Male Reproductive Flashcards
What are the primary and secondary sex organs?
Primary: testes
Secondary: ducts, glands, penis
What are the external and internal genitalia?
External: in perineum, scrotum and penis
Internal: in pelvic cavity (except testes)
What are the secondary sex characteristics?
facial hair, muscles, coarse hair
What is the spermatic cord?
—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
What are the testis temperature regulation mechanisms?
– 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
What is the tunica albuginea?
white fibrous capsule on testes
What are the seminiferous tubules?
ducts where sperm are produced
What are the sustentacular (Sertoli) cells
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
What are interstitial (leydig) cells?
between tubules
produce testosterone
What is the blood-testis barrier?
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
What is the path of sperm
Seminiferous tubules
→
Rete testis
→
Vasa efferentia
→
Epididymis
→
Vas deferens
→
Ejaculatory duct
→
Urethra.
What are the seminal vesicles?
- Pair of glands posterior to bladder
- Empties into ejaculatory duct
- Forms 60% of semen
What is the prostate gland?
- 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
What is semen made up of?
product of testes, prostate gland, and seminal vesicle
What is the bulbo-urethral gland?
- 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
What is benign prostatic hyperplasia?
noncancerous enlargement of the prostate
– Compresses urethra and obstructs flow of urine
– Promotes bladder and kidney infections
How is prostate cancer diagnosed?
elevated levels of serine protease and acid phosphatase, DRE
What are the components of the penis?
root, shaft, glans, prepuce
What are the types of erectile tissue?
– 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
What starts puberty? How old?
surge of pituitary gonatotropins, 10-12 years, adrenal gland responsible
What do the hormones do?
- 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
What are the parts of spermatozoon?
– 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
What is a normal sperm count? What is infertility?
50-120 million, below 20-25 million
What are the fluid’s roles in semen?
– 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
