Male Reproductive

Question 1

What are the primary and secondary sex organs?

Answer 1

Primary: testes
Secondary: ducts, glands, penis

Question 2

What are the external and internal genitalia?

Answer 2

External: in perineum, scrotum and penis
Internal: in pelvic cavity (except testes)

Question 3

What are the secondary sex characteristics?

Answer 3

facial hair, muscles, coarse hair

Question 4

What is the spermatic cord?

Answer 4

—bundle of fibrous connective
tissue containing the ductus deferens, blood and
lymphatic vessels, and testicular nerve
– Continues through inguinal canal into pelvic cavity
– External inguinal ring: inferior entrance to inguinal canal
– Internal inguinal ring: superior exit to pelvic cavity

Question 5

What are the testis temperature regulation mechanisms?

Answer 5

– Cremaster muscle: strips of the internal abdominal
oblique muscle
* Enmesh the spermatic cord
* In cold temperatures, contracts and draws testes upward
toward body
* In warm temperatures, relaxes suspending testes further
from body
– Dartos muscle: subcutaneous layer of smooth muscle
* Contracts when cold, wrinkling the scrotum, holding testes
against warm body
* Reduces surface area of the scrotum and heat loss
– Pampiniform plexus: an extensive network of veins
from the testes that surrounds the testicular artery and
spermatic cord
* Countercurrent heat exchanger—without the
pampiniform plexus, warm arterial blood would heat the
testis and inhibit sperm production
* Removes heat from the descending arterial blood
* By the time it reaches the testis, the blood is 1.5° to 2.5°C
cooler

Question 6

What is the tunica albuginea?

Answer 6

white fibrous capsule on testes

Question 7

What are the seminiferous tubules?

Answer 7

ducts where sperm are produced

Question 8

What are the sustentacular (Sertoli) cells

Answer 8

in between germ cells
* Protect the germ cells, and promote their development
* Germ cells depend on them for nutrients, waste removal,
growth factors, and other needs

Question 9

What are interstitial (leydig) cells?

Answer 9

between tubules
produce testosterone

Question 10

What is the blood-testis barrier?

Answer 10

formed by tight
junctions between sustentacular cells
– Separates sperm from immune system
– Prevents antibodies and other large molecules in the
blood from getting to germ cells
– Germ cells are immunologically different from body cells
and would be attacked by the immune system
– Some cases of sterility occur because the BTB failed to
form correctly during adolescence and the immune
system produces antibodies against the germ cell

Question 11

What is the path of sperm

Answer 11

Seminiferous tubules
→
Rete testis
→
Vasa efferentia
→
Epididymis
→
Vas deferens
→
Ejaculatory duct
→
Urethra.

Question 12

What are the seminal vesicles?

Answer 12

• Pair of glands posterior to bladder
• Empties into ejaculatory duct
• Forms 60% of semen

Question 13

What is the prostate gland?

Answer 13

• Surrounds urethra and ejaculatory duct just inferior to the
  bladder
• 30 to 50 compound tubuloacinar glands
• Empty through about 20 pores in the prostatic urethra
• Thin milky secretion forms 30% of semen

Question 14

What is semen made up of?

Answer 14

product of testes, prostate gland, and seminal vesicle

Question 15

What is the bulbo-urethral gland?

Answer 15

• Near bulb of penis
• During sexual arousal, they produce a clear slippery fluid
  that lubricates the head of the penis in preparation for
  intercourse
• Protects the sperm by neutralizing the acidity of residual
  urine in the urethra

Question 16

What is benign prostatic hyperplasia?

Answer 16

noncancerous enlargement of the prostate
– Compresses urethra and obstructs flow of urine
– Promotes bladder and kidney infections

Question 17

How is prostate cancer diagnosed?

Answer 17

elevated levels of serine protease and acid phosphatase, DRE

Question 18

What are the components of the penis?

Answer 18

root, shaft, glans, prepuce

Question 19

What are the types of erectile tissue?

Answer 19

– Single corpus spongiosum along ventral side of penis
* Encloses spongy (penile) urethra
* Distal end enlarges and forms the glans penis
– Two corpora cavernosa
* Diverge like arms of a Y
* Each arm, called a crus, attaches penis to pubic arch

Question 20

What starts puberty? How old?

Answer 20

surge of pituitary gonatotropins, 10-12 years, adrenal gland responsible

Question 21

What do the hormones do?

Answer 21

• Follicle-stimulating hormone (FSH)
  – Stimulates sustentacular cells to secrete androgen-
  binding protein that binds testosterone, keeping it in
  seminiferous tubule lumen to stimulate
  spermatogenesis
• Luteinizing hormone (LH) sometimes called interstitial
  cell–stimulating hormone (ICSH)
  – Stimulates interstitial cells to produce testosterone

Question 22

What are the parts of spermatozoon?

Answer 22

– Head is pear-shaped
* 4 to 5 μm long; structure contains nucleus, acrosome, and
basal body of tail flagellum
* Nucleus contains haploid set of chromosomes
* Acrosome—enzyme cap over the apical half of the nucleus
that contains enzymes that penetrate the egg
* Basal body—indentation in the basal end of the nucleus
where flagellum attaches
* Tail is divided into three regions
– Midpiece contains mitochondria around axoneme of the
flagella, produces ATP for flagellar movement
– Principal piece is axoneme surrounded by sheath of
supporting fibers
* Constitutes most of tail
– Endpiece is very narrow tip of flagella

Question 23

What is a normal sperm count? What is infertility?

Answer 23

50-120 million, below 20-25 million

Question 24

What are the fluid’s roles in semen?

Answer 24

– Prostate produces a thin, milky white fluid
* Contains calcium, citrate, and phosphate ions
* Clotting enzyme
* Protein-hydrolyzing enzyme called serine protease
(prostate-specific antigen)
– Seminal vesicles contribute viscous yellowish fluid
* Contains fructose and other carbohydrates, citrate,
prostaglandins, and protein called proseminogelin
– Stickiness of semen promotes fertilization
* Clotting enzyme from prostate activates proseminogelin
* Converts it to a sticky fibrin-like protein: seminogelin
* Entangles the sperm
* Sticks to the inner wall of the vagina and cervix
* Ensures semen does not drain back into vagina
* Promotes uptake of sperm-laden clots of semen into the
uterus
* 20 to 30 minutes after ejaculation, serine protease from
prostatic fluid breaks down seminogelin, and liquifies the
semen