query: parts of the male reproductive system and its function

pos: Male reproductive system Male reproductive system The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis. The main male sex organs are the penis and the testicles which produce semen and sperm, which, as part of sexual intercourse, fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus, which is later born as an infant. The corresponding system in females is the female reproductive system. The penis is the male intromittent organ. It

pos: Reproductive system of planarians Reproductive system of planarians The reproductive system of planarians is considerably regular among different families, although the structures associated can be more or less complex. All planarians are hermaphrodites, so their reproductive system has a male and a female part. Both parts communicate with the surface of the body via a single opening called gonopore, which is located on the ventral side of the posterior half of the body. The male part of the reproductive system in planarians has a set of several testicles, distributed throughout the body in two or more rows. They are usually concentrated in the anterior

pos: Semisulcospira libertina the snout). The reproductive system in a male has the following parts: testis, vas deferens, the spermatophore organ. There is no penis. The reproductive system in a female has the following parts: ovary, the pallial oviduct, the spermatophore bursa, the seminal receptacle and the brood pouch. The diploid chromosome number of "Semisulcospira libertina" is 2n=36. The complete mitochondrial genome of "Semisulcospira libertina" is known since 2015. Its length is 15,432 bp. It was the first mitochondrial genome resolved within the whole superfamily Cerithioidea. "Semisulcospira reiniana" is very similar species: its embryos are larger and embryos are with ribs, adult shells

pos: Male reproductive system Male reproductive system The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis. The main male sex organs are the penis and the testicles which produce semen and sperm, which, as part of sexual intercourse, fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus, which is later born as an infant. The corresponding system in females is the female reproductive system. The penis is the male intromittent organ. It

pos: Man or genetic features considered to be mixed or atypical for one sex or the other, may use other criteria in making a clear determination. There are also transgender and transsexual men, who were assigned as female at birth, but identify as men; there are varying social, legal and individual definitions with regard to these issues. (See trans man.) The male sex organs are part of the reproductive system, consisting of the penis, testicles, vas deferens, and the prostate gland. The male reproductive system's function is to produce semen which carries sperm and thus genetic information that can unite with an

pos: Male reproductive system anterior ends are represented by the appendices testis (hydatids of Morgagni of the male), while their terminal fused portions form the utriculus on the floor of the prostatic urethra. This is due to the production of Anti-Müllerian hormone by the Sertoli cells of the testes. Male reproductive system The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis. The main male sex organs are the penis and the testicles which produce semen and sperm, which,

pos: Reproductive system of planarians a structure formed basically by a fold of the walls of the male atrium called “penis papilla”. The penis papilla is a permanent structure that occupies part or the whole male atrium and is protruded during copulation, thus also called a protrusible penis. In species without a penis papilla, the penis is formed only during copulation by a projection of the walls in the male atrium and called an eversible penis. In land planarians, the structure of the male atrium may be quite variable between different genera. The most common constructions are: The female part of the reproductive system in

pos: Urology Urology Urology (from Greek οὖρον "ouron" "urine" and "-logia" "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the male and female urinary-tract system and the male reproductive organs. Organs under the domain of urology include the kidneys, adrenal glands, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymis, vas deferens, seminal vesicles, prostate, and penis). The urinary and reproductive tracts are closely linked, and disorders of one often affect the other. Thus a major spectrum of the conditions managed in urology exists under the domain of

pos: Human reproductive system Examples of unclassifiable disorders are Peyronie's disease in males and endometriosis in females. Many congenital conditions cause reproductive abnormalities, but are better known for their other symptoms. These include: Turner syndrome, Klinefelter's syndrome, Cystic fibrosis, and Bloom syndrome. Human reproductive system The human reproductive system usually involves internal fertilization by sexual intercourse. In this process, the male inserts his penis into the female's vagina and ejaculates semen, which contains sperm. A small proportion of the sperm pass through the cervix into the uterus, and then into the Fallopian tubes for fertilization of the ovum. Only one sperm is required to

pos: Male reproductive system penis, and a midline closure of the labioscrotal folds. This closure forms the wall of the scrotum the external genitalia. The external genitalia are completely formed by the end of the 12th week. At birth, the development of the prepubertal male reproductive system is completed. During the second trimester of pregnancy, testosterone secretion in the male declines so that at birth the testes are inactive. Gonadotropin secretion is low until the beginning of puberty. The genetic sex is determined by whether a Y bearing or next bearing sperm fertilizes the open; the presence or absence of a Y chromosome in

pos: Human reproductive system Human reproductive system The human reproductive system usually involves internal fertilization by sexual intercourse. In this process, the male inserts his penis into the female's vagina and ejaculates semen, which contains sperm. A small proportion of the sperm pass through the cervix into the uterus, and then into the Fallopian tubes for fertilization of the ovum. Only one sperm is required to fertilize the ovum. Upon successful fertilization, the fertilized ovum, or zygote, travels out of the Fallopian tube and into the uterus, where it implants in the uterine wall. This marks the beginning of gestation, better known as pregnancy,

pos: Reproductive system large breeds. The mare's reproductive system is responsible for controlling gestation, birth, and lactation, as well as her estrous cycle and mating behavior. The stallion's reproductive system is responsible for his sexual behavior and secondary sex characteristics (such as a large crest). Male and female birds have a cloaca, an opening through which eggs, sperm, and wastes pass. Intercourse is performed by pressing the lips of the cloacae together, which is sometimes known as intromittent organ which is known as a phallus that is analogous to the mammals' penis. The female lays amniotic eggs in which the young fetus continues

pos: Reproductive system disease Reproductive system disease A reproductive system disease is any disease of the reproductive system. Reproductive tract infection (RTI) are infections that affect the reproductive tract, which is part of the Reproductive System. For females, reproductive tract infections can affect the upper reproductive tract (fallopian tubes, ovary and uterus) and the lower reproductive tract (vagina, cervix and vulva); for males these infections affect the penis, testicles, urethra or the vas deferens. The three types of reproductive tract infections are endogenous infections, iatrogenic infections and the more commonly known sexually transmitted infections. Each has its own specific causes and symptoms, caused by

neg: Human reproductive system until birth. The male reproductive system has one function: to produce and deposit sperm. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, there are numerous differences in typical secondary sex characteristics. The male reproductive system is a series of organs located outside the body and around the pelvis region of a male that contribute towards the reproduction process. The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum. The major reproductive organs of the male can be grouped into three categories.

neg: Reproductive system and deposit sperm. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, numerous differences typically occur in secondary sexual characteristics. The male reproductive system is a series of organs located outside of the body and around the pelvic region of a male that contribute towards the reproduction process. The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum. The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place

neg: Reproductive system of gastropods capsule glands, which coat the egg in a protective jelly. Additional reproductive structures include: Hermaphrodites have both male and female reproductive parts. The male and female system act as separate units until the egg and sperm are ready to fuse together. The fusion of egg and sperm takes place in the uterus of the female system. Hermaphrodites also have a hermaphroditic duct, which helps change the sex of the gastropod during certain times of the year. This article incorporates CC-BY-2.0 text (but not under GFDL) from the reference Reproductive system of gastropods The reproductive system of gastropods (slugs and snails)

neg: Insect physiology changes more rapidly than other slower breeding animals. Although there are many forms of reproductive organs in insects, there remains a basic design and function for each reproductive part. These individual parts may vary in shape (gonads), position (accessory gland attachment), and number (testicular and ovarian glands), with different insect groups. The female insect's main reproductive function is to produce eggs, including the egg's protective coating, and to store the male spermatozoa until egg fertilisation is ready. The female reproductive organs include paired ovaries which empty their eggs (oocytes) via the calyces into lateral oviducts, joining to form the common

neg: Human reproductive system reproductive system and forms the Fallopian tubes, uterus, and vagina in the female system. In both sexes the gonads go on to form the testes and ovaries; because they are derived from the same undeveloped structure, they are considered homologous organs. There are a number of other homologous structures shared between male and female reproductive systems. However, despite the similarity in function of the female Fallopian tubes and the male epididymis and vas deferens, they are not homologous but rather analogous structures as they arise from different fetal structures. Gametes are produced within the gonads through a process known as

neg: Reproductive system of planarians the material that forms the shell of the eggcase (also called cocoon). Among the accessory structures of the reproductive system of planarians, one usually found in freshwater and marine species is the "bursa copulatrix", which has the function to store sperm after mating. Some planarians (such as the genera "Planaria", "Artioposthia", "Arthurdendyus", "Coleocephalus" and "Newzealandia") have a series of finger-like projections, called adenodactyls, near the male and female atria. Adenodactyls contain glands and produce several secretions believed to be useful during reproduction. Reproductive system of planarians The reproductive system of planarians is considerably regular among different families, although the structures

neg: Richard Sharpe (scientist) Richard Sharpe (scientist) Richard Sharpe is Emeritus Professor at the University of Edinburgh (UoE) College of Medicine & Veterinary Medicine and is recognized world-wide as a leading scientist in the field of male reproductive health and developmental disorders of the male reproductive system. Until March 2016 he headed a research programme in the MRC/UoE Centre for Reproductive Health (http://www.crh.ed.ac.uk). His expertise and research interests cover sexual differentiation, development and puberty (and disorders thereof), fetal programming, endocrinology, the effects of lifestyle, drugs and environmental chemical exposures on reproductive development and function. Professor Sharpe’s scientific career got off to a shaky start.

neg: Reproductive system labor. Labor consists of the muscles of the uterus contracting, the cervix dilating, and the baby passing out the vagina (the female genital organ). Human's babies and children are nearly helpless and require high levels of parental care for many years. One important type of parental care is the use of the mammary glands in the female breasts to nurse the baby. The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the offspring until birth. The male reproductive system has one function, and it is to produce

neg: Salix glauca species is dioecious, with male and female reproductive parts occurring on separate individuals. This species has secondary sexual dimorphism, with male and female individuals different in function or morphology in aspects other than their reproductive structures. For example, female plants are more sensitive to drought conditions. The seed stays on the plant until fall, when it is dispersed. The seed is coated in downy fibers that help it disperse on the wind and on water. Unlike the seeds of many other willows, these do not germinate immediately on contact with the substrate, but overwinter under the snow and sprout in

neg: Clean Water Act increase). The association was stronger in those over 75 than in the population aged 65–74. This example is a small reflection of residents of the United States remain at risk of waterborne gastrointestinal illness under current water treatment practices. Reproductive problems refer to any illness of the reproductive system. New research by Brunel University and the University of Exeter strengthens the relationship between water pollution and rising male fertility problems. Study identified a group of chemicals that act as anti-androgens in polluted water, which inhibits the function of the male hormone, testosterone, reducing male fertility. Neurological disorders are diseases of

neg: Gynodioecy Gynodioecy Gynodioecy is a rare breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate stage between hermaphroditism (exhibiting both female and male parts) and dioecy (having two distinct morphs: male and female). Gynodioecy is the opposite of androdioecy, which is a breeding system consisting of male and hermaphroditic plants in a population. Gynodioecy occurs as a result of a genetic mutation that inhibits a hermaphroditic plant from producing pollen, while keeping the female reproductive parts intact. Gynodioecy is extremely rare, with fewer than 1%

neg: Prostate that it produces the same protein markers, PSA and PAB, as the male prostate. This means Skene's gland functions as a female prostate, a histologic homolog to the male prostate gland. Monotremes and marsupial moles lack prostates, instead having simpler cloacal glands that carry their function. A prostate gland also occurs in some invertebrate species, such as gastropods. Prostate The prostate (from Ancient Greek προστάτης, "prostates", literally "one who stands before", "protector", "guardian") is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals. It differs considerably among species anatomically, chemically, and physiologically. The function of the

neg: Male reproductive system male reproductive system is the process whereby the reproductive organs grow, mature and are established. It begins with a single fertilized egg and culminates 38 weeks later with birth of a male child. It is a part of the stages of sexual differentiation. The development of the male reproductive system coincides with the urinary system. The development of them can also be described together as the development of the urinary and reproductive organs. Sexual identity is determined at fertilization when the genetic sex of the zygote has been initialized by a sperm cell containing either an X or Y chromosome.

neg: Selfish genetic element female reproductive functions at the expense of the male reproductive functions improves its own chance of transmission. Cytoplasmic male sterility is the loss of male fertility, typically through loss of functional pollen production, resulting from a mitochondrial mutation. In many species where cytoplasmic male sterility occurs, the nuclear genome has evolved so-called restorer genes, which repress the effects of the cytoplasmic male sterility genes and restore the male function, making the plant a hermaphrodite again. The co-evolutionary arms race between selfish mitochondrial genes and nuclear compensatory alleles can often be detected by crossing individuals from different species that have different

neg: Female reproductive system a blastocyst, which implants itself in the wall of the uterus. This begins the period of gestation and the embryo will continue to develop until full-term. When the foetus has developed enough to survive outside the uterus, the cervix dilates and contractions of the uterus propel the newborn through the birth canal (the vagina). The corresponding equivalent among males is the male reproductive system. The vulva consists of all of the external parts and tissues and includes the mons pubis, pudendal cleft, labia majora, labia minora, Bartholin's glands, clitoris, and vaginal opening. The female internal reproductive organs are the vagina,

neg: Sexual conflict and "Heliconius erato", have been found to transfer an antiaphrodisiac to the female during copulation. This compound is only produced in the male and is how males identify one another as male. Therefore, when it is transferred to the female, she then smells like a male. This prevents future males from attempting to copulate with her. While this behavior potentially benefits the female because harassment from males post mating has been found to decrease reproductive success by disturbing the production of eggs, its primary function is to increase the reproductive success of the male by ensuring that his sperm will

neg: Raillietina tetragona in comparison to other species are oval scolex and suckers, with relatively elongated neck. "R. tetragona" is strictly hermaphroditic having a complete reproductive system in itself. Each mature proglottid has a set of male and female reproductive organ and genital pores on one side. Testes are located on both sides of the ovary and behind vitellarium. Each egg capsule contained 4-12 eggs and many calcareous corpuscles, each of which is surrounded by a membrane. The male reproductive system matures first. As the two reproductive systems matured, the proglottids became gravid after fertilization. The tapeworm completes its life cycle in two

neg: Human reproductive system the development of the human fetus. Despite the differences between the adult female and male are derived from the intermediate mesoderm. The three main fetal precursors of the reproductive organs are the Wolffian duct, the Müllerian ducts, and the gonads. Endocrine hormones are a well-known and critical controlling factor in the normal differentiation of the reproductive system. The Wolffian duct forms the epididymis, vas deferens, ductus deferens, ejaculatory duct, and seminal vesicle in the male reproductive system, but essentially disappears in the female reproductive system. The reverse is true for the Müllerian duct, as it essentially disappears in the male

neg: Reproductive biology together in order to produce offspring. The female reproductive system includes the structures involved in ovulation, fertilization, development of an embryo, and birth. These structures include: Estrogen is one of the sexual reproductive hormones that aid in the sexual reproductive system of the female. The male reproductive system includes sex accessory glands, sex accessory ducts, testes, and external genitalia. Testosterone, although present in both males and females, is relatively more abundant in males. Testosterone serves as one of the sexual reproductive hormones in the male reproductive system. Animal reproduction occurs by two modes of action, including both sexual and asexual

neg: Reproductive system of gastropods of reproductive system in stylommatophorans is common feature. Such variability may include: also Examples of reproductive system of various land snails: The structure of the reproductive system is strictly hermaphroditic. From the gonads, a hermaphrodite duct, a duct which is designed to transport both sperm and eggs, leads to a portion of the reproductive tract where the duct splits into a strictly male and strictly female portion. The female portion includes a fertilization pouch and posterior and anterior mucus glands, which open up into a pallial cavity which leads to a small muscular vagina. The male portion of the reproductive

neg: Reproductive system of gastropods makes their reproduction system unique amongst many other invertebrates. Hermaphroditic gastropods possess both the egg and sperm gametes which gives them the opportunity to self-fertilize. The reproductive system of marine gastropods such as those from class Opisthobranchia and order Archaeogastropoda from the class Prosobranchia, is a continuous cycle of alternating male and female reproductive role prevalence. Immediately after spawning in late summer, the predominance of the female reproductive functions are terminated and gametogenesis initiates immediately, with the start of the predominance of the male reproductive role. Gametes remain in the gonads throughout the winter and early spring. The female reproductive

neg: Xenoestrogen and phthalates are known to decrease the anogenital distance in newborn rats. Although this article focuses on the effects of xenoestrogens and reproductive function in females, numerous animal studies also implicate environmental estrogens' and androgens' adverse effects on the male reproduction system. Administration of estrogens to developing male animals reduces testicular weight and decreases sperm production. The small phallus size of male alligators has been linked to contamination of their natural Florida habitat with DDT. Data from animal research is abundant demonstrating the adverse effects on reproduction of hormonally active compounds found in the environment. Atrazine is widely used as

neg: Reproductive success to sperm quality of the male and the compatibility of the sperms antigens with the females immune system. If the Humans in general, consider phenotypic traits that present their health and body symmetry. The pattern of constraints on female reprouction is consistent with human life-history and across all populations. A difficulty in studying human reproductive success is its high variability. Every person, male or female, is different, especially when it comes to reproductive success and also fertility. Reproductive success is determined not only by behavior (choices), but also physiological variables that cannot be controlled. The Blurnton-Jones 'backload model' "tested a

neg: Testicular self-examination relaxed and the testes are lower. Abnormal results of the TSE include the following: Some signs and symptoms of testicular cancer found during the TSE are common to other disorders of the male urinary tract and reproductive organs, some of which require prompt medical attention to preserve reproductive and urinary function. These include hydrocele testis, a varicocele, a spermatocele, genitourinary system cancers, urinary tract infections, sexually transmitted infections, or testicular torsion. Practitioners may recommend testicular self-exam (TSE) when the following risk factors are present: However, there is no medical consensus for recommendations on TSE. It is not clear that TSE

neg: Groove Phi Groove people of ancient Egypt created “phi” as a symbol of the creative function of the male reproductive system and, more loosely, as “reproduction in endless series,” which is a symbolic representation of “the fire of life.” The Fellowship has incorporated this symbol of fertility into its name to stand for continual growth and development. The “phi” symbol should not be confused with the Greek numeral representing 500 or the ancient Greek representation of [pʰ]. As a body, the governing structure of the Fellowship consists of: The National Headquarters Office of Groove Phi Groove Social Fellowship, Inc. is located at 2453

neg: Red harvester ant in the nest until weather permits them to fly away and mate. After copulation, the male usually dies, while the now-fertilized queen returns to the ground to search for a suitable nesting site. Once she has chosen a site, she sheds her wings and begins to reproduce, creating a new colony. She produces "worker ants" for 1–20 years until her death. Some queens have been known to live up to 30 years in the wild. In "P. barbatus", reproductive and nonreproductive tasks are divided into a caste system, as discussed above. Some individuals are specialized for reproductive function, while other

neg: C12orf40 the cell, "C12orf40" is predicted to be present in the nucleus based on signals within its sequence. An analysis of normal human tissues shows that "C12orf40" expression occurs primarily in the testis, suggesting importance to the male reproductive system. The function of "C12orf40" is not yet well understood. However, the three prime untranslated region (3' UTR) of "C12orf40" is highly similar to the 3' UTR of the cystic fibrosis transmembrane conductance regulator (CFTR), which may mean that the two genes share certain expression patterns. In the fibroblasts of hypertrophic scars, exposure to the immunosuppressant Tacrolimus causes "C12orf40" up-regulation. In pigs,

neg: Cecilia Lutwak-Mann Cecilia Lutwak-Mann Cecilia Lutwak-Mann (1900(?)-1987) was a Polish-British endocrinologist and physiologist. She was educated at the University of Lvov (now in Ukraine), where she obtained a doctorate of medicine. She studied the menstrual cycle, cellular respiration, and embryology, and served as chief scientific officer of the Agricultural Research Council of Great Britain. Lutwak-Mann was known for discovering that the hormone progesterone acts on the placenta to control carbonic anhydrase synthesis. She also co-authored the then-reference text on male reproductive function and semen ("Male Reproductive Function and Semen: Themes and Trends in Physiology, Biochemistry and Investigative Andrology", 1981) with Thaddeus Mann.

neg: Gongylonema neoplasticum is considerable larger, about 4–5 cm long and 0.23 mm to 0.33 mm in diameter. The tail is bluntly rounded. There is a single anus, but sucker and papillae are absent. "G. neoplasticum" completes its life cycle in two hosts, rats as definitive hosts, and cockroaches ("Periplaneta") as intermediate hosts. It is hermaphrodite, and has both male and female reproductive organs in the same body. The male reproductive system consists of a single testis, vas deferens, seminal vesicles, ejaculatory duct, two spicules, gubernaculum and bursa. Female reproductive organs include a pair of ovaries, oviducts, seminal receptacle, uteri and a long

neg: The Cremaster Cycle described the "Cremaster" cycle (1994–2002) as "a self-enclosed aesthetic system." The cycle includes the films as well as photographs, drawings, sculptures, and installations the artist produced in conjunction with each episode. Its conceptual departure point is the male cremaster muscle, the primary function of which is to raise and lower the testes in response to temperature. The project is filled with anatomical allusions to the position of the reproductive organs during the embryonic process of sexual differentiation: "Cremaster 1" represents the most "ascended" or undifferentiated state, "Cremaster 5" the most "descended" or differentiated. The cycle repeatedly returns to those moments

neg: Challenge hypothesis Challenge hypothesis The challenge hypothesis outlines the dynamic relationship between testosterone and aggression in mating contexts. It proposes that testosterone promotes aggression when it would be beneficial for reproduction, such as mate guarding, or strategies designed to prevent the encroachment of intrasexual rivals. The challenge hypothesis predicts that seasonal patterns in testosterone levels are a function of mating system (monogamy versus polygyny), paternal care, and male-male aggression in seasonal breeders. The pattern between testosterone and aggression was first observed in seasonally breeding birds, where testosterone levels rise modestly with the onset of the breeding season to support basic reproductive functions.

neg: Reproductive toxicity in adult life. BPA also affects male fertility by resulting in lower sperm quality and sex function. The toxicological impact of BPA is better understood and studied in females than in males. Lead is a heavy metal that has been associated not only with mental deficits, but also with male infertility and male reproductive issues. Lead is believed to predominantly affect male reproduction by the disruption of hormones, which reduces the quantity of sperm production in the seminiferous tubules. It has also been proposed that lead causes poor semen quality by increasing reactive oxygen species due to lipid peroxidation, leading

neg: Estradiol (medication) in the breasts, uterus, vagina, fat, skin, bone, liver, pituitary gland, hypothalamus, and other parts of the brain. In accordance, estradiol has numerous effects throughout the body. Among other effects, estradiol produces breast development, feminization, changes in the female reproductive system, changes in liver protein synthesis, and changes in brain function. The effects of estradiol can influence health in both positive and negative ways. In addition to the aforementioned effects, estradiol has antigonadotropic effects due to its estrogenic activity, and can inhibit ovulation and suppress gonadal sex hormone production. At sufficiently high dosages, estradiol is a powerful antigonadotropic, capable of

neg: PRR23C PRR23B and PRR23C are testis-specific genes. Ottolini et al. (2014) believes that this family may be a crucial part for the male reproductive system given their RNA-seq data findings. Proline-rich protein 23C "Homo sapiens" is 262 amino acids long with a calculated molecular weight of 27,674 Da. Proline-rich protein 23C "Homo sapiens" has a domain of unknown function (DUF2476) that spans the majority of the protein (1-259 aa) which is a conserved domain. DUF2476 belongs to pfam10630 which is a part of superfamily c|11241. DUF2476 is a family of proteins that are rich in proline residues and have unknown function.

neg: Reproductive system of gastropods Reproductive system of gastropods The reproductive system of gastropods (slugs and snails) varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly, see Mating of gastropods. In many marine gastropods there are separate sexes (male and female); most terrestrial gastropods however are hermaphrodites. Courtship is a part of the behaviour of mating gastropods. In some families of pulmonate land snails, one unusual feature of the reproductive system and reproductive behavior is the creation and utilization of love darts, the throwing of which have been identified as a

neg: Male reproductive system during puberty causes the male secondary sexual characteristics to be manifested. the manifestation of secondary sexual characteristics include the growth of: Secondary development includes the increased activity of the eccrine sweat glands and sebaceous glands along with the darkening of the skin in the scrotal region. Chromosomal abnormalities can occur during fertilization impacting the development of the male reproductive system. The genotype of the male consists of a Y chromosome paired with an X chromosome. Female gender is determined by the absence of a Y chromosome. Some individuals are male who have the XX male syndrome and androgen insensitivity syndrome.

neg: Female reproductive system and genital mutilation. Female genital mutilation is the complete or partial removal of a female's external genitals. It is claimed in the Hippocratic writings that both males and females contribute their seed to conception; otherwise, children would not resemble either or both of their parents. Four-hundred years later, Galen "identified" the source of 'female semen' as the ovaries in female reproductive organs. Female reproductive system The female reproductive system is made up of the internal and external sex organs that function in reproduction of new offspring. In the human the female reproductive system is immature at birth and develops to

neg: Estrogen receptor alpha over ERβ include: Antagonists of ERα selective over ERβ include: ERα plays a role in the physiological development and function of a variety of organ systems to varying degrees, including the reproductive, central nervous, skeletal, and cardiovascular systems. Accordingly, ERα is widely expressed throughout the body, including the uterus and ovary, male reproductive organs, mammary gland, bone, heart, hypothalamus, pituitary gland, liver, lung, kidney, spleen, and adipose tissue. The development and function of these tissues is disrupted in animal models lacking active ERα genes, such as the ERα knockout mouse (ERKO), providing a preliminary understanding of ERα function at specific

neg: Lepidoptera genitalia males of many species of Papilionoidea are furnished with secondary sexual characteristics. These consist of scent-producing organs, brushes, and brands or pouches of specialised scales. These presumably meet the function of convincing the female that she is mating with a male of the correct species. While the layout of internal genital ducts and openings of the female genitalia depends upon the taxonomic group that insect belongs to, the internal female reproductive system of all Lepidopterans consists of paired ovaries and accessory glands which produce the yolks and shells of the eggs. Female insects have a system of receptacles and ducts

neg: Euglandina rosea However, one disease that is known to affect the snail is caused by the pseudomonad bacterium or Aeromonas hydrophila. Infection occurs by ingesting the bacteria, if it rests on the snail’s food, or by contact with another individual who is infected. This causes reduced digestive function resulting in emaciation even when there is an abundance of food resources. This finally results in the slow death of starvation. The rosy wolf snail is a hermaphrodite and is oviparous. This means the snail has both male and female reproductive parts and lays eggs instead of having live birth. The courtship rituals for

neg: Female reproductive system Female reproductive system The female reproductive system is made up of the internal and external sex organs that function in reproduction of new offspring. In the human the female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a foetus to full term. The internal sex organs are the uterus, Fallopian tubes, and ovaries. The uterus or womb accommodates the embryo which develops into the foetus. The uterus also produces vaginal and uterine secretions which help the transit of sperm to the Fallopian tubes. The ovaries produce the

neg: Human reproductive ecology reduced sexual dimorphism in humans compared to other primates. This suggests that there was less male-male competition for female mates, which led to more male investment in offspring, rather than mate choices. Paternal investment strategies vary facultatively based on alloparental care, the costs and benefits of offspring investment, societal pressures, divisions of labor, cultural expectations and norms, and the individual qualities of males in any given society. In the field of reproductive ecology, it has been a recent interest to explore the endocrinology of social relationships, including the relation of paternal investment and endocrine function. It has been shown that

neg: Reproductive isolation hybrids. As important as identifying an isolation gene is knowing its function. The "Hmr" gene, linked to the X chromosome and implicated in the viability of male hybrids between "D. melanogaster" and "D. simulans", is a gene from the proto-oncogene family "myb", that codes for a transcriptional regulator. Two variants of this gene function perfectly well in each separate species, but in the hybrid they do not function correctly, possibly due to the different genetic background of each species. Examination of the allele sequence of the two species shows that change of direction substitutions are more abundant than synonymous substitutions,

neg: Antiandrogens in the environment the DDT metabolite dichlorodiphenyldichloroethylene (p.p’-DDE) have shown irregular reproductive development due to their function as androgen receptor antagonists that inhibit androgen-activated gene expression. Even with low doses of antiandrogenic pesticides, developmental effects such as reduced anogenital distance and induction of areolas were seen in male rats. Animal studies show that deformities result in offspring exposed to antiandrogens. Male mice can display malformations that resemble the reproductive organs of females as in the case of exposure to vinclozolin or proymidone. Exposure to vinclozolin or procymidone in utero feminized male offspring, as seen in abnormalities of anogenital distance, small or absent sex

neg: Sex evolved alongside the reproduction system, starting with similar gametes (isogamy) and progressing to systems that have different gamete types, such as those involving a large female gamete (ovum) and a small male gamete (sperm). In complex organisms, the sex organs are the parts that are involved in the production and exchange of gametes in sexual reproduction. Many species, both plants and animals, have sexual specialization, and their populations are divided into male and female individuals. Conversely, there are also species in which there is no sexual specialization, and the same individuals both contain masculine and feminine reproductive organs, and they

neg: David Crews adding to our fundamental understanding of reproductive biology and behavior. Through his studies he has uncovered the principles and constraints imposed by diverse reproductive strategies that have led to the evolution of neuroendocrine mechanisms underlying species-typical reproductive behaviors. Crew extended his investigations to address the origin of sexual behavior. Through both empirical and scholarly research he has argued that the primary function of sexual behavior, namely the stimulation and coordination of the reproductive physiologies of the interacting individuals (usually male and female), originated with the first unicellular organisms and hence predates the evolution of sexual recombination. As mentioned, Crews has

neg: Eucestoda including excretory canals, nerve fibers, and longitudinal muscles. The excretory system is responsible for osmoregulation and consists of blind-ending flame bulbs communicating through a duct system. The nervous system, often referred to as a "ladder system," is a system of longitudinal connectives and transverse ring commissures. The reproductive systems develop progressively along the differentiated proglottids of the strobila region, with each proglottid developing one or two sets of sexual organs that differentiate at different times in a species-specific pattern, usually male-first. Thus, moving in the posterior direction of the continuously maturing proglottid chain, there are proglottids with mature male reproductive

neg: Astatotilapia burtoni pursue female counterparts, and are reproductively suppressed due to regressed gonads. The transitions between different social roles cause several changes in the brain and reproductive system, such that the social transformation affects them both behaviorally and physically. To expand on reversibility, if a territorial male is placed with an individual that is significantly larger in size, it will then rapidly socially transform into the non-territorial type. This change can be detected by the behavior and alternate coloration that follows. The change in reproductive competence, however, occurs about three weeks after the formerly territorial male loses its territory to the larger

neg: Andrology Andrology Andrology (from , "anēr", genitive , "andros", "man"; and , "-logia") is the medical specialty that deals with male health, particularly relating to the problems of the male reproductive system and urological problems that are unique to men. It is the counterpart to gynaecology, which deals with medical issues which are specific to female health, especially reproductive and urologic health. Andrology covers anomalies in the connective tissues pertaining to the genitalia, as well as changes in the volume of cells, such as in genital hypertrophy or macrogenitosomia. From reproductive and urologic viewpoints, male-specific medical and surgical procedures include vasectomy,

neg: Paramesonephric duct The two are conjoined at the sinus tubercle. Paramesonephric ducts are present on the embryo of both sexes. Only in females do they develop into reproductive organs. They degenerate in males of certain species, but the adjoining mesonephric ducts develop into male reproductive organs. The sex based differences in the contributions of the paramesonephric ducts to reproductive organs is based on the presence, and degree of presence, of Müllerian inhibiting factor. During the formation of the reproductive system, the paramesonephric ducts are formed just lateral to the mesonephric ducts in both female and male embryos 6 weeks after fertilization. During

neg: Sex organ specifically the testes in the male or the ovaries in the female. Gonads as primary sex organs, generate reproductive gametes containing inheritable DNA. They also produce most of the primary hormones that affect sexual development, and regulate other sexual organs and sexually differentiated behaviors. In general zoology, given the great variety in organs, physiologies, and behaviors involved in copulation, male genitalia are more strictly defined as "all male structures that are inserted in the female or that hold her near her gonopore during sperm transfer"; female genitalia are defined as "those parts of the female reproductive tract that make direct

neg: Sexual differentiation in humans The sex of an early embryo cannot be determined because the reproductive structures do not differentiate until the seventh week. Prior to this, the child is considered bipotential because it cannot be identified as male or female. The internal genitalia consist of two accessory ducts: mesonephric ducts (male) and paramesonephric ducts (female). The mesonephric system is the precursor to the male genitalia and the paramesonephric to the female reproductive system. As development proceeds, one of the pairs of ducts develops while the other regresses. This depends on the presence or absence of the sex determining region of the Y chromosome,

neg: Sex differences in sensory systems form of the sex difference reflects the function it serves in terms of enhanced reproductive success. Male sphinx moths, "Manduca sexta", rely on female released sex-pheromones to guide typical zig-zagging flight behaviors used to locate mates. Although both males and females respond to host plant olfactory cues to locate food sources, detection of and response to sex-pheromones appears to be male specific. Males that are better at detecting female sex-pheromones are able to find signaling females faster, providing them with a reproductive advantage. Since females gain no such advantage for having olfactory systems that are more sensitive to pheromones, enhanced

neg: Female sperm storage also used to move sperm from the spermathecae so they can fertilize the egg. It has been observed in locusts, that the nervous system initiates female reproductive muscular contractions. In some species, such as "R. prolixus", the contractions that move spermatozoa into sperm storage are initiated by a male secretion in the ejaculate. Male secretions, such as the glycoprotein ACP36D in "Drosophila", can also play a role in preparing the female reproductive system for sperm storage. It causes changes in uterine shape allowing spermatozoa access to the sperm storage organs. The female insect nervous system affects many of the processes

neg: Tarantula muscles that surround them, and can cause the venom to be forcefully injected into prey. The pedipalpi are two six-segmented appendages connected to the thorax near the mouth and protruding on either side of both chelicerae. In most species of tarantula, the pedipalpi contain sharp, jagged plates used to cut and crush food often called the coxae or maxillae. As with other spiders, the terminal portions of the pedipalpi of males function as part of their reproductive system. Male spiders spin a silken platform (sperm web) on the ground onto which they release semen from glands in their opistoma. Then

neg: Prostate Prostate The prostate (from Ancient Greek προστάτης, "prostates", literally "one who stands before", "protector", "guardian") is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals. It differs considerably among species anatomically, chemically, and physiologically. The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance, that in humans usually constitutes roughly 30% of the volume of semen along with spermatozoa and seminal vesicle fluid. Semen is made alkaline overall with the secretions from other contributing glands, including, at least, seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity

neg: Phthalate in sperm, decreased sperm motility, decreased semen volume and other metrics. Phthalates causing harm to the male reproductive system is plausible, though perhaps not to the level of doom indicated in the popular press. Additional research is needed to make a more conclusive statement. Early research also shows phthalate exposure may be associated with diabetes and insulin resistance, breast cancer, obesity, metabolic disorders, and immune function. There are possible (though not conclusive) associations between phthalate exposure and adverse child neurodevelopment, including the development of ADHD and autistic behaviors. In many cases, there are studies that show connections between phthalates and

neg: NH41 NH41 The NR4A1 gene is a transcription factor important in the development of cells that secrete the hormone insulin-like 3 (INSL3). In general, the NR4A gene family regulates cell growth and differentiation. In humans, INSL3 aids in the regulation of testicular descent during fetal development. In an adult INSL3 helps in keeping germ cells alive, in both males and females. In the male reproductive system the NR4A1 gene is a promoter of insulin-like 3 in Leydig cells. Leydig cells are located in the testis and known for the function as a support cell in spermatogenesis. Along with other things they

neg: Longhead catshark the naked patches of skin and the interior of the mouth are black. The longhead catshark is unique among "Apristurus" species in that the duodenum is not short, but almost as long as the spiral valve intestine. The function of this trait is unknown, as the feeding habits of this shark have not been documented. The longhead catshark is the only known cartilaginous fish that is normally hermaphroditic: some 85% of the population is functionally male or female, but also possesses undeveloped reproductive organs of the opposite sex (called "rudimentary hermaphroditism"). The factors underlying the evolution of this system have

neg: Love dart the function of love darts in which the love dart is used by the male component to manipulate the female component’s sperm collection, increasing paternity. A closer look into the behavior of "Cornu aspersum", shows that it is not the mechanical action of the dart that increases paternity in sperm donors but instead the mucus that coats the dart. The mucus carries an that is transferred into the recipient snail’s hemolymph when the dart is stabbed. This allohormone reconfigures the female component of the reproductive system in the receiving individual: the bursa copulax (sperm digestion organ) is closed off, and

neg: Anorchia Anorchia Anorchia (also called anorchidism or anorchism) is a disorder of sex development in which a person with XY karyotype, which usually corresponds to male sex, is born without testes. Within a few weeks of fertilization, the embryo develops rudimentary gonads (testes), which produce hormones responsible for the development of the reproductive system. If the testes fail to develop within eight weeks, the baby will develop female genitalia (see Swyer syndrome). If the testes begin to develop but are lost or cease to function between eight and 10 weeks, the baby will have ambiguous genitalia when it is born. However,

neg: Reproductive biology Reproductive biology Reproductive biology includes both sexual and asexual reproduction. Reproductive biology includes a wide number of fields: Human reproductive biology is primarily controlled through hormones, which send signals to the human reproductive structures to influence growth and maturation. These hormones are secreted by endocrine glands, and spread to different tissues in the human body. In humans, the pituitary gland synthesizes hormones used to control the activity of endocrine glands. Internal and external organs are included in the reproductive system. There are two reproductive systems including the male and female, which contain different organs from one another. These systems work

neg: Endocrine disruptor and air fresheners. They are of potential health concern because they are known to disrupt the endocrine system of animals, and some research has implicated them in the rise of birth defects of the male reproductive system. Although an expert panel has concluded that there is "insufficient evidence" that they can harm the reproductive system of infants, California,Washington state and Europe have banned them from toys. One phthalate, bis(2-ethylhexyl) phthalate (DEHP), used in medical tubing, catheters and blood bags, may harm sexual development in male infants. In 2002, the Food and Drug Administration released a public report which cautioned against

neg: Reproductive system particularly testosterone. The testes release a hormone that controls the development of sperm. This hormone is also responsible for the development of physical characteristics in men such as facial hair and a deep voice. The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva, which leads to the vagina, the vaginal opening, to the uterus; the uterus, which holds the developing fetus; and the ovaries, which produce the female's

neg: Human reproductive system an Adam's apple. An important sexual hormone of males is androgen, and particularly testosterone. The testes release a hormone that controls the development of sperm. This hormone is also responsible for the development of physical characteristics in men such as facial hair and a deep voice. The human female reproductive system is a series of organs primarily located inside the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva, which leads to the vagina, the vaginal opening, to the uterus; the uterus, which

neg: Neuro biomechanics the senses and initiates actions. The human nervous system coordinates the functions of itself and all organ systems including but not limited to the cardiovascular system, respiratory system, skin, digestive system, immune system, hormonal, metabolic, musculoskeletal, endocrine system, blood and reproductive system. Optimal function of the organism as a whole depends upon the proper function of the nervous system. Biomechanics: (biology, physics) The branch of biophysics that deals with the mechanics of the human or animal body; especially concerned with muscles and the skeleton. The study of biomechanical influences upon nervous system function and load bearing joints. Research: Panjabi MM,

neg: Plant reproductive morphology separately in many different lineages, and monoecy in the plant lineage correlates with the evolution of dioecy, suggesting that dioecy can evolve more readily from plants that already produce separate male and female flowers. Plant reproductive morphology Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants (green algae, mosses, liverworts,

neg: Heterospory complete model for the origin of heterospory, known as the Haig-Westoby model, establishes a connection between minimum spore size and successful reproduction of bisexual gametophytes. For the female function, as minimum spore size increases so does the chance for successful reproduction. For the male function, reproductive success does not change as the minimum spore size increases. Heterospory Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore, is male and the larger megaspore is female. Heterospory evolved during the Devonian period from isospory independently in several

neg: Domestic rabbit thousand rabbit shows occur each year and are sanctioned in Canada and the United States by the ARBA. Today, the domesticated rabbit is the third most popular mammalian pet in Britain after dogs and cats. Rabbits have been, and continue to be, used in laboratory work such as the production of antibodies for vaccines and research of human male reproductive system toxicology. The Environmental Health Perspective, published by the National Institute of Health, states, "The rabbit [is] an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system." According to the Humane Society

neg: Cuniculture and the British Rabbit Council. Rabbits have been and continue to be used in laboratory work such as production of antibodies for vaccines and research of human male reproductive system toxicology. Experiments with rabbits date back to Louis Pausture's work in France in the 1800s. In 1972, around 450 000 rabbits were used for experiments in the United States, decreasing to around 240 000 in 2006. The Environmental Health Perspective, published by the National Institute of Health, states, "The rabbit [is] an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system." According

neg: Domestic rabbit used in laboratory work such as production of antibodies for vaccines and research of human male reproductive system toxicology. In 1972, around 450,000 rabbits were used for experiments in the United States, decreasing to around 240,000 in 2006. The Environmental Health Perspective, published by the National Institute of Health, states, "The rabbit [is] an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system." According to the Humane Society of the United States, rabbits are also used extensively in the study of bronchial asthma, stroke prevention treatments, cystic fibrosis, diabetes, and cancer. The

neg: Human reproductive ecology reproductive capabilities. The key components of fecundity are a person's reproductive maturation and the maintenance of their reproductive system. In humans, the timing of female reproductive maturation is particularly variable and is heavily influenced by ecological considerations. In addition, the age at menarche has decreased over time in many global populations. This phenomenon is referred to as the secular trend. Age at menarche is one measure of the fecundity of an individual female. Male reproductive maturity is less subject to environmental and ecological factors, and does not follow the secular trend that female puberty does. In adults, fecundity is determined

neg: Schistosoma mansoni behavioural, physiological and antigenic differences between males from single-sex, as opposed to bisex, infections have been reported. On the other hand, female schistosomes do not mature without a male. Female schistosomes from single-sex infections are underdeveloped and exhibit an immature reproductive system. Although the maturation of the female worm seems to be dependent on the presence of the mature male, the stimuli for female growth and for reproductive development seem to be independent from each other. The adult female worm resides within the adult male worm's gynaecophoric canal, which is a modification of the ventral surface of the male, forming

neg: Reproductive toxicity Reproductive toxicity Reproductive toxicity is a hazard associated with some chemical substances, which interfere in some way with normal reproduction; such substances are called reprotoxic. They may adversely affect sexual function and fertility in adult males and females, as well as causing developmental toxicity in the offspring. Reproductive toxicity is usually defined practically, to include several different effects which are unrelated to each other except in their outcome of lowered effective fertility. The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) separates reproductive toxicity from germ cell mutagenicity and carcinogenicity, even though both these hazards may also affect

neg: Polygyny in animals once, leading to extra-pair copulations in which a few females are able to mate with another male, while not being watched by the breeding male. (Some studies also show that EPC is less common in polygyny compared to monogamy.) These breeding males also have short tenure, and it is common for groups of males who do not have harems to attack a breeding male in order to gain reproductive access to his females. The largest advantage for males in a polygynous mating system is the increased fitness and reproductive success of the lone male because he will father all the

neg: Richard Sharpe (scientist) advisory bodies in the UK, Europe and USA, including: He has published more than 350 scientific papers and is currently a Deputy Editor of the journal Human Reproduction. Lives in Edinburgh with his wife. They have 4 children. Richard Sharpe (scientist) Richard Sharpe is Emeritus Professor at the University of Edinburgh (UoE) College of Medicine & Veterinary Medicine and is recognized world-wide as a leading scientist in the field of male reproductive health and developmental disorders of the male reproductive system. Until March 2016 he headed a research programme in the MRC/UoE Centre for Reproductive Health (http://www.crh.ed.ac.uk). His expertise and

neg: Biological ornament with the experimentally altered chicks. Male animals are typically more elaborately ornamented than females. The classic sexual selection theory notes that because sperm are cheaper to produce than eggs, and because males generally compete more intensely for reproductive opportunities and invest less in parental care than females, males can obtain greater fitness benefits from mating multiple times. Therefore, sexual selection typically results in male-biased sex differences in secondary sexual characteristics, which are non-reproductive body parts that help distinguish between sexes in a species. Female ornamentation has long been overlooked because of the greater prevalence of elaborate displays in males. However,

neg: Genitourinary system the expertise of renal pathologists. Genitourinary pathologists generally work closely with urologic surgeons. Genitourinary system The genitourinary system or urogenital system is the organ system of the reproductive organs and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways, like the male urethra. Also, because of their proximity, the systems are sometimes imaged together. The term "apparatus urogenitalis" is used in "Nomina Anatomica" (under Splanchnologia), but not in "Terminologia Anatomica". The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of

neg: Genitourinary system Genitourinary system The genitourinary system or urogenital system is the organ system of the reproductive organs and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways, like the male urethra. Also, because of their proximity, the systems are sometimes imaged together. The term "apparatus urogenitalis" is used in "Nomina Anatomica" (under Splanchnologia), but not in "Terminologia Anatomica". The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of the adult are preceded by a set of structures that are purely embryonic,

neg: Cestoda faeces, or migrate outwards as independent motile proglottids. The number of proglottids forming the tapeworm ranges from three to four thousand. Their layout comes in two forms: craspedote, meaning any given proglottid is overlapped by the previous proglottid, or acraspedote, indicating the proglottids do not overlap. Cestodes are exclusively hermaphrodites, with both male and female reproductive systems in each body. The reproductive system includes one or more testes, cirri, vas deferens, and seminal vesicles as male organs, and a single lobed or unlobed ovary with the connecting oviduct and uterus as female organs. The common external opening for both male

neg: Ethnoveterinary medicine is that of the Tzotzil Maya shepherdesses who developed their own breed of sheep and have their own husbandry and healthcare system based on their traditions (Perezgrovas, 1996). In research conducted in Trinidad it was noted that male farmers were using the reproductive knowledge of their female relatives to assist in the health care of their ruminants. Female farmers were using the same plants for their animals that they used for themselves (Lans, 2004). ANTHRA, an organization of women veterinary scientists, has been documenting and validating EVM since 1996 in different parts of the states of Andhra Pradesh and Maharashtra

neg: Paradidymis atrophied part of the Wolffian body. Paradidymis The term paradidymis (organ of Giraldés) is applied to a small collection of convoluted tubules, situated in front of the lower part of the spermatic cord, above the head of the epididymis. These tubes are lined with columnar ciliated epithelium, and probably represent the remains of a part of the Wolffian body, like the epididymis, but are functionless and vestigial. The Wolffian body operates as a kidney (mesonephros) in fishes and amphibians, but the corresponding tissue is co-opted to form parts of the male reproductive system in other classes of vertebrate. The paradidymis

neg: Paradidymis Paradidymis The term paradidymis (organ of Giraldés) is applied to a small collection of convoluted tubules, situated in front of the lower part of the spermatic cord, above the head of the epididymis. These tubes are lined with columnar ciliated epithelium, and probably represent the remains of a part of the Wolffian body, like the epididymis, but are functionless and vestigial. The Wolffian body operates as a kidney (mesonephros) in fishes and amphibians, but the corresponding tissue is co-opted to form parts of the male reproductive system in other classes of vertebrate. The paradidymis represents a remnant of an unused,

neg: Botany the genus. For the purposes of identification, Linnaeus's "Systema Sexuale" classified plants into 24 groups according to the number of their male sexual organs. The 24th group, "Cryptogamia", included all plants with concealed reproductive parts, mosses, liverworts, ferns, algae and fungi. Increasing knowledge of plant anatomy, morphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems of classification that grouped plants using a wider range of shared characters and were widely followed. The

neg: Parasitic castration Parasitic castration Parasitic castration is the strategy, by a parasite, of blocking reproduction by its host, completely or in part, to its own benefit. This is one of six major strategies within parasitism. For example, "Hemioniscus balani", a parasitic castrator of hermaphroditic barnacles, feeds on ovarian fluid, so that its host loses female reproductive ability but still can function as a male. This is a case of direct parasitic castration (feeding on host gonads). Indirect strategies are also seen such as diverting host energy from gonad development or secreting castrating hormones. The parasitic castration strategy is used by some larval

neg: Human male sexuality as it doesn't directly contribute to successfully producing offspring. However, male-male sexual behaviour has been argued to have served an adaptive function and an indirect reproductive advantage for males. Evidence suggests that male-male sexual relations in early human periods often occurred between younger adolescent boys and older males. Sexual acts have been viewed as a psychological factor in societies used for bonding. These same-sex relations between young adolescent boys and older men brought many benefits to the younger males, such as access to food, protection from aggression and overall helping them attain personal survival and an increased social standing. These

neg: Male reproductive system urogenital sinus, and the other embryonic structures differentiate into the external genitalia. In the absence of testicular secretions, the female genitalia are formed. At six weeks post conception, the differentiation of the external genitalia in the male and female has not taken place. At eight weeks, a distinct phallus is present during the indifferent stage. By the 10th-12th week, the genitalia are distinctly male or female being and derived from their homologous structures. At 16 weeks post conception, the genitalia are formed and distinct. The masculinization of the embryonic reproductive structures occurs as a result of testosterone secreted by the

neg: Male reproductive system have the potential to become either testes or ovaries. Reproductive sex organs for both male and female are derived from the same embryonic tissues and are considered homologous tissues or organs. After the testes have differentiated, male sex hormones, called androgens, are secreted from interstitial cells (cells of Leydig). The major androgens secreted by these cells is testosterone and secretion begins 8 to 10 weeks after conception. Testosterone secretion reaches a peak at 12 to 14 weeks, and declines to very low levels by the end of the second trimester (about 21 weeks). Levels are the barely detectable 4–6 months