Comprehensive Human Reproduction and Gametogenesis: Key Concepts and Processes

What is the process of meiosis?

Meiosis is the reductive division of DNA that reduces ploidy by half.

What are the sex chromosomes in humans?

Humans have 23 pairs of chromosomes, including 22 autosomes and 1 pair of sex chromosomes (X and Y).

What hormone is produced by Leydig cells?

Leydig cells secrete testosterone.

What is the function of Sertoli cells?

Sertoli cells create and maintain the blood-testis barrier, nourish developing sperm, and secrete inhibin.

What is the bipotential gonad?

The bipotential gonad is an undifferentiated gonad that cannot be morphologically distinguished as ovary or testes at 6 weeks of development.

What does the Y chromosome specify?

The Y chromosome specifies the development of testes.

What happens to the Müllerian duct in XY individuals?

The Müllerian duct degenerates due to the action of anti-Müllerian hormone produced by the testes.

What is the role of the corpus luteum?

The corpus luteum secretes progesterone and estrogens to maintain the uterine lining after ovulation.

What triggers ovulation?

A surge in luteinizing hormone (LH) triggers ovulation.

What is the primary function of the seminal vesicle?

The seminal vesicle produces alkaline fluid, fructose, and fibrinogen to support sperm viability and transport.

What is the composition of semen?

Semen is composed of 10% sperm and 90% fluids from the seminal vesicle, prostate gland, and bulbourethral gland.

What is the role of nitric oxide (NO) in erection?

Nitric oxide relaxes smooth muscle around penile arterioles, leading to increased blood flow and erection.

What is the function of gonadotropin-releasing hormone (GnRH)?

GnRH stimulates the anterior pituitary to release follicle stimulating hormone (FSH) and luteinizing hormone (LH).

What is the primary oocyte's status at puberty?

The primary oocyte is stored in a primordial follicle until puberty, when it resumes meiosis.

What is the significance of the zona pellucida during fertilization?

The zona pellucida forms around the zygote to prevent polyspermy and protect the developing embryo.

What is the fate of the corpus luteum if fertilization does not occur?

If fertilization does not occur, the corpus luteum degenerates into the corpus albicans, leading to a drop in estrogen and progesterone.

What is the role of hCG in pregnancy?

Human chorionic gonadotropin (hCG) is secreted by the fetus and prevents the degeneration of the corpus luteum.

What occurs during the cleavage stage of embryo development?

The embryo separates into two lineages: the inner cell mass and trophoblast, enabling the formation of the embryo and supporting membranes.

What is the role of the placenta?

The placenta forms from contributions of the fetus and maternal uterine wall, allowing maternal blood to bathe fetal capillary beds.

What is the mechanism behind parturition?

Parturition is stimulated by rising oxytocin levels, which promote uterine contractions and the opening of the birth canal.

What is the function of the bulbourethral gland?

The bulbourethral gland produces alkaline fluid and mucus for lubrication during ejaculation.

What is the significance of the acrosomal vesicle in sperm?

The acrosomal vesicle contains enzymes that help the sperm penetrate the egg during fertilization.

What is the difference between spermatogenesis and oogenesis?

Spermatogenesis produces four functional sperm from one spermatogonium, while oogenesis produces one functional ovum and polar bodies.

What is the function of inhibin in male physiology?

Inhibin decreases the release of FSH from the anterior pituitary, providing negative feedback on spermatogenesis.

What is the role of the urethra in male reproductive physiology?

The urethra serves as the passageway for sperm and urine to exit the body.

What is the primary function of the prostate gland?

The prostate gland contributes clotting and proteolytic enzymes to semen.

What are the stages of oogenesis?

Oogenesis includes the development of primordial follicles, primary follicles, secondary follicles, and mature (Graafian) follicles.

What triggers the release of FSH and LH from the anterior pituitary?

The release of GnRH from the hypothalamus triggers the secretion of FSH and LH.

What is the role of the clitoris in female physiology?

The clitoris becomes engorged with blood during sexual arousal, similar to the mechanism of erection in males.

What is the hormonal effect of rising estrogen levels during the menstrual cycle?

Rising estrogen levels stimulate the proliferation of the endometrial wall and increase GnRH release.

What is the significance of cytoplasmic bridges in spermatogenesis?

Cytoplasmic bridges allow for karyokinesis without cytokinesis, enabling shared resources among developing sperm.