Reproductive System PowerPoint

Reproductive Systems

• The reproductive systems enable continuation of the human species by producing offspring.
• Male and female reproductive systems create gametes (sperm and egg cells) and ensure their union during fertilization.

Meiosis

• Meiosis produces gametes.
• One cell with a diploid chromosome number (46) divides twice to produce four cells, each with a haploid chromosome number (23).

Spermatogenesis

• Occurs in the testes.
• Seminiferous tubules contain spermatogonia (sperm-generating cells).
• Follicle-stimulating hormone (FSH) initiates sperm production.
• Testosterone, stimulated by luteinizing hormone, promotes maturation of sperm.
• Inhibin decreases FSH secretion.
• For each primary spermatocyte that undergoes meiosis, four functional sperm cells form.
• Sperm production begins at puberty and continues throughout life.
• Millions of sperm are produced daily.

Oogenesis

• Oogenesis is the process of egg cell formation, through meiosis.
• This process happens in the ovaries.
• It's regulated by hormones.
• Follicle-stimulating hormone (FSH) stimulates the growth of ovarian follicles which contain oogonium or egg generating cells.
• FSH stimulates follicle cells to secrete estrogen that, in turn, promotes maturation of ovum.
• One primary oocyte produces one functional egg, and three polar bodies.
• Ovum production starts at puberty and continues until menopause.
• A mature ovum is produced roughly every 28 days.

Testes

• Located in the scrotum, a sac between the thighs.
• Temperature is 96 degrees, slightly lower than body temperature, for sperm production.
• During fetal development, testes develop near the kidneys, and descend into the scrotum before birth.
• Testes are divided into lobes, each with seminiferous tubules where spermatogenesis takes place.

Epididymis

• A 20-foot long, coiled tube on the posterior side of each testis.
• Sperm mature and gain motility here.
• Smooth muscle propels sperm into the ductus deferens.

Ductus Deferens

• Also called vas deferens.
• Extends from the epididymis into the abdominal cavity through the inguinal canal.
• The inguinal canal is a weak spot that can be a site of hernia formation.
• Inside the abdominal cavity, the ductus deferens travels over and down the urinary bladder to join with the ejaculatory duct.
• Smooth muscles in the ductus deferens contract to help expel sperm during ejaculation.

Ejaculatory Ducts

• Receive sperm from the ductus deferens and secretions from the seminal vesicle.
• Empty into the urethra.

Seminal Vesicles

• Located behind the bladder.
• Secrete fluid containing fructose, an energy source for sperm, and alkaline properties to enhance sperm motility.
• Each duct joins the ductus deferens on the same side forming the ejaculatory duct.

Prostate

• Muscular gland below the bladder.
• Surrounds the urethra.
• Glandular tissue releases an alkaline fluid that maintains sperm motility.
• Prostate smooth muscles help with expulsion of semen.

Bulbourethral Glands

• Also called Cowper's glands.
• Located below the prostate gland and empty into the urethra.
• Secrete an alkaline fluid that coats the urethra before ejaculation to neutralize acidic urine.

Urethra-Penis

• The urethra is the final duct for semen travel.
• It's primarily found within the penis.
• The distal end of the penis is called the glans penis.
• The penis is covered with skin called the foreskin.

Semen

• Semen consists of sperm and secretions from the seminal vesicles, prostate, and bulbourethral glands.
• The pH of semen is about 7.4.
• 2–4 mL of semen are expelled, with each mL containing around 100 million sperm cells.

Female Reproductive System

• Ovaries are paired oval structures, about 1.5 inches long.
• They are located on either side of the uterus in the pelvic cavity.
• Broad ligaments keep ovaries in position.
• Several hundred thousand primary follicles are present at birth; about 300–400 mature.
• Each follicle contains an oocyte (a potential egg cell).
• Follicle cells secrete estrogen.
• A graafian follicle is a mature follicle.
• LH triggers ovulation or follicle rupture, releasing the ovum.

Fallopian Tubes

• 4 inches long.
• Lateral end surrounds the ovary.
• Fimbriae creates currents in the fluid to pull ovum into the tube.
• The medial end opens into the uterus.
• Smooth muscles cause peristalsis, moving the ovum.
• Ciliated mucosa sweeps the ovum to the uterus.
• Fertilization occurs inside the fallopian tubes.
• If not fertilized, ovum dies within 24–48 hours and disintegrates.
• Fertilized ovum becomes a zygote and travels to the uterus (4–5 days).
• Ectopic pregnancy occurs when implantation happens outside of the uterus.

Uterus

• 3 inches long by 2 inches wide.
• Superior to the bladder, between the ovaries in the pelvic cavity.
• Broad ligaments cover the uterus.
• Composed of fundus, body, and cervix.
• Myometrium is the muscular layer, and endometrium is the inner lining divided into functional and basal layers.

Vagina

• Muscular tube about 4 inches in length.
• Extends from the cervix to the vaginal orifice in the perineum (pelvic floor).
• Posterior to the urethra and anterior to the rectum.
• Partially covered with the hymen.
• Serves as receiving area for sperm.
• Exit for menstrual blood flow and the birth canal.

External Genitals

• Another name for the vulva.
• Include the clitoris, labia majora, labia minora, and Bartholin's glands.

Mammary Glands

• Produce milk to nourish offspring.
• Composed of glandular tissue surrounded by adipose tissue.
• Alveolar glands create milk after pregnancy.
• Milk travels through lactiferous ducts to the nipple.
• The areola is pigmented skin surrounding the nipple.
• Estrogen and progesterone prepare glands for milk production.

Menstrual Cycle

• A 28-day cycle.
• Phases include menstrual, follicular, and luteal.
• Amenorrhea can be related to insufficient body fat.

Additional Conditions

• Prostatic hypertrophy is an enlargement of the prostate common in men over 60 years old.
• A prostatectomy is the surgical removal of part or all of the prostate.
• Cancer of the prostate is a common cancer in men over 50