The Reproductive System
Utilizing knowledge from your learning and assigned readings, respond to the following questions:
- How does mitosis differ from meiosis?
- The release of FSH and LH from gonadotropes in the adenohypophysis is separately controlled by the same hypothalamic releasing hormone, GnRH. How is it possible to organize their secretion during the menstrual cycle?
- Your male patient is having a vasectomy and is concerned about testosterone levels after the procedure. Explain what he should expect after his vasectomy.
- Describe the process of spermatogenesis.
- What hormones promote ovulation? Describe how the levels of these hormones change in the days prior to ovulation.
- A contraceptive pill “tricks the brain” into thinking you are pregnant. What does this mean?
Expert Solution Preview
Introduction:
In this assignment, we will focus on the reproductive system and explore various topics related to it. We will discuss the differences between mitosis and meiosis, the organization of FSH and LH secretion during the menstrual cycle, the effects of vasectomy on testosterone levels, the process of spermatogenesis, hormones promoting ovulation, and the concept of contraceptive pills “tricking the brain.”
1. How does mitosis differ from meiosis?
Mitosis is a process of cell division that produces two identical diploid daughter cells from one parent cell, while meiosis is a process of cell division that produces four genetically diverse haploid daughter cells from one parent cell. Mitosis involves only one round of chromosome replication and division, while meiosis involves two rounds of chromosome replication and division. Additionally, mitosis is involved in growth and repair of somatic cells, while meiosis is involved in the production of gametes.
2. The release of FSH and LH from gonadotropes in the adenohypophysis is separately controlled by the same hypothalamic releasing hormone, GnRH. How is it possible to organize their secretion during the menstrual cycle?
During the menstrual cycle, the secretion of FSH and LH is regulated by a negative feedback loop between the hypothalamus, pituitary gland, and ovaries. At the onset of the menstrual cycle, the hypothalamus releases GnRH, which stimulates the release of FSH and LH from the pituitary gland. FSH stimulates follicle growth and estrogen production in the ovary, while LH triggers ovulation and the development of the corpus luteum. As estrogen and progesterone levels increase, they inhibit the release of GnRH and FSH/LH from the pituitary gland, which leads to a decrease in follicular growth and the regression of the corpus luteum, respectively.
3. Your male patient is having a vasectomy and is concerned about testosterone levels after the procedure. Explain what he should expect after his vasectomy.
A vasectomy involves the surgical removal or blocking of the vas deferens, which prevents the release of sperm during ejaculation. The procedure does not affect testosterone production, as the testes continue to produce testosterone normally. The patient should not experience any significant changes in testosterone levels after the procedure, as it does not interfere with the hormonal regulation of the testes.
4. Describe the process of spermatogenesis.
Spermatogenesis is the process of sperm cell production in the testes. It involves three stages: mitotic proliferation, meiotic division, and differentiation. During the mitotic proliferation phase, spermatogonia divide to produce two types of cells: type A cells, which remain as stem cells, and type B cells, which differentiate into primary spermatocytes. Primary spermatocytes undergo meiosis I to produce two secondary spermatocytes, which then undergo meiosis II to produce four haploid spermatids. Finally, spermiogenesis occurs, during which the spermatids differentiate into mature sperm cells with a head, midpiece, and tail.
5. What hormones promote ovulation? Describe how the levels of these hormones change in the days prior to ovulation.
Estrogen and luteinizing hormone (LH) promote ovulation. In the days prior to ovulation, estrogen levels increase as the developing follicle produces more of this hormone. This increase in estrogen triggers a surge in LH levels, which triggers ovulation. After ovulation, LH levels decrease, and the corpus luteum begins to produce progesterone, which helps maintain the endometrium lining of the uterus.
6. A contraceptive pill “tricks the brain” into thinking you are pregnant. What does this mean?
Contraceptive pills contain synthetic versions of estrogen and progesterone. These hormones work together to suppress the release of FSH and LH from the pituitary gland, thereby preventing ovulation. The hormones also thicken the cervical mucus, making it difficult for sperm to reach the egg. By mimicking the hormonal changes that occur during pregnancy, the pill “tricks the brain” into thinking that ovulation has already occurred, which prevents the release of additional eggs.
