A&P II Module 10: The Reproductive System

True or False

The amount of testosterone and sperm produced by the testes is dependent on the influence of FSH alone.

False

True or False

Ovarian follicles contain mature eggs.

False

True or False

The corpus luteum secretes progesterone.

True

Which of the following hormones controls the release of anterior pituitary gonadotropins?

GnRH

If gametes were diploid like somatic cells, how many chromosomes would the zygote contain?

Twice the diploid number, and with every succeeding generation, the chromosome number would continue to double and normal development could not occur.

Which of the following is true of testosterone?

Testosterone is produced by the Leydig cells

During the secretory phase of the menstrual cycle, ________ reaches its highest levels.

Progesterone

Folliculogenesis and Oogenesis are interrelated processes that are both part of the ovarian cycle. Explain one way that the 2 processes are connected.

Folliculogenesis and oogenesis are connected because the developing follicle supports and nurtures the maturing oocyte (egg) inside it. As the follicle grows and develops during folliculogenesis, it provides the necessary environment and hormonal signals for the oocyte to resume meiosis and continue its development. Without folliculogenesis, oogenesis could not successfully occur.

Describe the process of spermatogenesis.

Spermatogenesis is the process by which sperm are produced in the seminiferous tubules of the testes. It begins with spermatogonia, which are stem cells that divide by mitosis. Some spermatogonia differentiate into primary spermatocytes. These primary spermatocytes undergo meiosis I to form two secondary spermatocytes. Each secondary spermatocyte undergoes meiosis II to produce two spermatids. Finally, spermatids mature into spermatozoa (sperm cells) through a process called spermiogenesis.

What structure of the male reproductive system undergoes surgery during a vasectomy and how does this lead to surgical sterilization?

During a vasectomy, the vas deferens is cut and sealed. The vas deferens is the tube that carries sperm from the epididymis to the urethra. By cutting the vas deferens, sperm can no longer be transported out of the body during ejaculation, leading to sterilization because sperm are absent from the semen.

Compare and contrast mitosis and meiosis in terms of number of cells produced, ploidy, and cell identity.

• Mitosis → 2 cells, diploid, identical

• Meiosis → 4 cells, haploid, non-identical

How may cells does Mitosis create, whats their ploidy, and cell identity?

2 cells, diploid, identical

How many cells does Meiosis produce, whats their ploidy, and cell identity?

4 cells, haploid, non-identical

Describe the process of spermatogenesis.

• Spermatogenesis occurs in the testes (seminiferous tubules).

• Begins with spermatogonia (diploid stem cells) dividing by mitosis.

• Primary spermatocytes (diploid) undergo meiosis I → two secondary spermatocytes (haploid).

• Secondary spermatocytes undergo meiosis II → four spermatids (haploid).

• Spermatids mature into sperm (spermatozoa) through spermiogenesis.

How does cutting and sealing the vas deferens (vasectomy) result in surgical sterilization?

Blocks the path sperm takes to exit the male reproductive system.

Explain the roles of the hypothalamus, anterior pituitary, Sertoli cells, Leydig cells, GnRH, FSH, LH, testosterone, ABP, and inhibin in testosterone regulation.

1. Hypothalamus → releases GnRH (gonadotropin-releasing hormone)
   ↓

2. Anterior pituitary → releases FSH and LH
   ↓

3. LH → stimulates Leydig cells → produce testosterone
   ↓

4. FSH → stimulates Sertoli cells → produce ABP (androgen-binding protein) → helps concentrate testosterone in seminiferous tubules
   ↓

5. Sertoli cells → release inhibin → negative feedback to anterior pituitary to decrease FSH
   ↓

6. Testosterone → negative feedback to hypothalamus and anterior pituitary → lowers GnRH and LH release

What are the male gonads and their function?

Testes → Produce sperm

What are the female gonads and their function?

ovaries → produce oocytes

What are the male and female gonads and their functions?

Male: testes → produce sperm; Female: ovaries → produce oocytes

Trace the path sperm travels after production in seminiferous tubules

Straight tubule → rete testis → efferent ductules → epididymis → vas deferens → penis

Describe the process of spermatogenesis

Spermatogonial stem cell → mitosis → primary spermatocyte → meiosis I → secondary spermatocytes → meiosis II → spermatids → spermiogenesis → spermatozoa (sperm)

Where is semen made and what does it consist of?

Seminal vesicles, prostate, bulbourethral glands → sperm + seminal vesicle secretions + prostate fluid + bulbourethral fluid

Explain the endocrine regulation of testosterone

Hypothalamus → GnRH → anterior pituitary → LH & FSH → LH → Leydig cells → testosterone; FSH → Sertoli cells → ABP → binds testosterone; Negative feedback: testosterone → ↓GnRH, LH, FSH; inhibin → ↓FSH

What are the three layers of the uterus wall?

Perimetrium, myometrium, endometrium

Describe the process of oogenesis

Ovarian stem cells → mitosis → primary oocytes (before birth) → puberty → meiosis I → secondary oocyte + polar body → if fertilized → meiosis II → haploid ovum → zygote

What are the six stages of folliculogenesis?

1. Primordial follicle;

2. Primary follicle (granulosa cells);

3. Secondary follicle (theca + granulosa cells);

4. Tertiary follicle (antrum forms);

5. Ovulating follicle (oocyte released);

6. Corpus luteum

Describe the hormonal regulation of ovulation.

"Hypothalamus → GnRH → anterior pituitary → LH, FSH → LH, FSH → follicle maturation → estrogen → estrogen → ↑GnRH, LH, FSH → LH surge → ovulation"

What are the three phases of the menstrual cycle and hormone changes?,

1. Menses → low estrogen & progesterone;

2. Proliferative → ↑estrogen;

3. Secretory → ↑progesterone