NCM 107: Male Reproductive System

Andrology

The study of reproductive system

Scrotum

Testes

Penis

External Structures of Male Reproductive System

Epididymis

Vas Deferens

Seminal Vesicles

Prostate Gland

Bulbourethral Glands

Urethra

Internal Structures of Male Reproductive System

Scrotum

Rugated, skin-covered muscular pouch suspended from the

perineum which contains the testes, epididymis and lower

portion of spermatic cord

37 degrees Celsius

Major function: Keep the testes cooler than ________ degrees Celsius (_____ degrees Fahrenheit)

Dartos Muscle

Cremaster Muscle

2 Muscles that regulate the temperature of the scrotum and testes.

Urethra

• Last part of the urinary tract

• Traverses the corpus spongiosum and its opening (MEATUS)

• Lies on the tip of the glans penis

• Both a passage for urine and for the ejaculation of semen

1.5 inches long

1 inch wide

Size of a testes

Seminiferous Tubules

• Functional units of the testis (spermatogenesis)

• Produced sperm move to seminiferous tubules (further

• maturation)

100 yards

Seminiferous Tubules Yards (each)

90% of the weight

Seminiferous tubules weight for each testes

Sertoli Cells

• A 'nurse' cell (part of a seminiferous tubule) Activated by FSH

• to nurture the developing sperm cells

• a "mother cell" role

• provides both secretory and structural support

Efferent Ductules

Serve as route for transport out of the sperm from the testis and into the epididymis

Blood Supply

• Testicular arteries (gonadal artery)

• Testicular veins

  • The right testicular vein drains directly into the Inferior vena cava (IVC)

  • The left testicular vein drains into the left renal vein

Epididymis

Seminiferous tubules join together to become the ________

• Place for complete their maturation of the sperm

  • flagella become functional

  • stores sperm until the next ejaculation

20 feet

How long is the tube of epididymis

Vas Deferens

From the epididymis in the scrotum on its own side into the abdominal cavity through the inguinal canal

Inguinal Canal

an opening in the abdominal wall for the spermatic cord (a connective tissue sheath that contains the ductus deferens, testicular blood vessels, and nerves)

Seminal Vesicles

Posterior to the urinary bladder

Joins the ductus deferens to form the ejaculatory duct

Fructose

What does the seminal vesicles secrete?

Alkalinity

What is the energy source of seminal vesicles?

Ejaculatory Ducts

• Each receives sperm from the ductus deferens and the secretions of the seminal vesicle on its own side

• Both ejaculatory ducts empty into the single urethra

Prostate Gland

Muscular gland

The smooth muscle of the _______ contracts during ejaculation to contribute to the expulsion of semen from the urethra

Bulbourethral Glands

• Located below the prostate gland and empty into

  the urethra

• The alkalinity of seminal fluid helps neutralize the acidic vaginal pH permits sperm mobility

Spermatozoa

• more commonly known as a sperm cell

• is the haploid cell that is the male gamete

• are the mature male gametes

Head

Mid (connecting) piece

Tail

End piece

Parts of the sperm

• Acrosome

• Plasma membrane

• Nucleus

• Centriole

Parts of the head of the sperm

Acrosome

a structure at the end of a sperm cell that releases enzymes to digest the cell membrane of an egg, enabling the sperm to penetrate the egg

Cell membrane

The membrane that surrounds the cytoplasm, through which substances pass in and out of the cell

Centriole

During cell division, ______move to opposite ends of the cell and form the poles of the spindle fibers that pull the chromosomes apart.

Nucleus

is a membrane-encased mass of protoplasm containing the chromosomes and other genetic information necessary to control cell growth and reproduction

Mitochondria

produces enzymes for the metabolic conversion of food to energy

Tail flagellates

propels the sperm cell (at about 1-3 mm/minute in humans) by rotating like a propeller (circular motion)

Chemotaxis

sperm cell movement during copulation caused by a chemical stimulus

Spermatogenesis

• Sperm production

• The process by which male spermatogonia develop into

  mature spermatozoa

• Occurs in the male testes and epididymis (approx 64 days)

• Starts at puberty until death

• Production is continuously uninterrupted until death (although with a slight decrease with increase in age)

White, opalescent

Color of the semen

1.028

Specific gravity of a semen

7.35-7.5

pH of the semen

3ml

Volume of the semen

Seminal Plasma

• from the seminal vesicle, prostate, and bulbourethral glands

• provides a nutritive and protective functions (acidity, viscosity and the immune cells of vagina)

Sperm

• the main reproductive cell in males

• each carry a set of chromosomes dividing