Blue 3D Gradient Thesis Defense Presentation

[Audio] Welcome everyone! Today we are here to explore the topic of sexual differentiation in humans. We will discuss how genetics and the S-R-Y master gene play a role in the process. It's sure to be a fascinating and informative discussion so let's get started..

[Audio] Sexual differentiation is the process in which biological differences between male and female arise. This involves the development of all distinguishing traits that make us male or female from genetic compositions to physical frameworks. This process is vital in allowing humans to reproduce and keep the species alive..

[Audio] Genetically humans are distinguished by the presence or absence of the Y chromosome. Most mammals have two sex chromosomes but humans and other primates possess only one. Both sexes possess an X chromosome however the Y chromosome is found only in males. This is the reason males have an XY genotype and females have an XX genotype..

[Audio] Humans experience sexual differentiation that is determined by the Y chromosome and the X chromosome. The gene S-R-Y on the Y chromosome is thought to be the main contributor to male sex while the X chromosome has additional genes that are involved in sex determination. The X chromosomes in females are usually inactive but one is active. This phenomenon explains the disparities between males and females..

[Audio] The S-R-Y gene located on the Y chromosome is responsible for male development. It encodes the sex-determining region Y protein which binds to certain regions of D-N-A and activates the necessary genes for the growth of testes. Testosterone and A-M-H hormones are consequently secreted to coordinate the formation of male reproductive organs and external genitalia..

[Audio] At slide six sexual differentiation in humans is discussed. Genes are activated to decide if the gonads become the testes or the ovaries. The testes produce testosterone and anti-Müllerian hormone which guide the development of other male reproductive organs and external genitalia..

[Audio] In human sexual differentiation all embryos begin with the same sex organs regardless of their genetic makeup. At around week 5 or 6 two sets of internal structures form in the embryo. These are the mesonephric ducts which have the potential to become the male reproductive organs and the paramesonephric ducts which have the potential to become the female reproductive organs. This is how the embryo begins the journey to becoming either male or female..

[Audio] "As we can observe from this slide embryos with XY chromosomes have the S-R-Y gene which triggers the development of testes and releases hormones. On the other hand embryos with XX chromosomes don't have the S-R-Y gene and because of this lack of hormonal signals the mesonephric ducts regress while the paramesonephric ducts develops into the female reproductive system. This is how sexual differentiation takes place..

[Audio] One of the most important aspects of human sexual differentiation is the development of the reproductive system. During embryological development certain hormones determine the formation of either male or female sex organs. These hormones are responsible not only for external organs but also for internal structures such as the uterus and testes. As the fetus grows the reproductive system will eventually be formed and ready to produce the gametes—the reproductive cells that will eventually come together to form a fertilized egg..

[Audio] The topic of discussion is Sexual Differentiation in Human. The human body consists of two accessory ducts: the mesonephric ducts and the paramesonephric ducts. The mesonephric ducts are the precursor to the male genitalia while the paramesonephric are the precursor to the female reproductive system. Additionally internal genital differentiation is also a decisive factor in sexual differentiation..

[Audio] At 8 to 12 weeks androgens enlarge the phallus and the urogenital groove and sinus fuse in the midline producing an ambiguous penis. This differentiation continues into puberty when male levels of testosterone directly induce growth of the penis and indirectly through the action of dihydrotestosterone. Additionally the paramesonephric duct's regression is caused by another substance..

[Audio] S-R-Y gene is an essential factor in deciding an individual's sex. For a baby with two X chromosomes the gene is absent. This causes the paramesonephric ducts to form uterus Fallopian tubes and upper vagina. Conversely in embryos with XY chromosomes SRY gene initiates the development of testes. These testes will produce testosterone and anti-Müllerian hormone. These hormones are important for the formation of male reproductive organs external genitalia and also halt the growth of female reproductive organs..

[Audio] Sexual differentiation in humans is controlled by the S-R-Y gene located on the Y chromosome. This gene is responsible for the development of testes in males and the lack of this gene results in the development of ovaries in females. The testes and ovaries then produce hormones which lead to the formation of internal and external genitalia..

[Audio] Sexual differentiation in humans is an interesting process largely determined by hormonal influence. The S-R-Y gene on the Y chromosome triggers male sex differentiation encouraging the growth of testes which produce testosterone leading to the development of male genitalia as well as anti-Müllerian hormone (A-M-H--). Testosterone is responsible for the male external genitalia while A-M-H promotes the regression of the Müllerian ducts. D-H-T another androgen is also involved in the development of the male external genitalia..

[Audio] Sexual differentiation in humans is a complex process. When the S-R-Y gene is absent the gonads develop into ovaries which do not secrete hormones such as testosterone and anti-müllerian hormone. This stimulates the growth of müllerian ducts forming female internal genitalia including Fallopian tubes uterus and the upper vagina. At the same time the mesonephric ducts diminish and finally development of external genitalia marks the completion of the process..

[Audio] Though there are physical differences between men and women that become more obvious with age there is also a psychological and behavioral divergence that can be attributed to biological and learned factors. Secondary sexual characteristics like breast development are caused by hormones during puberty. Furthermore psychological and behavioral sex differences can be seen cross-culturally which are a result of both biological and learned influences..

[Audio] Sex is a complex phenomenon that involves biological psychological and social elements. This presentation will explore the various variations associated with the process of determining and differentiating sex. For instance a zygote with a single X chromosome (X-O---) can lead to Turner Syndrome causing the individual to possess female physical characteristics. Congenital adrenal hyperplasia may result in the overproduction of testosterone which will cause 46XX females to exhibit more male traits. Furthermore persistent Mullerian duct syndrome is a rare form of pseudohermaphroditism among 46XY males; this condition is caused by a mutation either in the Mullerian inhibiting substance or in its type two receptor..

[Audio] This slide focuses on sexual differentiation in humans and examines three different disorders of sexual development: male pseudohermaphroditism Swyer syndrome and 5-alpha-reductase deficiency. Male pseudohermaphroditism is caused by either inadequate androgen production or an inability to respond correctly to androgen leading to incomplete masculinization in XY males. Swyer syndrome is a type of complete gonadal dysgenesis caused in most cases by S-R-Y gene mutations which play a major role in determining sex. 5-alpha-reductase deficiency is an androgen disorder that can result in a female phenotype or a severely undervirilized male phenotype that is characterized by the development of the epididymis vas deferens seminal vesicle and ejaculatory duct as well as a pseudovagina..

Male pseudohermaphroditism - failure of androgen production or inadequate androgen response, which can cause incomplete masculinization in XY males. Swyer syndrome - a form of complete gonadal dysgenesis, mostly due to mutations in the first step of sex determination; the SRY genes. A 5-alpha-reductase deficiency results in an androgen disorder characterized by female phenotype or severly undervirilized male phenotype with development of the epididymis, vas deferens, seminal vesicle, and ejaculatory duct, but also a pseudovagina..

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