General Biology 2

• The reproduction systems in both the male and female consist of primary and secondary sex organs and sex gonads
• The primary function of the reproduction systems is to perpetuate the species through sexual or germ cell fertilization and reproduction
• 1. Tail
  2. Plasma Membrane
  3. Middle piece
  4. Mitochondrion
  5. Neck
  6. Centriole
  7. Nucleus
  8. Acrosome
  9. Head

  
• The male reproductive system performs the following functions:

  • secretion of the male sex hormones
  • production of sperm cells
  • transfer of germ cells
• The male gonads are the testes
• The testes have compartments that contain tightly coiled tubes called seminiferous tubules
• The scrotum is a bag of skin that holds and helps to protect the testicles
• When a male is sexually aroused, sperm cells begin their journey through the vas deferens and exiting through the urethra
• The vas deferens is a tube in which the sperm is stored, and it carries the sperm through the scrotal sac
• The vas deferens are between the epididymis and the urethra and connect these together
• The urethra is a common passageway of urine and semen
• The penis is an external sex organ that allows the transfer of semen into the vagina of the female
• Three glands contribute fluid to the travelling sperm cells:

  • Seminal Vesicle
  • Prostate Gland
  • Bulbourethral Gland or Cowper’s Gland
• The seminal vesicle secretes a thick fluid that contains the nutrients
• The prostate gland secretes a thick, milky alkaline fluid to counteract the vagina and urethra and activates the sperm
• The bulbourethral gland or cowper’s gland produces the lubricant effect
• Altogether, the sperm and the fluids make up the semen
• Testosterone is the main male sex hormone secreted by the testes
• Testosterone is also necessary for the maturation of sperm cells with the help of another hormone, the follicle-stimulating hormone
• Follicle-stimulating hormone signals sperm production (spermatogenesis)
• Luteinizing hormone stimulates the production of testosterone
• A sperm has three main parts:

  • tail
  • middle piece
  • head
• The tail propels the sperm as it swings in the fluid
• The middle piece contains the mitochondria that provides the sperm with energy during its journey to the female body
• The head of the sperm contains acrosome enzymes that breaks the hyaluronic acid of the egg‘s membrane
• The head of the sperm houses the genetic information that will eventually unite with the egg’s nucleus during fertilization
• When a man ejaculates, about 200 to 500 million sperms are in the semen, and only less than 1% make it to the egg
• Releasing them in millions increases the sperm’s chances to find the egg
• The sperm faces a lot of obstacles to reach the egg due to the following reasons:

  • Millions already die in the vagina due to its acidic environment
  • Some sperms lose energy to continue their journey
  • Some sperms go to the oviduct or fallopian tube that does not contain the egg
  • some sperms are blocked in the mucus covering the cervix
  • Abnormal cells resulting from its mass production are unable to fertilize an egg
• The female reproductive system performs the following functions:

  • production of female sex hormones
  • Production of egg cells
  • receives the male sex organ for the transfer of sperm
  • protection and nourishment of the developing embryo
• The female reproduction system consists of:

  • Ovaries
  • fallopian tubes
  • uterus
  • vagina
• The pair of ovaries, lying on the right and left of the upper pelvic cavity, produce the mature egg cell
• This mature egg cell is swept by the tiny fingerlike projections of the oviducts or fallopian tube is called the cilia
• The two ovaries are attached to each side of the uterus by a ligament
• The ovaries are the oval-shaped and lie close to the fimbria at the end of the fallopian tubes
• Each ovary is filled, already at birth, with egg-containing sacs called follicles. Each egg cell is called an ovum
• 1. Nucleus
  2. First Polar Body
  3. Zona Pellucida or Jelly Coat
  4. Corona Radiata or Follicular cells
  5. Cytoplasm

  
• The fallopian tubes widen to form the ampulla
• the fallopian tube has the isthmus that is the portion that connects to the uterus
• Fimbria are the finger-like projections around the opening that traps the egg as it leaves the ovary