Whereas the stratum corneum of thin skin may be completely shed and replaced in about a week's time, this replacement may take about a month in thick skin. D: Hmm. I guess that from now on I won't say I have thick skin, but that I have an extra thick epidermis! Bark, Wikimedia Commons. In fact, all skin is either classified as thick or thin.
Most of the rest of your skin is thin, however, and is equipped with hair follicles, oil glands, and smooth muscle fibers. The thickness of thick skin is caused by a much thicker epidermis, the uppermost section of skin's composition. In particular, the bulk of thick skin is a result of the four upper layers of the epidermis, or the stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. A Moment of Science is a daily audio podcast, public radio program and video series providing the scientific story behind some of life's most perplexing mysteries.
Learn More ». Give Now ». Noon Edition. Note that the various layers of the epidermis are not as clearly seen in thin skin. Find the pigment in the region of the stratum basale. This pigment comes from the melanin producing melanocytes within the stratum basale, which synthesize melanin and transfer it to the regular epithelial cells of the stratum basale and stratum spinosum. The melanocytes are not attached to neighboring cells by desmosomes and so tend to shrink away with preparation and appear to be surrounded by a clear space.
You may also see the gold-brown pigment in the epithelial cells. Also observe hair follicles and hair shafts with associated sebaceous glands. The hair follicle an invagination of the epidermis has a terminal dilation, the hair bulb , composed of matrix cells and the dermal papilla.
The outermost layer of the follicle is composed of a connective tissue sheath with the underlying external root sheath The external root sheath is continuous with the epithelium.
Inside the external root sheath is the internal root sheath which is composed of Henle's layer , Huxley's layer , and a cuticle. Each hair shaft is composed of a cuticle , cortex , and medulla. Find the arrector pili muscle , smooth muscle that attaches to the connective tissue sheath of the hair follicle and erects the hair upon contraction. Supplemental Slide Skin of palm, human. This slide is sectioned very thin 1. Observe the layers of the epidermis and try to find Meissner's corpuscles within the dermal papillae.
Slide 24 Mammary gland, active, adult. This slide is a lactating or active gland. Note that the alveoli are well developed and branched from the duct system. The alveoli and lobules expand at the expense of the connective tissue; thus, in a lactating gland one should see a reduction in the amount of connective tissue.
Most alveoli are distended and partially to wholly filled with milk. It contains keratin and horny scales, which make it tougher and able to thicken into calluses.
The stratum corneum contains dead keratinocytes, which produce defensins. Defensins are strings of amino acids that protect the body from infection. Connecting the dermis and epidermis are structures called dermal papillae. Dermal papillae are more prominent in thick skin than thin skin.
Dermal papillae increase the surface area between the epidermis and dermis, allowing for more oxygen, food, and waste to pass between the layers. Skin in general has many different functions, such as protection, sensation, and thermoregulation. Both thin and thick skin have properties that allow the skin to function correctly.
For example, thin skin contains hair follicles, which are important in producing hair to help regulate temperature and protect from ultraviolet radiation. Hair follicles also provide epithelial stem cells, which help repair wounds. In addition, thin skin contains sebaceous glands, which produce sebum. Sebum helps to lubricate the skin and protect against infections. Thin skin also contains eccrine and apocrine sweat glands.
Sweat glands help to regulate body temperature by releasing sweat to cool the body, and also help to repair skin damage. Thick skin provides protection from damage in areas that experience more friction and abrasion, such as the palms of the hands and the soles of the feet.
Thick skin also contains eccrine sweat glands to help regulate body temperature. Skin is a large, complex organ with a wide range of vital roles. Thin skin and thick skin have different structures and functions in the body. The layers they contain provide their thickness and allow them to carry out their roles. Thin skin is present on most of the body, and helps to protect against infections, regulate temperature, and allows hair to grow.
Thick skin covers the palms of the hands and the soles of the feet and protects these areas from extra abrasion and friction. The skin is our largest organ. Here, we explain what it's made of, what it does, and how it does it. We also cover some common skin conditions. As a person ages, their skin naturally becomes thinner, less elastic, or papery. While there is no specific way to treat thin skin or to thicken the…. The skin is the largest organ of the human body. Many conditions can affect the skin.
Some of them are common, while others are rare. Many people have dry skin.
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