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Coagulative Necrosis
Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction. In coagulative necrosis, the architectures of dead tissue are preserved for at least a couple of days. It is believed that the injury denatures structural proteins as well as lysosomal enzymes, thus blocking the proteolysis of the damaged cells. The lack of lysosomal enzymes allows it to maintain a "coagulated" morphology for some time. Like most types of necrosis, if enough viable cells are present around the affected area, Regeneration (biology), regeneration will usually occur. Coagulative necrosis occurs in most bodily organs, excluding the brain. Different diseases are associated with coagulative necrosis, including acute tubular necrosis and acute myocardial infarction. Coagulative necrosis can also be induced by high local temperature; it is a desired effect of treatments such as high intensity focused ultrasound applied to cancerous cells. Causes Coagulative necrosis is mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Death
Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as diseases, localized injury, or the death of the organism of which the cells are part. Apoptosis or Type I cell-death, and Autophagy (cellular), autophagy or Type II cell-death are both forms of programmed cell death, while necrosis is a non-physiological process that occurs as a result of infection or injury. The term "cell necrobiology" has been used to describe the life processes associated with morphological, biochemical, and molecular changes which predispose, precede, and accompany cell death, as well as the consequences and tissue response to cell death. The word is derived from the Greek language, Greek νεκρό meaning "death", βìο meaning "life", and logos, λόγος meaning "the study of". The term was initially coined to bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permanent Cell
Permanent cells are cells that are incapable of regeneration. These cells are considered to be terminally differentiated and non-proliferative in postnatal life. This includes neurons, heart cells, skeletal muscle cells. Although these cells are considered permanent in that they neither reproduce nor transform into other cells, this does not mean that the body cannot create new versions of these cells. For instance, structures in the bone marrow produce new red blood cells constantly, while skeletal muscle damage can be repaired by underlying satellite cells, which fuse to become a new skeletal muscle cell. Disease and virology studies can use permanent cells to maintain cell count and accurately quantify the effects of vaccines. Some embryology studies also use permanent cells to avoid harvesting embryonic cells from pregnant animals; since the cells are permanent, they may be harvested at a later age when an animal is fully developed. See also * Labile cells, which multi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scarring
A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g., after accident, disease, or surgery) results in some degree of scarring. An exception to this are animals with complete regeneration, which regrow tissue without scar formation. Scar tissue is composed of the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrosis
Fibrosis, also known as fibrotic scarring, is the development of fibrous connective tissue in response to an injury. Fibrosis can be a normal connective tissue deposition or excessive tissue deposition caused by a disease. Repeated injuries, chronic inflammation and repair are susceptible to fibrosis, where an accidental excessive accumulation of extracellular matrix components, such as the collagen, is produced by fibroblasts, leading to the formation of a permanent fibrotic scar. In response to injury, this is called scarring, and if fibrosis arises from a single cell line, this is called a fibroma. Physiologically, fibrosis acts to deposit connective tissue, which can interfere with or totally inhibit the normal architecture and function of the underlying organ or tissue. Fibrosis can be used to describe the pathological state of excess deposition of fibrous tissue, as well as the process of connective tissue deposition in healing. Defined by the pathological accumulation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblasts
A fibroblast is a type of biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal 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 nucleus having two or more nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum (RER). Inactive fibroblasts, called ' fibrocytes', are smaller, spindle-shaped, and have less RER. Although disjointed and scattered when covering large spaces, fibroblasts often locally align in parallel clusters when crowded together. Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a polarizing attachment to a basal lamina on one side, although they may contribute to basal lamina components in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiomyocytes
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the cell's myofilaments to slide past each other in a pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurons
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural network in the nervous system. They are located in the nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all Animalia, animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitosis
Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the total number of chromosomes is maintained. Mitosis is preceded by the S phase of interphase (during which DNA replication occurs) and is followed by telophase and cytokinesis, which divide the cytoplasm, organelles, and cell membrane of one cell into two new cell (biology), cells containing roughly equal shares of these cellular components. The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the cell division, division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are preprophase (specific to plant ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labile Cell
In cellular biology, labile cells are cells that continuously multiply and divide throughout life . Labile cells replace the cells that are lost from the body. When injured, labile cells are repaired rapidly due to an aggressive TR response. This continual division of labile cells allows them to reproduce new stem cells and replace functional cells that are lost in the body. Functional cells may be lost through necrosis, which is the premature death of cells caused by environmental disturbances, such as diseases or injuries. Functional cells may also need to be replaced after undergoing apoptosis, which is the programmed death of cells that occurs normally as part of an organism's development. Labile cells continually regenerate by undergoing mitosis and are one of three types of cells that are involved in cell division, classified by their regenerative capacity. The other two cell types include stable cells and permanent cells. Each of these three cell types respond to injuries t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-intensity Focused Ultrasound
High-intensity focused ultrasound (HIFU), or MR-guided focused ultrasound surgery (MR-guided focused ultrasound ablation), is an incisionless therapeutic technique that uses non-ionizing ultrasonic waves to heat or ablate tissue. HIFU can be used to increase the flow of blood or lymph or to destroy tissue, such as tumors, via thermal and mechanical mechanisms. Given the prevalence and relatively low cost of ultrasound generation mechanisms, the premise of HIFU is that it is expected to be a non-invasive and low-cost therapy that can at least outperform care in the operating room. The technology is different from that used in ultrasonic imaging, though lower frequencies and continuous, rather than pulsed, waves are used to achieve the necessary thermal doses. However, pulsed waves may also be used if mechanical rather than thermal damage is desired. Acoustic lenses are often used to achieve the necessary intensity at the target tissue without damaging the surrounding tissue. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies that humans can hear (though these are not electromagnetic) and the lower limit of infrared frequencies, and also encompasses the microwave range. These are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves, so they are used in radio technology, among other uses. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granulation Tissue
Granulation tissue is new connective tissue and microscopic blood vessels that form on the surfaces of a wound during the healing process. Granulation tissue typically grows from the base of a wound and is able to fill wounds of almost any size. Examples of granulation tissue can be seen in pyogenic granulomas and pulp polyps. Its histological appearance is characterized by proliferation of fibroblasts and thin-walled, delicate capillaries (angiogenesis), and infiltrated inflammatory cells in a loose extracellular matrix. Appearance During the migratory phase of wound healing, granulation tissue is: * light red or dark pink, being perfused with new capillary loops or "buds"; * soft to the touch; * moist; * bumpy (granular) in appearance, due to punctate hemorrhages; * pulsatile on palpation; * painless when healthy; Structure Granulation tissue is composed of tissue matrix supporting a variety of cell types, most of which can be associated with one of the following function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
