https://padlet.com/279717/p00z5h77l03vcdte Made with the help of an ancient wizard en-us 2020-10-15 15:06:27 UTC 2025-12-16 20:59:56 UTC hello@padlet.com https://padlet.net/icons/png/1f52c.png 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832683842 You might be asking yourself "What is an epidermis? Does it in any way relate to the Epipen?" and most of all "Why am I reading this?"]]> 2020-10-15 15:11:09 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832683842 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832709919 This post will contain the answer to your first question. The epidermis is the outermost of the three layers that make up the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer (stratum basale) composed of columnar cells arranged perpendicularly.

The rows of cells develop from stem cells in the basal layer. Cellular mechanisms for regulating water and sodium levels (ENaCs) are found in all layers of the epidermis.]]> 2020-10-15 15:16:50 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832709919 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832718020 Now that you know what the epidermis is it's time to dive deeper and talk about the epidermis, the wonderful layer beneath the epidermis.]]> 2020-10-15 15:18:35 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832718020 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832775743 The dermis is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis. The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix. It also contains mechanoreceptors that provide the sense of touch and thermoreceptors that provide the sense of heat. In addition, hair follicles, sweat glands, sebaceous glands (oil glands), apocrine glands, lymphatic vessels, nerves and blood vessels are present in the dermis. Those blood vessels provide nourishment and waste removal for both dermal and epidermal cells]]> 2020-10-15 15:30:49 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832775743 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832821122 There are many different kinds of receptors in the human skin that allow us to feel things, whether they be hot or cold, wet or dry, these receptors are what tell us how things feel when we touch them. ]]> 2020-10-15 15:40:31 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832821122 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/832830992 Receptors in the skin include but are not limited to nerves, hair, the cutaneous receptor, nociceptors, thermoreceptors.]]> 2020-10-15 15:42:49 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/832830992 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835754377 The skin contains two main glands that basically excrete all the gross stuff under your skin, they're called the sweat and sebaceous glands. The purpose of the sweat glands is to let out small drops of water in order to keep the body cool and its temperature regulated, while the sebaceous glands are what make your skin all oily.]]> 2020-10-16 14:39:07 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835754377 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835816277 Your body is a complicated system that consists of many subsystems that help to keep it functioning properly. These subsystems serve a variety of purposes and require needed materials to function properly, as well as means of communicating information to other parts of the body. Thus, the skin and other parts of the integumentary system work with other systems in your body to maintain and support the conditions that your cells, tissues, and organs need to function properly. The skin is one of the first defense mechanisms in your immune system.  Tiny glands in the skin secrete oils that enhance the barrier function of the skin. Immune cells live in the skin and provide the first line of defense against infections. By helping to synthesize and absorb vitamin D, the integumentary system works with the digestive system to encourage the uptake of calcium from our diet.  This substance enters the bloodstream though the capillary networks in the skin. Healthy functioning of your skin also is related to the digestive system because the digestion and assimilation of dietary fats and oils are essential for the body to be able to make the protective oils for the skin and hair. The integumentary system also works closely with the circulatory system and the surface capillaries through your body. Because certain substances can enter the bloodstream through the capillary networks in the skin, patches can be used to deliver medications in this manner for conditions ranging from heart problems (nitroglycerin) to smoking cessation (nicotine patches). The skin also is important in helping to regulate your body temperature. If you are too hot or too cold, your brain sends nerve impulses to the skin, which has three ways to either increase or decrease heat loss from the body's surface: hairs on the skin trap more warmth if they are standing up, and less if they are lying flat; glands under the skin secrete sweat onto the surface of the skin in order to increase heat loss by evaporation if the body is too hot; capillaries near the surface can open when your body needs to cool off and close when you need to conserve heat. Your skin plays a vital role in your body as regards the sense of touch. The nervous system depends on neurons embedded in your skin to sense the outside world. It processes input from your senses, including touch, and initiates actions based on those inputs. For example, when you stub your toe, nerve cells in the foot send signals up the leg, through the spinal cord, and up into the brain. The nerve cell connections in the brain sense these signals as pain. As well as interacting with the body systems as explained above, the integumentary system also contributes to numerous physiological processes, especially those involved in the regulation of the body’s internal environment so as to maintain a stable condition. An example is provided by the way that the skin helps in temperature regulation by changes in the pattern of blood supply to the skin and by sweating, as mentioned above.]]> 2020-10-16 14:55:26 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835816277 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835824562 Everyone knows what hair is, unless they're bald but you shouldn't be bald just yet I don't think. To talk about hair in nerd terms: The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides and immune cells. This complex interaction induces the hair follicle to produce different types of hair as seen on different parts of the body. For example, terminal hairs grow on the scalp and lanugo hairs are seen covering the bodies of fetuses in the uterus and in some newborn babies. The process of hair growth occurs in distinct sequential stages. The first stage is called anagen and is the active growth phase, telogen is the resting stage, catagen is the regression of the hair follicle phase, exogen is the active shedding of hair phase and lastly kenogen is the phase between the empty hair follicle and the growth of new hair. The function of hair in humans has long been a subject of interest and continues to be an important topic in society, developmental biology and medicine. Of all mammals, humans have the longest growth phase of scalp hair compared to hair growth on other parts of the body. For centuries, humans have ascribed esthetics to scalp hair styling and dressing and it is often used to communicate social or cultural norms in societies. In addition to its role in defining human appearance, scalp hair also provides protection from UV sun rays and is an insulator against extremes of hot and cold temperatures. Differences in the shape of the scalp hair follicle determine the observed ethnic differences in scalp hair appearance, length and texture.]]> 2020-10-16 14:57:40 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835824562 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835835540 Hair serves a role not only in human aesthetics and appearance but in keeping the body safe from UV radiation and as protection from extreme temperature, this is why we grow it on our bodies and also wear over our skin as furs.]]> 2020-10-16 15:00:31 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835835540 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835852363 Human nails serve many purposes as weapons, something to chew on when stressed, as a tool to pick things up or off, or as a decoration depending on the person. Nails are made out of keratin which is also what's used to make hair and the top layer of your skin, in fact you had nails before you were even born! ]]> 2020-10-16 15:05:02 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835852363 279717 https://padlet.com/279717/p00z5h77l03vcdte/wish/835861335 When painted, they can add a girly sparkle to hands, and for some people they can substitute as a guitar pick or even a backscratcher.

These savvy services, though, are not the reason we humans sport the keratin-rich coverings atop our fingertips. "We have fingernails because we're primates," said John Hawks, a biological anthropologist at the University of Wisconsin-Madison.

Fingernails are one of the features that distinguish primates, including humans, from other mammals. They are essentially flattened forms of claws.

"Most mammals have claws," Hawks told LiveScience. "[They] use them to grab onto things, to climb things, to scratch things, and to dig holes."

Scientists suspect primates sort of lost their claws and fashioned broad fingertips topped with nails to aid in locomotion. While claws would have provided excellent grip as our mammalian ancestors clambered up large tree trunks, they would have been a nuisance for larger-bodied primates trying to grasp smaller branches while scrambling across tree canopies for fruits. Rather, primates developed broader fingertips made for grasping.

About 2.5 million years ago, fossil evidence suggests early humans first picked up stone tools, which is about the same time our ancestors also developed even broader fingertips than earlier primates. To this day, humans sport broader fingertips than other primates.

Whether fingernails are an adaptation that helps to support broad fingertips or a side effect from the loss of claws is unclear, Hawks said.

Another reason for fingernails: They serve as a visual advertisement of a person's health, he said. For instance, malnutrition can change the coloring of nails, while small pits in fingernails can signal the skin condition psoriasis.]]> 2020-10-16 15:07:19 UTC https://padlet.com/279717/p00z5h77l03vcdte/wish/835861335