Blue 3D Gradient Thesis Defense Presentation

:. SEXUAL DIFFERENTIATION IN HUMAN. PRESENTED BY : BOLO, JOHN LLOYD CONSON, VINCE CHRISTIAN INFANTADO, RONALYN MEJIAS, JOSHUA QUIBEL, KENNETH TORRENTIRA, JAYNARD.

WHAT IS SEXUAL DIFFERENTIATION?. Introduction Sexual differentiation is the process by which the anatomical and physiological differences between males and females develop from an undifferentiated zygote..

Chromosomes play a major role in determining an individual's genetic sex. Here's a breakdown: Sex Chromosomes: Two of our chromosomes, called the X and Y chromosomes, are different from the others and are known as sex chromosomes. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY)..

The Y Chromosome's Role: The Y chromosome carries a special gene called SRY (Sex-determining Region Y). This gene plays a key role in triggering the development of testes in males. In the absence of a Y chromosome (or a non-functioning SRY gene), the embryo develops ovaries by default. X Chromosomes: While the Y chromosome holds the key for male development, X chromosomes also contain genes important for sex determination and development. However, females with two X chromosomes typically only have one active X chromosome per cell due to a process called X-chromosome inactivation..

Master Switch: In the presence of a Y chromosome (XY), the SRY gene acts as a master switch that initiates the cascade of events leading to male sex development..

Testes on the Rise: These activated genes promote the development of testes from the initially undifferentiated gonads..

Mesonephric ducts: These have the potential to become the vas deferens, epididymis, and other parts of the male reproductive system. Paramesonephric ducts: These hold the potential to develop into the fallopian tubes, uterus, cervix, and upper vagina in females..

XY Chromosomes and the SRY Gene: If the embryo has XY chromosomes, a gene called SRY on the Y chromosome triggers the development of testes. The testes then release hormones that cause the mesonephric ducts to flourish and the paramesonephric ducts to regress..

Differentation between the sexes of the sex organs occurs throughout embyrological, fetal,and later life. This includes both internal and external genital differentiation. These are the organs that produce gametes(egg and sperm), the reproductive cells that will eventually meet to form the fertilized egg (zygote)..

Consist of two accessory ducts: mesonephric ducts (male) and paramesonerphic ducts (female). The mesonephric system is the precursor to the male genitalia and the paramesonephric to the female reproductive system..

EXTERNAL GENITAL DIFFERENTIATION. Males become externally distinct between 8 and 12 weeks, as androgens enlarge the phallus and cause the urogenital groove and sinus to fuse in the midline, producing an ambiguous penis with a phallic urethra, and a thinned, rugated scrotum. Further sex differentiation of the external genitalia occurs at puberty, when androgen levels again become disparate. Male levels of testosterone directly induce growth of the penis, and indirectly (via DHT). Alfred Jost observed that while testosterone was required for mesonephric duct development, the regression of the paramesonephric duct was due to another substance..

The SRY gene plays a critical role in hormonal influence during sex differentiation. In embryos with XY chromosomes, the SRY gene flips the switch on testes development. These testes become the factories for two key hormones: Testosterone: This hormone acts as the "masculine fuel," stimulating the development of the mesonephric ducts into the vas deferens, epididymis, and other male reproductive structures. It also influences the development of male external genitalia.Testosterone causes the development of the male reproductive organs (wolffian ducts) and male external genitalia. Anti-Müllerian hormone (AMH): This hormone acts like a bully towards the paramesonephric ducts in males. AMH causes the regression of the paramesonephric ducts..

The SRY gene on the Y chromosome is responsible for testis development in males. In females, the absence of the SRY gene leads to the development of ovaries. Ovaries do not produce AMH, so the paramesonephric ducts develop into the female reproductive organs. The wolffian ducts regress in females. The hormones produced by the testes and ovaries cause the development of the internal and external genitalia..

HORMONAL INFLUENCE. Male sex differentiation The SRY gene on the Y chromosome triggers the development of testes. Testes produce testosterone and anti-Müllerian hormone (AMH). Testosterone causes the development of the male internal and external genitalia, including the epididymis, vas deferens, seminal vesicles, penis, and scrotum. AMH causes the regression of the Müllerian ducts, which would otherwise develop into the female internal genitalia. Androgens, including testosterone and DHT, cause the development of the male external genitalia..

Female sex differentiation In the absence of SRY, the gonads develop into ovaries. Ovaries do not produce testosterone or AMH. Müllerian ducts develop into the female internal genitalia, including the uterus, Fallopian tubes, and upper vagina. Mesonephric ducts regress. External genital differentiation.

Secondary Sexual Characteristics Breast- visible differentiation occurs at puberty, when estradiol and other hormones cause breasts to develop in typical females. Psychological and Behavioral Differentiation - human adults and children show many psychological and behavioral sex differences. Some are learned and obviously cultural. Others are demonstrate across cultures and have both biological and learned determinants..

Intersexual Variations .Following variations are associated with atypical determination and differentiation process: A zygote with only X chromosome (XO) results in Tuber syndrome and will develop with female characteristics. Congenital adrenal hyperplasia - Inability of adrenal to produce sufficient cortisol, leading to increased production of testosterone resulting in severe masculinization of 46 XX females. Persistent mullerian duct syndrome - A rare type of pseudohermaphroditism that occurs in 46 XY males, caused by either a mutation in the Mullerian inhibiting substance (MIS) gene, on 19p13, or its type II receptor, 12q13..

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..

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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