Information: - A penis (plural "penises" or "penes" ) is the primary sexual organ that male animals use to inseminate sexually receptive mates (usually females and hermaphrodites respectively) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penes in the various species are not necessarily homologous. For example, the penis of a mammal is at most analogous to the penis of a male insect or barnacle. - A sperm bank, semen bank or cryobank is a facility or enterprise that collects and stores human sperm from sperm donors for use by women who need donor-provided sperm to achieve pregnancy. Sperm donated by the sperm donor is known as donor sperm, and the process for introducing the sperm into the woman is called artificial insemination, which is a form of third-party reproduction. - Seminiferous tubules are located within the testes , and are the specific location of meiosis , and the subsequent creation of male gametes , namely spermatozoa . The epithelium of the tubule consists of a type of sustentacular cells known as Sertoli cells , which are tall , columnar type cells that line the tubule . In between the Sertoli cells are spermatogenic cells , which differentiate through meiosis to sperm cells . Sertoli cells function to nourish the developing sperm cells . They secrete testis - determining factor , a binding protein which increases the concentration of testosterone inside the seminiferous tubules . Embryologically , they also secrete the anti-Mullerian hormone ( AMH ) necessary for the female Mullerian ducts to regress . There are two types : convoluted and straight , convoluted toward the lateral side , and straight as the tubule comes medially to form ducts that will exit the testis . The seminiferous tubules are formed from the testis cords that develop from the primitive gonadal cords , formed from the gonadal ridge . - Anisogamy (also called heterogamy) is the form of sexual reproduction that involves the union or fusion of two gametes, which differ in size and/or form. (The related adjectives are "anisogamous" and "anisogamic"). The smaller gamete is considered to be male (sperm cell), whereas the larger gamete is regarded as female (egg cell). - Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis), and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes (meiosis). Meiosis results in twelve haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle, and both are believed to be present in the last eukaryotic common ancestor. Prokaryotes also undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication. - A chromosome is a packaged and organized structure containing most of the DNA of a living organism. Most eukaryotic cells have a set of chromosomes (46 in humans) with the genetic material spread among them. - A zygote (from Greek "zygtos" "joined" or "yoked", from "zygoun" "to join" or "to yoke"), is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual. In multicellular organisms, the zygote is the earliest developmental stage. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring. - A eukaryote (or or ) is any organism whose cells contain a nucleus and other organelles enclosed within membranes. Eukaryotes belong to the taxon Eukarya or Eukaryota. The defining feature that sets eukaryotic cells apart from prokaryotic cells (Bacteria and Archaea) is that they have membrane-bound organelles, especially the nucleus, which contains the genetic material and is enclosed by the nuclear envelope. The presence of a nucleus gives eukaryotes their name, which comes from the Greek ("eu", "well" or "true") and ("karyon", "nut" or "kernel"). Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus. In addition, plants and algae contain chloroplasts. Eukaryotic organisms may be unicellular or multicellular. Only eukaryotes form multicellular organisms consisting of many kinds of tissue made up of different cell types. - A spermatozoon (pronounced , alternate spelling spermatozoon; plural spermatozoa; from "seed" and "living being") is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing a X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed by Anton van Leeuwenhoek in 1677. - Oogamy is the familiar form of sexual reproduction. It is a form of anisogamy (heterogamy) in which the female gamete (e.g. egg cell) is significantly larger than the male gamete and is non-motile. The male gametes are typically highly motile to the zygote, but it is usually tasked with all of the travel necessary to bring the respective gametes together. The prevalence of oogamy in higher animals leads to the conclusion that this specialization of the gametes results in their performing their respective tasks better and more efficiently than those tasks could be performed by generalist isogametes, particularly the ability to concentrate high-energy substances in a smaller number of ova. - The testicle or testis is the male gonad in animals. Like the ovaries to which they are homologous, the testicles (testes) are components of both the reproductive system and the endocrine system. The primary functions of the testes are to produce sperm (spermatogenesis) and to produce androgens, primarily testosterone. - Ploidy is the number of sets of chromosomes in a cell. Usually a gamete (sperm or egg, which fuse into a single cell during the fertilization phase of sexual reproduction) carries a full set of chromosomes that includes a single copy of each chromosome, as aneuploidy generally leads to severe genetic disease in the offspring. The gametic or haploid number ("n") is the number of chromosomes in a gamete. Two gametes form a diploid zygote with twice this number (2"n", the zygotic or diploid number) i.e. two copies of autosomal chromosomes. For humans, a diploid species, "n"=23. A typical human somatic cell contains 46 chromosomes: 2 complete haploid sets, which make up 23 homologous chromosome pairs. - A man is a male human. The term "man" is usually reserved for an adult male, with the term boy being the usual term for a male child or adolescent. However, the term "man" is also sometimes used to identify a male human, regardless of age, as in phrases such as "men's basketball". - Meiosis is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them. This process occurs in all sexually reproducing single-celled and multicellular eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. - Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes, which is called "euploidy". An extra or missing chromosome is a common cause of genetic disorders, including some human birth defects. Some cancer cells also have abnormal numbers of chromosomes. Aneuploidy originates during cell division when the chromosomes do not separate properly between the two cells. - Modern humans ("Homo sapiens", primarily ssp. "Homo sapiens sapiens") are the only extant members of Hominina tribe (or human tribe), a branch of the tribe Hominini belonging to the family of great apes. They are characterized by erect posture and bipedal locomotion; manual dexterity and increased tool use, compared to other animals; and a general trend toward larger, more complex brains and societies. - Sperm is the male reproductive cell and is derived from the Greek word () "sperma" (meaning "seed"). In the types of sexual reproduction known as anisogamy and its subtype oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. In mammals, sperm develops in the testicles and is released from the penis. It is also possible to extract sperm through TESE. Some sperm banks hold up to of sperm. - Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells. They are created by a specialized type of cell division, which only occurs in eukaryotic cells, known as meiosis. The two gametes fuse during fertilization to produce DNA replication and the creation of a single-celled zygote which includes genetic material from both gametes. In a process called genetic recombination, genetic material (DNA) joins up so that homologous chromosome sequences are aligned with each other, and this is followed by exchange of genetic information. Two rounds of cell division then produce four daughter cells with half the number of chromosomes from each original parent cell, and the same number of chromosomes as both parents, though self-fertilization can occur. For instance, in human reproduction each human cell contains 46 chromosomes, 23 pairs, except gamete cells, which only contain 23 chromosomes, so the child will have 23 chromosomes from each parent genetically recombined into 23 pairs. Cell division initiates the development of a new individual organism in multicellular organisms, including animals and plants, for the vast majority of whom this is the primary method of reproduction. - A gamete (from Ancient Greek "gamete" from gamein "to marry") is a cell that fuses with another cell during fertilization (conception) in organisms that sexually reproduce. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gametecalled an ovum (or egg)and a male produces the smaller tadpole-like typecalled a sperm. This is an example of anisogamy or heterogamy, the condition in which females and males produce gametes of different sizes (this is the case in humans; the human ovum has approximately 100,000 times the volume of a single human sperm cell). In contrast, isogamy is the state of gametes from both sexes being the same size and shape, and given arbitrary designators for mating type. The name gamete was introduced by the Austrian biologist Gregor Mendel. Gametes carry half the genetic information of an individual, one ploidy of each type, and are created through meiosis. - Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the choanoflagellates. Sponges are the most basal clade of animals. Animals are motile, meaning they can move spontaneously and independently at some point in their lives. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs: they must ingest other organisms or their products for sustenance. After reading the paragraphs above, choose the best answer for the entity that related to 'seminiferous tubule' with the relationship of 'part of'. Choices: - animal - animals - cell - cell cycle - cell division - chromosome - disease - dna - egg - embryo - facility - family - genome - golgi apparatus - human - insemination - life - name - nucleus - organism - part - penis - process - recombination - sexual reproduction - testicle
The answer to this question is:
testicle