What kind of tissue composes the dermis of the skin

Which connective tissue composes the dermis of the skin? Saikat R. Feb 15, Explanation: Our skin has two principal layers : epidermis and dermis. Diagram of different layers of skin : The dermis contains two layers : the outermost papillary layer and the deeper reticular layer. Related questions Is dry skin a deficiency symptom of vitamin A? What are the three main functions of integumentary system?

How do the integumentary and immune systems work together? What is the name of the outer layer of epidermis? What is the name for the glands that are The reticular layer serves to strengthen the skin and also provides our skin with elasticity. Elasticity refers to how our skin is able to spring back into shape if deformed by something like a pinch.

The reticular layer also contains hair follicles, sweat glands, and sebaceous glands. The sweat gland can either be apocrine, such as those found in the armpits and the groin area, or the eccrine glands, which are found all over the body. The former help contribute to body odor along with the bacteria on our skin , and the latter help regulate our body temperature through the process of evaporation.

The sebaceous glands found in the dermis secrete a substance called sebum that helps to lubricate and protect our skin from drying out. Beneath the dermis is the deepest layer of our skin.

It is alternatively termed hypodermis, subcutis, or subcutaneous tissue. It contains many collagen cells as well as fat. Fat, in particular, helps insulate our body from the cold and act as a cushion for our internal structures such as muscles and organs when something hits us. Fat can also be called upon by the body in times of great need as an energy source. Given the alternative names for this layer, it should come as no surprise that this is the layer where subcutaneous injections are given into via a hypodermic needle.

Skin sensory receptors: Those nearest the surface of the skin include receptors that detect gentle pressure, temperature, and vibrations, as well as naked nerve endings dendrites that detect pain. Within the papillary layer are fibroblasts, a small number of fat cells adipocytes , and an abundance of small blood vessels. In addition, the papillary layer contains phagocytes, defensive cells that help fight bacteria or other infections that have breached the skin.

This layer also contains lymphatic capillaries, nerve fibers, and touch receptors called the Meissner corpuscles. Underlying the papillary layer is the much thicker reticular layer , composed of dense, irregular connective tissue. This layer is well vascularized and has a rich sensory and sympathetic nerve supply.

The reticular layer appears reticulated net-like due to a tight meshwork of fibers. Elastin fibers provide some elasticity to the skin, enabling movement. Collagen fibers provide structure and tensile strength, with strands of collagen extending into both the papillary layer and the hypodermis.

In addition, collagen binds water to keep the skin hydrated. Collagen injections and Retin-A creams help restore skin turgor by either introducing collagen externally or stimulating blood flow and repair of the dermis, respectively. The hypodermis also called the subcutaneous layer or superficial fascia is a layer directly below the dermis and serves to connect the skin to the underlying fascia fibrous tissue of the bones and muscles.

It is not strictly a part of the skin, although the border between the hypodermis and dermis can be difficult to distinguish. The hypodermis consists of well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument.

Lipid Storage The hypodermis is home to most of the fat that concerns people when they are trying to keep their weight under control. Adipose tissue present in the hypodermis consists of fat-storing cells called adipocytes. This stored fat can serve as an energy reserve, insulate the body to prevent heat loss, and act as a cushion to protect underlying structures from trauma.

Where the fat is deposited and accumulates within the hypodermis depends on hormones testosterone, estrogen, insulin, glucagon, leptin, and others , as well as genetic factors.

Fat distribution changes as our bodies mature and age. Men tend to accumulate fat in different areas neck, arms, lower back, and abdomen than do women breasts, hips, thighs, and buttocks. The body mass index BMI is often used as a measure of fat, although this measure is, in fact, derived from a mathematical formula that compares body weight mass to height.

Therefore, its accuracy as a health indicator can be called into question in individuals who are extremely physically fit. In many animals, there is a pattern of storing excess calories as fat to be used in times when food is not readily available.

In much of the developed world, insufficient exercise coupled with the ready availability and consumption of high-calorie foods have resulted in unwanted accumulations of adipose tissue in many people. Although periodic accumulation of excess fat may have provided an evolutionary advantage to our ancestors, who experienced unpredictable bouts of famine, it is now becoming chronic and considered a major health threat.

Not only is this a problem for the individuals affected, but it also has a severe impact on our healthcare system. Changes in lifestyle, specifically in diet and exercise, are the best ways to control body fat accumulation, especially when it reaches levels that increase the risk of heart disease and diabetes.

The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome Figure. Melanin occurs in two primary forms. Eumelanin exists as black and brown, whereas pheomelanin provides a red color.

Dark-skinned individuals produce more melanin than those with pale skin. Exposure to the UV rays of the sun or a tanning salon causes melanin to be manufactured and built up in keratinocytes, as sun exposure stimulates keratinocytes to secrete chemicals that stimulate melanocytes. The accumulation of melanin in keratinocytes results in the darkening of the skin, or a tan.

This increased melanin accumulation protects the DNA of epidermal cells from UV ray damage and the breakdown of folic acid, a nutrient necessary for our health and well-being. In contrast, too much melanin can interfere with the production of vitamin D, an important nutrient involved in calcium absorption. Thus, the amount of melanin present in our skin is dependent on a balance between available sunlight and folic acid destruction, and protection from UV radiation and vitamin D production.

It requires about 10 days after initial sun exposure for melanin synthesis to peak, which is why pale-skinned individuals tend to suffer sunburns of the epidermis initially.

Dark-skinned individuals can also get sunburns, but are more protected than are pale-skinned individuals. Melanosomes are temporary structures that are eventually destroyed by fusion with lysosomes; this fact, along with melanin-filled keratinocytes in the stratum corneum sloughing off, makes tanning impermanent.

Too much sun exposure can eventually lead to wrinkling due to the destruction of the cellular structure of the skin, and in severe cases, can cause sufficient DNA damage to result in skin cancer. When there is an irregular accumulation of melanocytes in the skin, freckles appear. Moles are larger masses of melanocytes, and although most are benign, they should be monitored for changes that might indicate the presence of cancer Figure.

Disorders of the… Integumentary System The first thing a clinician sees is the skin, and so the examination of the skin should be part of any thorough physical examination. Most skin disorders are relatively benign, but a few, including melanomas, can be fatal if untreated. A couple of the more noticeable disorders, albinism and vitiligo, affect the appearance of the skin and its accessory organs. Although neither is fatal, it would be hard to claim that they are benign, at least to the individuals so afflicted.

Albinism is a genetic disorder that affects completely or partially the coloring of skin, hair, and eyes. The defect is primarily due to the inability of melanocytes to produce melanin. Individuals with albinism tend to appear white or very pale due to the lack of melanin in their skin and hair. Recall that melanin helps protect the skin from the harmful effects of UV radiation. Individuals with albinism tend to need more protection from UV radiation, as they are more prone to sunburns and skin cancer.

They also tend to be more sensitive to light and have vision problems due to the lack of pigmentation on the retinal wall. Treatment of this disorder usually involves addressing the symptoms, such as limiting UV light exposure to the skin and eyes. In vitiligo , the melanocytes in certain areas lose their ability to produce melanin, possibly due to an autoimmune reaction. This leads to a loss of color in patches Figure. Neither albinism nor vitiligo directly affects the lifespan of an individual.

Other changes in the appearance of skin coloration can be indicative of diseases associated with other body systems. Tumors of the pituitary gland can result in the secretion of large amounts of melanocyte-stimulating hormone MSH , which results in a darkening of the skin. A sudden drop in oxygenation can affect skin color, causing the skin to initially turn ashen white. This happens when the oxygen supply is restricted, as when someone is experiencing difficulty in breathing because of asthma or a heart attack.

This ABC video follows the story of a pair of fraternal African-American twins, one of whom is albino. Watch this video to learn about the challenges these children and their family face. Which ethnicities do you think are exempt from the possibility of albinism?