Module 3—The Male and Female Reproductive Systems

 
Answers to “The Male Reproductive System: Perpetuating the Species”
  1. The following are three characteristics that set the reproductive system apart from other body systems:
    1. System becomes functional at the time of puberty under the influence of hormones.
    2. Reproduction accounts for the major differences between males and females.
    3. Reproduction serves more than the individual; it perpetuates the species.

  2. Sexual reproduction is important because it results in genetically unique offspring. The variations enhance biodiversity, increasing the chances of survival in changing environments.

  3. Reproduction ensures continuity and survival of the species.

  4. The following are three factors that have led to fewer eggs and increased survival rate of offspring in vertebrates:

    1. internal fertilization
    2. protection of the developing embryo
    3. caring for young after birth

  5. The following are three functions of the male reproductive system:

    1. produce sperm (gamete) and sex cells
    2. release hormones
    3. deposit sperm into the female

  6. The following are three unique features of a sperm cell:

    1. smallest human cell
    2. carry half the genetic material
    3. each sperm has a tail (flagellum)

  7. Only one sperm is needed to fertilize an egg.

  8. Between 200 and 400 million sperm are released in one ejaculation.

  9. The difference between the size of the sperm and the egg is due to the amount of cytoplasm within each cell.

  10. The sperm are produced in the testes, which are paired organs.

  11. The sack that holds the testes is called the scrotum.

  12. The testes are held outside the body to control the temperature of the developing sperm.

  13. The ideal temperature for producing sperm is 3°C below body temperature, i.e., 34°C.

  14. Testicles include supporting structures like the epididymis and the vas deferens; testes do not.

  15. In a cold environment, the scrotum muscles contract, pulling the testes closer to the body and decreasing their surface area. In a warm environment, the scrotum muscles extend, lowering the testes away from the body and increasing their surface area.

  16. Seminiferous tubules (in which sperm are produced) are inside the testes.

  17. Sperm takes 64 to 72 days to develop, and another 10 to 14 days to mature in the epididymis.

  18. The epididymis is a coiled tube that sits on top of the testis. The sperm matures inside this structure.

  19. Sperm survive at body temperature for 24 to 72 hours.

  20. Sperm leave the testes through the vas deference or ductus deferens.

  21. Acidic conditions are found in two places: the urethra (through which urine and sperm pass) and the female vagina.

  22. Seminal fluid is alkaline (to counteract the acidic environments) and nutrient-rich (so sperm can survive for 2 to 3 days).

  23. The three glands that contribute to the secretion of seminal fluid and their contributions are:

    1. seminal vesicle—yellowish fluid rich in nutrients, including fructose, to sustain sperm
    2. prostate gland—milky, alkaline fluid to neutralize acidic environments; also contains enzymes that activate the sperm
    3. Cowper’s gland—thin, clear mucus fluid to neutralize the urethra and act as a lubricant prior to ejaculation

  24. The testes contain the seminiferous tubules, in which sperm are produced; and the epididymis, in which sperm mature.

  25. Fructose provides a source of energy to sperm.

  26. The parasympathetic nervous system stimulates increased blood flow to the penis.

  27. The penis delivers sperm to the egg.