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Vertex (anatomy)
In arthropod and vertebrate anatomy, the vertex (or ''cranial vertex'') is the highest point of the head. In humans, the vertex is formed by four bones of the skull: the frontal bone, the two parietal bones, and the occipital bone. These bones are connected by the coronal suture between the frontal and parietal bones, the sagittal suture between the two parietal bones, and the lambdoid suture between the parietal and occipital bones. ''Vertex baldness'' refers to a form of male pattern baldness in which the baldness is limited to the vertex, resembling a tonsure. In childbirth, ''vertex birth'' refers to the common head-first presentation of the baby, as opposed to the buttocks-first position of a breech birth. In entomology, the color and shape of an insect's vertex and the structures arising from it are commonly used in identifying species. See also *Calvaria (skull) * Crown (anatomy) *Male pattern baldness Pattern hair loss (also known as androgenetic alopecia (AGA)) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Male Pattern Baldness
Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front hairline, loss of hair on the crown and vertex of the scalp, or a combination of both. Female-pattern hair loss (FPHL) typically presents as a diffuse thinning of the hair across the entire scalp. The condition is caused by a combination of male sex hormones (balding never occurs in castrated men) and genetic factors. Some research has found evidence for the role of oxidative stress in hair loss, the microbiome of the scalp, genetics, and circulating androgens; particularly dihydrotestosterone (DHT). Men with early onset androgenic alopecia (before the age of 35) have been deemed the male phenotypic equivalent for polycystic ovary syndrome (PCOS). The cause in female pattern hair loss remains unclear; androgenetic alopecia for wom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown (anatomy)
The crown is the top portion of the head behind the Vertex (anatomy), vertex. The anatomy of the crown varies between different organisms. The human crown is made of three layers of the scalp above the skull. The crown also covers a range of Fibrous joint, bone sutures, and contains blood vessels and branches of the trigeminal nerve. The structure of the human crown provides a protective cavity for the brain and optimizes the crown's ability to ensure the Neocortex#:~:text=The neocortex, also called the,commands, spatial reasoning and language., neocortex is safe. Different parts of the neocortex, such as the frontal lobe and the parietal lobe, are protected by the meninges and bone structures. Other organisms, such as whales, have their Blowhole (anatomy), blowholes on their crown, causing a flattened head shape. Some bird species have a Crest (feathers), crest located on their crown, used for communication and courtship. Macroevolution of the human crown has led to different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calvaria (skull)
The calvaria is the top part of the skull. It is the superior part of the neurocranium and covers the cranial cavity containing the brain. It forms the main component of the skull roof. The calvaria is made up of the superior portions of the frontal bone, occipital bone, and parietal bones. In the human skull, the suture (joint), sutures between the bones normally remain flexible during the first few years of postnatal development, and fontanelles are palpable. Premature complete ossification of these sutures is called craniosynostosis. In Latin, the word ''calvaria'' is used as a feminine noun with plural ''calvariae''; however, many medical texts incorrectly list the word as ''calvarium'', a neuter Latin noun with plural ''calvaria''. Structure The outer surface of the skull possesses a number of landmarks. The point at which the frontal bone and the two parietal bones meet is known as the bregma. The point at which the two parietal bones and the occipital bone meet is kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
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. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists 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. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entomology
Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In the past, the term ''insect'' was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arachnids, myriapods, and crustaceans. The field is also referred to as insectology in American English, while in British English insectology implies the study of the relationships between insects and humans. Over 1.3million insect species have been described by entomology. History Entomology is rooted in nearly all human cultures from prehistoric times, primarily in the context of agriculture (especially biological control and beekeeping). The natural Roman philosopher Pliny the Elder (23–79 CE) wrote a book on the kinds of insects, while the scientist Grammarians ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breech Birth
A breech birth is when a baby is born bottom first instead of Cephalic presentation, head first, as is normal. Around 3–5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Due to their higher than average rate of possible complications for the baby, breech births are generally considered higher risk. Breech births also occur in many other mammals such as dogs and horses, see veterinary obstetrics. Most babies in the breech position are delivered via caesarean section because it is seen as safer than being Vaginal birth, born vaginally. Doctors and Midwife, midwives in the developing world often lack many of the skills required to safely assist women giving birth to a breech baby vaginally. Also, delivering all breech babies by caesarean section in developing countries is difficult to implement as there are not always resources available to provide this service. Cause With regard to the fetal presentation during pregnancy, three periods have been distingu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Childbirth
Childbirth, also known as labour, parturition and delivery, is the completion of pregnancy, where one or more Fetus, fetuses exits the Womb, internal environment of the mother via vaginal delivery or caesarean section and becomes a newborn to the world. In 2019, there were about 140.11 million human births globally. In Developed country, developed countries, most deliveries occur in hospitals, while in Developing country, developing countries most are home births. The most common childbirth method worldwide is vaginal delivery. It involves four stages of labour: the cervical effacement, shortening and Cervical dilation, opening of the cervix during the first stage, descent and birth of the baby during the second, the delivery of the placenta during the third, and the recovery of the mother and infant during the fourth stage, which is referred to as the Postpartum period, postpartum. The first stage is characterised by abdominal cramping or also back pain in the case of B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonsure
Tonsure () is the practice of cutting or shaving some or all of the hair on the scalp as a sign of religious devotion or humility. The term originates from the Latin word ' (meaning "clipping" or "shearing") and referred to a specific practice in medieval Catholicism, abandoned by papal order in 1972. Tonsure, in its earliest Greek and Roman origin, was used as a sign or signifier for slavery. Tonsure can also refer to the secular practice of shaving all or part of the scalp to show support or sympathy, or to designate mourning. Current usage more generally refers to cutting or shaving for monks, devotees, or mystics of any religion as a symbol of their renunciation of worldly fashion and esteem. Tonsure is still a traditional practice in Catholicism by specific religious orders (with papal permission). It is also commonly used in the Eastern Orthodox Church for newly baptised members and is frequently used for Buddhist novices, Bhikkhu, monks, and Bhikkhunī, nuns. The complete sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambdoid Suture
The lambdoid suture, or lambdoidal suture, is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture. Structure The lambdoid suture is between the paired parietal bones and the occipital bone of the skull. It runs from the asterion on each side. Nerve supply The lambdoid suture may be supplied by a branch of the supraorbital nerve, a branch of the frontal branch of the trigeminal nerve. Clinical significance At birth, the bones of the skull do not meet. If certain bones of the skull grow too fast, then craniosynostosis (premature closure of the sutures) may occur. This can result in skull deformities. If the lambdoid suture closes too soon on one side, the skull will appear twisted and asymmetrical, a condition called "plagiocephaly". Plagiocephaly refers to the shape and not the condition. The condition is craniosynostosis. The lambdoid s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebrata with some 65,000 species, by far the largest ranked grouping in the phylum Chordata. The vertebrates include mammals, birds, amphibians, and various classes of fish and reptiles. The fish include the jawless Agnatha, and the jawed Gnathostomata. The jawed fish include both the Chondrichthyes, cartilaginous fish and the Osteichthyes, bony fish. Bony fish include the Sarcopterygii, lobe-finned fish, which gave rise to the tetrapods, the animals with four limbs. Despite their success, vertebrates still only make up less than five percent of all described animal species. The first vertebrates appeared in the Cambrian explosion some 518 million years ago. Jawed vertebrates evolved in the Ordovician, followed by bony fishes in the Devonian. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal Suture
The sagittal suture, also known as the interparietal suture and the ''sutura interparietalis'', is a dense, fibrous connective tissue joint between the two parietal bones of the skull. The term is derived from the Latin word ''sagitta'', meaning arrow. Structure The sagittal suture is formed from the fibrous connective tissue joint between the two parietal bones of the skull. It has a varied and irregular shape which arises during development. The pattern is different between the inside and the outside. Two anatomical landmarks are found on the sagittal suture: the bregma, and the vertex of the skull. The bregma is formed by the intersection of the sagittal and coronal sutures. The vertex is the highest point on the skull and is often near the midpoint of the sagittal suture. Development At birth, the bones of the skull do not meet. The gap that remains, which is approximately 5 mm wide, allows for the brain to continue to grow normally after birth. The inner parts of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
