as the ‘basement membrane’.
Take a moment to touch the surface of your arm.
You’re touching a part of your skin that forms the outermost, protective layer between your body and the world around it.There are many layers that make up our skin, similar to the layers in a cake. These layers include the epithelium, which makes up the outer part of our skin. Epithelial cells also line the majority of our digestive organs and respiratory surfaces. Beneath the epithelial layers is a layer of thick connective tissue known as the dermis, which acts like a cushion for our skin and our internal tissues.Sandwiched in between the epithelial cells of our body and the dermis, is a thin layer of gel-like fluid excreted by the epithelial cells. This is known as the basal lamina.
It’s like padding for the epithelium above. Directly beneath the basal lamina sits the reticular lamina portion of the basement membrane, which acts as a net of collagen fibers, a type of connective tissue that provides support and structure to the overall basement membrane layers.Just underneath the reticular lamina sits the dermis. Just like a basement is the underground area of a house, the basal lamina along with the reticular lamina is sometimes referred to as the basement membrane. The basal lamina layer is actually so thin that it is only clearly visible under an electron microscope.
An easy way to remember the term basal lamina is to think of the word ‘lamina’ as a ‘layer,’ and the word ‘basal’ as ‘bottom-most.
‘ So, the basal lamina is the bottom-most layer of the epithelium, reducing friction between the epithelium and the dermis, and serving to further cushion these two layers of tissue.Basal lamina layers can also be found along the lining of blood vessels, a surface known as endothelium. Here, the basal lamina acts as a support structure for veins, arteries, and capillaries.
When basal lamina is found surrounding muscle and fat tissue, it also takes on a support structure role, like reinforcing bars in a building.Studies have shown that during the development of a mammalian embryo, the basal lamina may play a role in the final formation of organs such as the salivary and mammary glands. When teeth develop, basal lamina appear to be a part of the barrier that helps the different layers of tooth structure form in the proper order.
It’s like a border between different tissue types, preventing the incorrect mixture of tissues at the wrong developmental time. Basal lamina may well be the reason for perfect teeth.The basal lamina may have lots of functions in the overall development of vertebrate embryos, the full extent of which hasn’t been explored.
Just like a layered cake, our tissues are made up of a variety of stacked layers, each with its own function. Our skin’s outside layer is called the epithelium. Excreted by those cells is the next layer, a thin layer of gel-like fluid called the basal lamina. Below that is the net-like reticular lamina, which is made up of fibers of dense connective tissue called collagen.
These two lamina make up what’s called the basement membrane. Below that is the dermis, a layer of thick connective tissue that acts as a cushion for our skin and our internal tissues. Basal lamina can also be found along the lining of blood vessels, a surface known as endothelium.
Although its full function is still being explored, the basal lamina may play an important role in coordinating the boundaries between developing tissues, including mammary glands and teeth.