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Showing posts from May, 2011

Types Of Glands - Lesson 246

In this post we   would learn about glands of different types. 1. Sebaceous Glands: These glands are located in the corium layer of the skin over the entire body, ;with the exception of the palms (hands) and soles (feet). The oily substance which they secrete is called sebum. Sebum, which contains lipids, lubricates the skin and minimizes water loss. The sebaceous glands which are closely associated with hair follicles, and their ducts open into the hair follicle through which the sebum is released. These sebaceous are influenced by sex hormones, which cause them to hypertrophy at puberty and atrophy in old age. Overproduction of sebum during puberty contributes to blackhead (comedo) formation and acne in some individuals. 2. Sweat Glands: These glands are tiny, coiled glands found on almost all body surfaces (about two million in the body). In the palm of the hand they are very large in number (3000 glands per sq in) and on the sole of the foot. The coiled sweat glan

Accessory Organs Of The Skin - - Lesson 245

In this post we would learn about ‘accessory organs of the skin’. Then in our mind one question may arise? What are the accessory organs of the skin? 1. Hair: A fiber of hair is composed or consisted of a tightly fused meshwork of horny cells filled with the hard protein also called keratin. The growth of hair is similar to the growth of the epidermal layer of the skin. Deep-lying cells in the hair root which produce horny cells that move upwards or to the top through the hair follicles (shafts or sacs that hold the hair fibers). At the root of the hair follicle, melanocytes are located and they support the melanin pigment for the horny cells of the hair fiber. Whenever the melanocytes stop producing melanin, hair turns gray. Out of the five million hairs on the body, about 100,000 are on the head. They grow about a half inch (1.3cm) a month, and cutting the hair has no effect on its rate of growth. 2. Nails: Nails are hard, the plates called keratin plates covering the dorsal

FUNCTIONS OF DERMIS AND SUBCUTANEOUS LAYER -- LESSON 244

In this post we would learn about the remaining part of the dermis and subcutaneous layer. In the previous post we came across that the dermis is a layer of skin which is between epidermis and the subcutaneous tissues. This corium consists of interwoven elastic and collagen fibers in which colla- means glue is a fibrous protein material found in bone, cartilage, tendons, and ligaments, as well as in the skin. It is not only tough and resistant but also flexible. In kids, collagen is loose and delicate, and it becomes harder as the body ages. In women who bears pregnancy, overstretching of a woman’s skin may break the elastic collagen fibers and stretch the collagen resulting in linear markings called striae or stretch marks. Collagen fibers support and protect the blood and nerve networks that pass through the corium. This collagen diseases affect the connective tissues of the body. The examples of these connective tissue collages disorders are systemic lupus erythematosus an

FUNCTIONS OF EPIDERMIS AND CORIUM - LESSON 243

In this post we will learn the functions of epidermis and about Dermis or Corium. In the last lesson we have learnt upto Melanocytes. Melanocytes form and consist of a black pigment called melanin that is transferred to other epidermal cells and gives color to the skin. In several races, the amount of melanin accounts for the color differences, but the number of melanocytes in all races is same. Individuals who possess darker skin contain more melanin within the melanocytes, not a larger number of melanocytes. For protection against the harmful effects of ultraviolet radiation, the presence of melanin in the epidermis is vital, which can manifest themselves as skin cancer. The persons or individuals who, through a flaw in their chemical makeup are incapable of forming melanin at all which are called albino (means white). Those persons will get skin and hair white. Their eyes because in the absence of pigment, the tiny blood vessels are visible in the iris (normally pigmented