Comprehensive Male and Female Reproductive System: Anatomy, Hormones, and Cycle

What are the primary functions of the male and female reproductive systems?

To produce and nurture sex cells, and transport them to the site of fertilization.

Which hormones are important for both male and female reproductive systems?

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

What are the primary sex organs in the male reproductive system?

The testes, which produce sperm and hormones.

What is the function of secondary sex organs in males?

They have a supportive function in the reproductive process.

What structures are the testes suspended by?

The spermatic cord in the scrotum.

What do the lobules of the testes contain?

1-4 coiled seminiferous tubules lined with stratified epithelium that produce sperm cells.

What are interstitial cells and what do they produce?

Cells that lie between seminiferous tubules and produce male hormones (androgens).

What are the three main parts of sperm cells?

Head, midpiece, and flagellum.

What is the role of the acrosome in sperm cells?

It contains digestive enzymes that help penetrate the tissues surrounding the female egg cell.

How long does spermatogenesis take?

65-75 days.

What are spermatogonia?

Undifferentiated spermatogenic cells (stem cells) in the male embryo.

What is the process by which primary spermatocytes divide?

Meiosis, forming haploid secondary spermatocytes.

What is the function of the epididymis?

It is the site of sperm maturation.

What is the vas deferens?

A muscular tube that transports sperm from the epididymis to the ejaculatory duct.

What does the seminal vesicle secrete?

An alkaline fluid containing fructose, prostaglandins, and clotting proteins.

What is the function of the prostate gland?

It secretes a thin, milky fluid containing citric acid and proteolytic enzymes.

What do bulbourethral glands secrete?

Mucus to lubricate the tip of the penis during sexual arousal.

What is semen composed of?

Sperm cells and secretions from the seminal vesicles, prostate gland, and bulbourethral glands.

What is the typical volume of semen?

2.5-5 mL with 50-150 million sperm per mL.

What is capacitation in sperm cells?

A series of functional changes that prepare sperm for fertilization.

What triggers the production of gonadotropins at puberty?

The release of gonadotropin-releasing hormone (GnRH) from the hypothalamus.

What are the two gonadotropins produced by the anterior pituitary?

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

What hormone promotes the development of interstitial cells in the testes?

Luteinizing hormone (LH)

What is the role of Follicle-stimulating hormone (FSH) in the male reproductive system?

It stimulates the supporting cells of the seminiferous tubules, leading to spermatogenesis.

What is the most abundant male sex hormone?

Testosterone

When is testosterone secreted during a male's life?

Secreted in a fetus until birth, then not again until puberty, after which it is continuously secreted.

What are some effects of testosterone at puberty?

Stimulates the development of male reproductive organs and causes the testes to descend.

What are male secondary sexual characteristics influenced by testosterone?

Deep voice, body hair, thickening of the skin, broadening of shoulders.

What triggers an erection?

Parasympathetic impulses release nitric oxide, causing vasodilation and increased blood flow to the penis.

What is the process that leads to ejaculation?

Somatic motor action potentials cause rhythmic contractions of skeletal muscles, forcing semen out of the urethra.

What are the paired glands in females homologous to the testes?

Ovaries

What do ovaries produce?

Secondary oocytes and hormones.

What is the structure that holds the ovaries in place?

A series of ligaments.

What are ovarian follicles?

Structures in the cortex of the ovaries that consist of an oocyte in various stages of development.

What is a mature (Graafian) follicle?

A large, fluid-filled follicle ready to expel an oocyte during ovulation.

What does the corpus luteum produce?

Progesterone, estrogens, relaxin, and inhibin until it degenerates into corpus albicans.

When does oogenesis begin in females?

Before females are born, during early fetal development.

What happens to most primordial cells before birth?

They degenerate through a process called atresia.

What are the three layers of the uterine wall?

Perimetrium, myometrium, and endometrium.

What is the function of the stratum functionalis?

It lines the uterine cavity and sloughs off during menstruation.

What is the role of Gonadotropin-releasing hormone (GnRH)?

It stimulates the release of FSH and LH from the anterior pituitary.

What does FSH do in the female reproductive cycle?

It initiates follicular growth and stimulates ovarian follicles to secrete estrogens.

What triggers ovulation?

A surge in Luteinizing hormone (LH).

What is the role of estrogens in the female reproductive system?

They promote the development and maintenance of ovaries, uterus, and secondary sex characteristics.

What does progesterone do?

Prepares and maintains the endometrium for implantation and mammary glands for milk production.

What hormone is produced by the corpus luteum that relaxes the uterus?

Relaxin

What is the function of inhibin in the reproductive cycle?

Inhibits secretion of FSH and LH

What are the four phases of the reproductive cycle?

Follicular Phase, Pre-Ovulatory Phase, Ovulation, Postovulatory Phase

What marks the first day of a new menstrual cycle?

The first day of menstruation

During which phase do several primordial follicles develop into primary and secondary follicles?

Follicular Phase

What happens to the endometrium during the proliferative phase?

It undergoes repair and thickens due to estrogen

What triggers ovulation on day 14 of a typical cycle?

Surge in LH due to positive feedback from high estrogen levels

What is the role of the corpus luteum after ovulation?

Secretes progesterone, estrogen, relaxin, and inhibin

What happens to the corpus luteum if fertilization does not occur?

It degenerates into corpus albicans after 2 weeks

What hormone is produced by the embryo to maintain the corpus luteum if fertilization occurs?

Human chorionic gonadotropin (hCG)

What are the primary organs of the male reproductive system?

Testes

What is the function of interstitial cells (Leydig cells) in the testes?

Produce male hormones (androgens), specifically testosterone

What is the structure of sperm cells?

Head, acrosome, midpiece, and flagellum

What is the duration of spermatogenesis?

65-75 days

What are the stages of cell progression in spermatogenesis?

Spermatogonia, Primary Spermatocytes, Secondary Spermatocytes, Spermatids

What is the haploid number of chromosomes in secondary spermatocytes?

23 chromosomes

What is the first stage of sperm cell development?

Spermatogonia

What occurs during the first meiotic division in spermatogenesis?

Primary spermatocytes undergo meiosis I to become secondary spermatocytes

What happens to spermatids before they become functional sperm?

They must undergo further maturation

What is the unique feature of sperm cells compared to other human cells?

Sperm cells have a flagellum for motility

What is the role of FSH and LH in the male reproductive system?

They are key hormones involved in sperm production and regulation

What happens to the endometrium if fertilization does not occur?

Hormone levels decline, leading to menstruation

What is the typical duration of the postovulatory phase?

14 days in a 28-day cycle

What is the significance of the stratum basalis in the uterus?

It remains after menstruation and is responsible for regenerating the stratum functionalis

What is the chromosome number retained by mature sperm cells?

23 chromosomes

What type of cell is formed when a haploid sperm combines with a haploid egg?

Diploid zygote (46 chromosomes)

What are the two main stages of meiosis in male reproduction?

Meiosis I and Meiosis II

How many haploid daughter cells are produced from one diploid parent cell during meiosis?

Four haploid daughter cells

What is the primary function of the epididymis?

Site where sperm mature and complete final development

What is the length of the vas deferens?

Approximately 45 centimeters

What is the path of sperm from the epididymis to the urethra?

Epididymis → body wall → inguinal canal → ejaculatory duct → urethra

What is the main function of seminal vesicles?

Secrete alkaline fluid and nutrients to nourish sperm

What is the role of fructose secreted by seminal vesicles?

Nourishes sperm and is used for ATP production

What do prostaglandins secreted by seminal vesicles do?

Cause smooth muscle contractions in the female reproductive tract

What is the primary function of the prostate gland?

Surrounds urethra and contributes to semen composition

What is the pH of the fluid secreted by the prostate gland?

Slightly acidic (pH 6.5)

What is the significance of PSA (Prostate-Specific Antigen) in the bloodstream?

Indicates potential prostate issues if present in blood

What is the volume range of semen per ejaculation?

2.5-5 mL

What is the sperm concentration in semen?

50-150 million sperm per mL

What is the pH range of semen?

7.2-7.7 (slightly alkaline)

What happens to semen within the first 5 minutes after ejaculation?

Semen coagulates due to clotting proteins

What is the purpose of the coagulation-liquefaction cycle in semen?

Initial thickening keeps semen in female tract; liquefaction allows sperm to swim

Where does capacitation occur?

In the female reproductive tract

What is the first functional change during sperm capacitation?

Acrosome thinning

What is released during the enzyme release phase of capacitation?

Digestive enzymes to act on protective layers of the egg

What happens to the flagellum during capacitation?

It becomes activated and beats vigorously to help penetrate the egg

What is the role of female secretions in sperm capacitation?

They remove cholesterol, glycoproteins, and proteins from the sperm plasma membrane, allowing digestive enzymes to penetrate the oocyte.

What hormone does the hypothalamus release to initiate male reproductive functions?

Gonadotropin-releasing hormone (GnRH).

What are the two gonadotropins released by the anterior pituitary?

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

What is the target of luteinizing hormone (LH) in males?

Interstitial cells (Leydig cells) of the testes.

What is the primary effect of follicle-stimulating hormone (FSH) in males?

It stimulates supporting cells in the seminiferous tubules, promoting spermatogenesis.

What happens to testosterone levels during puberty?

Testosterone is released continuously after being halted during childhood.

What are some secondary sexual characteristics influenced by testosterone?

Deep voice, body hair, thickening of skin, and broadening of shoulders.

What physiological changes can occur due to declining testosterone levels with age?

Decreased muscle mass, libido, possible erectile dysfunction, and decreased energy levels.

What triggers the male sexual arousal response?

Sensory input from visual, tactile, auditory, olfactory stimuli, and mental imagery.