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1.6: Nomenclature Review - Biology

1.6: Nomenclature Review - Biology


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Learning Objectives

  • Apply the conventions for writing botanical names.

True or False. Apply binomial nomenclature conventions to each of the plant names.

An interactive or media element has been excluded from this version of the text. You can view it online here:
https://kpu.pressbooks.pub/plant-identification/?p=127

An interactive or media element has been excluded from this version of the text. You can view it online here:
kpu.pressbooks.pub/plant-identification/?p=127

An interactive or media element has been excluded from this version of the text. You can view it online here:
kpu.pressbooks.pub/plant-identification/?p=127


Nomenclature and Classification of Enzymes

In early days the suffix – ase was added to the substrate for naming the enzymes.

Example : Lipase acts on lipids.

These names are known as trivial names. They do not convey complete information about the enzymatic reaction.

The International Union of Biochemistry and Molecular Biology (IUBMB) have assigned a systematic nomenclature for enzymes. The systematic name has two parts.

· The first part represents the substrate. In enzyme catalyzed reactions the reactants are known as substrates.

· The second part, ending in –ase, indicates the type of reaction catalysed.

Each enzyme is assigned a four-digit code number called Enzyme Commission (EC) number.

· The first digit represents the major class to which the enzyme belongs.

· The second digit denotes the subclass.

· The third digit denotes the sub-sub class of the enzyme within the major class.

· The fourth digit represents the serial number of the enzyme within the sub-sub class.

Example: Hexokinase (EC 2.7.1.1) and Glutamine synthetase (EC 6.3.1.2)

According to International Union of Biochemistry and Molecular Biology, the enzymes are classified into six major classes on the basis of the reaction they catalyse. The six major classes of enzymes are,


1) Oxidoreductases:

These are enzymes which catalyze the oxidation – reduction reactions between two substrates.

a) Dehydrogenase (Alcohol Dehydrogenase)

b) Oxidase (Cytochrome Oxidase)

c) Peroxidase (Glutathione Peroxidase)

Alcohol dehydrogenase (EC 1.1.1.1) :

This enzyme oxidizes ethanol into acetaldehyde. It requires the coenzyme NAD + (Niacinamide Adenine Dinucleotide) which gets reduced to NADH.


2) Transferases:

These are enzymes which catalyze the transfer of certain groups such as phosphate, amino or acetyl groups from one substrate to another.

Examples:

· Transaminase (Transfers an amino group Example Aspartate amino transferase)

· Transacylase (Transfers an acyle group Example Malonyl transacylase)

· Phosphorylase (Transfers a phosphate group Example Glycogen phosphorylase)

Transaminase:

They catalyse the transfer of amino group from amino acid to keto acid. Example: Glutamate oxaloacetate transaminase (GOT) or Aspartate transaminase (AST EC 2.6.1.1). This enzyme catalyses the transfer of amino group from glutamic acid to oxaloacetic acid. It requires pyridoxal phosphate (PLP) as coenzyme for its activity.


3) Hydrolase:

These are enzymes which catalyze the hydrolysis of substrates. They bring about the hydrolysis by adding water.

Example : a) Lipase b) Urease c) Glycosidase.


These are enzymes which hydrolyze the ester linkage. For example triacyl glycerol lipase (EC 3.1.1.3) splits the ester linkage between glycerol and fatty acid.


4) Lyases:

These enzymes catalyze the addition or elimination of groups like H 2 O, CO 2 , and NH 3 etc. Example: Aldolase, decarboxylase


A. Fructose bisphosphate aldolase (EC 4.1.2.13):

It catalyzes the reversible conversion of fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate by aldol cleavage of the C3–C4 bond.


5) Isomerases:

These enzymes catalyze the inter-conversion of isomers such as optical, geometrical or positional isomers.

a)Alanine racemase (EC 5.1.1.1)


B) Triosephosphate isomerase (EC 5.3.1.1):

This enzyme catalyzes the isomerization of glyceraldehyde-3-phosphate into dihydroxy acetone phosphate.


6) Ligases:

These enzymes catalyze the synthetic reactions. They link two substrates together with the utilization of ATP or GTP.

Example : Glutamine synthetase.

Glutamine synthetase (EC 6.3.1.2):

This is a ligase which catalyzes the synthesis of glutamine from glutamate and NH 3 .


A dynamic nomenclature proposal for SARS-CoV-2 lineages to assist genomic epidemiology

The ongoing pandemic spread of a new human coronavirus, SARS-CoV-2, which is associated with severe pneumonia/disease (COVID-19), has resulted in the generation of tens of thousands of virus genome sequences. The rate of genome generation is unprecedented, yet there is currently no coherent nor accepted scheme for naming the expanding phylogenetic diversity of SARS-CoV-2. Here, we present a rational and dynamic virus nomenclature that uses a phylogenetic framework to identify those lineages that contribute most to active spread. Our system is made tractable by constraining the number and depth of hierarchical lineage labels and by flagging and delabelling virus lineages that become unobserved and hence are probably inactive. By focusing on active virus lineages and those spreading to new locations, this nomenclature will assist in tracking and understanding the patterns and determinants of the global spread of SARS-CoV-2.

Conflict of interest statement

Competing interests. The authors declare no competing interests.

Figures

Maximum likelihood phylogeny of globally…

Maximum likelihood phylogeny of globally sampled sequences of SARS-CoV-2 downloaded from the GISAID…


An example is steroids, which are lipids that have had their carbon skeleton bent to form fused rings. Another example is phospholipids which are a major com.

The positive and negative charges attract this causes the formation of a hydrogen bond. A hydrogen bond is “a weak bond between two molecules resulting from.

The two most fundamental sorts of securities are portrayed as either ionic or covalent. In ionic holding, particles exchange electrons to each other. Ionic b.

Carbohydrates are macronutrients which can be found in all types of food. A carbohydrate molecule contains carbon, oxygen, and hydrogen (Yacoub, n.d.). When .

The reaction rate is measured in enzyme kinetics as well as the impacts of alter the conditions of the reaction are investigated. The Studying of kinetics en.

INTRODUCTION The determination of whether a body of water is fit for consumption and all other factors concerning its physical and chemical state is known as.

(Bioinfo.org.cn, 2015) Reaction rates controlled by enzyme can be measured using experimental methods where the factors such as enzyme, pH and temperature .

“If it had not been developed Chemistry may not be around as we know it”1.It contains useful information that affects everyone, whether in a direct way, or a.

The Chemistry of H2O. Principles of the Octet Rule, Electronegativity, Polarity, Density, and their effect on H2O Aryeh L. Strauss Suny Rockland Atoms are .

By calculating the rate of reaction and studying the effects of varied conditions on the reaction, a great deal can be learnt about the enzyme, including how.


Genetics

To facilitate accurate communication, it is important that standard genetic nomenclature be used whenever possible and that deviations or proposals for new naming systems be endorsed by an appropriate authoritative body. Review and/or publication of submitted manuscripts that contain new or nonstandard nomenclature may be delayed by the editor or the Journals Department so that they may be reviewed.

Bacteria. The genetic properties of bacteria are described in terms of phenotypes and genotypes. The phenotype describes the observable properties of an organism. The genotype refers to the genetic constitution of an organism, usually in reference to some standard wild type. The guidelines that follow are based on the recommendations of Demerec et al. (Genetics 54:61–76, 1966).

(i) Phenotype designations must be used when mutant loci have not been identified or mapped. They can also be used to identify the protein product of a gene, e.g., the OmpA protein. Phenotype designations generally consist of three-letter symbols these are not italicized, and the first letter of the symbol is capitalized. It is preferable to use Roman or Arabic numerals (instead of letters) to identify a series of related phenotypes. Thus, a series of nucleic acid polymerase mutants might be designated Pol1, Pol2, and Pol3, etc. Wild-type characteristics can be designated with a superscript plus (Pol + ), and, when necessary for clarity, negative superscripts (Pol – ) can be used to designate mutant characteristics. Lowercase superscript letters may be used to further delineate phenotypes (e.g., Str r for streptomycin resistance). Phenotype designations should be defined.

(ii) Genotype designations are also indicated by three-letter locus symbols. In contrast to phenotype designations, these are lowercase italic (e.g., ara his rps). If several loci govern related functions, these are distinguished by italicized capital letters following the locus symbol (e.g., araA araB araC). Promoter, terminator, and operator sites should be indicated as described by Bachmann and Low (Microbiol Rev 44:1–56, 1980), e.g., lacZp, lacAt, and lacZo.

(iii) Wild-type alleles are indicated with a superscript plus (ara + his + ). A superscript minus is not used to indicate a mutant locus thus, one refers to an ara mutant rather than an ara – strain.

(iv) Mutation sites are designated by placing serial isolation numbers (allele numbers) after the locus symbol (e.g., araA1 araA2). If only a single such locus exists or if it is not known in which of several related loci the mutation has occurred, a hyphen is used instead of the capital letter (e.g., ara-23). It is essential in papers reporting the isolation of new mutants that allele numbers be given to the mutations. For Escherichia coli, there is a registry of such numbers: the Coli Genetic Stock Center (http://cgsc2.biology.yale.edu/). For the genus Salmonella, the registry is the Salmonella Genetic Stock Centre (http://people.ucalgary.ca/

kesander/). For the genus Bacillus, the registry is the Bacillus Genetic Stock Center (http://www.bgsc.org/).

(v) The use of superscripts with genotypes (other than + to indicate wild-type alleles) should be avoided. Designations indicating amber mutations (Am), temperature-sensitive mutations (Ts), constitutive mutations (Con), cold-sensitive mutations (Cs), production of a hybrid protein (Hyb), and other important phenotypic properties should follow the allele number [e.g., araA230(Am) hisD21(Ts)]. All other such designations of phenotype must be defined at the first occurrence. If superscripts must be used, they must be approved by the editor and defined at the first occurrence in the text.

Subscripts may be used in two situations. Subscripts may be used to distinguish between genes (having the same name) from different organisms or strains e.g., hisE. coli or hisK-12 for the his gene of E. coli or strain K-12, respectively, may be used to distinguish this gene from the his gene in another species or strain. An abbreviation may also be used if it is explained. Similarly, a subscript is also used to distinguish between genetic elements that have the same name. For example, the promoters of the gln operon can be designated glnAp1 and glnAp2. This form departs slightly from that recommended by Bachmann and Low (e.g., desC1p).

(vi) Deletions are indicated by the symbol Δ placed before the deleted gene or region, e.g., ΔtrpA432, Δ(aroP-aceE)419, or Δ(hisQ-hisJo)1256. Similarly, other symbols can be used (with appropriate definition). Thus, a fusion of the ara and lac operons can be shown as Φ(ara-lac)95. Likewise, Φ(araB'-lacZ + )96 indicates that the fusion results in a truncated araB gene fused to an intact lacZ gene, and Φ(malE-lacZ)97(Hyb) shows that a hybrid protein is synthesized. An inversion is shown as IN(rrnD-rrnE)1. An insertion of an E. coli his gene into plasmid pSC101 at zero kilobases (0 kb) is shown as pSC101 Ω(0kb::K-12hisB)4. An alternative designation of an insertion can be used in simple cases, e.g., galT236::Tn5. The number 236 refers to the locus of the insertion, and if the strain carries an additional gal mutation, it is listed separately. Additional examples, which utilize a slightly different format, can be found in the papers by Campbell et al. and Novick et al. cited below. It is important in reporting the construction of strains in which a mobile element was inserted and subsequently deleted that this fact be noted in the strain table. This can be done by listing the genotype of the strain used as an intermediate in a table footnote or by making a direct or parenthetical remark in the genotype, e.g., (F – ), ΔMu cts, or mal::ΔMu cts::lac. In setting parenthetical remarks within the genotype or dividing the genotype into constituent elements, parentheses and brackets are used without special meaning brackets are used outside parentheses. To indicate the presence of an episome, parentheses (or brackets) are used (λ, F + ). Reference to an integrated episome is indicated as described above for inserted elements, and an exogenote is shown as, for example, W3110/F'8(gal + ).

For information about the symbols in current use, consult Berlyn (Microbiol Mol Biol Rev 62:814–984, 1998) for E. coli K-12, Sanderson and Roth (Microbiol Rev 52:485–532, 1988) for Salmonella serovar Typhimurium, Holloway et al. (Microbiol Rev 43:73–102, 1979) for the genus Pseudomonas, Piggot and Hoch (Microbiol Rev 49:158–179, 1985) for Bacillus subtilis, Perkins et al. (Microbiol Rev 46:426–570, 1982) for Neurospora crassa, and Mortimer and Schild (Microbiol Rev 49:181–213, 1985) for Saccharomyces cerevisiae. For yeasts, Chlamydomonas spp., and several fungal species, symbols such as those given in the Handbook of Microbiology, 2nd ed. (A. I. Laskin and H. A. Lechevalier, ed., CRC Press, Inc., Cleveland, OH, 1988), should be used.

Conventions for naming genes. It is recommended that (entirely) new genes be given names that are mnemonics of their function, avoiding names that are already assigned and earlier or alternative gene names, irrespective of the bacterium for which such assignments have been made. Similarly, it is recommended that, whenever possible, orthologous genes present in different organisms receive the same name. When homology is not apparent or the function of a new gene has not been established, a provisional name may be given by one of the following methods. (i) The gene may be named on the basis of its map location in the style yaaA, analogous to the style used for recording transposon insertions (zef) as discussed below. A list of such names in use for E. coli has been published by Rudd (Microbiol Mol Biol Rev 62:985–1019, 1998). (ii) A provisional name may be given in the style described by Demerec et al. (e.g., usg, gene upstream of folC). Such names should be unique, and names such as orf or genX should not be used. For reference, the Coli Genetic Stock Center's database includes an updated listing of E. coli gene names and gene products. It is accessible on the Internet (http://cgsc.biology.yale.edu/index.php). A list can also be found in the work of Riley (Microbiol Rev 57:862–952, 1993). For the genes of other bacteria, consult the references given above.

For prokaryotes, gene names should not begin with prefixes indicating the genus and species from which the gene is derived. (However, subscripts may be used where necessary to distinguish between genes from different organisms or strains, as described in section v of "Bacteria" above.) For eukaryotes, such prefixes may be used for clarity when discussing genes with the same name from two different organisms (e.g., ScURA3 versus CaURA3) the prefixes are not considered part of the gene name proper and are not italicized.

Locus tags. Locus tags are systematic, unique identifiers that are assigned to each gene in GenBank. All genes mentioned in a manuscript should be traceable to their sequences by the reader, and locus tags may be used for this purpose in manuscripts to identify uncharacterized genes. In addition, authors should check GenBank to make sure that they are using the correct, up-to-date format for locus tags (e.g., uppercase versus lowercase letters and the presence or absence of an underscore, etc.). Locus tag formats vary between different organisms and also may be updated for a given organism, so it is important to check GenBank at the time of manuscript preparation.

"Mutant" versus "mutation." Keep in mind the distinction between a mutation (an alteration of the primary sequence of the genetic material) and a mutant (a strain carrying one or more mutations). One may speak about the mapping of a mutation, but one cannot map a mutant. Likewise, a mutant has no genetic locus, only a phenotype.

"Homology" versus "similarity." For use of terms that describe relationships between genes, consult the articles by Theissen (Nature 415:741, 2002) and Fitch (Trends Genet 16:227–231, 2000). "Homology" implies a relationship between genes that have a common evolutionary origin partial homology is not recognized. When sequence comparisons are discussed, it is more appropriate to use the term "percent sequence similarity" or "percent sequence identity," as appropriate.

Strain designations. Do not use a genotype as a name (e.g., "subsequent use of leuC6 for transduction"). If a strain designation has not been chosen, select an appropriate word combination (e.g., "another strain containing the leuC6 mutation").

Viruses. The genetic nomenclature for viruses differs from that for bacteria. In most instances, viruses have no phenotype, since they have no metabolism outside host cells. Therefore, distinctions between phenotype and genotype cannot be made. Superscripts are used to indicate hybrid genomes. Genetic symbols may be one, two, or three letters. For example, a mutant strain of λ might be designated λ Aam11 int2 red114 cI857 this strain carries mutations in genes cI, int, and red and an amber-suppressible (Am) mutation in gene A. A strain designated λ att 434 imm 21 would represent a hybrid of phage λ that carries the immunity region (imm) of phage 21 and the attachment (att) region of phage 434. Host DNA insertions into viruses should be delineated by square brackets, and the genetic symbols and designations for such inserted DNA should conform to those used for the host genome. Genetic symbols for phage λ can be found in reports by Szybalski and Szybalski (Gene 7:217–270, 1979) and Echols and Murialdo (Microbiol Rev 42:577–591, 1978).

Eukaryotes. FlyBase (http://flybase.org/) is the genetic nomenclature authority for Drosophila melanogaster. WormBase (https://www.wormbase.org/#01-23-6) is the genetic nomenclature authority for Caenorhabditis elegans. When naming genes for Aspergillus species, the nomenclature guidelines posted at http://www.aspergillusgenome.org/Nomenclature.shtml should be followed, and the Aspergillus Genome Database (http://www.aspgd.org/) should be searched to ensure that any new name is not already in use. The Saccharomyces Genome Database (https://www.yeastgenome.org/) and the Candida Genome Database (http://www.candidagenome.org/) are authorities for Saccharomyces cerevisiae and Candida albicans genetic nomenclature, respectively. Authors should use nomenclature consistent with community databases, including SGD, CGD, AspGD, PomBase, the Broad Institute genomic databases, and the EuPathDB family of databases. &ldquoClassification and Nomenclature of Human Parasites&rdquo offers useful information on current parasite nomenclature.

Transposable elements, plasmids, and restriction enzymes. Nomenclature of transposable elements (insertion sequences, transposons, and phage Mu, etc.) should follow the recommendations of Campbell et al. (Gene 5:197–206, 1979), with the modifications given in section vi of "Bacteria" above. The Internet site where insertion sequences of eubacteria and archaea are described and new sequences can be recorded is https://www-is.biotoul.fr.

The system of designating transposon insertions at sites where there are no known loci, e.g., zef-123::Tn5, has been described by Chumley et al. (Genetics 91:639–655, 1979). The nomenclature recommendations of Novick et al. (Bacteriol Rev 40:168–189, 1976) for plasmids and plasmid-specified activities, of Low (Bacteriol Rev 36:587–607, 1972) for F' factors, and of Roberts et al. (Nucleic Acids Res 31:1805–1812, 2003) for restriction enzymes, DNA methyltransferases, homing endonucleases, and their genes should be used whenever possible. The nomenclature for recombinant DNA molecules constructed in vitro follows the nomenclature for insertions in general. DNA inserted into recombinant DNA molecules should be described by using the gene symbols and conventions for the organism from which the DNA was obtained.

Tetracycline resistance determinants. The nomenclature for tetracycline resistance determinants is based on the proposal of Levy et al. (Antimicrob Agents Chemother 43:1523–1524, 1999). The style for such determinants is, e.g., Tet B the space helps distinguish the determinant designation from that for phenotypes and proteins (TetB). The above-referenced article also gives the correct format for genes, proteins, and determinants in this family.

For mouse strain and genetic nomenclature, ASM encourages authors to refer to the guidelines set forth by the International Committee on Standardized Genetic Nomenclature for Mice, available on the Mouse Genome Informatics home page at http://www.informatics.jax.org/ and in Genetic Variants and Strains of the Laboratory Mouse, 3rd ed. (M. F. Lyon et al., ed., Oxford University Press, Oxford, England, 1996).


1.6 Anatomical Terminology

Anatomists and health care providers use terminology that can be bewildering to the uninitiated. However, the purpose of this language is not to confuse, but rather to increase precision and reduce medical errors. For example, is a scar “above the wrist” located on the forearm two or three inches away from the hand? Or is it at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. Anatomical terms derive from ancient Greek and Latin words. Because these languages are no longer used in everyday conversation, the meaning of their words does not change.

Anatomical terms are made up of roots, prefixes, and suffixes. The root of a term often refers to an organ, tissue, or condition, whereas the prefix or suffix often describes the root. For example, in the disorder hypertension, the prefix “hyper-” means “high” or “over,” and the root word “tension” refers to pressure, so the word “hypertension” refers to abnormally high blood pressure.

Anatomical Position

To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position , is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.12. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.

A body that is lying down is described as either prone or supine. Prone describes a face-down orientation, and supine describes a face up orientation. These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures.

Regional Terms

The human body’s numerous regions have specific terms to help increase precision (see Figure 1.12). Notice that the term “brachium” or “arm” is reserved for the “upper arm” and “antebrachium” or “forearm” is used rather than “lower arm.” Similarly, “femur” or “thigh” is correct, and “leg” or “crus” is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body’s regions using the terms from the figure.

Directional Terms

Certain directional anatomical terms appear throughout this and any other anatomy textbook (Figure 1.13). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.

  • Anterior (or ventral ) Describes the front or direction toward the front of the body. The toes are anterior to the foot.
  • Posterior (or dorsal ) Describes the back or direction toward the back of the body. The popliteus is posterior to the patella.
  • Superior (or cranial ) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.
  • Inferior (or caudal ) describes a position below or lower than another part of the body proper near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.
  • Lateral describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.
  • Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe.
  • Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.
  • Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.
  • Superficial describes a position closer to the surface of the body. The skin is superficial to the bones.
  • Deep describes a position farther from the surface of the body. The brain is deep to the skull.

Body Planes

A section is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain “virtual sections” of living bodies. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made. A plane is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure 1.14.

  • The sagittal plane is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section.
  • The frontal plane is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion. The frontal plane is often referred to as a coronal plane. (“Corona” is Latin for “crown.”)
  • The transverse plane is the plane that divides the body or organ horizontally into upper and lower portions. Transverse planes produce images referred to as cross sections.

Body Cavities and Serous Membranes

The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The dorsal (posterior) cavity and the ventral (anterior) cavity are the largest body compartments (Figure 1.15). These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions. The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs.

Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities

The posterior (dorsal) and anterior (ventral) cavities are each subdivided into smaller cavities. In the posterior (dorsal) cavity, the cranial cavity houses the brain, and the spinal cavity (or vertebral cavity) encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the posterior (dorsal) cavity.

The anterior (ventral) cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity (see Figure 1.15). The thoracic cavity is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage. The thoracic cavity contains the lungs and the heart, which is located in the mediastinum. The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity. The abdominopelvic cavity is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, the division that houses the digestive organs, and the pelvic cavity, the division that houses the organs of reproduction.

Abdominal Regions and Quadrants

To promote clear communication, for instance about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.16).

The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).

Membranes of the Anterior (Ventral) Body Cavity

A serous membrane (also referred to a serosa) is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity (Figure 1.17).

There are three serous cavities and their associated membranes. The pleura is the serous membrane that encloses the pleural cavity the pleural cavity surrounds the lungs. The pericardium is the serous membrane that encloses the pericardial cavity the pericardial cavity surrounds the heart. The peritoneum is the serous membrane that encloses the peritoneal cavity the peritoneal cavity surrounds several organs in the abdominopelvic cavity. The serous membranes form fluid-filled sacs, or cavities, that are meant to cushion and reduce friction on internal organs when they move, such as when the lungs inflate or the heart beats. Both the parietal and visceral serosa secrete the thin, slippery serous fluid located within the serous cavities. The pleural cavity reduces friction between the lungs and the body wall. Likewise, the pericardial cavity reduces friction between the heart and the wall of the pericardium. The peritoneal cavity reduces friction between the abdominal and pelvic organs and the body wall. Therefore, serous membranes provide additional protection to the viscera they enclose by reducing friction that could lead to inflammation of the organs.


Consensus nomenclature rules for radiopharmaceutical chemistry — Setting the record straight ☆,☆☆

Over recent years, within the community of radiopharmaceutical sciences, there has been an increased incidence of incorrect usage of established scientific terms and conventions, and even the emergence of ‘self-invented’ terms. In order to address these concerns, an international Working Group on ‘Nomenclature in Radiopharmaceutical Chemistry and related areas’ was established in 2015 to achieve clarification of terms and to generate consensus on the utilisation of a standardised nomenclature pertinent to the field.

Upon open consultation, the following consensus guidelines were agreed, which aim to: •

Provide a reference source for nomenclature good practice in the radiopharmaceutical sciences.

Clarify the use of terms and rules concerning exclusively radiopharmaceutical terminology, i.e. nuclear- and radiochemical terms, symbols and expressions.

Address gaps and inconsistencies in existing radiochemistry nomenclature rules.

Provide source literature for further harmonisation beyond our immediate peer group (publishers, editors, IUPAC, pharmacopoeias, etc.).


Watch the video: Nomenclature Review (July 2022).


Comments:

  1. Hadar

    I want to see

  2. Krystine

    Can't the fault be here?

  3. Lonato

    The idea is great, I support it.

  4. Linly

    I must admit, the one who wrote the nishtyak was sprinkled.



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