Human Reproductive System, Study notes of Family and Consumer Science

Download Human Reproductive System and more Study notes Family and Consumer Science in PDF only on Docsity! Reproductive System Male parts and functions external reproductive structures Diploid zygote: is formed from the fusion of male and female sex cells, which are both haploid, through fertilization. This organ system produces sperm cells (male gametes) and delivers them into the female reproductive system. Testicles (testes): are oval-shaped organs found inside the protective sac of skin called scrotum. The location of the testes in the scrotum, which is outside the body, is essential for the development of the sperm. Since the scrotum lies in the external part of the male body, its temperature is 1OC to 3OC lower than the internal body temperature (3 70C), making it ideal for sperm production, which requires a lower temperature. The testes begin to produce sperm only after males reach the adolescent stage known as Puberty. The testes are responsible for making testosterone, the primary male sex hormone, and for producing sperm.  Scrotum: the loose pouch-like sac of skin that hangs behind the penis. It holds the testicles (also called testes), as well as, many nerves and blood vessels. The scrotum protects your testes, as well as, providing a sort of climate control system. Seminiferous tubules: a long, coiled tube that rests on the backside of each testicle. It carries and stores sperm cells that are created in the testes. It’s also the job of the epididymis to bring the sperm to maturity — the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens. internal male reproductive system Vas deferens: is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra in preparation for ejaculation. Ejaculatory ducts: are formed by the fusion of vas deferens and the seminal vesicles. The ejaculatory ducts empty into the urethra. Seminal Vesicles: are sac-like pouches that attach to the vas deference near the base of the bladder. The seminal vesicles make a sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with the sperm's ability to move (motility). The fluid of the seminal vesicles makes up most of the volume of your ejaculatory fluid, or ejaculate. prostate gland: a walnut-sized structure that is located below the urinary bladder in front of the rectum. The prostate contributes additional fluid to the ejaculate. Prostate fluid also helps to nourish the sperm. The urethra, which carries the ejaculate to be expelled during orgasm, runs through the center of the prostate gland. Bulbourethral glands: or Cowper's glands, are pea-sized structures located at the side of the urethra, just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra. – covered by epithelial and dense connective tissues Internal reproductive of female Female internal accessory organs Fallopian tube - oviduct Infundibulum and fimbriae – fringed, expanded end of the fallopian tube near the ovary – function to "catch" an ovum Muscular tube – lined with mucous membranes and cilia – propels ovum toward the uterus Uterus – a hollow, muscular organ – receives embryo and sustains its development – divisions Fundus- doomed upper portion body- the main portion Cervix – narrow, lower section extending into the vagina (cervical) – wall of the uterus Endometrium – innermost lining – vascular – tubular glands- mucus Myometrium – middle, thick, muscular layer Perimetrium – thin layer covering the myometrium – secretes serous fluid to coast and project Uterus – harbors the embryo – provides nutrients – expels the fetus at the end of its development Vagina – tubular, muscular organ – extends from uterus to outside body (vaginal introitus) – muscular folds - rugae - enable expansion Formation of Sperm and Its Pathway throughout the Body Human sperm cell Formation of sperm spermatogenesis: the process of forming sperm cells, takes place within the seminiferous tubules.  > Spermatogenesis begins with undifferentiated cells, the spermatogonia, in the walls of the seminiferous tubules. > The spermatogonia (diploid cells) divide by mitosis and produce more spermatogonia. > Some enlarge and become primary spermatocytes, which undergo meiosis and produce gametes (haploid) > Each primary spermatocyte undergoes meiosis I, which produces two secondary > In meiosis Il, each of the two secondary spermatocytes gives rise to two spermatids (haploid). Four spermatids are produced from the original primary spermatocyte. > Each spermatid differentiates into mature sperm. Sperm Pathway ST- seminiferous tubules E- epididymis V- vas defrens E- ejaculatory duct ------------------------------------------------------------------------------------------------ S- seminiferous tubules E- epididymis V- vas defrens E- ejaculatory duct N- none U- urethra P- penis OVARIES AND FORMATION OF EGG Egg production – at birth, all females are born with all the two million egg cells they will ever produce. By the time a female reaches puberty, the number of egg cells would have gone down to about 400,000. Oogenesis – the development of an ovum, occurs in the ovary. The ovary at birth contains all the follicles (from which ova are formed) a female will ever have. Oogenesis begins before birth. The diploid cells in the ovaries or oogonia undergo mitosis-producing daughter cells called primary oocytes each residing in a follicle. Around 2 million primary oocytes are produced when the female baby is born. Only about 300000 remain by the time she reaches 7 years old since most of these primary oocytes are reabsorbed in her body. The primary oocytes remain dormant for a time in the prophase of meiosis I until it can be triggered hormonally to develop further. After puberty, about every 28 days, the anterior pituitary gland stimulates one of the dormant follicles to develop and the primary oocyte completes meiosis I. This results in daughter cells with an unequal division of the cytoplasm, a single secondary oocyte receiving almost all of the cytoplasmic content, and a smaller daughter cell called the first polar body with almost no cytoplasm• The secondary oocyte is released by the ovary during ovulation. This is one of the events in the menstrual cycle.