What organelles are present in keratinocytes, and how can you tell which are which?
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http://www.nmsl.chem.ccu.edu.tw/tea/SKIN_910721.htm#keratinocytes\n\nThis website might help.
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Here's what they have in common:\n1. Cell membrane is present.\n2. Vacuoles are present.\n3. Both are living cells.\n4. Mitochondria is present.\n5. Both are eukaryotic cells. \n6. Nucleus, nuclear membrane and chromatin fibers are present.\n7. Both can reproduce through mitosis. (Advanced animal cells reproduce through meiosis)\n\nPS : Don't take note of those who talk of the absence of mitochondria in plants. It's present. Only chloroplast is absent in animal cell.
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Water, fats, proteins, random cells (like leukocytes) and cell fragments.
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I would say mitochondria.
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Many tissues have cells that are constantly replaced: skin dermal keratinocytes, , cheek epithelial cells, all blood cells (made by your bone marrow) intestinal epithelial cells......
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Mitochondria is said to be a living organelle because it has its own DNA and it can reproduce separately from the cell it self (just like chloroplast). Mitochondria is a living cell inside another living cell. It has its own DNA (which is different from the cell's DNA) and has 2 layers of membrane: the outer layer has the same composition as the cell membrane but the inner layer has a different composition, unique to the mitochondria. There are evidence that at one point, mitochondria (as well as chloroplast) was a free living cell. That is why both mitochondria and chloroplast are called living organelles.\n\nPlatelets are said to be non living because they are not real cells, they are cell particles. They don't have nucleus and don't metabolize anything. They are more like free chemicals in blood.
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That would be the mitochondria. The energy store of the human body. \n\nLearn how to spell ORGANELLE!!!!
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1) nucleus\n2) vacoule\n3) cell membrane\n4) cytoplasm\n5) chromosomes
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More detail is needed!\nWhich cell(s). Red blood cells, neurones, muscle cells, squamous epithelia in alveoli. ? ?\n\nYour answer will depend on the cell.
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The Epidermis\n\nThe epidermis is the outermost layer of the skin, and protects the body from the environment. The thickness of the epidermis varies in different types of skin; it is only .05 mm thick on the eyelids, and is 1.5 mm thick on the palms and the soles of the feet. The epidermis contains the melanocytes (the cells in which melanoma develops), the Langerhans' cells (involved in the immune system in the skin), Merkel cells and sensory nerves. The epidermis layer itself is made up of five sublayers that work together to continually rebuild the surface of the skin: \n\nThe Basal Cell Layer\nThe basal layer is the innermost layer of the epidermis, and contains small round cells called basal cells. The basal cells continually divide, and new cells constantly push older ones up toward the surface of the skin, where they are eventually shed. The basal cell layer is also known as the stratum germinativum due to the fact that it is constantly germinating (producing) new cells.\n\nThe basal cell layer contains cells called melanocytes. Melanocytes produce the skin coloring or pigment known as melanin, which gives skin its tan or brown color and helps protect the deeper layers of the skin from the harmful effects of the sun. Sun exposure causes melanocytes to increase production of melanin in order to protect the skin from damaging ultraviolet rays, producing a suntan. Patches of melanin in the skin cause birthmarks, freckles and age spots. Melanoma develops when melanocytes undergo malignant transformation.\n\nMerkel cells, which are tactile cells of neuroectodermal origin, are also located in the basal layer of the epidermis. \n\nThe Squamous Cell Layer \nThe squamous cell layer is located above the basal layer, and is also known as the stratum spinosum or “spiny layer” due to the fact that the cells are held together with spiny projections. Within this layer are the basal cells that have been pushed upward, however these maturing cells are now called squamous cells, or keratinocytes. Keratinocytes produce keratin, a tough, protective protein that makes up the majority of the structure of the skin, hair, and nails. \n\nThe squamous cell layer is the thickest layer of the epidermis, and is involved in the transfer of certain substances in and out of the body. The squamous cell layer also contains cells called Langerhans cells. These cells attach themselves to antigens that invade damaged skin and alert the immune system to their presence. \n\nThe Stratum Granulosum & the Stratum Lucidum \nThe keratinocytes from the squamous layer are then pushed up through two thin epidermal layers called the stratum granulosum and the stratum lucidum. As these cells move further towards the surface of the skin, they get bigger and flatter and adhere together, and then eventually become dehydrated and die. This process results in the cells fusing together into layers of tough, durable material, which continue to migrate up to the surface of the skin.\n\nThe Stratum Corneum\nThe stratum corneum is the outermost layer of the epidermis, and is made up of 10 to 30 thin layers of continually shedding, dead keratinocytes. The stratum corneum is also known as the “horny layer,” because its cells are toughened like an animal’s horn. As the outermost cells age and wear down, they are replaced by new layers of strong, long-wearing cells. The stratum corneum is sloughed off continually as new cells take its place, but this shedding process slows down with age. Complete cell turnover occurs every 28 to 30 days in young adults, while the same process takes 45 to 50 days in elderly adults.\n\nThe Dermis\nThe dermis is located beneath the epidermis and is the thickest of the three layers of the skin (1.5 to 4 mm thick), making up approximately 90 percent of the thickness of the skin. The main functions of the dermis are to regulate temperature and to supply the epidermis with nutrient-saturated blood. Much of the body’s water supply is stored
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Presence of Mitochondria\nCilia or Flagella used for cellular locomotion\nPresence of RNA
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Fibroblasts have a branched cytoplasm surrounding an elliptical, speckled nucleus having 1 or 2 nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum. Inactive fibroblasts, which are also called fibrocytes, are smaller and spindle shaped. They have a reduced rough endoplasmic reticulum.\nEpithelial tissues cover or line all body parts both externally and internally. With cells tightly packed together and with little intercellular space, the epithelial tissues form effective barriers between underlying tissues and external media. Thus, the epithelial tissues are extremely important in regulating the exchange of materials between different body parts. The portions of cell membranes found on the outer surface of an epithelial tissue are specialized to act as the regulators of the tissue strictly managing the flow of materials into and out of the epithelium. In contrast, those portions of cell membranes that are adjacent only to other epithelial cell membranes allow a less restricted flow of materials between epithelial cells. The outside surfaces of epithelial tissues often are highly specialized in other ways possessing cilia, hairs, or glands, which may arise from individual cells or groups of cells that have invaginated and which are capable of covering the outer surface of an epithelial tissue with mucous or waxy secretions. Epithelial tissues are separated from underlying tissues by extra cellular basement membranes. \nThree types of epithelial cells exist: Squamous cells are thin and flat, cuboidal cells have a square shape in section and a polygonal shape when looking at the surface of a tissue, and columnar cells are much taller than they are wide. Simple epithelial tissues are only one cell-layer thick and are named on the basis of their cell type: Simple squamous, simple cuboidal, and simple columnar epithelia are the three types of simple epithelial tissues.
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Actually the Dermis is the second layer of skin the Epidermis is the outer most layer.\n\nThe dermis lies below the epidermis and contains a number of structures including blood vessels, nerves, hair follicles, smooth muscle, glands and lymphatic tissue.
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IS of 2 types\n\nBullous dermatoses: The formation of vesicles takes place as a result of the disturbed adhesive process of keratinocytes of the skin and mucous membranes. Keratinocytes possess specific adhesion molecules that maintain the cell-to-cell and cell-to-extracellular-matrix contact. The adhesion molecules are not made in sufficient quantities due to hereditary disease (epidermolysis bullosa) or are broken down by an auto-immune illness (pemphigus, pemphigoid). The research is oriented towards the pathology of adhesion molecules of the skin and mucous membranes by means of immunological, cell-biological, and molecular-biological techniques, and the development of interventions based on gene correction and pharmaco-immunotherapy. The research programme has been accommodated in the Centre for Vesicle Diseases of the Academic Hospital. \nEczema and workers' dermatoses: Patient-linked research on the role of allergens and weak-toxic factors in the working environment or in the household, which can cause chronic skin complaints. A central topic here is the concept of eczema in which specifically the allergic, atopic and orthoergic variants are studied as the clinical end result of an inflammatory reaction with different, partly overlapping pathophysiology. Attention is paid to aspects involving work and health, epidemiology, and MTA. The programme has been accommodated in the Expert Centre for Eczematous Complaints, which is allied to the CCZ-NN.
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In cell biology, a mitochondrion (from Greek mitos thread + khondrion granule) is an organelle found in most eukaryotic cells, including those of plants, animals, fungi, and protists. A few cells, such as the trypanosome protozoan, have a single large mitochondrion, but usually a cell has hundreds or thousands of mitochondria. The exact number of mitochondria depends on the cell's level of metabolic activity: more activity means more mitochondria. Mitochondria can occupy up to 25% of the cell's cytosol.\n\nMitochondria are sometimes described as "cellular power plants", because their primary function is to convert organic materials into energy in the form of ATP via the process of oxidative phosphorylation.
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Eukaryotic cells (typical plant and animal cells) are considered to be more advanced than prokayotic cells. Their DNA is contained within a membrane bound nucleus and they contain membrane bound organelles such as mitochondria. They also contain a cytoskeleton which is a series of tubes and microfilaments which are involved with movement within the cell.\n\nProkaryotic cells (eg. bacteria) have no membrane bound nucleus - their DNA is restricted to a region called the nuceoid which is not membrane bound. They contain no membrane bound organelles and have no cytoskeleton. They do contain non membrane bound organelles such as ribosomes ( eukaryotes also contain these)\n\nHope this is of some help.
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The upper and lower epidermal cell layers, the waxy cuticle layer over the epidermal layers.  The stomata and their associated guard cells.