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Labioscrotal Folds
The labioscrotal swellings (genital swellings or labioscrotal folds) are paired structures in the human embryo that represent the final stage of development of the caudal end of the external genitals before sexual differentiation. In both males and females, the two swellings merge: * In the ''female'', they become the posterior labial commissure. The sides of the genital tubercle grow backward as the genital swellings, which ultimately form the labia majora; the tubercle itself becomes the mons pubis. In contrast, the labia minora are formed by the urogenital folds. * In the ''male'', they become the scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum co .... References External links "Development of Male External Genitalia", at mcgill.caDiagram at mhhe.com* * {{Authority ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive System
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring. Reproductive System 2001 Body Guide powered by Adam Animals In mammals, the major organs of the reproductive system include the external |
Genital Tubercle
A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In the human fetus, the genital tubercle develops around week 4 of gestation, and by week 9 becomes recognizably either a clitoris or penis. This should not be confused with the sinus tubercle which is a proliferation of endoderm induced by paramesonephric ducts. Even after the phallus is developed, the term genital tubercle remains, but only as the terminal end of it, which develops into either the glans penis or the glans clitoridis. The genital tubercle is sensitive to dihydrotestosterone and rich in 5-alpha-reductase, so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth. See also *Sexual differentiation Sexual differentiation is the process of development of the sex differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labia Majora
The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia majora are homologous to the male scrotum. Etymology ''Labia majora'' is the Latin plural for big ("major") lips; the singular is ''labium majus.'' The Latin term ''labium/labia'' is used in anatomy for a number of usually paired parallel structures, but in English it is mostly applied to two pairs of parts of female external genitals (vulva)—labia majora and labia minora. Labia majora are commonly known as the outer lips, while labia minora (Latin for ''small lips''), which run alongside between them, are referred to as the inner lips. Traditionally, to avoid confusion with other lip-like structures of the body, the labia of female genitals were termed by anatomists in Latin as ''labia majora (''or ''minora) pudendi.'' Embryology Embryolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scrotum
The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum contains the external spermatic fascia, testes, epididymis, and ductus deferens. It is a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein, and pampiniform plexus. The perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. In humans and some other mammals the scrotum becomes covered with pubic hair at puberty. The scrotum will usually tighten during penile erection and when exposed to cold temperatures. One testis is typically lower than the other to avoid compression in the event of an impact. The scrotum is biologicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudal (anatomical Term)
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axis, anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genitals
A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, are called the ''primary sex organs''. All others are called ''secondary sex organs'', divided between the external sex organs—the genitals or external genitalia, visible at birth in both sexes—and the internal sex organs. Mosses, ferns, and some similar plants have gametangia for reproductive organs, which are part of the gametophyte. The flowers of flowering plants produce pollen and egg cells, but the sex organs themselves are inside the gametophytes within the pollen and the ovule. Coniferous plants likewise produce their sexually reproductive structures within the gametophytes contained within the cones and pollen. The cones and pollen are not themselves sexual organs. Terminology The ''primary sex organs'' are the gonads, a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Differentiation
Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. Sex determination is often distinct from sex differentiation; sex determination is the designation for the development stage towards either male or female, while sex differentiation is the pathway towards the development of the phenotype. In many species, testicular or ovarian differentiation begins with appearance of Sertoli cells in males and granulosa cells in females. As male and female individuals develop from embryos into mature adults, sex differences at many levels develop, such as genes, chromosomes, gonads, hormones, anatomy, and psyche. Beginning with determination of sex by genetic and/or environmental factors, humans and other organisms proceed down different pathways of differentiation as they grow and develop. These processes are not fixed, and can change over one organism's lifetime or over many generations evolutionarily. Sex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Labial Commissure
The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia majora are homologous to the male scrotum. Etymology ''Labia majora'' is the Latin plural for big ("major") lips; the singular is ''labium majus.'' The Latin term ''labium/labia'' is used in anatomy for a number of usually paired parallel structures, but in English it is mostly applied to two pairs of parts of female external genitals (vulva)—labia majora and labia minora. Labia majora are commonly known as the outer lips, while labia minora (Latin for ''small lips''), which run alongside between them, are referred to as the inner lips. Traditionally, to avoid confusion with other lip-like structures of the body, the labia of female genitals were termed by anatomists in Latin as ''labia majora (''or ''minora) pudendi.'' Embryology Embryolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labia Majora
The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia majora are homologous to the male scrotum. Etymology ''Labia majora'' is the Latin plural for big ("major") lips; the singular is ''labium majus.'' The Latin term ''labium/labia'' is used in anatomy for a number of usually paired parallel structures, but in English it is mostly applied to two pairs of parts of female external genitals (vulva)—labia majora and labia minora. Labia majora are commonly known as the outer lips, while labia minora (Latin for ''small lips''), which run alongside between them, are referred to as the inner lips. Traditionally, to avoid confusion with other lip-like structures of the body, the labia of female genitals were termed by anatomists in Latin as ''labia majora (''or ''minora) pudendi.'' Embryology Embryolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mons Pubis
In human anatomy, and in mammals in general, the ''mons pubis'' or pubic mound (also known simply as the mons, and known specifically in females as the ''mons Venus'' or ''mons veneris'') is a rounded mass of fatty tissue found over the pubic symphysis of the pubic bones. Anatomy For females, the ''mons pubis'' forms the anterior portion of the vulva. It divides into the labia majora (literally "larger lips"), on either side of the furrow known as the pudendal cleft, that surrounds the labia minora, clitoris, urethra, vaginal opening, and other structures of the vulval vestibule. Although present in both men and women, the ''mons pubis'' tends to be larger in women. Its fatty tissue is sensitive to estrogen, causing a distinct mound to form with the onset of female puberty. This pushes the forward portion of the labia majora out and away from the pubic bone. The mound also becomes covered with pubic hair. It often becomes less prominent with the decrease in bodily estrogen experie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labia Minora
The labia minora (Latin for 'smaller lips', singular: ''labium minus'', 'smaller lip'), also known as the inner labia, inner lips, vaginal lips or nymphae are two flaps of skin on either side of the human vaginal opening in the vulva, situated between the labia majora (Latin for 'larger lips'; also called outer labia, or outer lips). The labia minora vary widely in size, color and shape from individual to individual. The labia minora are homologous to the male urethral surface of the penis. Structure and functioning The labia minora extend from the clitoris obliquely downward, laterally, and backward on either side of the vulval vestibule, ending between the bottom of the vulval vestibule and the labia majora. The posterior ends (bottom) of the labia minora are usually joined across the middle line by a flap of skin, named the frenulum of labia minora or fourchette. On the front, each lip forks dividing into two portions surrounding the clitoris. The upper part of each lip pas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
