Science all lessons 3rd quarter

• Organ


  A group of tissues in a living organism that have been adapted to perform a specific function
• Genitals


  A person or animal's external organs of reproduction
• Anatomy


  A field in the biological sciences concerned with the identification and description of the body structures of living things
• Reproduce


  Making a copy, a likeness, and thereby providing for the continued existence of species
• Semen


  The thick fluid that comes from men's penis when they ejaculate during sexual activity
• Ovum


  Single cell released from either of the female reproductive organs, the ovaries, which is capable of developing into a new organism when fertilized (united) with a sperm cell
• Fertilized


  Cause by an egg cell to develop a new individual by introducing male reproductive cell
• The reproductive system is designed to facilitate the process of human sexual reproduction
• Due to its vital role in the survival of the species, many scientists feel that the reproductive system is among the most important systems in the entire body
• Of the body's major systems, the reproductive system is the one that differs most between sexes, and the only system that does not function until puberty
• The male reproductive system is responsible for delivering sperm to the female reproductive system
• Gametogenesis


  The production of sex cells or gametes and the process of fertilization that eventually leads to the development of a human embryo
• Testes


  • They are oval-shaped glands responsible for the manufacture of sperm and the sex hormone testosterone
  • They lie outside the body in a pouch of skin called the scrotum, where they can maintain the optimum temperature for sperm production – approximately 5° F, lower than body temperature
• Main parts of the male reproductive system

  • Testis (plural, testes)
  • Scrotum
  • Seminiferous Tubules
  • Epididymis
  • Penis
  • Vas deferens (tube)
  • Urethra
  • Glands
• Seminal vesicle


  Secretes a fluid that makes up most of the components of the semen
• Prostate gland


  Secretes a slightly alkaline milky fluid that is discharged as part of the semen
• Bulbourethral gland (Cowper's gland)


  Secretes a thick and clear mucus that lubricates and neutralizes any trace of acidic urine in the urethra
• Organ/component and their primary functions in the male reproductive system

  • Testes - produce sperm and hormones
  • Epididymis - Acts as site of sperm maturation
  • Ductus Deferens (sperm duct) - Conducts sperm between epididymis and prostate gland
  • Seminal vesicles - Secret fluid that makes up much of volume of semen
  • Prostate gland - Secretes fluid and enzymes
  • Urethra - Conducts semen to exterior
  • Penis - Contains erectile tissue deposits sperm in vagina or female produces pleasurable sensations during sexual activities
  • Scrotum - Surrounds the testes and controls their temperature
• Spermatogenesis


  The process of producing sperm cells
• Thousands of sperm are produced every second, each taking about two months to mature
• Sperm


  • The head contains the nucleus with densely coiled chromatin fibers (chromosomes), with a front section – the Acrosome that contains enzymes for penetrating the female egg
  • The midpiece has a central filamentous core with many Mitochondria spiraled around it, to give it energy to move the tail which propels it forward
• Semen


  Seminal fluid, is much more than just sperm. Sperm is only about 5 to 10% of any given male single ejaculation and the rest is fructose (aka sugar), fatty acids, and proteins to nourish the sperm during their journey
• There are around 200 to 500 million sperm in an average in a single human ejaculation
• Functions of the female reproductive system

  • Produces female sex cells
  • Receives sperm cells from the male
  • Nurtures the development of and provides nourishment for the new individual
• Female reproductive system


  • The vulva and its structures form the external genitalia
  • The internal genitalia include a three-part system of ducts: the uterine tubes, the uterus, and the vagina
  • This system of ducts connects to the ovaries, the primary reproductive organs
  • The ovaries produce egg cells and release them for fertilization
  • Fertilized eggs develop inside the uterus
  • From Puberty, their function is to ripen and release an egg at regular intervals, and, if the egg is fertilized, to protect and nourish the embryo and fetus
  • No eggs are manufactured after birth; a female is born with a full set
• Ovary


  • They are slightly flattened bean-shaped bodies, each about two to five cm in length and two to three cm in width
  • They contain thousands of immature egg cells called follicles, from these the female sex cells, egg cells, or ova develops
• Ovulation


  1. Follicle-stimulating hormone (FSH) causes one egg to begin development inside a primary follicle

  2. The follicle enlarges as its cells proliferate, and begins to fill with fluid, becoming a secondary follicle that moves to the ovary's surface

  3. It also increases its production of the hormone Estrogen

  4. A surge of luteinizing hormone (LH) causes the follicle to rupture and release the ripe egg–this is ovulation

  5. The lining of the empty follicle thickens into a corpus luteum–a temporary source of hormones
• Oviduct


  Serves as passageway of eggs from the ovary to the uterus, and is also the site of egg fertilization. Also known as Fallopian tube
• Uterus


  Serves as site of egg implantation, and is where the fertilized egg develops
• Vagina


  Receives the penis of male during mating, carries menstrual flow outside the body, and serves as a birth canal during labor
• Fertilization


  The union of two kinds of gametes resulting in the formation of a fertilized egg called zygote
• Fertilization: A sperm and an egg form a zygote


  1. The sperm and the egg are called gametes. They each contain half of the genetic information necessary for reproduction. When a sperm cell penetrates and fertilizes an egg, that genetic information combines

  2. The 23 chromosomes from the sperm pair with 23 chromosomes in the egg, forming a 46-chromosome cell called a zygote. The zygote starts to divide and multiply. As it travels toward the uterus it divides to become a blastocyst, which will burrow into the uterine wall
• Embryo


  Refers to the earliest stage of development of an organism into which the zygote develops through a series of cell divisions
• Development prior to and during implantation

  1. The blastocyst attaches to the wall of the uterus and gradually implants itself into the uterine lining. During implantation, its cells differentiate further

  2. At day 15 after conception, the cells that will form the embryo becomes an embryonic disc. Other cells begin to form support structures like the yolk sac and amnion

  3. Other cell groups initiate the placenta and umbilical cord, which will bring in nutrients and eliminate waste
• Oogenesis


  Formation of egg cells or Ova, which takes place in numerous round structures called Follicles
• What happens if the egg is not fertilized

  1. Deterioration of the corpus luteum

  2. Maturation of a new follicle for the next reproductive cycle of the female

  3. Breaking down of the uterus lining which is discharged as menstrual flow
• Menstruation


  A discharging of blood, secretions, and tissue debris from the uterus that occurs in non pregnant females
• Components of the reproductive system

  • Gonad - Male: Testes, Female: Ovary
  • Gamete - Male: Sperm, Female: Ovum (egg)
  • Hormones - Androgens: Testosterone, Estrogen: progesterone
• Cells of the Testes

  • Leydig (interstitial) cells synthesize hormones
  • Sertoli cells synthesize sperm (spermatogenesis)
• Androgen


  Testosterone, both hormones are released from testes