1.
Emergency medicine
–
Different models for emergency medicine exist internationally. In developing countries, emergency medicine is still evolving and international emergency medicine programs offer hope of improving basic emergency care where resources are limited and it further encompasses an understanding of the development of pre-hospital and in-hospital emergency medical systems and the skills necessary for this development. The field of emergency medicine encompasses care involving the care of internal medical and surgical conditions. Emergency physicians also provide primary care to patients during off hours. Emergency medicine is distinct from urgent care, which refers to immediate healthcare for less emergent medical issues, however, many emergency physicians work in urgent care settings, since there is obvious overlap. Emergency medicine also includes aspects of acute primary care, and shares with family medicine the uniqueness of seeing all patients regardless of age. The emergency physician workforce also includes many competent physicians who trained in other specialties, the practice of emergency medicine is often quite different in rural areas where there are far fewer consultants and health care resources. In these areas, family physicians with additional skills in emergency medicine often staff emergency departments, rural emergency physicians may be the only health care providers in the community, and require skills that include primary care and obstetrics. Patterns vary by country and region, in the United States, the employment arrangement of emergency physician practices are either private, institutional, corporate, or governmental. In the United Kingdom, all consultants in emergency medicine work in the National Health Service, rural emergency departments may be headed by general practitioners alone, sometimes with non-specialist qualifications in emergency medicine. Dominique Jean Larrey is sometimes called the father of medicine for his strategies during the French wars. Emergency medicine as an independent medical specialty is relatively young, in many smaller emergency departments, nurses would triage patients and physicians would be called in based on the type of injury or illness. Family physicians were often on call for the department. Many of the pioneers of medicine were family physicians and other specialists who saw a need for additional training in emergency care. During this period, groups of physicians began to emerge who had left their respective practices in order to devote their work completely to the ED, in the UK in 1952, Maurice Ellis was appointed as the first casualty consultant at Leeds General Infirmary. In 1967, the Casualty Surgeons Association was established with Maurice Ellis as its first President, many hospitals and care centers feature departments of emergency medicine, where patients can receive acute care without an appointment. While many patients are treated for life-threatening injuries, others utilize the emergency department for non-urgent reasons such as headaches or a cold. As such, EDs can adjust staffing ratios and designate an area of the department for faster patient turnover to accommodate a variety of patient needs and volumes
Emergency medicine
–
Emergency physician
Emergency medicine
–
Schematic diagram of a normal sinus rhythm for a human heart as seen on an
ECG.
2.
Blood plasma
–
Blood plasma is a straw coloured liquid component of blood that normally holds the blood cells in whole blood in suspension, this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the total blood volume. It is the fluid part of extracellular fluid. It is mostly water, and contains dissolved proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, Plasma also serves as the protein reserve of the human body. It plays a role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection. Blood plasma is prepared by spinning a tube of fresh blood containing an anticoagulant in a centrifuge until the blood fall to the bottom of the tube. The blood plasma is then poured or drawn off, Blood plasma has a density of approximately 1025 kg/m3, or 1.025 g/ml. Blood serum is blood plasma without clotting factors, in other words, plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration. Fresh frozen plasma is on the WHO Model List of Essential Medicines, Blood plasma volume may be expanded by or drained to extravascular fluid when there are changes in Starling forces across capillary walls. For example, when blood pressure drops in circulatory shock, Starling forces drive fluid into the interstitium, standing still for a prolonged period will cause an increase in transcapillary hydrostatic pressure. As a result, approximately 12% of blood plasma volume will cross into the extravascular compartment and this causes an increase in hematocrit, serum total protein, blood viscosity and, as a result of increased concentration of coagulation factors, it causes orthostatic hypercoagulability. The use of plasma as a substitute for whole blood and for transfusion purposes was proposed in March 1918, in the correspondence columns of the British Medical Journal. Dried plasmas in powder or strips of material format were developed, prior to the United States involvement in the war, liquid plasma and whole blood were used. The Blood for Britain program during the early 1940s was quite successful based on Charles Drews contribution, a large project began in August 1940 to collect blood in New York City hospitals for the export of plasma to Britain. Drew was appointed supervisor of the Plasma for Britain project. His notable contribution at this time was to transform the test tube methods of many blood researchers into the first successful mass production techniques. Nonetheless, the decision was made to develop a dried plasma package for the forces as it would reduce breakage and make the transportation, packaging. The resulting dried plasma package came in two tin cans containing 400 cc bottles, one bottle contained enough distilled water to reconstitute the dried plasma contained within the other bottle
Blood plasma
–
Dried plasma packages used by the British and US militaries during WWII
Blood plasma
–
Private Roy W. Humphrey is being given blood plasma after he was wounded by shrapnel in Sicily in August, 1943.
Blood plasma
–
A unit of donated frozen plasma
3.
Blood donation
–
A blood donation occurs when a person voluntarily has blood drawn and used for transfusions and/or made into biopharmaceutical medications by a process called fractionation. Donation may be of whole blood, or of components directly. Blood banks often participate in the process as well as the procedures that follow it. Today in the world, most blood donors are unpaid volunteers who donate blood for a community supply. In poorer countries, established supplies are limited and donors usually give blood when family or friends need a transfusion. Many donors donate as an act of charity, but in countries that allow paid donation some donors are paid, Donors can also have blood drawn for their own future use. Donating is relatively safe, but some donors have bruising where the needle is inserted or may feel faint, potential donors are evaluated for anything that might make their blood unsafe to use. The screening includes testing for diseases that can be transmitted by a transfusion, including HIV. The donor must also answer questions about history and take a short physical examination to make sure the donation is not hazardous to his or her health. How often a donor can donate varies from days to months based on what component they donate, for example, in the United States, donors must wait eight weeks between whole blood donations but only seven days between plateletpheresis donations and twice per seven-day period in plasmapheresis. The amount of blood drawn and the methods vary, the collection can be done manually or with automated equipment that takes only specific components of the blood. Most of the components of used for transfusions have a short shelf life. Blood donations are divided into groups based on who will receive the collected blood, an allogeneic donation is when a donor gives blood for storage at a blood bank for transfusion to an unknown recipient. A directed donation is when a person, often a family member, directed donations are relatively rare when an established supply exists. A replacement donor donation is a hybrid of the two and is common in developing such as Ghana. In this case, a friend or family member of the recipient donates blood to replace the blood used in a transfusion. When a person has blood stored that will be transfused back to the donor at a date, usually after surgery. Blood that is used to make medications can be made from allogeneic donations or from donations exclusively used for manufacturing and this blood is sometimes treated as a blood donation, but may be immediately discarded if it cannot be used for transfusion or further manufacturing
Blood donation
–
A blood collection bus (
bloodmobile) from Children's Hospital Boston at a manufacturing facility in Massachusetts: Blood banks sometimes use a modified bus or similar large vehicle to provide mobile facilities for donation.
Blood donation
–
Blood donation pictogram
Blood donation
–
A college student in a campaign of blood donation.
Blood donation
–
A donor's arm at various stages of donation. The two photographs on the left show a blood pressure cuff being used as a tourniquet.
4.
Perfusion
–
Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue. The word is derived from the French verb perfuser meaning to pour over or through, all animal tissues require an adequate blood supply for health and life. Poor perfusion, that is, ischemia, causes problems, as seen for example in coronary artery disease, deep vein thrombosis. Tests verifying that adequate perfusion exists are a part of an assessment process that are performed by medical or emergency personnel. The most common methods include evaluating a bodys skin color, temperature, condition, during major surgery, especially cardiothoracic surgery, perfusion must be maintained and managed by the health professionals involved, rather than left to the bodys homeostasis alone. As the lead surgeons are often too busy to handle all hemodynamic control by themselves, there are more than one hundred thousand perfusion procedures annually. In 1920, August Krogh was awarded the Nobel Prize in Physiology or Medicine for his discovering the mechanism of regulation of capillaries in skeletal muscle. Krogh was the first to describe the adaptation of blood perfusion in muscle, underperfusion is also called poor perfusion and malperfusion is any type of incorrect perfusion. Heart tissues, for example, are classified as being overperfused because they normally are receiving more blood than the rest of tissues in the organism. In the case of cells, extra blood flow in them is used for thermoregulation of a body. In equations, the symbol Q̇ often represents perfusion or, relatedly, microspheres that are labeled with radioactive isotopes have been widely used since the 1960s. Radioactively labeled particles are injected into the test subject and a detector measures radioactivity in tissues of interest. Application of this process is used to develop radionuclide angiography, a method of diagnosing heart problems, in the 1990s, methods for using fluorescent microspheres became a common substitute for radioactive particles. Perfusion of various tissues can be measured in vivo with nuclear medicine methods which are mainly positron emission tomography. The first is based on the use of an injected contrast agent that changes the magnetic susceptibility of blood, brain perfusion can be estimated with contrast-enhanced computed tomography. Perfusion can be determined by measuring the thermal diffusion and then separating it into thermal conductivity. RCBF is usually measured continuously in time and it is necessary to stop the measurement periodically to cool down and reassess the thermal conductivity
Perfusion
–
A perfusion pump, c. 1935, an early device for simulating natural perfusion
Perfusion
–
Diving medicine:
5.
Internal bleeding
–
Internal bleeding is a loss of blood that occurs from the vascular system into a body cavity or space. It is a medical emergency and the extent of severity depends on bleeding rate. It can cause death and cardiac arrest if proper medical treatment is not received quickly, a number of medical conditions may lead to internal bleeding. Common causes include trauma, various conditions and complications of medical therapy. Common locations include the gastrointestinal tract, the aorta and intracranial hemorrhage, internal bleeding can be caused by blunt trauma such as high speed deceleration in an automobile accident, or by penetrating trauma such as a ballistic or stab wound. A number of conditions and diseases can lead to internal bleeding. These include blood vessel rupture as a result of blood pressure, aneurysms. Another common cause of bleeding is carcinoma, either of the gastro-intestinal tract, of the lung, or more rarely of other organs such as the prostate. Some viruses may cause a type of internal bleeding called viral hemorrhagic fever, such as the Ebola, Dengue or Marburg viruses, internal bleeding could be an iatrogenic artifact as a result of complications after surgical operations or medical treatment. Some medication effects may lead to internal bleeding, such as the use of anticoagulant drugs or antiplatelet drugs in the treatment of coronary artery disease. If there is pressure, it may lead to death or a brain hemorrhage, cases of internal bleeding are usually termed as hemorrhage, even though the term is general to all kinds of bleeding. A minor case of internal bleeding results in ecchymosis, or a bruise, blood expands under the skin, causing discoloration
Internal bleeding
–
Internal bleeding in the brain
6.
Vasoconstriction
–
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels, the process is particularly important in staunching hemorrhage and acute blood loss. When blood vessels constrict, the flow of blood is restricted or decreased and this makes the skin turn paler because less blood reaches the surface, reducing the radiation of heat. On a larger level, vasoconstriction is one mechanism by which the body regulates, medications causing vasoconstriction, also known as vasoconstrictors, are one type of medicine used to raise blood pressure. Generalized vasoconstriction usually results in an increase in blood pressure. The extent of vasoconstriction may be slight or severe depending on the substance or circumstance, many vasoconstrictors also cause pupil dilation. Medications that cause vasoconstriction include, antihistamines, decongestants, and stimulants, severe vasoconstriction may result in symptoms of intermittent claudication. The mechanism that leads to results from the increased concentration of calcium within vascular smooth muscle cells. However, the mechanisms for generating an increased intracellular concentration of calcium depends on the vasoconstrictor. Smooth muscle cells are capable of generating action potentials, but this mechanism is utilized for contraction in the vasculature. Hormonal or pharmokinetic components are more physiologically relevant, two common stimuli for eliciting smooth muscle contraction are circulating epinephrine and activation of the sympathetic nervous system that directly innervates the muscle. These compounds interact with cell surface adrenergic receptors, the rise in intracellular calcium complexes with calmodulin, which in turn activates myosin light-chain kinase. This enzyme is responsible for phosphorylating the light chain of myosin to stimulate cross-bridge cycling and this reduction in calcium removes the stimulus necessary for contraction, allowing for a return to baseline. Factors that trigger vasoconstriction can be of exogenous or endogenous origin, ambient temperature is an example of the former. Cutaneous vasoconstriction will occur because of the exposure to the severe cold. Examples of endogenous factors include the nervous system, circulating hormones. Examples include amphetamines, antihistamines and cocaine, many are used in medicine to treat hypotension and as topical decongestants. Vasoconstrictors are also used clinically to increase blood pressure or to reduce blood flow
Vasoconstriction
–
Vasoconstriction of a microvessel by
pericytes and
endothelial cells that encircle an
erythrocyte (E).
7.
Mottling
–
Mottle is a pattern of irregular marks, spots, streaks, blotches or patches of different shades or colours. It is commonly used to describe the surface of plants or the skin of animals, in plants, mottling usually consists of yellowish spots on plants, and is usually a sign of disease or malnutrition. The medical term for mottled skin is dyschromia, although this is not always the case, mottling can occur in the dying patient and commonly indicates that the end of life is near. Mottling usually occurs in the extremities and progresses up as cardiac function declines, in animals, mottling may be a sign of disease, but may also be a hereditary trait, such as seen with the champagne and leopard complex genes in horses. Mottles can also refer to discoloration in processed food, such as butter, in geology, mottled refers to a patchy/blotch texture of alteration or interbedding, commonly found in limestone and commonly caused by bioturbation. Mottling can also refer to a defect which can occur with effect coatings. The total color impression shows irregular areas of lightness variations and these patches are usually visually evaluated, described as a mottling effect. Some also feel that it reminds them of clouds and this effect is especially noticeable on large body panels. It can be caused by the formulation, as well as variations in the application process. For example, disorientation of the flakes or film thickness variations of the basecoat can lead to various mottle sizes resulting in a non-uniform appearance. The visual perception of mottling is dependent on the distance, Large mottles can be seen in far distance evaluation. The visual evaluation of mottling is very subjective, as it depends on the conditions, the observing distance. In graphics printing mottling refers to an uneven coloration resulting from letterpressed printing of textured papers, due to the uneven surface, not all fibers of the paper are evenly saturated with color unlike offset printing. The irregular lightness variations caused by mottling can be measured with specially made instruments. These instruments simulate visual evaluation under different observing angles and characterize clouds / mottles by their size, small to large mottles are measured under three observing angles, in which the scan length can usually be varied from 10 to 100 cm. The measurement results are independent of color and curvature of the surface, the specific measurement process for one such instrument is as follows. It first optically scans the surface and measures the lightness variations, the mottling meter is rolled across the surface for a defined distance of 10 to 100 cm and measures the lightness variations point by point. The measurement signal is divided via mathematical filter functions into 6 different size ranges, the higher the value is, the more visible the mottling effect
Mottling
–
This
Appaloosa horse shows mottling around its mouth and nostrils. In this particular case, it is a normal hereditary trait linked to a spotted
coat color pattern and not a sign of disease
Mottling
–
Flecktarn camouflage
8.
Intravenous drip
–
Intravenous therapy is the infusion of liquid substances directly into a vein. Intravenous infusions are commonly referred to as drips, the intravenous route is the fastest way to deliver fluids and medications throughout the body. Intravenous therapy may be used for administration, to correct electrolyte imbalances, to deliver medications. IVs can be categorized by type of vein the tube inserted, called the catheter. A peripheral IV is used on peripheral veins and this is the most common type of IV therapy used. Central IV lines have their catheters that are advanced through a vein and empty into a central vein, usually the superior vena cava. Other advantages are that because it empties near the heart, medications can also be distributed to the rest of the body. As there is room for multiple parallel compartments within the catheter, caregivers can also measure central venous pressure and other physiological variables through the line. They are also longer, which as reflected in Poiseuilles law, requires higher pressure to achieve the same flow, central IV lines carry risks of bleeding, infection, gangrene, thromboembolism and gas embolism. Surrounding structures such as the pleura and carotid artery are also at risk of damage with the potential for pneumothorax or even cannulation of the artery. There are several types of central IVs, depending on the route that the catheter takes from the outside of the body to the vein, typical uses for a PICC include, long chemotherapy regimens, extended antibiotic therapy, or total parenteral nutrition. This is usually done by measuring the distance to a landmark, such as the suprasternal notch. An X-ray must be used to verify that the tip is in the place when fluoroscopy was not used during the insertion. A PICC may have a tube and connector, two or three compartments, each with its own external connector. Power-injectable PICCs are now available as well, from the outside, a single-lumen PICC resembles a peripheral IV, except that the tubing is slightly wider. The insertion site requires better protection than that of a peripheral IV, however, a PICC poses less of a systemic infection risk than other central IVs, because the insertion site is usually cooler and dryer than the sites typically used for other central lines. This helps to slow the growth of bacteria which could reach the bloodstream by traveling under the skin along the outside of the catheter, although special training is required, a PICC does not require the skill level of a physician or surgeon. It is also externally unobtrusive, and with proper hygiene and care can be left in place for months to years if needed for patients who require extended treatment, also, as a PICC travels through the axilla, it can become kinked, causing poor function
Intravenous drip
–
Infusion therapy: A person receiving medication via intravenous therapy.
Intravenous drip
–
IV bags on a pole connected to IV lines.
Intravenous drip
–
A person receiving intravenous fluid
Intravenous drip
–
Saline and 5%
glucose solution (Left),
levofloxacin 750mg (Right)
9.
Clotting factor
–
Coagulation is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, the mechanism of coagulation involves activation, adhesion, and aggregation of platelets along with deposition and maturation of fibrin. Disorders of coagulation are disease states which can result in bleeding or obstructive clotting, Coagulation is highly conserved throughout biology, in all mammals, coagulation involves both a cellular and a protein component. The system in humans has been the most extensively researched and is the best understood, Coagulation begins almost instantly after an injury to the blood vessel has damaged the endothelium lining the vessel. Platelets immediately form a plug at the site of injury, this is called primary hemostasis and this localization of platelets to the extracellular matrix promotes collagen interaction with platelet glycoprotein VI. Binding of collagen to glycoprotein VI triggers a cascade that results in activation of platelet integrins. Activated integrins mediate tight binding of platelets to the extracellular matrix and this process adheres platelets to the site of injury. Activated platelets will release the contents of stored granules into the blood plasma, the granules include ADP, serotonin, platelet-activating factor, vWF, platelet factor 4, and thromboxane A2, which, in turn, activate additional platelets. The granules contents activate a Gq-linked protein receptor cascade, resulting in increased concentration in the platelets cytosol. The calcium activates protein kinase C, which, in turn, pLA2 then modifies the integrin membrane glycoprotein IIb/IIIa, increasing its affinity to bind fibrinogen. The activated platelets change shape from spherical to stellate, and the fibrinogen cross-links with glycoprotein IIb/IIIa aid in aggregation of adjacent platelets, the coagulation cascade of secondary hemostasis has two initial pathways which lead to fibrin formation. These are the activation pathway, and the tissue factor pathway which both lead to the same fundamental reactions that produce fibrin. Coagulation factors are generally indicated by Roman numerals, with a lowercase a appended to indicate an active form, the coagulation factors are generally serine proteases, which act by cleaving downstream proteins. For example, FVIII and FV are glycoproteins, and Factor XIII is a transglutaminase, the coagulation factors circulate as inactive zymogens. The coagulation cascade is therefore divided into three pathways. The tissue factor and contact activation pathways both activate the final common pathway of factor X, thrombin and fibrin, fVIIa circulates in a higher amount than any other activated coagulation factor. FVII is itself activated by thrombin, FXIa, FXII and FXa, the activation of FX by TF-FVIIa is almost immediately inhibited by tissue factor pathway inhibitor. FXa and its co-factor FVa form the complex, which activates prothrombin to thrombin
Clotting factor
–
Blood plasma after the addition of Tissue Factor forms a gel-like structure (Test for prothrombin time).
Clotting factor
–
Blood coagulation pathways in vivo showing the central role played by thrombin
10.
Dopamine
–
Dopamine is an organic chemical of the catecholamine and phenethylamine families that plays several important roles in the brain and body. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical L-DOPA, dopamine is also synthesized in plants and most multicellular animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons to send signals to nerve cells. The brain includes several distinct dopamine pathways, one of plays a major role in reward-motivated behavior. Most types of rewards increase the level of dopamine in the brain, other brain dopamine pathways are involved in motor control and in controlling the release of various hormones. These pathways and cell groups form a system which is neuromodulatory. Outside the central system, dopamine functions primarily as a local chemical messenger. With the exception of the vessels, dopamine in each of these peripheral systems is synthesized locally. Several important diseases of the system are associated with dysfunctions of the dopamine system. Parkinsons disease, a condition causing tremor and motor impairment, is caused by a loss of dopamine-secreting neurons in an area of the midbrain called the substantia nigra. Its metabolic precursor L-DOPA can be manufactured, and in its pure form marketed as Levodopa is the most widely used treatment for the condition. There is evidence that schizophrenia involves altered levels of dopamine activity, similar dopamine antagonist drugs are also some of the most effective anti-nausea agents. Restless legs syndrome and attention deficit hyperactivity disorder are associated with decreased dopamine activity, dopaminergic stimulants can be addictive in high doses, but some are used at lower doses to treat ADHD. A dopamine molecule consists of a structure with one amine group attached via an ethyl chain. As such, dopamine is the simplest possible catecholamine, a family that includes the neurotransmitters norepinephrine and epinephrine. The presence of a ring with this amine attachment makes it a substituted phenethylamine. Like most amines, dopamine is an organic base, as a base, it is generally protonated in acidic environments. The protonated form is highly water-soluble and relatively stable, but can become oxidized if exposed to oxygen or other oxidants, in basic environments, dopamine is not protonated
Dopamine
–
Primary pathways for dopamine metabolism MAO:
Monoamine oxidase COMT:
catechol-O-methyltransferase HVA:
Homovanillic acid
Dopamine
–
Dopamine
Dopamine
–
Dopamine HCl preparation, single dose vial for intravenous administration
Dopamine
–
Metamphetamine hydrochloride also known as crystal meth
11.
International Standard Book Number
–
The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
International Standard Book Number
–
A 13-digit ISBN, 978-3-16-148410-0, as represented by an
EAN-13 bar code
12.
PubMed Identifier
–
PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby
PubMed Identifier
–
PubMed
13.
Medical Subject Headings
–
Medical Subject Headings is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences, it serves as a thesaurus that facilitates searching. Created and updated by the United States National Library of Medicine, it is used by the MEDLINE/PubMed article database, MeSH is also used by ClinicalTrials. gov registry to classify which diseases are studied by trials registered in ClinicalTrials. gov. MeSH was introduced in 1960, with the NLMs own index catalogue, the yearly printed version of MeSH was discontinued in 2007 and MeSH is now available online only. It can be browsed and downloaded free of charge through PubMed, originally in English, MeSH has been translated into numerous other languages and allows retrieval of documents from different languages. The 2009 version of MeSH contains a total of 25,186 subject headings, most of these are accompanied by a short description or definition, links to related descriptors, and a list of synonyms or very similar terms. This additional information and the structure make the MeSH essentially a thesaurus. The descriptors or subject headings are arranged in a hierarchy, a given descriptor may appear at several locations in the hierarchical tree. The tree locations carry systematic labels known as numbers. The tree numbers of a given descriptor are subject to change as MeSH is updated, every descriptor also carries a unique alphanumerical ID that will not change. Most subject headings come with a description or definition. See the MeSH description for diabetes type 2 as an example, the explanatory text is written by the MeSH team based on their standard sources if not otherwise stated. References are mostly encyclopaedias and standard textbooks of the subject areas, references for specific statements in the descriptions are not given, instead readers are referred to the bibliography. In addition to the hierarchy, MeSH contains a small number of standard qualifiers. For example, Measles is a descriptor and epidemiology is a qualifier, the epidemiology qualifier can be added to all other disease descriptors. Not all descriptor/qualifier combinations are allowed some of them may be meaningless. In all there are 83 different qualifiers, in addition to the descriptors, MeSH also contains some 139,000 supplementary concept records. These do not belong to the vocabulary as such, instead they enlarge the thesaurus. Many of these records describe chemical substances, by default, a search for a descriptor will include all the descriptors in the hierarchy below the given one
Medical Subject Headings
–
Medical Subject Headings
14.
National Institutes of Health
–
The National Institutes of Health is a biomedical research facility primarily located in Bethesda, Maryland. An agency of the United States Department of Health and Human Services, it is the agency of the United States government responsible for biomedical. The NIH comprises 27 separate institutes and centers that conduct research in different disciplines of biomedical science, NIHs roots extend back to a Marine Hospital Service in the late 1790s that provided medical relief to sick and disabled men in the U. S. Navy. By 1870, a network of hospitals had developed and was placed under the charge of a medical officer within the Bureau of the Treasury Department. In 1887 a laboratory for the study of bacteria, the Hygienic Laboratory, was established at the Marine Hospital in New York, in the early 1900s, Congress began appropriating funds for the Marine Hospital Service. By 1922, this changed its name to Public Health Services. This marked the beginning of a partnership with universities, in 1930, the Hygienic Laboratory was re-designated as the National Institute of Health by the Ransdell Act and was given $750,000 to construct two NIH buildings. Over the next few decades, Congress would increase its funding tremendously to the NIH, in 1944, the Public Health Service Act was approved, and National Cancer Institute became a division of NIH. In 1948, the changed from National Institute of Health to National Institutes of Health. In the 1960s prominent virologist and cancer researcher Chester M. Southam injected HeLa cancer cells into patients at the Jewish Chronic Disease Hospital, when three doctors resigned after refusing to inject patients without their consent, this experiment gained considerable media attention. The NIH was a source of funding for Southam’s research and had required all research involving human subjects to obtain their consent prior to any experimentation. }Upon investigating all of their grantee institutions. From then on, the NIH has required all grantee institutions to approve any research involving human experimentation with review boards. In 1967 the Division of Regional Medical Programs was created to administer grants for research for heart disease, cancer, and strokes. That same year, the NIH director lobbied the White House for increased funding in order to increase research. An advisory committee was formed to further development of the NIH. The funding of NIH has often been a source of contention in Congress and this contention was seen most dramatically during the 1980s, when President Reagan repeatedly tried to cut funding for research, only to see Congress partly restore funding. But it was not until July 1987, as NIH celebrated its 100th anniversary, by the 1990s, the focus of the NIH committee had shifted to DNA research, and the Human Genome Project was launched. In 2009, President Obama reinstated federally funded research, revoking the ban imposed by President Bush in 2001
National Institutes of Health
–
Aerial photo of the NIH Mark O. Hatfield Clinical Research Center, Bethesda, Maryland
National Institutes of Health
–
National Institutes of Health logo
National Institutes of Health
–
The Laboratory of Hygiene in 1887
National Institutes of Health
–
Ida A. Bengtson, a
bacteriologist who in 1916 was the first woman hired to work in the Hygienic Laboratory.
15.
Electrolyte
–
An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent, electrically, such a solution is neutral. The movement of anions and cations in opposite directions within the solution amounts to a current and this includes most soluble salts, acids, and bases. Some gases, such as chloride, under conditions of high temperature or low pressure can also function as electrolytes. Electrolyte solutions can also result from the dissolution of some biological and synthetic polymers, termed polyelectrolytes, a substance that dissociates into ions in solution acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, magnesium, and phosphate are examples of electrolytes, in medicine, electrolyte replacement is needed when a patient has prolonged vomiting or diarrhea, and as a response to strenuous athletic activity. Commercial electrolyte solutions are available, particularly for children and athletes. Electrolyte monitoring is important in the treatment of anorexia and bulimia, the word electrolyte derives from the Greek lytós, meaning able to be untied or loosened. Arrheniuss explanation was that in forming a solution, the salt dissociates into charged particles, faradays belief had been that ions were produced in the process of electrolysis. Arrhenius proposed that, even in the absence of an electric current and he thus proposed that chemical reactions in solution were reactions between ions. For example, carbon dioxide gas dissolves in water to produce a solution that contains hydronium, carbonate, molten salts can also be electrolytes as, for example, when sodium chloride is molten, the liquid conducts electricity. An electrolyte in a solution may be described as concentrated if it has a concentration of ions. If a high proportion of the solute dissociates to form ions, the electrolyte is strong, if most of the solute does not dissociate. The properties of electrolytes may be exploited using electrolysis to extract constituent elements, in physiology, the primary ions of electrolytes are sodium, potassium, calcium, magnesium, chloride, hydrogen phosphate, and hydrogen carbonate. The electric charge symbols of plus and minus indicate that the substance is ionic in nature and has a distribution of electrons. Sodium is the main electrolyte found in extracellular fluid and potassium is the main intracellular electrolyte, all known higher lifeforms require a subtle and complex electrolyte balance between the intracellular and extracellular environments. In particular, the maintenance of precise osmotic gradients of electrolytes is important, such gradients affect and regulate the hydration of the body as well as blood pH, and are critical for nerve and muscle function. Various mechanisms exist in living species that keep the concentrations of different electrolytes under tight control, both muscle tissue and neurons are considered electric tissues of the body
Electrolyte
–
Types
16.
Sodium
–
Sodium is a chemical element with symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal, Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell that it readily donates, creating a positively charged atom—the Na+ cation. Its only stable isotope is 23Na, the free metal does not occur in nature, but must be prepared from compounds. Sodium is the sixth most abundant element in the Earths crust, Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful compounds, sodium hydroxide is used in soap manufacture, and sodium chloride is a de-icing agent. Sodium is an element for all animals and some plants. Sodium ions are the major cation in the fluid and as such are the major contributor to the ECF osmotic pressure. Loss of water from the ECF compartment increases the sodium concentration, isotonic loss of water and sodium from the ECF compartment decreases the size of that compartment in a condition called ECF hypovolemia. In nerve cells, the charge across the cell membrane enables transmission of the nerve impulse—an action potential—when the charge is dissipated. The melting and boiling points of sodium are lower than those of lithium but higher than those of the alkali metals potassium, rubidium. All of these high-pressure allotropes are insulators and electrides.3 nm, spin-orbit interactions involving the electron in the 3p orbital split the D line into two, at 589.0 and 589.6 nm, hyperfine structures involving both orbitals cause many more lines. Twenty isotopes of sodium are known, but only 23Na is stable, 23Na is created in the carbon-burning process in stars by fusing two carbon atoms together, this requires temperatures above 600 megakelvins and a star of at least three solar masses. Two nuclear isomers have been discovered, the one being 24mNa with a half-life of around 20.2 milliseconds. Sodium atoms have 11 electrons, one more than the stable configuration of the noble gas neon. This process requires so little energy that sodium is oxidized by giving up its 11th electron. In contrast, the ionization energy is very high, because the 10th electron is closer to the nucleus than the 11th electron. As a result, sodium usually forms ionic compounds involving the Na+ cation, the most common oxidation state for sodium is +1. It is generally less reactive than potassium and more reactive than lithium, Sodium metal is highly reducing, with the reduction of sodium ions requiring −2.71 volts, though potassium and lithium have even more negative potentials
Sodium
–
Sodium, 11 Na
Sodium
–
Spectral lines of sodium
Sodium
–
Emission spectrum for sodium, showing the
D line.
Sodium
–
A positive
flame test for sodium has a bright yellow color.
17.
Potassium
–
Potassium is a chemical element with symbol K and atomic number 19. It was first isolated from potash, the ashes of plants, in the periodic table, potassium is one of the alkali metals. Potassium in nature only in ionic salts. It is found dissolved in sea water, and is part of many minerals, naturally occurring potassium is composed of three isotopes, of which 40K is radioactive. Traces of 40K are found in all potassium, and it is the most common radioisotope in the human body, Potassium is chemically very similar to sodium, the previous element in Group 1 of the periodic table. They have a similar energy, which allows for each atom to give up its sole outer electron. That they are different elements combine with the same anions to make similar salts was suspected in 1702. Most industrial applications of potassium exploit the high solubility in water of potassium compounds, heavy crop production rapidly depletes the soil of potassium, and this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production. Potassium ions are necessary for the function of all living cells, fresh fruits and vegetables are good dietary sources of potassium. Potassium is the second least dense metal after lithium and it is a soft solid with a low melting point, and can be easily cut with a knife. Freshly cut potassium is silvery in appearance, but it begins to tarnish toward gray immediately on exposure to air, in a flame test, potassium and its compounds emit a lilac color with a peak emission wavelength of 766.5 nanometers. Neutral potassium atoms have 19 electrons, one more than the stable configuration of the noble gas argon. This process requires so little energy that potassium is readily oxidized by atmospheric oxygen, in contrast, the second ionization energy is very high, because removal of two electrons breaks the stable noble gas electronic configuration. Potassium therefore does not readily form compounds with the state of +2 or higher. Potassium is an active metal that reacts violently with oxygen in water. With oxygen it forms potassium peroxide, and with water potassium forms potassium hydroxide, the reaction of potassium with water is dangerous because of its violent exothermic character and the production of hydrogen gas. Hydrogen reacts again with atmospheric oxygen, producing water, which reacts with the remaining potassium and this reaction requires only traces of water, because of this, potassium and the liquid sodium-potassium — NaK — are potent desiccants that can be used to dry solvents prior to distillation. Because of the sensitivity of potassium to water and air, reactions with other elements are only in an inert atmosphere such as argon gas using air-free techniques
Potassium
–
Potassium pearls under paraffin oil. The large pearl measures 0.5 cm.
Potassium
–
Spectral lines of potassium
Potassium
–
Potassium in
feldspar
Potassium
–
Humphry Davy
18.
Serum chloride
–
Chloride is an anion in the human body needed for metabolism. It also helps keep the bodys acid-base balance, the amount of serum chloride is carefully controlled by the kidneys. Chloride ions have important physiological roles, for instance, in the central nervous system, the inhibitory action of glycine and some of the action of GABA relies on the entry of Cl− into specific neurons. The normal blood reference range of chloride for adults in most labs is 96 to 106 milliequivalents per liter, the normal range may vary slightly from lab to lab. Normal ranges are shown next to results in the lab report. A diagnostic test may use a chloridometer to determine the serum chloride level, the North American Dietary Reference Intake recommends a daily intake of between 2300 and 3600 mg/day for 25-year-old males
Serum chloride
–
Reference ranges for blood tests, showing blood content of chloride at far right in the spectrum.
19.
Calcium in biology
–
Calcium ions play a vital role in the physiology and biochemistry of organisms and the cell. Many enzymes require calcium ions as a cofactor, those of the blood-clotting cascade being notable examples, extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation. Calcium levels in mammals are tightly regulated, with acting as the major mineral storage site. Calcium ions, Ca2+, are released from bone into the bloodstream under controlled conditions, calcium is transported through the bloodstream as dissolved ions or bound to proteins such as serum albumin. Calcitriol, the form of vitamin D3, promotes absorption of calcium from the intestines. Calcitonin secreted from the cells of the thyroid gland also affects calcium levels by opposing parathyroid hormone, however. Calcium storages are intracellular organelles, that constantly accumulate Ca2+ ions, intracellular Ca2+ storages include mitochondria and the endoplasmic reticulum. Characteristic concentrations of calcium in model organisms are, in E. coli 3mM, 100nM, in budding yeast 2mM, in mammalian cell 10-100nM and this is evidenced by human plasma calcium, which is one of the most closely regulated physiological variables in the human body. Normal plasma levels vary between 1 and 2% over any given time, different tissues contain calcium in different concentrations. For instance, Ca2+ is the most important element of bone, in humans, the total body content of calcium is present mostly in the form of bone mineral. In this state, it is unavailable for exchange/bioavailability. The way to overcome this is through the process of bone resorption, the remainder of calcium is present within the extracellular and intracellular fluids. Within a typical cell, the concentration of ionized calcium is roughly 100 nM. The intracellular calcium level is relatively low with respect to the extracellular fluid, by an approximate magnitude of 12. This gradient is maintained through various plasma membrane calcium pumps that utilize ATP for energy, in electrically excitable cells, such as skeletal and cardiac muscles and neurons, membrane depolarization leads to a Ca2+ transient with cytosolic Ca2+ concentration reaching 400 nM and above. Mitochondria are capable of sequestering and storing some of that Ca2+ and it has been estimated that mitochondrial matrix free calcium concentration rises to the tens of micromolar levels in situ during neuronal activity. The effects of calcium on human cells are specific, meaning that different types of cells respond in different ways, however, in certain circumstances, its action may be more general. Ca2+ ions are one of the most widespread second messengers used in signal transduction, levels of intracellular calcium are regulated by transport proteins that remove it from the cell
Calcium in biology
–
Calcium regulation in the human body.
20.
Mixed disorder of acid-base balance
–
Acid–base homeostasis is the part of biologic homeostasis concerning the proper balance between acids and bases, also called body pH. The body is very sensitive to its extracellular pH level, so strong mechanisms exist to maintain it, outside the acceptable range of pH, proteins are denatured and digested, enzymes lose their ability to function, and death may occur. The principles of general acid–base equilibrium apply in the physiology of living systems, in various animals, including humans, the acid–base homeostasis system can be analyzed into 3 subsystems that are interrelated. They are the buffer system, the phosphate buffer system. Respiratory compensation and renal compensation are two ways that the body can excrete excess molecules to maintain pH, acidosis or alkalosis results if the balance is disturbed. The bodys acid–base balance is normally regulated by buffering agents, the respiratory system. Several buffering agents that reversibly bind hydrogen ions and impede any change in pH exist, the bicarbonate buffering system is especially key, as carbon dioxide can be shifted through carbonic acid to hydrogen ions and bicarbonate as shown below. This alters the concentration of carbon dioxide in the blood, shifting the above reaction according to Le Chateliers principle, the kidneys are slower to compensate, but renal physiology has several powerful mechanisms to control pH by the excretion of excess acid or base. Acid–base imbalance occurs when a significant insult causes the blood pH to shift out of the normal range, in the fetus, the normal range differs based on which umbilical vessel is sampled. An excess of acid in the blood is called acidemia and an excess of base is called alkalemia, the process that causes the imbalance is classified based on the etiology of the disturbance and the direction of change in pH. There are four processes, metabolic acidosis, respiratory acidosis, metabolic alkalosis. One or a combination may occur at any given time
Mixed disorder of acid-base balance
–
An acid-base
nomograph of human serum
21.
Referred pain
–
Referred pain, also called reflective pain, is pain perceived at a location other than the site of the painful stimulus. An example is the case of angina pectoris brought on by an infarction, where pain is often felt in the neck, shoulders, and back rather than in the thorax. The International Association for the Study of Pain has not officially defined the term, radiating pain is slightly different from referred pain, for example, the pain related to a myocardial infarction could either be referred or radiating pain from the chest. Referred pain is when the pain is located away from or adjacent to the organ involved, for instance, when a person has only in their jaw or left arm. Referred pain has been described since the late 1880s, despite an increasing amount of literature on the subject, the biological mechanism of referred pain is unknown, although there are several hypotheses. The size of referred pain is related to the intensity and duration of ongoing/evoked pain, temporal summation is a potent mechanism for generation of referred muscle pain. Central hyperexcitability is important for the extent of referred pain, patients with chronic musculoskeletal pains have enlarged referred pain areas to experimental stimuli. The proximal spread of referred pain is seen in patients with chronic musculoskeletal pain. Modality-specific somatosensory changes occur in referred areas, which emphasize the importance of using a multimodal sensory test regime for assessment, referred pain is often experienced on the same side of the body as the source, but not always. There are several proposed mechanisms for referred pain, currently there is no definitive consensus regarding which is correct. The cardiac general visceral sensory pain fibers follow the back to the spinal cord and have their cell bodies located in thoracic dorsal root ganglia 1-4. The central nervous system perceives pain from the heart as coming from the portion of the body supplied by the thoracic spinal cord segments 1-4. Classically the pain associated with a myocardial infarction is located in the mid or left side of the chest where the heart is actually located, the pain can radiate to the left side of the jaw and into the left arm. Myocardial infarction can rarely present as referred pain and this occurs in people with diabetes or older age. This represents one of the earliest theories on the subject of referred pain and it is based on the work of W. A. Sturge and J. Ross from 1888 and later TC Ruch in 1961. Additionally, experimental evidence shows that when local pain is intensified the referred pain is intensified as well, criticism of this model arises from its inability to explain why there is a delay between the onset of referred pain after local pain stimulation. Experimental evidence also shows that referred pain is often unidirectional, lastly, the threshold for the local pain stimulation and the referred pain stimulation are different, but according to this model they should both be the same. Convergence facilitation was conceived in 1893 by J MacKenzie based on the ideas of Sturge and he believed that the internal organs were insensitive to stimuli
Referred pain
–
Conscious perception of visceral sensations map to specific regions of the body, as shown in this chart. Some sensations are felt locally, whereas others are perceived as affecting areas that are quite distant from the involved organ.
22.
Heart sounds
–
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut, in cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart. In healthy adults, there are two normal heart sounds often described as a lubb and a dub, that occur in sequence with each heartbeat and these are the first heart sound and second heart sound, produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds. Heart murmurs are generated by turbulent flow of blood, which may occur inside or outside the heart, Murmurs may be physiological or pathological. Abnormal murmurs can be caused by restricting the opening of a heart valve. Abnormal murmurs may occur with valvular insufficiency, which allows backflow of blood when the incompetent valve closes with only partial effectiveness. Different murmurs are audible in different parts of the cardiac cycle, normal heart sounds are associated with heart valves closing, The first heart sound, or S1, forms the lub of lub-dub and is composed of components M1 and T1. It is caused by the closure of the valves, i. e. tricuspid and mitral, at the beginning of ventricular contraction. When the ventricles begin to contract, so do the muscles in each ventricle. The papillary muscles are attached to the cusps or leaflets of the tricuspid, when the papillary muscles contract, the chordae tendineae become tense and thereby prevent the backflow of blood into the lower pressure environment of the atria. It is the pressure created from ventricular contraction that closes the valve, the contraction of the ventricle begins just prior to AV valves closing and prior to the semilunar valves opening. The S1 sound results from reverberation within the associated with the sudden block of flow reversal by the valves. If M1 occurs slightly after T1, then the patient likely has a dysfunction of conduction of the side of the heart such as a left bundle branch blockage. The second heart sound, or S2, forms the dub of lub-dub and is composed of components A2, normally A2 precedes P2 especially during inhalation where a split of S2 can be heard. It is caused by the closure of the valves at the end of ventricular systole. As the left ventricle empties, its pressure falls below the pressure in the aorta, aortic blood flow quickly reverses back toward the left ventricle, catching the pocket-like cusps of the aortic valve, and is stopped by aortic valve closure. Similarly, as the pressure in the right ventricle falls below the pressure in the pulmonary artery, the S2 sound results from reverberation within the blood associated with the sudden block of flow reversal
Heart sounds
–
Front of
thorax, showing surface relations of
bones,
lungs (purple),
pleura (blue), and
heart (red outline). The location of best auscultation for each
heart valve are labeled with "M", "T", "A", and "P". First heart sound: caused by atrioventricular valves -
Mitral (M) and
Tricuspid (T). Second heart sound caused by semilunar valves --
Aortic (A) and
Pulmonary/Pulmonic (P).
23.
Split S2
–
A split S2 is a finding upon auscultation of the S2 heart sound. It is caused when the closure of the valve and the closure of the pulmonary valve are not synchronized normally. In a healthy person A2 is followed by P2, during inspiration, the chest wall expands and causes the intrathoracic pressure to become more negative. The increased negative pressure allows the lungs to fill with air, simultaneously, there is a reduction in blood volume returning from the lungs into the left atrium. Thus the P2 component of S2 is delayed relative to that of the A2 component, during expiration, the chest wall collapses and decreases the negative intrathoracic pressure. Therefore, there is no longer an increase in return to the right ventricle versus the left ventricle. This allows the valve to close earlier such that it overlaps the closing of the aortic valve. It is physiologically normal to hear a splitting of the second heart tone in younger people, during inspiration and in the pulmonary area, the pressure in the right ventricle tries to open the pulmonary valve. The pressure in the pulmonary artery tries to close the pulmonary valve, remember that the higher pressure will win. The change in A2 is not that evident, thus P2 appears after A2 in inspiration. The different types of split S2 can be associated with conditions, Split during inspiration. Wide splitting, seen in conditions that delay RV emptying, delay in RV emptying causes delayed pulmonic sound, it is an exaggeration of normal splitting sounds. Split during expiration, Reverse splitting indicates pathology, aortic stenosis, hypertrophic cardiomyopathy, left bundle branch block, and a ventricular pacemaker could all cause a reverse splitting of the second heart sound. Split during both inspiration and expiration, If splitting does not vary with inspiration, it is termed a fixed split S2 and is due to a septal defect. A bundle branch block either LBBB or RBBB, will produce continuous splitting, when the pulmonary valve closes before the aortic valve, this is known as a paradoxically split S2. On physical exam, paradoxical splitting is appreciated as increased splitting on expiration relative to inspiration and it is seen in conditions that delay left ventricular emptying
Split S2
–
Wiggers diagram of various events of a
cardiac cycle, with 2nd heart sound at bottom.
24.
Systolic heart murmur
–
Systolic heart murmurs are heart murmurs heard during systole. They can be classified by when the murmur begins and ends, many involve stenosis of the semilunar valves or regurgitation of the atrioventricular valves. Mid-systolic ejection murmurs are due to flow through the semilunar valves. They occur at the start of blood ejection — which starts after S1 —, the resultant configuration of this murmur is a crescendo-decrescendo murmur. Late systolic murmurs starts after S1 and, if left sided, extends up to S2, causes include mitral valve prolapse, tricuspid valve prolapse and papillary muscle dysfunction. Holosystolic murmurs start at S1 and extends up to S2 and they are usually due to regurgitation in cases such as mitral regurgitation, tricuspid regurgitation, or ventricular septal defect
Systolic heart murmur
–
Auscultogram from normal and abnormal heart sounds
25.
Diastolic heart murmur
–
Diastolic heart murmurs are heart murmurs heard during diastole. Diastolic murmurs start at or after S2 and end before or at S1, many involve stenosis of the atrioventricular valves or regurgitation of the semilunar valves. Early diastolic murmurs start at the time as S2 with the close of the semilunar valves. Common causes include aortic or pulmonary regurgitation and left anterior descending artery stenosis, mid-diastolic murmurs start after S2 and end before S1. They are due to turbulent flow across the atrioventricular valves during the filling phase from mitral or tricuspid stenosis. Late diastolic murmurs start after S2 and extend up to S1 and have a crescendo configuration and they can be associated with AV valve narrowing. They include mitral stenosis, tricuspid stenosis, myxoma, and complete heart block
Diastolic heart murmur
–
Auscultogram from normal and abnormal heart sounds
26.
Continuous murmurs
–
Heart murmurs are most frequently organized by timing, into systolic heart murmurs and diastolic heart murmurs. However, continuous murmurs can not be placed into either category. These murmurs are due to flow from a high pressure chamber or vessel to a lower pressure system. PDA is a connection between the aorta and the pulmonary artery, which normally should be closed in infancy. Since aortic pressure is higher than pulmonary pressure, a continuous murmur occurs and this murmur is often described as a machinery murmur, or Gibsons murmur. This is named for George Alexander Gibson, who characterized it in 1898, usually a left to right shunt through a small atrial septal defect in the presence of mitral valve obstruction
Continuous murmurs
–
Auscultogram from normal and abnormal heart sounds
27.
Pulse
–
In medicine, a pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. Pulse is equivalent to measuring the heart rate, the heart rate can also be measured by listening to the heart beat directly, traditionally using a stethoscope and counting it for a minute. The radial pulse is measured using three fingers. The study of the pulse is known as sphygmology, the pulse is a decidedly low tech and high yield and antiquated term still useful at the bedside in an age of computational analysis of cardiac performance. Claudius Galen was perhaps the first physiologist to describe the pulse, the pulse is an expedient tactile method of determination of systolic blood pressure to a trained observer. Diastolic blood pressure is non-palpable and unobservable by tactile methods, occurring between heartbeats, pressure waves generated by the heart in systole move the arterial walls. Forward movement of blood occurs when the boundaries are pliable and compliant and these properties form enough to create a palpable pressure wave. The heart rate may be greater or lesser than the pulse rate depending upon physiologic demand, in this case, the heart rate is determined by auscultation or audible sounds at the heart apex, in which case it is not the pulse. The pulse deficit is determined by simultaneous palpation at the artery and auscultation at the PMI. It may be present in case of premature beats or atrial fibrillation, pulse velocity, pulse deficits and much more physiologic data are readily and simplistically visualized by the use of one or more arterial catheters connected to a transducer and oscilloscope. This invasive technique has been used in intensive care since the 1970s. The rate of the pulse is observed and measured by tactile or visual means on the outside of an artery and is recorded as beats per minute or BPM, the pulse may be further indirectly observed under light absorbances of varying wavelengths with assigned and inexpensively reproduced mathematical ratios. Applied capture of variances of light signal from the blood component hemoglobin under oxygenated vs. deoxygenated conditions allows the technology of pulse oximetry, normal pulse rates at rest, in beats per minute, The pulse rate can be used to check overall heart health and fitness level. Generally lower is better, but bradycardias can be dangerous, symptoms of a dangerously slow heartbeat include weakness, loss of energy and fainting. A normal pulse is regular in rhythm and force, an irregular pulse may be due to sinus arrhythmia, ectopic beats, atrial fibrillation, paroxysmal atrial tachycardia, atrial flutter, partial heart block etc. Intermittent dropping out of beats at pulse is called intermittent pulse, examples of regular intermittent pulse include pulsus bigeminus, second-degree atrioventricular block. An example of irregular intermittent pulse is atrial fibrillation, the degree of expansion displayed by artery during diastolic and systolic state is called volume. It is also known as amplitude, expansion or size of pulse, a weak pulse signifies narrow pulse pressure
Pulse
–
Pulse evaluation at the radial artery.
