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Gummata
A gumma (plural gummata or gummas) is a soft, non-cancerous growth resulting from the tertiary stage of syphilis (and yaws). It is a form of granuloma. Gummas are most commonly found in the liver (''gumma hepatis''), but can also be found in brain, heart, skin, bone, testis, and other tissues, leading to a variety of potential problems including neurology, neurological disorders or heart valve disease. Presentation Gummas have a firm, necrotic center surrounded by inflamed tissue, which forms an amorphous proteinaceous mass. The center may become partly hyaline, hyalinized. These central regions begin to die through coagulative necrosis, though they also retain some of the structural characteristics of previously normal tissues, enabling a distinction from the granulomas of tuberculosis where caseous necrosis obliterates preexisting structures. Other histological features of gummas include an ''intervening zone'' containing epithelium, epithelioid cells with indistinct borders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gummata Hepatis
A gumma (plural gummata or gummas) is a soft, non-cancerous growth resulting from the tertiary stage of syphilis (and yaws). It is a form of granuloma. Gummas are most commonly found in the liver (''gumma hepatis''), but can also be found in brain, heart, skin, bone, testis, and other tissues, leading to a variety of potential problems including neurology, neurological disorders or heart valve disease. Presentation Gummas have a firm, necrotic center surrounded by inflamed tissue, which forms an amorphous proteinaceous mass. The center may become partly hyaline, hyalinized. These central regions begin to die through coagulative necrosis, though they also retain some of the structural characteristics of previously normal tissues, enabling a distinction from the granulomas of tuberculosis where caseous necrosis obliterates preexisting structures. Other histological features of gummas include an ''intervening zone'' containing epithelium, epithelioid cells with indistinct borders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexually Transmitted Diseases And Infections
Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are spread by sexual activity, especially vaginal intercourse, anal sex, and oral sex. STIs often do not initially cause symptoms, which results in a risk of passing the infection on to others. Symptoms and signs of STIs may include vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain. Some STIs can cause infertility. Bacterial STIs include chlamydia, gonorrhea, and syphilis. Viral STIs include genital herpes, HIV/AIDS, and genital warts. Parasitic STIs include trichomoniasis. STI diagnostic tests are usually easily available in the developed world, but they are often unavailable in the developing world. Some vaccinations may also decrease the risk of certain infections including hepatitis B and some types of HPV. Safe sex practices, such as use of condoms, having a smaller number of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histopathology
Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία '' -logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopathology refers to the examination of a biopsy or surgical specimen by a pathologist, after the specimen has been processed and histological sections have been placed onto glass slides. In contrast, cytopathology examines free cells or tissue micro-fragments (as "cell blocks"). Collection of tissues Histopathological examination of tissues starts with surgery, biopsy, or autopsy. The tissue is removed from the body or plant, and then, often following expert dissection in the fresh state, placed in a fixative which stabilizes the tissues to prevent decay. The most common fixative is 10% neutral buffered formalin (corresponding to 3.7% w/v formaldehyde in neutral buffered water, such as phosphate buf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirochaete
A spirochaete () or spirochete is a member of the phylum Spirochaetota (), (synonym Spirochaetes) which contains distinctive diderm (double-membrane) gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells. Spirochaetes are chemoheterotrophic in nature, with lengths between 3 and 500 μm and diameters around 0.09 to at least 3 μm. Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, called endoflagella which are sometimes called ''axial filaments''. Endoflagella are anchored at each end (pole) of the bacterium within the periplasmic space (between the inner and outer membranes) where they project backwards to extend the length of the cell. These cause a twisting motion which allows the spirochaete to move about. When reproducing, a spirochaete will undergo asexual transverse binary fission. Most spirochaetes are free-living and anaerobic, but there are numero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated digestion of cell components. In contrast, apoptosis is a naturally occurring programmed and targeted cause of cellular death. While apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal. Cellular death due to necrosis does not follow the apoptotic signal transduction pathway, but rather various receptors are activated and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates in the surrounding tissue an inflammatory response, which attracts leukocytes and nearby phagocytes which eliminate the dead cells by phagocytosis. However, microbial damaging substances released by leukocytes would crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Cell
Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B lymphocytes and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens. These antibodies are transported from the plasma cells by the blood plasma and the lymphatic system to the site of the target antigen (foreign substance), where they initiate its neutralization or destruction. B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell. Structure Plasma cells are large lymphocytes with abundant cytoplasm and a characteristic appearance on light microscopy. They have basophilic cytoplasm and an eccentric nucleus with heterochromatin in a characteristic cartwheel or clock face arrangement. Their cytoplasm also contains a pale zone that on electron microscopy contains an extensive Golgi apparatus and centrioles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte". Lymphocytes make up between 18% and 42% of circulating white blood cells. Types The three major types of lymphocyte are T cells, B cells and natural killer (NK) cells. Lymphocytes can be identified by their large nucleus. T cells and B cells T cells (thymus cells) and B cells ( bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies). The function of T cells and B cells is to recognize sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capillary
A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: they convey blood between the arterioles and venules. These microvessels are the site of exchange of many substances with the interstitial fluid surrounding them. Substances which cross capillaries include water, oxygen, carbon dioxide, urea, glucose, uric acid, lactic acid and creatinine. Lymph capillaries connect with larger lymph vessels to drain lymphatic fluid collected in the microcirculation. During early embryonic development, new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a '' de novo'' production of endothelial cells that then form vascular tubes. The term '' angiogenesis'' denotes the formation of new capillaries from pre-existing blood vessels and already present ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast
A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. Structure Fibroblasts have a branched cytoplasm surrounding an elliptical, speckled cell nucleus, nucleus having two or more nucleoli. Active fibroblasts can be recognized by their abundant Endoplasmic reticulum#Rough endoplasmic reticulum, rough endoplasmic reticulum. Inactive fibroblasts (called fibrocytes) are smaller, spindle-shaped, and have a reduced amount of rough endoplasmic reticulum. Although disjointed and scattered when they have to cover a large space, fibroblasts, when crowded, often locally align in parallel clusters. Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Cell
A giant cell (also known as multinucleated giant cell, or multinucleate giant cell) is a mass formed by the union of several distinct cells (usually histiocytes), often forming a granuloma. Although there is typically a focus on the pathological aspects of multinucleate giant cells (MGCs), they also play many important physiological roles. Osteoclasts specifically are invaluable to healthy physiological functions and are key players in the skeletal system. Osteoclasts are frequently classified and discussed separately from other MGCs which are more closely linked with human pathologies. Non-osteoclast MGCs can arise in response to an infection, such as from tuberculosis, herpes, or HIV, or foreign body. These MGCs are cells of monocyte or macrophage lineage fused together. Similar to their monocyte precursors, they are able to phagocytose foreign materials. However, their large size and extensive membrane ruffling make them better equipped to clear up larger particles. They utiliz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caseous Necrosis
Caseous necrosis or caseous degeneration () is a unique form of cell death in which the tissue maintains a cheese-like appearance.Robbins and Cotran: Pathologic Basis of Disease, 8th Ed. 2010. Pg. 16 It is also a distinctive form of coagulative necrosis. The dead tissue appears as a soft and white proteinaceous dead cell mass. Etymology The word ''caseous'' means 'pertaining or related to cheese', and comes from the Latin word ''caseus'' 'cheese'. Necrosis refers to the fact that cells do not die in a programmed and orderly way as in apoptosis. Causes Frequently, caseous necrosis is encountered in the foci of tuberculosis infections. It can also be caused by syphilis and certain fungi. A similar appearance can be associated with histoplasmosis, cryptococcosis, and coccidioidomycosis. Pathophysiology This begins as infection is recognized by the body and macrophages begin walling off the microorganisms or pathogens. As macrophages release chemicals that digest cells, the cells beg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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