Lab 15: Male Reproductive Organs

Testes

-gonads to produce sperm

Epididymides (singular Epididymis)

-ductus deferens and urethra- accessory ducts for storage, maturation, and transport of sperm

Prostate Gland
Seminal vesicles
Bulbourethral glands

-accessory glands that secrete the fluid portion of semen

Penis + Scrotum

the external genitalia

Penis

-contains erectile tissue
-delivers sperm into vagina
-produces sexual sensations

Testis

-male gonad
-pair of organs
-produces sperm
-secretes testosterone
-plural is testes

Scrotum

-tissue sac
-encases testes, epididymides, and spermatic cords

Epididymis

-one associated with each testis
-receives sperm from testes
-site of sperm maturation

Prostate Gland

-single gland
-secretes part of semen fluid

Bulbourethral Gland

-pair of glands
-secrete part of semen fluid

Seminal Vesicle

-pair of glands
-secrete part of semen fluid

Ductus Deferens

-one associated with each testis ductus deferens
-receives sperm from epididymis
-transports sperm from epididymis through pelvic cavity to the urethra

Urethra

-receives semen from ductus deferens
-transports semen through penis to exterior

Head of epididymis

-portion of epididymis proximal to the testis

Efferent Ductule

-transport sperm from rete testis to epididymis

Rete Testis

-network of tubules
-collect sperm from seminiferous tubules
-transport sperm to efferent ductules

Body of epididymis

-begins distal to last efferent ductile and passes inferiorly along posterior margin of testis to the tail

Tail of epididymis

-begins near inferior border of testis where number of coils decreases

Spermatic Cord

-consists of ductus deferen, arteries, veins nerves, and lymphatic vessels
-pathway between scrotum and pelvic cavity

Seminiferous Tubule

-highly coiled tubule
-one per lobule
-sperm are produced in walls of tubule and then released into tubule lumen

Septum

-fibrous septa subdivided testis into lobules
-formed by infolding of tunica albuginea

Lobule

-subdivisions of testis
-each contains a seminiferous tubule

Tunica Albuginea

-tough fibrous capsule around each testis
-whitish in color

Tunica Vaginalis

-sheath of serous membrane
-encases testis and epididymis
-derived from peritoneum
-has two layers

Sperm Production

Step 1. Spermatogenesis
Step 2. Spermiogenesis

Spermatogenesis

-involves a diploid stem cell, the spermatogonium, undergoing meiosis to produce haploid gametes, the spermatids
-each spermatogonium produces four spermatids

Spermiogenesis

-is the physical change that converts a spermatid into a spermatozoan

Second Function of the testes

-is to secrete testosterone
-is performed by endocrine cells called interstitial cells

Testosterone has many targets

-assisting in the stimulation of sertoli cells to promote spermatogenesis
-stimulating bone and muscle growth
-establishing and maintaining secondary sexual characteristics
-maintaining libido
-maturing and maintaining male accessory glands

Spermatogonium

-stem cell
-constantly undergoes mitosis to maintain a relatively constant number

Primary Spermatocyte

-a spermatogonium cell that has entered spermatogenesis
-destined to become four sperm cells

Secondary Spermatocytes

-cells that have completed meiosis I

Spermatids

-cell that has completed meiosis II
-ready to undergo spermiogenesis

Spermatozoa

-immature sperm cells that have completed spermiogenesis
-now in lumen of seminiferous tubule
-ready for transport to epididymis

Sertoli Cell

-also called nurse cells
-adjacent sertoli cells create a channel for developing spermatocytes
-support and protect spermatocytes

Interstitial Cell

-also called Leydig cell
-located in spaces between adjacent seminiferous tubules
-endocrine cell that secretes testosterone

Acrosomal Cap

-membranous covering over head
-contains enzymes vital for fertilization

Head

-contains haploid sperm nucleus

Neck

-contains centrioles from spermatid cell

Midpiece

-contains mitochondria in spiral formation
-produces ATP to power flagellum for swimming

Flagellum

-moves in whip-like pattern to propel sperm forward

Ampulla

-widened terminal end of ductus deferens

Ejaculatory Duct

-carries sperm from ampulla and fluid from seminal vesicles to prostatic urethra

Prostatic Urethra

-portion of urethra that passes through prostate gland

Membranous Urethra

-short length of urethra between prostatic and penile urethra
-passes through urogenital diaphragm

Penile Urethra

-also called spongy urethra
-portion of urethra that extends the length of the penis

Bulbourethral Gland 2

-also called Cowper's Gland
-fluid secreted is alkaline to neutralize acidic environment of urethra and female reproductive tract and contains mucus to lubricate lining of urethra and tip of penis during intercourse

Prostate Gland 2

-encircles urethra
-fluid secreted is 20-30% of semen volume
-fluid secreted contains sugars, nutrients, and enzymes to nourish and assist sperm

Seminal Vesicle 2

-fluid secreted is 60% of semen volume
-fluid secreted is alkaline to neutralize acidic environment of urethra and female reproductive tract, supplies fructose for sperm to use for ATP synthesis , and aids in sperm motility and viability

Prepuce

-commonly called foreskin
-covering of skin over glans penis

Glans Penis

-expanded tip of penis
-formed by enlarging corpus spongiosum
-surrounds external urethral meatus

Shaft of penis

cylindrical portion of penis

Corpus spongiosum

Single column of erectile tissue running length of shaft
-network of vascular spaces
-when sexually aroused, spaces fill with blood to produce erection

Crus of Penis

-one on each side
-part of root of penis
-formed by each corpus cavernosa
-anchored to ischium and pubis

Bulb of penis

-expanded base of penis
-part of root of penis
-formed by corpus spongiosum

Root of Penis

-attaches penis to body wall
-consists of bulb of penis and crura of penis

Testicular Pathologies

-Cryptorchidism
-Epididymitis
-Hydrocele
-Orchitis
-Spermatic cord varicocele
-Testicular torsion

Cryptorchidism

the migration from pelvic cavity to scrotum fails to occur for either one or both testes. If the condition does not correct itself by age 2, then a surgical procedure is performed, called orchiopexy, to correctly position the testes

Epididymitis

is swelling and inflammation of the epididymis
-frequently is the result of an infection spreading from the urethra into the epididymis
Symptoms Include:
-pain
-tenderness in the scrotum
-blood in the semen

Hydrocele

this occurs when excess fluid escapes from the peritoneal cavity and collects in the cavity between the two layers of the tunica vaginalis
-exists at birth, it typically corrects itself and the excess fluid is reabsorbed
Symptoms:
-painless
-swollen scrotum
-feels like water balloon

Orchitis

pain and swelling in one or both testes
-may be caused by a variety of bacteria and viruses
-is a potential complication of mumps and can result in infertility by damaging the testes
-may be associated with infections of the prostate gland or epididymis
Symptoms:
-pain
-swelling in scrotum
-blood in semen

Spermatic Cord Varicocele

is a dilated vein
-it is one of the veins in the spermatic cord
-typically develops after puberty and is caused by too few valves in the vein allowing blood to pool
-condition is mild and is usually pain free
-if condition is severe, then there is tenderness and the possibility of infertility. Infertility may be due to the impaired flow to the testicles and the increased testicular temp. Spermatogenesis is a temperature-dependent process
-if there is increased flow of warm blood to the testes, then their internal temp may be increased

Testicular Torsion

caused by a twisting of the spermatic cord
-threatens to cut off blood supply to the testes if not quickly corrected
-condition may develop testicular trauma
-some men are congenitally prone because they have insufficient connective tissue surrounding and protecting the blood vessels in the spermatic cord

Which of the following pairs is NOT correctly matched?
a. male gonad-penis
b. male gamete-sperm
c. female gonad-ovary
d. female gamete-ovum

a. male gonad-penis

The tough, white, fibrous capsule around the testis is the:
a. tunica vaginalis
b. testicular septum
c. tunica albuginea
d. testicular lobule

c. tunica albuginea

which of the following statements regarding the epididymis is NOT true?
a. it is tubular organ
b. it sits along the lateral border of each testis
c. it is the site of sperm maturation
d. it releases sperm into the ductus deferens

b. it sits along the lateral border of each testis

Which is NOT part of the spermatic cord?
a. blood vessels
b. nerves
c. lymphatic vessels
d. efferent ductules

d. efferent ductules

Which cells secrete testosterone?
a. Sertoli cells
b. spermatogonium
c. interstitial cells
d. nurse cells

c. interstitial cells

Which of the following pairs is NOT correctly matched?
a. spermatid-is ready to undergo spermiogenesis
b. secondary spermatocyte- has completed meiosis II
c. primary spermatocyte-cell that has entered spermatogenesis
d. spermatogonium-diploid stem cell

b. secondary spermatocyte-has completed meiosis II

The sperm nucleus is located in the:
a. neck
b. acrosomal cap
c. midpiece
d. head

d. head

which accessory gland secretes sugars and nutrients to nourish the sperm?
a. prostate gland
b. seminal vesicles
c. glans penis
d. bulbourethral gland

a. prostate gland

The penile urethra is located within:
a. corpus spongiosum
b. bulbourethral gland
c. corpus cavernosa
d. prostate gland

a. corpus spongiosum

Which section of the urethra is also called the spongy urethra?
a. membranous
b. penile
c. prostatic
d. ampulla

b. penile