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Encyclopedia > Calcium in biology

Calcium (Ca2+) plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. The skeleton acts as a major mineral storage site for the element and releases Ca2+ ions into the bloodstream under controlled conditions. Circulating calcium is either in the free, ionized form or bound to blood proteins such as serum albumin. The hormone secreted by the parathyroid gland, parathyroid hormone, regulates the resorption of Ca2+ from bone. For other uses, see Calcium (disambiguation). ... Human heart and lungs, from an older edition of Grays Anatomy. ... This article or section does not cite any references or sources. ... Biochemistry (from Greek: , bios, life and Egyptian kēme, earth[1]) is the study of the chemical processes in living organisms. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another, most often involving ordered sequences of biochemical reactions inside the cell, that are carried out by enzymes and linked through second messengers resulting in what is thought of as... For other uses, see Skeleton (disambiguation). ... Minerals are natural compounds formed through geological processes. ... This article is about the electrically charged particle. ... You may be looking for albumen, or egg white. ... For other uses, see Hormone (disambiguation). ... The four human parathyroid glands are adjacent to the thyroid. ...

Contents

In humans

Different tissues contain Ca in different concentrations. For instance, Ca2+ (mostly calcium phosphate and some calcium sulfate) is the most important (and specific) element of bone and calcified cartilage. Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... Calcium phosphate is the name given to a family of minerals containing calcium ions (Ca2+) together with orthophosphates (PO43-), metaphosphates or pyrophosphates (P2O74-) and occasionally hydrogen or hydroxide ions. ... Calcium sulphate is a common laboratory and industrial chemical. ... This article is about the skeletal organs. ... Cartilage is a type of dense connective tissue. ...


Ca2+ ions are one of the most widespread second messengers used in signal transduction. They make their entrance into the cytoplasm either from outside the cell through the cell membrane via calcium channels (such as Ca-binding proteins), or from some internal calcium storages. In neurons, voltage-dependent, calcium-selective ion channels are important for synaptic transmission. Levels of intracellular calcium are regulated by transport proteins that remove it from the cell. For example, the sodium-calcium exchanger uses energy from the electrochemical gradient of sodium by pumping calcium out of the cell in exchange for the entry of sodium. The plasma membrane Ca2+ ATPase (PMCA) obtains energy to pump calcium out of the cell by hydrolysing adenosine triphosphate (ATP). In biology, second messengers are low-weight diffusible molecules that are used in signal transduction to relay signals within a cell. ... Cross section of cell with cytoplasm labeled at center right. ... Look up cell membrane in Wiktionary, the free dictionary. ... Ca storages (in cell biology) are intracellular organelles, that constantly accumulate Ca2+ ions and release them on some cell events. ... This article is about cells in the nervous system. ... Voltage-dependent calcium channels (VDCC) are a group of voltage-gated ion channels found in excitable cells (neurons, glial cells, muscle cells, etc. ... Illustration of the major elements in a prototypical synapse. ... A transport protein is a protein involved in facilitated diffusion. ... The sodium-calcium exchanger (often denoted Na+/Ca2+ exchanger or exchange protein) is an antiporter ion pump membrane protein which removes calcium from cells. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... The plasma membrane Ca2+ ATAase (PMCA) is a transport protein in the plasma membrane of cells that serves to remove calcium (Ca2+) from the cell. ... Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...


Effects

The effects of calcium in human cells are both general, i.e. almost all types of cells respond in the same way. Mostly, however, they are specific, where different types of cells respond differently.


General

Ca2+ ions can damage cells if they enter in excessive numbers (for example in the case of excitotoxicity, or overexcitation of neural circuits, which can occur in neurodegenerative diseases or after insults such as brain trauma or stroke). Excessive entry of calcium into a cell may damage it or even cause it to undergo apoptosis or death by necrosis. Excitotoxicity is the pathological process by which nerve cells are damaged and killed by glutamate and similar substances. ... From Texture of the Nervous System of Man and the Vertebrates by Santiago Ramón y Cajal. ... Neurodegenerative disease (Greek νέυρο-, néuro-, nerval and Latin dēgenerāre, to decline or to worsen) is a condition in which cells of the brain and spinal cord are lost. ... This article needs to be cleaned up to conform to a higher standard of quality. ... For other uses, see Stroke (disambiguation). ... A section of mouse liver showing an apoptotic cell indicated by an arrow Apoptosis (pronounced apo tō sis) is a process of suicide by a cell in a multicellular organism. ... Necrosis (in Greek Νεκρός = Dead) is the name given to accidental death of cells and living tissue. ...


One cause of hypercalcemia is hyperparathyroidism. Hypercalcaemia is an elevated calcium level in the blood. ... Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH). ...


Specific

Ca2+ entering the cell plasma causes specific actions of the cell, depending on the type of cell. For instance, most secretory cells release vesicles with their secretion, muscle cells contract, synapses release synaptic vesicles and go into processes of synaptic plasticity, etc. In cell biology, a vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid bilayer. ... Secretion is the process of segregating, elaborating, and releasing chemicals from a cell, or a secreted chemical substance or amount of substance. ... A simplified, global view of a neuromuscular junction: 1. ... Illustration of the major elements in a prototypical synapse. ... In a neuron, synaptic vesicles, also called neurotransmitter vesicles, store the various neurotransmitters that are released during calcium-regulated exocytosis at the presynaptic terminal into the synaptic cleft of a synapse. ... In neuroscience, synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength. ...


Calcium's function in muscle contraction was found as early as 1882 by Ringer and led the way for further investigations to reveal its role as a messenger about a century later. Because its action is interconnected with cAMP, they are called synarchic messengers. Calcium can bind to several different calcium-modulated proteins such as troponin-C (the first one to be identified) or calmodulin. The ions are stored in the sarcoplasmic reticulum of muscle cells. A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ... Year 1882 (MDCCCLXXXII) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Friday of the 12-day slower Julian calendar). ... Structure of cAMP Cyclic adenosine monophosphate (cAMP, cyclic AMP or 3-5-cyclic adenosine monophosphate) is a molecule that is important in many biological processes; it is derived from adenosine triphosphate (ATP). ... Troponin Troponin C is a part of the troponin complex. ... oommen sir is a fool. ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ...


Calcium acts as one of the primary regulators of osmotic stress (Osmotic shock). Osmotic shock is a condition that inhibits cellular activity. ...

cell type Effect
secretory cells (mostly) ↑secretion
juxtaglomerular cell ↓secretion[1]
Parathyroid chief cells ↓secretion[1]
myocytes
Various Activation of protein kinase C
Further reading: Function of protein kinase C

A cell type is a distinct morphological or functional form of cell. ... The juxtaglomerular cells are specialized cells that stimulate the secretion of the adrenal hormone aldosterone and play a major role in renal autoregulation, the kidneys self-governance. ... Parathyroid chief cells are cells in the parathyroid glands which produce parathyroid hormone. ... Myocyte is the technical term for a muscle cell. ... A protein kinase is an enzyme that can transfer a phosphate group from a donor molecule (usually ATP) to an amino acid residue of a protein. ... A protein kinase is an enzyme that can transfer a phosphate group from a donor molecule (usually ATP) to an amino acid residue of a protein. ...

Non-humans

===formula here</math></math>phosphate]] (and some calcium sulfate) is the most important (and specific) element of bone and calcified cartilage. <nowiki>[[Media:Insert non-formatted]] text hereInsert non-formatted text here</nowiki> ===Other eukaryotes==<nowiki>Insert non-formatted text hereInsert non-formatted text here</nowiki> In all eukaryotes, Ca2+ ions are one of the most widespread second messengers used in signal transduction. Calcium sulphate is a common laboratory and industrial chemical. ... This article is about the skeletal organs. ... Cartilage is a type of dense connective tissue. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... In biology, second messengers are low-weight diffusible molecules that are used in signal transduction to relay signals within a cell. ...


Invertebrates

Some invertebrates use calcium compounds for building their exoskeleton (shells and carapaces) or endoskeleton (echinoderm plates and poriferan calcareous spicules). Many protists also make use of calcium. Invertebrate is an English word that describes any animal without a spinal column. ... An exoskeleton is an external anatomical feature that supports and protects an animals body, in contrast to the internal endoskeleton of, for example, a human. ... Various seashells Danielle A shell is the hard, rigid outer covering, or integument, allanimals. ... The term carapace refers to a dorsal section of an exoskeleton or shell, in a number of animal groups. ... Endoskeleton of a swordfish An endoskeleton is an internal support structure of an animal. ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... The sponge, in the phylum Porifera, is a very primitive and specialized animal. ... Spicules Spicules are skeletal structures that occur in most sponges. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all...


Plants

Structural roles

Ca2+ ions are an essential component of plant cell walls and cell membranes, and are used as cations to balance organic anions in the plant vacuole.[2] The Ca2+ concentration of the vacuole may reach millimolar levels. The most striking use of Ca2+ ions as a structural element in plants occurs in the marine coccolithophores, which use Ca2+ to form the calcium carbonate plates with which they are covered. A cell wall is a more or less solid layer surrounding a cell. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that encapsulate the cell. ... An ion is an atom or group of atoms with a net electric charge. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. ... ... Schematic of typical animal cell, showing subcellular components. ... Coccolithophores are single-celled algae, or phytoplankton, belonging to the haptophytes. ... Calcium carbonate is a chemical compound, with the chemical formula CaCO3. ...


Some plants that accumulate Ca in their tissues, thus making them more firm. Calcium is stored as Ca-oxalate crystals in plastids. For other uses, see Plant (disambiguation). ... An oxalate (called also: ethanedioate) is a salt or ester of oxalic acid. ... Plant cells with visible chloroplasts. ...


Cell signalling

Ca2+ ions are usually kept at nanomolar levels in the cytosol of plant cells, and act in a number of signal transduction pathways. The cytosol (cf. ... The cells of plants are quite different from the cells of most other organisms. ...


Measuring Ca2+ in living tissue

The total amount of Ca2+ present in a tissue may be measured using atomic absorption spectrometry, in which the tissue is vapourized and combusted. To measure Ca2+ in vivo, a range of fluorescent dyes may be used. These dyes are based on Ca2+-binding molecules such as BAPTA and so care is required in their use, because they may actually buffer the Ca2+ changes which they are used to measure. In vivo (Latin for (with)in the living). ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... A dye can generally be described as a coloured substance that has an affinity to the substrate to which it is being applied. ... Categories: Stub | Amines | Aromatic compounds | Carboxylic acids | Ethers ... Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acid-base extraction Acids: Strong acids Weak acids Superacids Lewis acids Mineral acids Organic acids Bases: Strong bases Weak bases Superbases Lewis bases Organic bases edit Buffer solutions are solutions which resist change...


Food sources

The USDA web site has a very complete table of calcium content (in mg) of common foods per common measures (link below). USDA redirects here. ...


Calcium amount in foods, 100g: BIC pen cap, about 1 gram. ...

Parmesan cheese. ... Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ... Molasses or treacle is a thick syrup by-product from the processing of the sugarcane or sugar beet into sugar. ... Binomial name Corylus avellana L. Male catkins on Common Hazel The Common Hazel (Corylus avellana) is a shrub native to Europe and Asia. ... For other uses, see Almond (disambiguation). ... Ricotta cheese is an Italian cheese made from the whey which results when making cheeses such as mozzarella or provolone. ... This article is about sugar as food and as an important and widely traded commodity. ... This article is about the species Lens culinaris. ... Species T. aestivum T. boeoticum T. dicoccoides T. dicoccon T. durum T. monococcum T. spelta T. sphaerococcum T. timopheevii References:   ITIS 42236 2002-09-22 Wheat Wheat For the indie rock group, see Wheat (band). ... Binomial name (L.) Millsp. ... Binomial name Cicer arietinum L. Percentages are relative to US recommendations for adults. ... For other uses, see Flour (disambiguation). ... Binomial name (L.) Osbeck Orange—specifically, sweet orange—refers to the citrus tree Citrus sinensis (syn. ... A glass of cows milk. ... For other uses, see Trout (disambiguation). ... For other uses, see Beef (disambiguation). ... COD may refer to many different topics, including: Cash on delivery Completion of discharge, shipping College of DuPage, a public Junior College with campuses in the suburbs of Chicago Call of Duty (series), a series of computer games Canadian Oxford Dictionary Carrier onboard delivery Catastrophic optical damage, a failure mode... Musculature of horse Horse meat is the culinary name for meat cut from a horse. ... For other uses, see Honey (disambiguation). ...

See also

Disorders of calcium metabolism occur when the body has too little or too much calcium. ...

References

  1. ^ a b Walter F., PhD. Boron (2003). Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders, 1300. ISBN 1-4160-2328-3.  Page 867
  2. ^ White, Philip J.; Martin R. Broadley (2003). "Calcium in Plants". Annals of Botany 92 (4): 487–511. Retrieved on 2006-09-01.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ...

External links

  • USDA national nutritional database, Calcium content of selected foods
  • Calcium and vitamin D.

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