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Karyolysis
Karyolysis (from Greek κάρυον ''karyon—''kernel, seed, or nucleus), and λύσις ''lysis'' from λύειν ''lyein'', "to separate") is the complete dissolution of the chromatin of a dying cell due to the enzymatic degradation by endonucleases. The whole cell will eventually stain uniformly with eosin after karyolysis. It is usually associated with karyorrhexis and occurs mainly as a result of necrosis, while in apoptosis after karyorrhexis the nucleus usually dissolves into ''apoptotic bodies''. Disintegration of the cytoplasm, pyknosis of the nuclei, and karyolysis of the nuclei of scattered transitional cells may be seen in urine from healthy individuals as well as in urine containing malignant cells. Cells with an attached tag of partially preserved cytoplasm were initially described by Papanicolaou and are sometimes called comet or decoy cells. They may have some of the characteristics of malignancy, and it is therefore important that they be recognized for what the ... [...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. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is often regarded as one of the founders of modern pathology. 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 an inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyorrhexis
Karyorrhexis (from Greek κάρυον ''karyon'' 'kernel, seed, nucleus' and ῥῆξις ''rhexis'' 'bursting') is the destructive fragmentation of the nucleus of a dying cell whereby its chromatin is distributed irregularly throughout the cytoplasm. It is usually preceded by pyknosis and can occur as a result of either programmed cell death (apoptosis), cellular senescence, or necrosis. In apoptosis, the cleavage of DNA is done by Ca2+ and Mg2+ -dependent endonucleases. Image:nuclear changes.jpg, Morphological characteristics of pyknosis and other forms of nuclear destruction. File:Apoptotic neutrophil with nuclear fragmentation.jpg, Microscopy of an apoptotic neutrophil with nuclear fragmentation (H&E stain) Overview During apoptosis, a cell goes through a series of steps as it eventually breaks down into apoptotic bodies, which undergo phagocytosis. In the context of karyorrhexis, these steps are, in chronological order, pyknosis (the irreversible condensation of chrom ... [...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. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is often regarded as one of the founders of modern pathology. 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 an inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyorrhexis
Karyorrhexis (from Greek κάρυον ''karyon'' 'kernel, seed, nucleus' and ῥῆξις ''rhexis'' 'bursting') is the destructive fragmentation of the nucleus of a dying cell whereby its chromatin is distributed irregularly throughout the cytoplasm. It is usually preceded by pyknosis and can occur as a result of either programmed cell death (apoptosis), cellular senescence, or necrosis. In apoptosis, the cleavage of DNA is done by Ca2+ and Mg2+ -dependent endonucleases. Image:nuclear changes.jpg, Morphological characteristics of pyknosis and other forms of nuclear destruction. File:Apoptotic neutrophil with nuclear fragmentation.jpg, Microscopy of an apoptotic neutrophil with nuclear fragmentation (H&E stain) Overview During apoptosis, a cell goes through a series of steps as it eventually breaks down into apoptotic bodies, which undergo phagocytosis. In the context of karyorrhexis, these steps are, in chronological order, pyknosis (the irreversible condensation of chrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Cell
A muscle cell, also known as a myocyte, is a mature contractile Cell (biology), cell in the muscle of an animal. In humans and other vertebrates there are three types: skeletal muscle, skeletal, smooth muscle, smooth, and Cardiac muscle, cardiac (cardiomyocytes). A skeletal muscle cell is long and threadlike with multinucleated, many nuclei and is called a ''muscle fiber''. Muscle cells develop from embryonic precursor cells called myoblasts. Skeletal muscle cells form by cell fusion, fusion of myoblasts to produce multinucleated cells (syncytium, syncytia) in a process known as myogenesis. Skeletal muscle cells and cardiac muscle cells both contain myofibrils and sarcomeres and form a striated muscle tissue. Cardiac muscle cells form the cardiac muscle in the walls of the heart chambers, and have a single central Cell nucleus, nucleus. Cardiac muscle cells are joined to neighboring cells by intercalated discs, and when joined in a visible unit they are described as a ''cardiac m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fragmentation (cell Biology)
Fragmentation describes the process of splitting into several pieces or fragments. In cell biology, fragmentation is useful for a cell during both DNA cloning and apoptosis. DNA cloning is important in asexual reproduction or creation of identical DNA molecules, and can be performed spontaneously by the cell or intentionally by laboratory researchers. Apoptosis is the programmed destruction of cells, and the DNA molecules within them, and is a highly regulated process. These two ways in which fragmentation is used in cellular processes describe normal cellular functions and common laboratory procedures performed with cells. However, problems within a cell can sometimes cause fragmentation that results in irregularities such as red blood cell fragmentation and sperm cell DNA fragmentation. DNA Cloning DNA cloning can be performed spontaneously by the cell for reproductive purposes. This is a form of asexual reproduction where an organism splits into fragments and then each of thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Space
Extracellular space refers to the part of a multicellular organism outside the cells, usually taken to be outside the plasma membranes, and occupied by fluid. This is distinguished from intracellular space, which is inside the cells. The composition of the extracellular space includes metabolites, ions, proteins, and many other substances that might affect cellular function. For example, neurotransmitters "jump" from cell to cell to facilitate the transmission of an electric current in the nervous system. Hormones also act by travelling the extracellular space towards cell receptors. In cell biology, molecular biology and related fields, the word extracellular (or sometimes extracellular space) means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid (see extracellular matrix). The term is used in contrast to intracellular (inside the cell). According to the Gene Ontology, the extracellular space is a cellular component def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage
Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This self-protection method can be contrasted with that employed by Natural killer cell, Natural Killer cells. This process of engulfment and digestion is called phagocytosis; it acts to defend the host against infection and injury. Macrophages are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adapti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocyte
Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ''kutos,'' "hollow vessel". They are essential for fighting infections and for subsequent immunity. Phagocytes are important throughout the animal kingdom and are highly developed within vertebrates. One litre of human blood contains about six billion phagocytes. They were discovered in 1882 by Ilya Ilyich Mechnikov while he was studying starfish larvae.Ilya Mechnikov retrieved on November 28, 2008. Fro ''Physiology or Medicine 1901–192 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Envelope
The nuclear envelope, also known as the nuclear membrane, is made up of two lipid bilayer membranes that in eukaryotic cells surround the nucleus, which encloses the genetic material. The nuclear envelope consists of two lipid bilayer membranes: an inner nuclear membrane and an outer nuclear membrane. The space between the membranes is called the perinuclear space. It is usually about 10–50 nm wide. The outer nuclear membrane is continuous with the endoplasmic reticulum membrane. The nuclear envelope has many nuclear pores that allow materials to move between the cytosol and the nucleus. Intermediate filament proteins called lamins form a structure called the nuclear lamina on the inner aspect of the inner nuclear membrane and give structural support to the nucleus. Structure The nuclear envelope is made up of two lipid bilayer membranes, an inner nuclear membrane and an outer nuclear membrane. These membranes are connected to each other by nuclear pores. Two sets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Blood Cell
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen () to the body tissue (biology), tissues—via blood flow through the circulatory system. Erythrocytes take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillary, capillaries. The cytoplasm of a red blood cell is rich in hemoglobin (Hb), an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological Cell (biology), cell function such as erythrocyte deformabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
