sexual reproduction in humans

• What are the main components of the male reproductive system?

  A pair of testes, ducts connecting the testes with the penis, and accessory glands
• What is the function of the accessory glands in the male reproductive system?

  They secrete fluids that mix with sperm to form semen
• What is contained within each testis?

  • About five hundred coiled tubes called seminiferous tubules
  • Cells lining the seminiferous tubules undergo spermatogenesis
• What happens to cells during spermatogenesis in the seminiferous tubules?

  Cells move towards the lumen as they develop into sperm
• What are the vas deferens?

  Coiled tubes that carry sperm to the head of the epididymis
• What occurs to sperm in the epididymis?

  Sperm become motile before passing into the vas deferens
• What does the vas deferens do?

  It carries sperm from the epididymis towards the penis
• What do the seminal vesicles secrete into the vas deferens?

  Mucus containing fructose for sperm energy
• What is the role of zinc-containing prostate fluid?

  It is secreted by the prostate gland and is part of semen
• What are the functions of the secretions from accessory glands in the male reproductive system?

  • Maintain sperm mobility
  • Provide nutrients (fructose, amino acids, zinc)
  • Neutralise acidity of urine in the urethra
  • Neutralise acidity of the vaginal tract
• What is semen composed of?

  A mixture of sperm and seminal and prostate fluids
• What is the function of the urethra in the male reproductive system?

  It carries semen through the penis
• What is the plural form of testis?

  Testes
• What are the primary structures involved in the female reproductive system?

  Two ovaries where oocytes mature in follicles
• What happens to mature follicles in the ovaries?

  They migrate to the surface of the ovary and release a secondary oocyte at ovulation
• What role do cilia play in the female reproductive system?

  Cilia sweep the secondary oocyte into the oviduct
• How does the oviduct convey the secondary oocyte to the uterus?

  Through the action of ciliated epithelial cells
• What can be observed in a histological examination of a testis under a microscope?

  • Lumen
  • Seminiferous tubules
  • Connective tissue and blood vessels
• What can be identified in the seminiferous tubules during a high power objective examination?

  Germinal cells, primary spermatocytes, secondary spermatocytes, and spermatids
• What are Sertoli cells and their function?

  Columnar cells that nourish developing sperm and protect them from the immune system
• What do interstitial cells (Leydig cells) secrete?

  Testosterone, the male sex hormone
• What is the structure of a section through the ovary?

  • Oval or circular outline
  • May contain an empty area (antrum of a mature Graafian follicle)
  • Ruptured follicle may be seen after ovulation
• What happens to the ovaries each month?

  They alternate in releasing the oocyte
• What is the significance of the Graafian follicle in the ovary?

  It is a mature follicle that releases a secondary oocyte at ovulation
• What is the role of the oviduct in the female reproductive system?

  It conveys the secondary oocyte to the uterus
• What is the appearance of a section through the ovary just before ovulation?

  The Graafian follicle may be at the edge of the ovary
• What can be seen in a section of the ovary after ovulation?

  The ruptured follicle can be seen at the edge of the ovary
• What is the germinal epithelium in the ovary comprised of?

  Chunters of cells, each with a larger primary oocyte in the middle
• What surrounds the primary oocytes in the ovary?

  Cumulus cells
• What is the stroma in the ovary?

  The mark of the ovary
• How do you measure the diameter of a secondary oocyte under a microscope?

  Using an eyepiece graticule and calibration value
• What is gametogenesis?

  • The formation of gametes in the sex organs
  • Involves spermatogenesis in the testis and oogenesis in the ovary
• What type of divisions do germinal epithelium cells undergo to form haploid gametes?

  Mitosis and meiosis
• Why is it important that gametes are haploid?

  To restore the diploid number after fertilization
• What are spermatogonia?

  Diploid cells in the testis that divide by mitosis
• What happens to primary spermatocytes during spermatogenesis?

  They undergo meiosis to form secondary spermatocytes
• What is the final product of spermatogenesis?

  Spermatozoa
• What is the process of oogenesis?

  The formation of secondary oocytes in the ovary
• What happens to primary oocytes at birth?

  They begin meiosis I but stop at prophase I
• What triggers the development of primary follicles from primary oocytes?

  Hormones from puberty onwards