The reproductive systems
Your body has had the organs of a reproductive system since you were born, but they do not really start working until puberty. From then on they produce gametes: the cells that, when they join together, can give rise to a new person.
The gametes
If you cut yourself, the skin cells divide to close the wound, but none of them can join with another cell to create a whole person. What special cells does our body need to make reproduction possible, and what makes them different from all the others?
Name the two types of human gametes, state in which organs each is produced, and cite one observable difference between them.
Name the two types of human gametes, state in which organs each is produced, and cite one observable difference between them.
Explain what gametes are and how they differ from the rest of the body's cells in terms of their function.
Explain what gametes are and how they differ from the rest of the body's cells in terms of their function.
The female reproductive system
In the image of the female reproductive system, four structures have been marked with numbers. Write the name of the marked structures and state in which of them egg…
In the image of the female reproductive system, four structures have been marked with numbers. Write the name of the marked structures and state in which of them egg cells (ova) are formed.
Name in order the structures of the female reproductive system through which the egg cell (ovum) passes from where it is formed until it reaches the uterus.
Name in order the structures of the female reproductive system through which the egg cell (ovum) passes from where it is formed until it reaches the uterus.
Explain where fertilisation usually takes place in the female reproductive system and what path the zygote takes afterwards until it becomes implanted in the place where…
Explain where fertilisation usually takes place in the female reproductive system and what path the zygote takes afterwards until it becomes implanted in the place where it will develop.
The male reproductive system
In the cross-sectional image of the male reproductive system, four structures have been marked with numbers. Write the name of the marked structures and describe the…
In the cross-sectional image of the male reproductive system, four structures have been marked with numbers. Write the name of the marked structures and describe the path sperm cells travel from where they are formed in the testes until they leave the body, naming the structures they pass through.
Explain what semen is and which glands, besides the testes, provide the fluids that form it.
Explain what semen is and which glands, besides the testes, provide the fluids that form it.
The testes are located outside the abdominal cavity, in the scrotum, because sperm production requires a temperature slightly lower than that inside the body. Reason…
The testes are located outside the abdominal cavity, in the scrotum, because sperm production requires a temperature slightly lower than that inside the body. Reason what might happen to sperm production if the testes were always kept at internal body temperature.
Gonads, hormones and differences between the two systems
During puberty, body changes such as the appearance of body hair or muscle development coincide exactly with the first maturation of sex cells. Which organs manage to coordinate, at the same time, the production of gametes and the chemical signals that transform the body?
In addition to producing gametes, the ovaries and testes produce sex hormones. Explain what type of organs ovaries and testes are, therefore, and state two changes that…
In addition to producing gametes, the ovaries and testes produce sex hormones. Explain what type of organs ovaries and testes are, therefore, and state two changes that these hormones cause during puberty.
The female reproductive system works in a cyclic way and the male one continuously. Relate this difference to the way gametes mature in each case, and explain what…
The female reproductive system works in a cyclic way and the male one continuously. Relate this difference to the way gametes mature in each case, and explain what consequence it has for the fertile days of each cycle.
Look at the compared characteristics of the two human gametes: Sperm cell: length of about 0,05 mm, no nutrient reserves, motile via flagellum, continuous production of…
Look at the compared characteristics of the two human gametes:
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Sperm cell: length of about 0,05 mm, no nutrient reserves, motile via flagellum, continuous production of about 100 million per day.
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Egg cell: diameter of about 0,15 mm (a volume hundreds of times greater), non-motile, loaded with nutrient reserves, maturation of 1 every 28 days.
- a) Justify why the sperm cell requires such a light design and such a massive production, relating it to the physical obstacles and the journey it faces within the female reproductive system.
- b) Explain why it would be biologically unfeasible and detrimental for a woman to mature millions of egg cells at once, taking into account the energy cost of producing reserves and the type of mammalian gestation.
Contraception and prevention of STIs
Preventing a pregnancy and preventing a sexually transmitted infection (STI) are related but different goals. Some STIs may cause no symptoms. Prevention combines information, shared decisions, barriers, recommended vaccination and healthcare.
| Method | Prevention of pregnancy | Protection against STIs |
|---|---|---|
| External or internal condom | Yes, with correct and consistent use | Reduces the risk of most of them; does not eliminate it completely |
| Pill, implant, ring or other hormonal methods | Yes, depending on their use and schedule | No |
| Copper or hormonal IUD | Yes | No |
| Calendar method or withdrawal | Lower reliability in typical use | No |