Body human sex

Human Anatomy

The human body’s sex organs are what distinguish men from women.​ The reproductive process begins when spermatozoa, the male reproductive cells, enter the tubes following sexual intercourse.​ During sexual intercourse, the penis, or male sexual organ, penetrates the vagina. And just how does human sexuality differ compared to that of a bonobo towards the body's carnal desires, most sexual psychologists agree. Provisionally: 'sex' denotes human females and males depending on . Nicholson calls this 'the coat-rack view' of gender: our sexed bodies. Axis Scientific Part Deluxe Dual-Sex Human Torso Model | Detailed Life-Size Human Body Model has 27 Removable Human Organs. Provisionally: 'sex' denotes human females and males depending on . Nicholson calls this 'the coat-rack view' of gender: our sexed bodies. Human sexual activity, human sexual practice or human sexual behaviour is the manner in . Men and women experience a "sex flush" on the skin of the upper body and face. Typically, a woman's vagina becomes lubricated and her clitoris.

The relative roles of the sex chromosome genes and their expression explains As the complete DNA sequence of the human genome has now been . under the microscope as the Barr chromatin body in the nucleus of the female cells. Development of the reproductive organs and secondary sex characteristics and he may begin to wonder whether he will ever develop his body properly or be. The male body has sexual organs both inside and outside the body. The internal organs include the epididymis, vas deferens, seminal vesicles, and prostate.

The images below illustrate the male and female body parts that are body in human activity and reproduction. These body parts are also commonly referred to as genitals, reproductive organs, or sex organs.

The male body has sexual organs both inside and outside the human. The internal organs include the epididymis, vas deferens, seminal vesicles, and prostate, and the external organs include the penis and testicles. The female body has sexual organs sex inside and outside the body.

The internal organs include the fallopian tubes, ovaries, uterus, and cervix. The external organs include the vagina, body and the sex part of the vulva. Resources We use cookies to improve functionality and performance. By clicking "OK" or by continuing to browse this site, sex agree to the use of cookies. To find out more, visit the cookies human of our privacy policy.

Home Your Body The Human Body The images human illustrate the male and female body sex that are involved in sexual activity sex reproduction.

Male Body Female Body The male body has sexual body both inside and outside the body. Select the term to body more about the male body. Select the term to learn more about the female body. Human use cookies to improve functionality and performance.

In other words, the genomes of individuals may differ at some 4 to 6 million base positions. Some of these differences will lead to gene products that are functionally distinct, for example, receptors that differ in their affinity or rate of turnover, enzymes that differ in their steady-state levels, and genes that differ in their degree of hormone responsiveness. Although ongoing studies of human DNA variation will soon provide a more robust estimate, one can calculate from previous studies of enzyme variation and more recent investigations of gene variation Zwick et al.

Notwithstanding this degree of population-level variation in the DNA sequence, most of the genes in the genome are thought to not differ in either sequence or level of expression as a simple consequence of the sex of the individual. However, as will be illustrated more fully in the following sections, there are three types of genes see also Box 2—1 in which an individual's sex per se is likely to play a role.

First, genes on the Y chromosome are expressed only in males, and many of these have no counterpart on the X chromosome or autosomes; thus, expression of these genes will be limited to males.

Second, some genes on the X chromosome are expressed at higher levels in females than in males. Although the process of X-chromosome inactivation equalizes the effective dosage of most X-chromosome genes between male and female cells by inactivating one of the two X chromosomes in female cells, not all genes on the inactivated X chromosome respond to this mechanism. The relatively few genes that are not equalized can have significant effects on the phenotypes of cells.

Third, the expression of many genes is likely to be influenced by hormonal differences between the two sexes. For example, some of these may be genes whose expression is limited to sexually dimorphic tissues or cell types e. Although only a limited number of genes have been examined to date, from the standpoint of sexual dimorphism, new approaches to quantification of the expression of genes in different samples on a genomewide basis promise to change this.

Such studies will yield a large database of gene expression data. More difficult will be determination of the relative effects of differences in gene expression on the characteristic phenotypic differences seen between males and females.

Nonetheless, this new technology with DNA arrays promises to provide a comprehensive functional view of the genome in different cellular states, and studies that address differences in expression throughout the male and female genomes should reap a rich harvest.

The issue of whether there should be genetic differences in basic cellular biochemistry between female and male cells as a direct result of sex chromosome constitution rather than hormonal influences see Figure 2— 1 and Box 2—1 is often approached from two opposing perspectives. If the basic biochemistries of organisms separated by a billion years of evolution are so similar, then so goes the logic why should one expect that males and females within the same species should exhibit important differences in their basic biochemistries?

An opposing perspective acknowledges that the majority of human disease-causing mutations exhibit dominant or semidominant effects McKusick, Thus, a change in the activity of a single gene can have a large effect on the organism that carries that gene. Because the sex chromosomes comprise approximately 5 percent of the total human genome Figure 2—2 , there is the potential for 1 in 20 biochemical reactions to be differentially affected in male versus female cells.

From this standpoint, it is difficult to imagine that male and female cells will not differ in at least some aspects of basic biochemistry, given the complexity of most biological pathways. Comparison of gene contents and gene organizations on the X and Y chromosomes see text for details. The male genome differs from the female genome in the number of X chromosomes that it contains, as well as by the presence of a Y chromosome.

It is the overriding presence of a gene on the Y chromosome SRY that results in development of the male gonadal phenotype. Surprisingly, recent studies show that the Y chromosome carries some genes that are involved in basic cellular functions and that are expressed in many tissues Lahn and Page, Cytologically, the Y chromosome consists of two genetically distinct parts Figure 2—2.

The most distal portion of the Y-chromosome short arm Yp is shared with the most distal portion of the X-chromosome short arm Xp and normally recombines with its X-chromosome counterpart during meiosis in males. There is also a second pseudoautosomal region involving sequences on the distal long arms of the sex chromosomes Watson et al.

The pseudoautosomal region s reflects the role of the Y chromosome as an essential pairing homologue of the X chromosome during meiosis in males Rappold, , whereas the Y-chromosome-specific region, including the testis-determining factor gene, SRY, provides the chromosomal basis of sex determination.

The Y chromosome is one of the smallest human chromosomes, with an estimated average size of 60 million base pairs, which is less than half the size of the X chromosome. Cytologically, much of the long arm Yq is heterochromatic and variable in size within populations, consisting largely of several families of repetitive DNA sequences that have no obvious function.

A significant proportion of the Y-chromosome-specific sequences on both Yp and Yq are, in fact, homologous but not identical to sequences on the X chromosome.

These sequences, although homologous, should not be confused with the pseudoautosomal regions. Pseudoautosomal sequences may be identical on the X and Y chromosomes, reflecting their frequent meiotic exchange, whereas the sequences on Yp and Yq homologous with the Y and X chromosomes are more distantly related to each other, reflecting their divergence from a common ancestral chromosome Lahn and Page, Only about two dozen different genes are encoded on the Y chromosome although some are present in multiple copies.

Unlike collections of genes that are located on the autosomes and the X chromosome and that reflect a broad sampling of different functions without any obvious chromosomal coherence, Y-chromosome-linked genes demonstrate functional clustering and can be categorized into only two distinct classes Lahn and Page, One class consists of genes that are homologous to X-chromosome-linked genes and that are, for the most part, expressed ubiquitously in different tissues.

Some of these genes are involved in basic cellular functions, thus providing a basis for functional differences between male and female cells. For example, the ribosomal protein S4 genes on the X and Y chromosomes encode slightly different protein isoforms Watanabe et al.

The second class of Y-chromosome-linked genes consists of Y-chromosome-specific genes that are expressed specifically in the testis and that may be involved in spermatogenesis Figure 2—2. Deletion or mutation of some of these genes has been implicated in cases of male infertility, but otherwise, these genes have no obvious phenotypic effects Kent-First et al.

Male and female genomes also differ in the other sex chromosome, the X chromosome , in that females have twice the dose of X-chromosomelinked genes that males have. The X chromosome consists of approximately million base pairs of DNA about 5 percent of the total haploid genome and encodes an estimated 1, to 2, genes Figure 2—2.

By the nature of X-chromosome-linked patterns of inheritance, females can be either homozygous or heterozygous for X-chromosome-linked traits, whereas males, because they have only a single X chromosome, are hemizygous. Of those X-chromosome-linked genes known to date, most are X chromosome specific; only pseudoautosomal genes and a few genes that map outside of the pseudoautosomal region have been demonstrated to have functionally equivalent Y-chromosome homologues Willard, Products of X-chromosome-linked genes, like those on the autosomes, are involved in virtually all aspects of cellular function, intermediary metabolism, development, and growth control.

Although many are responsible for general cellular functions and are expressed widely in different tissues, others are specific to particular tissues or particular time points during development, and several are known to be responsible for steps in gonadal differentiation Pinsky et al.

The twofold difference between males and females in the dosage of genes on the X chromosome is negated at many loci by the process of X-chromosome inactivation Figure 2—3. X-chromosome inactivation is, on a cytological level, a large-scale process in which one of the two X chromosomes becomes heterochromatic. The end result of this process can be seen under the microscope as the Barr chromatin body in the nucleus of the female cells. X-chromosome inactivation is associated with extensive silencing of genes on the affected X chromosome and occurs in almost every cell of XX females but does not occur in XY males.

The one documented exception to this rule occurs, reciprocally, in reproductive cells; the single X chromosome of males becomes heterochromatic in spermatocytes, whereas both X chromosomes are thought to be active in primary oocytes. This unusual characteristic in which both X chromosomes are active in a single cell also occurs very early in the development of female embryos. Because the process of X-chromosome inactivation is not completed until near the time of implantation reviewed by Willard [] , there is a preimplantation developmental window during which there may be basic differences in cellular chemistry between female and male embryos.

It is unknown whether the differences in gene expression that have been shown to occur Gutierrez-Adan et al. Schematic representation of X-chromosome inactivation in female somatic cells. Inactivation early in development is believed to be random, with an equal probability a priori that the maternal or paternal X chromosome will be active or inactive. Females more In any case, the simple fact of X-chromosome inactivation leads to two levels of difference between males and females.

The first is that XX cells must operate whatever cellular machinery is required to initiate and establish the inactivation of an X chromosome in all mitotically active cells and also perhaps to actively maintain the inactive state of one X chromosome in terminally differentiated cells first.

There has been substantial recent progress in understanding the biochemistry and molecular biology of the X-chromosome inactivation process.

These advances have been described in detail in several recent reviews Heard et al. Although some of the genes in the X-chromosome inactivation pathway may be expressed at some level or at some time in males Daniels et al. Here, then, is a basic biochemical process that is a fundamental consequence of having two X chromosomes. The biochemical results of the process can be measured and quantified in the tissues of individual females or in cells in culture dishes.

The process affects genes that are involved in many important metabolic processes as well as genes that are known to be important in the regulation of expression of other genes Amir et al. Because there is a stochastic or random component in the choice of which of the two X chromosomes is inactivated Puck and Willard, , individual females have two epigenetically distinct populations of cells: those in which the maternally derived X chromosome remains active and those in which the paternally derived X chromosome remains active Figure 2—3.

By contrast, males have only an active maternally derived X chromosome in all of their cells. This X-chromosome-based, female-specific mosaicism is often invoked as the reason for much of the dramatic sex differences observed in the severities of recessive X-chromosome-linked disease phenotypes McKusick, All cells of XY males must suffer the consequences of a mutation in an X-chromosome-linked gene, but only that fraction of a female's cells that carry the mutation on the active X chromosome will be affected.

Such situations have resulted, in some cases, in strong somatic selection against cells that bear the mutation on the active X chromosome and thus avoidance or minimization of the disease phenotype Belmont, ; Willard, It should be noted that the stochastic nature of the initial choice of which X chromosome to inactivate can be influenced by many factors. Environmental, epigenetic, and genetic factors have all been demonstrated to influence the X-chromosome inactivation pattern the proportion of a female's cells with a designated active X chromosome of individual females Puck and Willard, The relative importance of each may be different in different individuals, to the extent that all sisters within an individual family may show nearly identical patterns of X-chromosome inactivation, whereas identical twins in other families may exhibit wide variations in the proportions of their cells that have one or the other active X chromosome.

Not all of the genes on the X chromosome respond to the inactivation process by transcriptional silencing Willard, This fact may lead secondarily to biochemical differences between XX cells and XY cells. Some of these are transcribed from both the active and the inactive X chromosome at similar levels, whereas others appear to be transcribed from the inactive X chromosome at reduced, but still significant, levels Carrel and Willard, ; Fisher et al.

Regardless of the level at which such genes escape X-chromosome inactivation, it is likely that XX cells will produce higher levels of gene product from some of these loci than XY cells will. It has been suggested that some of these differences may lead to sex-specific levels of risk for certain diseases, such as the suspected relationship between gastrin-releasing peptide receptor and smoking-related lung cancer Shriver et al.

Gastrin-releasing peptide is expressed by both the active and the inactive X chromosomes, and elevated levels of gastrin-releasing peptide are hypothesized to be associated with an elevated risk of lung cancer in women who smoke.

An interesting genomic consideration resulting from the study of genes that escape X-chromosome inactivation is that their distribution along the X chromosome is not random. A higher proportion of the genes on the short arm of the X chromosome than on the long arm of the X chromosome escape X-chromosome inactivation Carrel et al.

This issue may reflect the different evolutionary histories of the X-chromosome arms Lahn and Page, but may also be related to whether particular X-chromosome-linked genes have homologues on the Y chromosome Jegalian and Page, It is of some interest that the particular genes that escape inactivation appear to differ among different females Carrel and Willard, , thus providing additional avenues for differences between and within the sexes.

It is unknown whether there are significant population variations in patterns of inactivation and thus X-chromosome-linked gene expression. In general, the possible effect s of any variant in an X-chromosome-linked gene may differ between the sexes for a variety of reasons, as outlined below.

The incidence of a number of diseases whose etiologies cannot be traced to the sex chromosomes differ dramatically between males and females McKusick, Although the basis for these differences in incidence is most often ascribed to hormonal influences, the possibility that other genetic differences are at fault cannot be discounted.

Because autosomes are transmitted equally to both sexes, it is not predicted that inheritance of imprinted genetic information on the autosomes should have a differential effect on male versus female offspring. The situation is different for sex chromosomes. Imprinting-related differences between the sexes do exist for the X chromosome. Males have only a maternal X chromosome, but females have both a maternal X chromosome and a paternal X chromosome; therefore, X-chromosome-linked genes that pass through the paternal germ line have the potential to affect the phenotype of female offspring but not that of male offspring.

In this regard, there is direct evidence that the imprinting process affects the expression of alleles in females at the Xist locus a gene that is critical to the process of X-chromosome inactivation and that is expressed primarily from the paternal allele in some extraembryonic cells in females reviewed by Lyon [].

There is also indirect evidence that imprinting affects the expression of a locus on Xp that has female-specific effects on cognitive and behavioral phenotypes.

The latter evidence is derived from studies of patients with Turner syndrome, who have inherited only one X chromosome XO from either the mother or the father Skuse et al. These findings may have broader implications for cognitive function or behavior in males and females because males inherit only a maternal X chromosome, whereas females inherit both a maternal X chromosome and a paternal X chromosome.

Although the basic mechanism of meiosis, the creation of haploid gametes from diploid precursors, is universal, there are both quantitative and qualitative differences between males and females in the production of gametes. These differences have characteristic effects on the ways that males and females drive the evolutionary process, as well as the mechanisms by which diseases that result from genetic defects are manifest.

BDSM is a variety of erotic practices or roleplaying involving bondage , dominance and submission , sadomasochism , and other interpersonal dynamics. Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture is usually dependent on self-identification and shared experience. BDSM communities generally welcome anyone with a non-normative streak who identifies with the community; this may include cross-dressers , extreme body modification enthusiasts, animal players , latex or rubber aficionados , and others.

Bondage includes the restraint of the body or mind. A submissive is someone who gives up the control to a person who wishes to take control.

Masochism means an individual who takes pleasure from their own pain or humiliation. Unlike the usual "power neutral" relationships and play styles commonly followed by couples, activities and relationships within a BDSM context are often characterized by the participants' taking on complementary, but unequal roles; thus, the idea of informed consent of both the partners becomes essential.

Participants who exert sexual dominance over their partners are known as dominants or tops , while participants who take the passive, receiving, or obedient role are known as submissives or bottoms. Individuals are also sometimes abbreviated when referred to in writing, so a dominant person may be referred to as a "dom" for a man or a woman. Sometimes a woman may choose to use the female specific term "Domme". Both terms are pronounced the same when spoken. The precise definition of roles and self-identification is a common subject of debate within the community.

In a study, the researchers state that BDSM is a sexual act where they play role games, use restraint, use power exchange, use suppression and pain is sometimes involved depending on individual s. According to the findings, one who participates in BDSM may have greater strength socially and mentally as well as greater independence than those who do not practice BDSM.

Before any sexual act occurs, the partners must discuss their agreement of their relationship. They discuss how long the play will last, the intensity, their actions, what each participant needs or desires.

The sexual acts are all recorded as consensual and pleasurable to both parties. In a study, interviewed BDSM participants have mentioned that the activities have helped to create higher levels of connection, intimacy, trust and communication between partners. The participants have remarked that they enjoy pleasing their partner in any way they can and many surveyed have felt that this is one of the best things about BDSM.

It gives a submissive pleasure to do things in general for their dominant. Where a Dominant enjoys making their encounters all about the submissive.

They enjoy doing things that makes their submissive happy. The findings indicate that the surveyed submissives and dominants found BDSM play more pleasurable and fun. The participants have also mentioned improvements in their personal growth, romantic relationships, sense of community and self, the dominant's confidence, and their coping with everyday things by giving them a psychological release. There are many laws and social customs which prohibit, or in some way affect sexual activities.

These laws and customs vary from country to country, and have varied over time. They cover, for example, a prohibition to non-consensual sex, to sex outside marriage, to sexual activity in public, besides many others.

Many of these restrictions are non-controversial, but some have been the subject of public debate. Most societies consider it a serious crime to force someone to engage in sexual acts or to engage in sexual activity with someone who does not consent. This is called sexual assault , and if sexual penetration occurs it is called rape, the most serious kind of sexual assault.

The details of this distinction may vary among different legal jurisdictions. Also, what constitutes effective consent in sexual matters varies from culture to culture and is frequently debated. Laws regulating the minimum age at which a person can consent to have sex age of consent are frequently the subject of debate, as is adolescent sexual behavior in general.

Some societies have forced marriage, where consent may not be required. Many locales have laws that limit or prohibit same-sex sexual activity. In the West, sex before marriage is not illegal [ example needed ]. There are social taboos and many religions condemn pre-marital sex. Those found guilty, especially women, may be forced to wed the sexual partner, publicly beaten, or stoned to death.

Other studies have analyzed the changing attitudes about sex that American adolescents have outside marriage. Adolescents were asked how they felt about oral and vaginal sex in relation to their health, social, and emotional well-being. Overall, teenagers felt that oral sex was viewed as more socially positive amongst their demographic. The laws of each jurisdiction set the minimum age at which a young person is allowed to engage in sexual activity.

In many jurisdictions, age of consent is a person's mental or functional age. Age of consent may vary by the type of sexual act, the sex of the actors, or other restrictions such as abuse of a position of trust. Some jurisdictions also make allowances for young people engaged in sexual acts with each other.

Most jurisdictions prohibit sexual activity between certain close relatives. These laws vary to some extent; such acts are called incestuous. Non-consensual sexual activity or subjecting an unwilling person to witnessing a sexual activity are forms of sexual abuse , as well as in many countries certain non-consensual paraphilias such as frotteurism , telephone scatophilia indecent phonecalls , and non-consensual exhibitionism and voyeurism known as " indecent exposure " and " peeping tom " respectively.

People sometimes exchange sex for money or access to other resources. Work takes place under many varied circumstances. The person who receives payment for sexual services is called a prostitute and the person who receives such services is known by a multitude of terms, including and most commonly "john. The legal status of prostitution varies from country to country , from being a punishable crime to a regulated profession. Survival sex is a form of prostitution engaged in by people in need, usually when homeless or otherwise disadvantaged people trade sex for food, a place to sleep, or other basic needs , or for drugs.

From Wikipedia, the free encyclopedia. This is the latest accepted revision , reviewed on 30 November This article is about sexual practices and related social aspects. For broader aspects of sexual behaviour, see Human sexuality. For sexual behaviour of other animals, see Animal sexual behaviour. Human behaviour which is sexually motivated. For the American rock band, see Pity Sex. The examples and perspective in this section may not represent a worldwide view of the subject.

You may improve this section , discuss the issue on the talk page , or create a new article , as appropriate. June Learn how and when to remove this template message. See also: Sexually active life expectancy. Further information: Adolescent sexuality. Main article: Unintended pregnancy. Main article: Sexually transmitted infection.

See also: Sexuality in older age. Main article: Sexual orientation. Main article: Heterosexuality. Main article: Homosexuality. See also: Gay sexual practices and Lesbian sexual practices. Main articles: Bisexuality and Pansexuality. Main articles: Sexual morality , Religion and sexuality , and Norm sociology. Khajuraho Hindu and Jain temple complex is famous for erotic arts. Main article: BDSM. Main article: Sex and the law. Main article: LGBT rights by country or territory.

Main article: Age of consent. This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. Main article: Legality of incest. Main articles: Sexual abuse , Rape , and Sexual assault. Main article: Prostitution.

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