...up of three different layers, the epidermis, the dermis and the sub-cutaneous. It is the organ system that is constantly changing and regenerating itself over a period of four to six weeks as it protects our internal body parts from damage. It also performs necessary functions like, temperature regulation, waste excretion and it is the protective coating over the internal body tissues. The skin also serves as the sensory receptor for pain and pleasurable sensations from pressure and temperature and, when we are exposed to sunlight, our integumentary system also generates necessary vitamin D. (Sanders, 2007) The integumentary system makes up around seven percent of a human being’s total body weight and is composed of the skin, skin derivatives, glands, hair and nails. (Graaff, 2001 ) How Skin cells are formed: The human skin is composed of several layers. The surface layer, or the one you can see, is the epidermis. The epidermis is composed of multiple layers of cells made up of Keratinocytes and they comprise roughly 85 percent of the cells in the epidermis. These cells make keratin, a hard protein substance which provides structural integrity and also makes up your nails and hair. New keratinocytes are grown at the lowest level of the epidermis, the mitotic layer, through a process called mitosis. Here the keratinocytes divide to form two identical cells, one of which remains for future mitosis and the other moves upward to the differentiation layer for further changes....
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...Dermis Attachment of epidermis to dermis is enhanced by an increased interface between the two tissues. The junction between the dermis and epidermis is seen in the light microscope as an uneven boundary except in the thinnest skin. Sections of skin cut perpendicular to the surface reveal numerous fingerlike connective tissue protrusions, dermal papillae, that project into the undersurface of the epidermis (see Figs. 15.1 and 15.2). The papillae are complemented by what appear to be similar epidermal protrusions, called epidermal ridges or rete ridges, that project into the der- mis. If the plane of section is parallel to the surface of the epi- dermis and passes at a level that includes the dermal papillae, however, the epidermal tissue appears as a continuous sheet of epithelium, containing circular islands of connective tissue within it. The islands are cross sections of true fingerlike der- mal papillae that project into the epidermis. At sites where in- creased mechanical stress is placed on the skin, the epidermal ridges are much deeper (the epithelium is thicker), and the dermal papillae are much longer and more closely spaced, creating a more extensive interface between the dermis and epidermis. This phenomenon is particularly well demon- strated in histologic sections that show both palmar and dor- sal surfaces of the hand, as in a section of a finger. True dermal ridges are present in thick skin in addition to dermal papillae. Dermal ridges tend to have a parallel...
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...structure of skin Epidermis, and Dermis The epidermis is the relatively thin, tough, outer layer of the skin. Most of the cells in the epidermis are keratinocytes. They originate from cells in the deepest layer of the epidermis called the basal layer. New keratinocytes slowly migrate up toward the surface of the epidermis. Once the keratinocytes reach the skin surface, they are gradually shed and are replaced by newer cells pushed up from below. The outermost portion of the epidermis, known as the stratum corneum, is relatively waterproof and, when undamaged, prevents most bacteria, viruses, and other foreign substances from entering the body. The epidermis also protects the internal organs, muscles, nerves, and blood vessels against trauma. In certain areas of the body that require greater protection the outer keratin layer of the epidermis is much thicker. Scattered throughout the basal layer of the epidermis are cells called melanocytes, which produce the pigment melanin, one of the main contributors to skin color. Melanin's primary function, however, is to filter out ultraviolet radiation from sunlight which damages DNA, resulting in numerous harmful effects, including skin cancer. The epidermis also contains Langerhans cells, which are part of the skin's immune system. Although these cells help detect foreign substances and defend the body against infection, they also play a role in the development of skin allergies. The dermis, the skin's next layer, is a thick...
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...properly. Parts of the Integumentary System Skin The skin is the most important organ of the body, as it protects the delicate organs of the body. The skin is divided into three separate layers as follows: * Epidermis: This is the outermost layer of the skin that contains four separate layers of epithelial tissue. The outer most layer is the stratum corneum that is about 2 to 30 cells thick. These are keratinized and dead cells that make the skin waterproof! The second and third layer consists of the stratum granulosum and stratum lucidum, which contain cells that are not keratinised as yet. As these skin grows, the cells are pushed outward and come towards the surface. The last and the deepest layer of the epidermis is the stratum germinativum. These cells are active mitotically and have the ability to reproduce, as these cells are living, thus, making them the manufacturing center for growing skin. * Dermis: The dermis lies immediately after the epidermis. The dermis consists of its own blood supply and thus contains many complex structures. The sweat glands are present in this layer that collect waters and waste products from the blood stream. This waste is excreted from the pores in the epidermis along with the water in form of sweat. The hair roots are also present in this layer that help in the growth of hair. When the hair reaches...
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...normal body temperature through either insulation or evaporative cooling, as needed. Synthesis of Vitamin D3, a steroid that is subsequently converted to the hormone calcitriol, important to normal calcium metabolism. Storage of nutrients. Lipids are stored in adipocytes in the dermis and in adipose tissue in the subcutaneous layer. Detection of touch, pressure, pain, and temperature stimuli and the relay of that information to the nervous system. 2. What are five layers of the skin? Describe each. There are actually three layers to the skin; The Epidermis, The Dermis, and the Subcutaneous Fat Layer. However there are five skin layers that take place in the epidermis. * The Epidermis: provides mechanical protection and helps keep microorganisms outside the body. * Stratum Spinosum: the outermost epidermis layer that protects against foreign materials and to produce and retain moisture, which it does through a series of cellular-level interactions and interchanges. * Stratum Germinativum: the innermost epidermal layer that helps the skin regenerate. * Stratum Granulosum: creates a waterproof barrier between these outer layers and the inner, live cells. * Stratum Lucidum: designed to help the body handle friction, is transparent when viewed under a microscope. * Stratum Corneum: keeping molecules from passing into and out of the skin,...
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...Lipopolysaccharrides on KB cells Proliferation. Sobukonla Timothy and Karen Louis ABSTRACT Keratinocytes are stratified, squamous, epithelial cells that make up 95% of the cells in the epidermis. These cells are found in the basal layer of the stratified epithelium of the epidermis, and are to as basal cells, or basal keratinocytes. Keratinocytes play a vital role in the structural component of the skin, as well as a vital function in immune response. Platelet derived growth factor is a powerful mitogen for many cell types such with keratinocytes growth and motility. Lippolysaccharide (LPS) is found on the cell surface of gram-negative bacteria and assist in the stabilization of the overall cell wall structure. LPS along with CD14 and Toll-like receptor 4 expressed on the cell surface of keratinocytes, play a vital role in regulating the innate immune response system and influencing the adaptive immune response mechanism. INTRODUCTION Keratinocyte cells are stratified, squamous, epithelial cells that comprise of skin and mucosa, including oral, esophageal, and genital epithelia. 95% of the cells in the epidermis are keratinocytes. Keratinocytes are tightly bonded together to form a strong layer between the nerves of the skin and underlying tissues of the epidermis. These cells originate in basal layer of the stratified epithelium and are referred to as basal cells or basal keratinocytes. In addition to their structural role of preserving the health and integrity of the skin, basal...
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...Full-depth epidermis tomography using a Mirau-based full-field optical coherence tomography Chien-Chung Tsai,1 Chia-Kai Chang,1 Kuang-Yu Hsu,1 Tuan-Shu Ho,1 Ming-Yi Lin,2 Jeng-Wei Tjiu,2,4 and Sheng-Lung Huang1,3,* 2 1 Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan Department of Dermatology, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan 3 Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan 4 jengweitjiu@gmail.com * shuang@ntu.edu.tw Abstract: With a Gaussian-like broadband light source from high brightness Ce3+:YAG single-clad crystal fiber, a full-field optical coherence tomography using a home-designed Mirau objective realized high quality images of in vivo and excised skin tissues. With a 40 × silicone-oilimmersion Mirau objective, the achieved spatial resolutions in axial and lateral directions were 0.9 and 0.51 μm, respectively. Such a high spatial resolution enables the separation of lamellar structure of the full epidermis in both the cross-sectional and en face planes. The number of layers of stratum corneum and its thickness were quantitatively measured. This label free and non-invasive optical probe could be useful for evaluating the water barrier of skin tissue in clinics. As a preliminary in vivo experiment, the blood vessel in dermis was also observed, and the flowing of the red blood cells...
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...I. Connective Tissue - (type of tissue) A. Adipose - (specific tissue) 1. lipid droplet - (structure) 2. cytoplasm - (structure) 3. nucleus - (structure) B. Bone - (specific tissue) 1. osteon - (structure) 2. haversian canal (contains blood vessels and nerves) - (structure) 3. volkmanns canal (connects two haversian canals; contains blood vessels and nerves) - (structure) 4. matrix - (structure) 5. canaliculus (canaliculi (plural) - (structure) 6. lacuna (containing ostecyte) - (structure) C. Blood - (specific tissue) 1. red blood cells (erythrocytes) - (structure) 2. white blood cells (leukocytes) - (structure) 3. platelets (thrombocytes) - (structure) 4. plasma - (structure) D. Hyaline Cartilage - (specific tissue) 1. lacuna (structure) 2. chondrocyte (structure) 3. matrix (structure) II. Nervous Tissue - (type of tissue or specific tissue) can be referred to as either per notes A. Neuroglial Cell (Not a specific organ) 1. neuron (entire cell) - (structure) 2. cell body (perikaryon) - (structure) 3. cytoplasm - (structure) 4. nucleus - (structure) 5. axon - (structure) 6. dendrite - (structure) 7. nuclei of neuroglial cells - (structure) III. Muscle - (type of tissue) A. Cardiac Muscle - (specific tissue) 1. striations - (structure) 2. nucleus - (structure) 3. intercalated disc - (structure) 4. action of muscle is involuntary (cannot control consciously) B. Skeletal Muscle (multi-nucleated)...
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...Skin is the largest structure in the body, and it has three layers, Epidermis, dermis, and hypodermis. Epidermis provides a waterproof barrier and creates the skin tone. Dermis contains blood vessel that feeds the skin, and hypodermis: helps body from getting too cold or too warm, protects muscles and bones from pumps and falls. Malignant Melanoma is the most life threatening and deadliest skin cancer in the world. Malignant melanoma develops in the melanocytes, and melanocyte give the skin its color, and it will be easier to spread in the skin. The melanoma in women mostly occur on the legs, while in men they are most common on the back. It can also form in your eyes in internal organs, like intestines. There are three types of malignant...
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...Biology - Plants 13.1 - Plants as Valuable Bioresources - The Biosphere Depends on Plants * photosynthesis: a series of chemical reactions that converts energy from sunlight into chemical energy stored in molecules * cellulose: a large carbohydrate molecule - Plants as a Source of Food * agriculture: farming or forestry practices that produce food and goods - Food Security * food security: the state where all people, at all times, have access to enough safe and nutritious food to meet their dietary needs and preferences and allow them to lead an active and healthy life * sustainable agriculture: an approach to agricultural production that integrates economics, the environment, and society in meeting the nutritional needs of the world - Plants as a Source of Fibres and Building Materials * textile: a fabric, flexible material, or related product made from natural or synthetic fibres, threads or yarns * timber: trees in their natural state or wood that has been prepared for use as a building material - Plants as a Source of Biochemicals * medicinal uses - Plants as a Source of Fuel biofuels a fuel that is produced from renewable biological sources - Plants and Erosion Control - Plants, Recreational and Ecotourism 13.2 - The Vascular Plant Body - Plant Classification : Vascular vs. Non Vascular - Vascular Plant Systems : Shoot System (above ground): the stems and leaves of a plant; stems: bear structural...
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...toxic agents and mechanical insults. There are three structural layers to the skin: the epidermis, the dermis and subcutis. Hair, nails, sebaceous, sweat and apocrine glands are regarded as derivatives of skin (see Figure 1.1). Skin is a dynamic organ in a constant state of change, as cells of the outer layers are continuously shed and replaced by inner cells moving up to the surface. Although structurally Figure 1.1 Cross-section of the skin. 2 Aromadermatology Table 1.1 Layers of the skin. Skin layer Description Epidermis The external layer mainly composed of layers of keratinocytes but also containing melanocytes, Langerhans cells and Merkel cells. Basement membrane The multilayered structure forming the dermoepidermal junction. Dermis The area of supportive connective tissue between the epidermis and the underlying subcutis: contains sweat glands, hair roots, nervous cells and ®bres, blood and lymph vessels. Subcutis The layer of loose connective tissue and fat beneath the dermis. consistent throughout the body, skin varies in thickness according to anatomical site and age of the individual. Skin anatomy The epidermis is the outer layer, serving as the physical and chemical barrier between the interior body and exterior environment; the dermis is the deeper layer providing the structural support of the skin, below which is a loose connective tissue layer, the...
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...Review SKIN FUNCTION AND WOUND HEALING PHYSIOLOGY John Timmons is Clinical Manager, Wounds UK and Tissue Viabiliy Nurse, Aberdeen Regular evaluation and the setting of goals is essential to monitor the progress of the patient and their wound.To do this, is important to understand the physiology of the skin and the way normal wound healing progresses in order to plan and provide effective wound management. This article describes the structure and function of the skin and outlines the four normal phases of healing. Wound healing is an exciting and continually developing field, with new technologies and research playing a large part in improving the quality of patient care. The role of the nurse in wound care is all encompassing, stretching from the initial assessment of the wound and the patient, to making the correct decisions about treatment and beyond. Regular evaluation, and the setting of goals is essential to monitor the progress of the patient and the wound. To do this, a baseline knowledge of the functions and anatomy of the skin and wound healing physiology is required. Figure 1. When the skin is breached, it is important to close the defect as quickly as possible, thereby preventing infection from occurring. vital substances (Graham-Brown and Burns, 1998). the nerve endings present in the skin allow the body to detect pain, and changes in temperature, touch and pressure. 8Sensation: Functions of the skin The skin, often referred to as the largest body...
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...receptors that respond to heat, cold, pressure, touch, vibration and pain. 5. Performs metabolic functions as I he synthesis of melanin keratin, and vitamin D. 6. Contains organs like the sweat glands responsible for the excretion of nitrogenous wastes. 7. Acts as blood reservoir. SKIN: DESCRIPTION AND LAYERS: It is the largest skin of the body in terms of surface area that is about (2 sq. meter/2.2 sq. ft. Also the heaviest which weigh about 4-4.5kg/10-11 lbs. which is almost 7% of the total body weight. The following are its layers: EPIDERMIS: This the outer protective layer of the skin. The thickness is about 30-50 cell layers. Also called as the surface skin. There are our types of cells found in the epidermis namely: • Keratinocytes- produces keratin – waterproof materials • Melancocytes- produces melanin for pigmentation • Langerhans cells- macrophages- garbage patrol • Merkel cells- photoreceptors The epidermis itself is composed of layers namely: • Stratum corneum- outermost layer and is composed of 20-30 layers o keratinized and cornified dead and flattened cells. • Stratum lucidum- below the Stratum corneum and is composed of lucid and thin layers of cells that are found only I the palm of the hands and the soles of the feet. • Stratum granulosum- below the...
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...(cushion organs moving against each other during muscle activity). Integumentary System * The skin and its derivatives serve a number of functions, mostly protective, and together they form the integumentary system. * Components: * skin * hair * nails * glands Functions 1. Protection: from water loss, against microbes, UV light 2. Sensation: e.g. hot, cold, pain, pressure, touch 3. Temperature regulation: helps maintain homeostasis e.g. sweat 4. Excretion: removes waste 5. Vitamin D production: UV light stimulates production of vitamin D Structure of the Skin * The skin is composed of two types of tissue: * epidermis * dermis Epidermis * Outer skin region * Composed of stratified squamous epithelium (many layers of flat tile-like cells) * These cells undergo a process called keratinization where new cells (with keratin) push old cells to surface * Takes approximately 40-56 days for new cells to...
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...two distinct layers: 1. The epidermis connective tissue 2. Dermis connective tissue Beneath the 2nd layer is loose connective/adipose tissue called hypodermis epidermis The epidermis has five layers: 1. Stratum Germinativum (deepest) 2. Stratum Spinosum 3. Stratum Granulosum 4. Stratum Lucidum 5. Stratum Corneum (most superficial) The two deepest layers are called the Germinative Zone or Basal Zone The other layers are called the Horny Zone Epithelial cells in the skin undergo a process called keratinisation, which means the cytoplasm is replaced with keratin. Keratin contains nitrogen, amino acids and varying propotions of sulphur. Hard Keratin contains 4-5 % and is found in nails and hair. Soft Keratin contains 2 % and is found in skin. Cells found in epidermis are 1. Epithelial cells 2. Melanocytes Features of: Stratum germinativum: consists of a single layer of columnar shaped cells with nuclei. These cells have tiny processes on their lower surfaces, which seem to anchor them to the underlying dermis. Stratum spinosom is several layers thick, and is composed of irregular cells, slightly separated from each other. There are intercellular bridges between these cells, which appear as spiny processes. Stratum granulosum is a layer consisting of three or five rows of flattened cells,lying parallel to the skin surface, Stratum lucidum is a clear, translucent layer of three or...
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