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Supernumerary Body Parts
Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs. Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line. Specific types of occurrence Specific types of additional body parts include: *Accessory breast – one or more additional breastsOnline Mendelian Inheritance in Man. Nipples, Supernumerary. Accessed 10 July 2006. *Accessory spleen – one or more additional spleens *Cervical rib – an additional rib *Diphallia – having two penes/penises *Hermaphroditism – having both male and female sex organs *Hyperdontia – additional teeth *Pelvic digit – a bony growth in the soft tissue of the pelvic region *Polycephaly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydactyly 01 Rhand AP
Polydactyly or polydactylism (), also known as hyperdactyly, is an anomaly in humans and animals resulting in supernumerary fingers and/or toes. Polydactyly is the opposite of oligodactyly (fewer fingers or toes). Signs and symptoms In humans/animals this condition can present itself on one or both hands or feet. The extra digit is usually a small piece of soft tissue that can be removed. Occasionally it contains bone without joints; rarely it may be a complete functioning digit. The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits. These are respectively known as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly. The extra digit is most commonly an abnormal fork in an existing digit, or it may rarely originate at the wrist as a normal digit does. The incidence of congenital deformities in newborns is approximately 2%, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymelia
Polymelia is a birth defect in which an affected individual has more than the usual number of limbs. It is a type of dysmelia. In humans and most land-dwelling vertebrates, this means having five or more limbs. The extra limb is most commonly shrunken and/or deformed. The term is from Greek πολυ- "many", μέλεα "limbs". Sometimes an embryo started as conjoined twins, but one twin degenerated completely except for one or more limbs, which end up attached to the other twin. Sometimes small extra legs between the normal legs are caused by the body axis forking in the dipygus condition. Notomelia (from Greek for "back-limb-condition") is polymelia where the extra limb is rooted along or near the midline of the back. Notomelia has been reported in Angus cattle often enough to be of concern to farmers. Cephalomelia (from Greek for "head-limb-condition") is polymelia where the extra limb is rooted on the head. Origin Tetrapod legs evolved in the Devonian or Carboniferous geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolution by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function (biology), function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic research, basic sciences that are applied in medicine. The discipline of anatomy is divided into macroscopic scale, macroscopic and microscopic scale, microscopic. Gross anatomy, Macroscopic anatomy, or gross anatomy, is the examination of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vestigial Structures
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species. Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ; and the hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uterus Didelphys
Uterus didelphys (sometimes also ''uterus didelphis'') represents a uterine malformation where the uterus is present as a paired organ when the embryogenetic fusion of the Müllerian ducts fails to occur. As a result, there is a double uterus with two separate cervices, and possibly a double vagina as well. Each uterus has a single horn linked to the ipsilateral fallopian tube that faces its ovary. Most non-human mammals do not have a single uterus with no separation of horns. Marsupials and rodents have a double uterus (uterus duplex). In other animals (''e.g.'' nematodes), the term 'didelphic' refers to a double genital tract, as opposed to monodelphic, with a single tract. Signs and symptoms Persons with the condition may be asymptomatic and unaware of having a double uterus. However, a study by Heinonen showed that certain conditions are more common. In his study of 26 women with a double uterus gynecological complaints included dysmenorrhea and dyspareunia. All patients dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and diprotodontia, but is an unusual condition in humans. The term is from Greek σύν, ''syn'' 'together' and δάκτυλος, ''daktulos'' 'finger'. Classification Syndactyly can be simple or complex. * In simple syndactyly, adjacent fingers or toes are joined by soft tissue. * In complex syndactyly, the bones of adjacent digits are fused. The kangaroo exhibits complex syndactyly. Syndactyly can be complete or incomplete. * In complete syndactyly, the skin is joined all the way to the tip of the involved digits. * In incomplete syndactyly, the skin is only joined part of the distance to the tip of the involved digits. Complex syndactyly occurs as part of a syndrome (such as Apert syndrome) and typically involves more digits than simple syndactyly. Fenestrated syndactyly, also known as acrosyndactyly or terminal syndactyly, means the skin is joine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernumerary Phantom Limb
Supernumerary phantom limb is a condition where the affected individual believes and receives sensory information from limbs of the body that do not actually exist, and never have existed, in contradistinction to phantom limbs, which appear after an individual has had a limb removed from the body and still receives input from it. An fMRI study of a subject with a supernumerary phantom left arm was done by Khateb ''et al.'' at the Laboratory of Experimental Neuropsychology at the University of Geneva. When the subject was told to touch her right cheek with the phantom limb, there was increased activity in the motor cortex of her brain in the area roughly corresponding to the left arm. When she announced that she had touched the phantom limb to her cheek, activity was monitored in the area of the somatosensory cortex that corresponded to the right cheek. At times during the experiment, the subject was asked to move the phantom limb to a location that was obstructed or otherwise un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernumerary Nipple
A supernumerary nipple is an additional instance of nipple occurring in mammals, including humans. They are often mistaken for moles. Studies variously report the prevalence of supernumerary nipples as approximately 1 in 18 and 1 in 40. https://link.springer.com/article/10.1007/s004310050944 Supernumerary nipples: prevalence, size, sex and side predilection – a prospective clinical study, H. Schmidt, European Journal of Pediatrics volume 157, pages 821–823 (1998). https://jamanetwork.com/journals/jamapediatrics/article-abstract/511138 Occurrence of Supernumerary Nipples in Newborns Francis Mimouni, MD; Paul Merlob, MD; Salomon H. Reisner, MB, ChB, Am J Dis Child. 1983;137(10):952-953. The nipples appear along the two vertical "milk lines", which start in the armpit on each side, run down through the typical nipples and end at the groin. They are classified into eight levels of completeness from a simple patch of hair to a milk-bearing breast in miniature. Types ''Polyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernumerary Musculature
Supernumerary means "exceeding the usual number". Supernumerary may also refer to: * Supernumerary actor, a performer in a film, television show, or stage production who has no role or purpose other than to appear in the background, more commonly referred to as an "extra" * Supernumerary body part, most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan * Supernumerary judge, a semi-retired judge appointed to hear cases on a part-time basis * Supernumerary rainbow, extra colored bands sometimes seen inside the arc of a rainbow * Jewish Supernumerary Police, a Jewish militia active in the British Mandate of Palestine * Small supernumerary marker chromosome (sSMC), an extra, 47th autosomal chromosome * Supernumerary sexes (or ''supernumerary genders''), gender categories beyond male and female * Supernumerary Tooth (or Hyperdontia Hyperdontia is the condition of having supernumerary teeth, or teeth that ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
