11 Unexpected Facts About the Reproductive Program

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The vagina has something in common with tomatoes: they’re both ac

Tomatoes are quite acidic, with a pH that varies between 4. zero and 4. 7 (7 is considered neutral), according to the Food and Drug Administration. The pH of the vagina averages four. 5.

How could the genitals so acidic?

The vagina is home to several microorganisms that could thrive simply in an acidic environment, including the lactic acid-producing bacteriaLactobacillus. Without these helpful bacteria ranking guard, other pathogenic (disease-causing) bacteria can move in and take over the vaginal environment.

Ancient Egyptians used contraception thousands of years in the past

You might think contraception is a fresh invention, but birth control may well have got its commence nearly 5, 000 yrs ago, according to a 2011 content in the Diary of Family Planning and Reproductive Health Care.

The earliest created record of contraception comes from the Egypt Kahun Gynaecological Papyrus, which dates back to 1825 N. C. A single birth control approach mentioned in the document needed a doctor to apply honey to the inside of the vaginal area while the woman lay on the bed of sodium carbonate.

Another birth control method technique involved crocodile muck, which may have already been packed up against the cervix or perhaps burned as an incense (the text message is unclear on the manure’s exact use).

Ovarian ageing

Because women age group, they encounter a decline in reproductive : performance resulting in menopause. This kind of decline is definitely tied to a decline in the number of ovarian follicles. Although about 1 million oocytes are present when they are born in the human being ovary, no more than 500 (about 0. 05%) of these ovulate, and the relax are wasted. The drop in ovarian reserve appears to occur by a continuously increasing charge with grow older, and leads to nearly complete fatigue of the book by about era 52. As ovarian hold and fertility decline with age, additionally there is a parallel increase in pregnancy failure and meiotic errors resulting in chromosomally irregular conceptions. [medical quotation needed]

Women with an inherited mutation in the DNA repair gene BRCA1 undergo menopause prematurely, suggesting that naturally occurring DNA damages in oocytes are repaired less efficiently in these women, and this inefficiency leads to early reproductive failure. The BRCA1 protein plays a key role in a type of DNA repair termed homologous recombinational repair that is the only known cellular process that can accurately repair DNA double-strand breaks. Titus et al. showed that DNA double-strand breaks accumulate with age in humans and mice in primordial follicles. Primordial follicles contain oocytes that are at an intermediate (prophase I) stage of meiosis. Meiosis is the general process in eukaryotic organisms by which germ cells are formed, and it is likely an adaptation for removing DNA damages, especially double-strand breaks, from germ line DNA. (see Meiosis and Origin and function of meiosis). Homologous recombinational repair is especially promoted during meiosis. Titus et al. also found that expression of 4 key genes necessary for homologous recombinational repair of DNA double-strand breaks (BRCA1, MRE11, RAD51 and ATM) decline with age in the oocytes of humans and mice. They hypothesized that DNA double-strand break repair is vital for the maintenance of oocyte reserve and that a decline in efficiency of repair with age plays a key role in ovarian aging.

Some animals have very strange reproductive systems

The internal body systems of animals are often similar to ours, but there’s a remarkable variation in reproductive systems in the animal kingdom.

For example, female kangaroos have three vaginas. The two lateral vaginas are used for accepting sperm during mating, and the central vagina is used for birthing. Male kangaroos have a two-pronged penis to inseminate the lateral vaginas.

Most birds, on the other hand, don’t have penises or vaginas. Both sexes have what’s called a cloaca it’s a single orifice used for waste and reproduction.

The reproductive system contains the largest and smallest human cells

Human cells come in a variety of shapes and sizes, and carry out a wide range of different functions. But the largest and smallest cells in the human body are both gametes, or reproductive cells.

Males produce the smallest human cell the sperm, which is only 5 micrometers by 3 micrometers in size, not including the sperm’s tail. By comparison, the red blood cell is about 8 micrometers in diameter, or about a tenth of the diameter of a human hair.

A female’s ovum, or egg, is the largest human cell, coming in at about 120 micrometers in diameter.


The Vespidae family is currently classified into six subfamilies that are apparently monophyletic: Euparagiinae, Masarinae, Eumeninae, Stenogastrinae, Vespinae, and Polistinae (Carpenter 1991). The molecular phylogeny of Vespidae and the evolution of sociality in wasps supported closer phylogenetic relationships of Eumeninae to Polistinae + Vespinae than to Stenogastrinae, from which they concluded that social behavior has independently evolved twice in the wasp family Vespidae (Schmitz and Moritz 1998). Analysis of the realigned sequences also supports monophyly of Vespidae, as well as monophyly of social wasps, with the Stenogastrinae being more closely related to Polistinae + Vespinae than are Eumeninae (Carpenter 2003).

In the subfamily Polistinae Polistes has about 200 species distributed throughout the world mostly in the tropical region (Richards 1978; Gauld and Hanson 1995). This genus has been widely studied and is considered the key genus for understanding evolution of the social insects and social behavior among wasps (Evans 1959; Schmitz and Moritz 1998; Carpenter 2003).

The reproductive system in males of Hymenoptera demonstrates considerable morphological differences among the species. Such differences may be related to the presence or absence and size or shape of structures, as well as its position along the reproductive tract (Dirks and Sternburg 1972; Dallacqua and Cruz-Landim 2003; Ferreira et al. 2004; Araet al. 2005a; Bushrow et al. 2006; Moreira et al. 2008). Sperm morphology has revealed a considerable number of features that differ among taxa (Araet al. 2005b; Brito et al. 2005; Zama et al. 2007; Lino-Neto et al. 2008a; Mancini et al. 2006, 2008), indicating another possible source of characters that may contribute to understanding the systematics of these insects.

In insects, germ cell development of males generally occur in compartments, called cysts. These cysts are found inside tubules or testicular follicles and are formed by clones of germ cells surrounded by a layer of non-germ epithelial cells (Baccetti and Bairati 1964). During spermatogenesis, the spermatogonia undergo mitotic divisions that generate a constant number of cells in each cyst. After two meiotic divisions, these cells become spermatids (Lindsley and Tokuyasu 1980; Oguma and Kurokawa 1984; Cruz-Landim 2001; Lino-Neto et al. 2008b). Each species has a particular number of spermatids inside the cyst, which is expressed as 2n, where n is usually equal to 5, 6, 7 or 8.

The number of spermatids/spermatozoa per cyst, which is determined by the number of cell divisions, is constant for each species, but may vary from species to species. Thus, this number has been used as additional information in the systematics of Hymenoptera (Schiff et al. 2001; Zama et al. 2007; Lino-Neto et al. 2008a).

Variation in the morphology of the reproductive system in males of Polistes was observed between European (Bordas 1895) and North American species (Dirks and Sternburg 1972). In the present work, the morphology of the male reproductive system, the spermatozoa and the number of spermatozoa per cyst were described for Polistes versicolor versicolor Oliver (Vespidae: Polistini). The aim is to contribute to knowledge of the male reproductive biology and also to reveal characters that may be useful for future studies in taxonomy and phylogeny of Hymenoptera, especially within Aculeata.

Infertility is more common than you may think

In medicine, a couple is considered infertile if they are unable to become pregnant after a year of unprotected sex. In the United States, almost 1 in 6 adult couples are infertile, according to a 2013 study in the journal Fertility and Sterility. The study did not look at whether a couple’s infertility was more likely to be due to fertility problems in the man or the woman.

But infertility is not on the rise. In fact, research shows that infertility rates among women have dropped over the last three decades.

Men have vastly more gametes than women

A huge difference exists between the number of gametes men and women produce. At birth, women have 1 million to 2 million eggs, but only about 300,000 eggs will be left by the time puberty hits, according to WebMD. Only 300 to 400 of these eggs will be ovulated before menopause.

Each man, on the other hand, produces more than 500 billion sperm cells in his lifetime. During ejaculation, a healthy man can release upward of about 1.2 million sperm cells that’s more gametes released in a single moment than some woman ever have.

Gamete production

The ovaries are the site of production and periodical release of egg cells, the female gametes. In the ovaries, the developing egg cells (or oocytes) mature in the flu >#@@#@!: 833

When the oocyte finishes its maturation inside the ovary, an outburst of luteinizing hormone secreted by the pituitary gland stimulates the release from the oocyte throughout the rupture with the follicle, a process called after. The follicle is still functional and reorganizes into a corpus luteum, which secretes progesterone to be able to prepare the uterus pertaining to an ultimate implantation in the embryo. #@@#@!: 839


Variation inside the morphology of the adult man reproductive program among several groups of Hymenoptera offer characteristics that help studies of behavior plus the evolutionary history of this group. The purpose of this analyze was to describe the mature male reproductive system of the waspPolistes versicolor versicolorOlivier (Vespidae: Polistini). The reproductive devices were examined, fixed and embedded to get light microscopy. InP. sixth is v. versicolor, the reproductive : system features a pair of copie, each one particular with three fusiform hair follicles. From every follicle comes forth an efferent duct that later become a member of together, building a deferent duct. The first half of the deferent duct is increased and differentiated into a area specialized pertaining to sperm storage, the seminal vesicle. In the post-vesicular area of each with the deferent system an item gland emerges. The seminal vesicle plus the accessory gland are protected with a tablet forming a vesicle-gland sophisticated, also seen in some types of North AmericanPolistes. Sperm happen to be released by testes in bundles, that are disorganized inside seminal vesicles. In the testicular follicles, 95 spermatozoa had been observed every cyst usually.


The male reproductive system ofS. v. versicolorconsists of a pair of souffrance, each with three fusiform follicles ( Figures 1A). Three follicles will be covered by an individual capsule and therefore are entirely filled up with cysts ( Figure 1C ). Every cyst provides up to 96 spermatozoa usually ( Physique 1D ), indicating that, in least half a dozen mitotic cycles occur. During spermatogenesis, the cysts get started migrating along the follicles whilst they continue to differentiate. When the spermatozoa are completely older, the vulgaris break open. The unveiled bundles of spermatozoa (spermatodesmata) remain with each other, held by extracellular material that surrounds the informe portion of their particular heads ( Figure 1E ). The spermatodesmata migrate to the efferent duct ( Figure 1E ), pass into the deferent duct, and they are transferred to the seminal vesicles, where they may be disorganized ( Figures 1F).

Photomicrograph of the structure (Aand histology (Cof the reproductive system of menPolistes vesicolor.A.Reproductive : system showing the examen (T), seminal vesicles (sv) and equipment glands (g) separated by the broken series, deferent duct (dd) as well as the ejaculatory duct andB.showing the follicles (F) and the vesicle-gland complex engaged by a single capsule (circle of broken lines).C.Transverse area of the souffrance showing 6 testicular hair follicles (F) and the testicular capsule (arrow).D.Inset: a cyst with 95 spermatozoa.At the.Longitudinal section of a follicle (F), where the package of spermatozoa (arrow) is definitely observed released from the hair follicles (F) to the efferent duct (ed).F.Transverse area of the seminal vesicle demonstrating the thick muscular layer (m), the epithelium (ep) and the lumen (L) with spermatozoa.G.Detail in the seminal vesicle’s wall showing the epithelium comprising refractive cells with spherical and basal nuclei (white arrow) and at the apical third, some vesicular inclusions (circle of broken lines); the epithelium is usually separated from your external buff layer (m) by a thicker basal membrane layer (black arrow).They would.Longitudinal section of the accessory gland (g) and seminal vesicle (sv).I.Transverse portion of the accessory gland completely filled with secretions (black arrow). Note the epithelium with basal nuclei (white arrow). Bars: A and W = five-hundred C, F and I = one hundred and fifty G = five Elizabeth, G, They would and L = 55 Superior quality figures can be obtained online.

The center portion of the deferent duct is bigger and gives a modified epithelium getting transformed into a seminal vesicle ( Physique 1F ). The accessory glands connect to the beginning of the post-vesicular deferent ducts. The seminal vesicle and the item gland are surrounded by a single layer of conjunctive tissues or capsule, forming the vesicle-accessory sweat gland complex ( Figures 1A).

The epithelium with the seminal vesicle consists of prismatic cells with spherical, essentiel nuclei. Inside the apical third of these cells, some vesicular inclusions ( Figure 1G ) may be observed. In mature men, the vesicular lumen is completely filled with spermatozoa. The epithelium is segregated from the external muscular part by a solid basal membrane layer ( Statistics 1F).

The equipment glands happen to be oval ( Figures 1H), and the epithelium consists of prismatic cells with spherical and fondamental nuclei and large secretory vesicles in the apical cell portion ( Statistics 1I and and2A). 2A ). The lumen is filled with granular secretions ( Figures 1H).

Afrom the male reproductive : system ofPolistes vesicolor.Din the spermatozoa along with the nucleus stained with DAPI, respectively.A.Longitudinal section through the region with the insertions of the deferent system (dd) in to the accessory gland (g). Be aware the difference between the epithelium with the deferent duct (dd), demonstrating basal and spherical nuclei (arrow), as well as the striated edge (arrowhead) as well as the epithelium with the accessory sweat gland (g) with several secretory vesicles with the apical part (circle of broken lines).N.Slanted section of the deferent system (dd) demonstrating the striated border (arrow).C.Transverse section of the ejaculatory duct (ej), displaying the cuticle (arrow).D.Photomicrograph with the spermatozoon.E.Head place, stained with DAPI. Pubs: A and D sama dengan 10 B and C sama dengan 25 E sama dengan 5 High quality statistics are available on the web.

The deferent duct epithelium is formed by simply cubical cells with a pretty evident striated border ( Figures 2A). The deferent duct opens into the ejaculatory duct, whose epithelium, consisting of cubical cells, is totally covered by a skinny cuticle ( Figure 2C ).

The spermatozoa ofG. v. vesicolormeasure about 128 long ( Number 2D ), and the center is about 17 long ( Figure 2E ).

Light microscopy

For the histological evaluation, the reproductive systems of six men were fixed for 12 h in 2 . five per cent glutaraldehyde in 0. 1 M sodium cacodylate stream, pH several. 2, and post-fixed in 1% osmium tetroxide. The material was dehydrated in increasing alcohol concentrations and stuck in Historesin(GMA, Leica, www.leica-microsystems.com). Semithin sections were stained with 1% salt toluidine borate and installed in Entelan(Merck, www.merck.com). The analysis and photographic records were created with an Olympus BX60 (www.olympus.com) microscope.

Suspensions of spermatozoa removed from the seminal vesicles of six men were propagate on clean glass microscope slides, that were fixed pertaining to 20 mins in a answer of 4% (w/v) paraformaldehyde in 0. 1 Meters sodium phosphate buffer, ph level 7. 2 . After blow drying at area temperature, 75 randomly discovered spermatozoa had been photographed within a photomicroscope (Olympus, BX60) furnished with phase comparison.

For elemental measurements, half a dozen slides of different males had been stained intended for 15 minutes with 0. 2 5, 6-diamino-2-phenylindole (DAPI) in PBS, washed and mounted in 50% sucrose. They were then examined using an epifluorescence microscope (Olympus, BX60) built with a BP 360nm excitation filter, and 100 nuclei had been randomly took pictures of. All the procedures were acquired with the Graphic Pro-Plussoftware, version some. 5 (Media Cybernetics Incorporation., www.mediacy.com), and the lengths were related to the overall number of spermatozoa analyzed.

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