Science 12

• Humans begin their lives as a single cell formed by the union of an egg and a sperm from the parents
• Chromosomes contain genetic information for inherited traits such as skin color or hair color
• Human sex cells contain half the number of chromosomes of a regular body cell
• Haploid (n) sex cells have 23 chromosomes, while diploid (2n) somatic cells have 46 chromosomes
• Zygote is a fertilized egg produced after the union of egg and sperm, containing 46 chromosomes
• Organs of the Female Reproductive System:

  • Upper Outside: Areola, Nipple, Breast
  • Upper Inside: Fatty tissue, Duct, Lobule
  • Lower: Fallopian tube, Uterus, Cervix, Vagina, Ovary
• Organs of the Male Reproductive System:

  • Seminal Vesicle, Prostate Gland, Vas deferens, Epididymis, Testis, Scrotum, Penis
• Testes are the primary reproductive organs of males, producing sperm cells and located in the scrotum
• Seminiferous Tubules are compartments with tiny, coiled tubes where sperm cells are produced
• Male hormones LH and FSH regulate testes function and sperm production
• Mature Sperm Cells are produced in the testes, stored in the epididymis, and have three parts: Head, Midpiece, Tail
• Sperm cells are transported through the vas deferens and urethra, mixed with fluids from neighboring glands to form semen
• Ovaries are female reproductive structures responsible for producing eggs and hormones like estrogen
• Egg production starts with approximately two million egg cells at birth, decreasing to about 400,000 by puberty
• Ovum is released from the ovary every 28 days, traveling through the fallopian tube to the uterus
• The Ovarian Cycle includes ovulation, follicular phase, and luteal phase, regulated by hormones from the hypothalamus and pituitary gland
• The Menstrual Cycle prepares the body for pregnancy, shedding the uterine lining if fertilization does not occur
• Menstruation is the shedding of blood and tissues from the uterus, occurring about 14 days after ovulation
• Menopause marks the end of ovulation and fertility in women, typically around the mid-40s
• Common sexually transmitted diseases include Gonorrhea, Syphilis, AIDS, and Genital Herpes
• Gonorrhea is caused by Neisseria gonorrhea, leading to pelvic inflammatory disease and treated with antibiotics
• Syphilis is caused by Treponema Pallidum, presenting with painless sores and treated with antibiotics
• AIDS is caused by HIV, attacking the immune system, first reported in 1981, and notable individuals like Isaac Asimov have died from complications
• Genital Herpes is caused by HSV-2 and is currently incurable
• The testes are oval shaped organs found inside a protective sac of skin called the Scrotum
• Inside the testes are clusters of hundreds of compartments with many tiny coiled tubes called seminiferous tubules
• Luteinizing Hormone, stimulates the secretion of sex hormone
• Follicle Stimulating Hormone stimulates sperm production
• After being produced in the seminiferous glands, they enter a long coiled tube called the epididymes, where they mature then to the vas deferens and then the urethra
• Head is made up of nucleus covered by a cap called acrosome
• Tail of the sper if a powerful flagellum that enables the sperm cell to move
• Prostate Glands - Alkaline fluid that neutralizese the acids present in the female reproductive system
• Seminal Vesicle - a fluid rich in sugars that sperm cells use for energy
• Bulbourethral Glands - Alkaline fluid that neutralizes traces of acidic urine in the urethra
• The male organ that deposits the sperm into the female reproductive system during intercourse is called copulation
• Sperm exits th penis through ejaculation
• Ovaries are the female reproductive structures responsible for producing eggs
• Estrogen triggers the development of secondary female characteristics
• The onset of mature egg cell production among females start around the ages of 11 to 14 years during the first dicharge of blood from the vagina is called Menarche
• The female reporudctive system will begin its role in nourishing and protecting the fertilized egg during nine months of development, this is called gestation or pregnancy