Male Reproductive Histology

Question 1

each testis is covered by a visceral layer of _______ and reside in a _______ lined by a parietal layer of _________

Answer 1

each testis is covered by a visceral layer of processus vaginalis and reside in a serous cavity lined by a parietal layer of processus vaginalis

processus (tunica) vaginalis: out-pouching of the peritoneum that leads the descent of each testis

Question 2

tough, fibrous capsule surrounding each testis

Answer 2

tunica albuginia (“white tunic”)

at the posterior end this is thickened to form the mediastinum testis, from which septa extend to divide testis into lobules

Question 3

what is contained in each testis lobule?

Answer 3

1-4 seminiferous tubules - site of sperm production

solid cords until puberty when they acquire a lumen

Question 4

loose, highly vascular connective tissue surrounding the testis

Answer 4

tunica vasculosa - deep to the fibrous tunica albuginia and continuous with the vascular connective tissue surrounding the seminiferous tubules

Question 5

which cells are found in small clusters in the vascular connective tissue surrounding the seminiferous tubules?

Answer 5

Leydig interstitial cells - secrete androgens

Question 6

what are the layers of the testis from superficial to deep? (3)

Answer 6

1. tunica albuginia
2. tunica vasculosa
3. seminiferous tubules (containing Leydig cells)

Question 7

seminiferous tubules are lined with these 2 populations of cells:

Answer 7

1. germinal epithelium - site of spermatogenesis
2. Sertoli cells - “nurse”/supportive cells

outermost layer is 3-5 layers of peritubular myoid (contractile) cells

Question 8

order the following from the lumen of the seminiferous tubules moving outwards: spermatogonia, primary spermatocytes, Sertoli cells, spermatids

Answer 8

1. spermatids (innermost)
2. primary spermatocytes
3. Sertoli (“nurse” cells - larger and more pale)
4. spermatogonia (outermost, stem cells)

Question 9

the blood-testis barrier is made of _____ and separates which 2 populations of cells?

Answer 9

blood-testis barrier: made of Sertoli cell cytoplasmic processes (form occluding junctions), separates spermatogonia (basal compartment) from primary spermatocytes (adluminal compartment)

Question 10

what are the 4 phases of spermiogenesis?

Answer 10

1. Golgi phase - hydrolytic enzymes sorted, centrioles migrate
2. Cap phase - acrosome sac flattens
3. Acrosomal phase - distal centriole gives rise to axoneme, mitochondria migrates
4. Maturation phase - outer dense fibers of Keratin develop along the axoneme

this produces immobile spermatozoa not yet capable of fertilizing an egg

[Guys Can Always Mature]

Question 11

what causes Kartagener’s syndrome?

Answer 11

aka immotile cilia syndrome: inherited disorder in which cilia lack dynein

—> infertility (males), chronic sinusitis and bronchitis

Question 12

during spermiogenesis, maturing spermatids are embedded in…

Answer 12

… cytoplasm of the Sertoli cells

Question 13

what are the functions of the following hormones secreted by Sertoli cells?
A. Activin
B. Inhibin
C. Androgen binding proteins
D. Mullerian inhibitory substance

Answer 13

A. Activin: promotes the release of FSH (—> increased spermatogenesis)
B. Inhibin: suppresses the release of FSH
C. Androgen binding proteins: essential for keeping the level of testosterone higher inside the seminiferous tubules relative to outside
D. Mullerian inhibitory substance: suppresses müllerian duct development (female)

Question 14

On which male reproductive cells does luteinizing hormone act and what is its function?

Answer 14

LH from the anterior pituitary stimulates the interstitial cells of Leydig to produce testosterone

therefore, it makes sense that Leydig cells are found near blood supply

it also then makes sense that Leydig cells contain lipid droplets for steroid hormone production

Question 15

what is the skeletal vs smooth muscle of the testis called?

Answer 15

skeletal = Cremaster
smooth = Dartos

Question 16

The testicular arteries are surrounded by what plexus?

Answer 16

Pampiniform venous plexus – important for countercurrent heat exchange (spermatogenesis is temperature sensitive)

Question 17

name the structures of the male reproductive duct system, beginning with the seminiferous tubules and ending with the urethra (8)

Answer 17

1. seminiferous tubules
2. straight tubules
3. rete testis
4. efferent ductules (beginning of extra-testicular ducts)
5. epididymis
6. ductus (vas) deferens
7. ampulla (storage of spermatozoa)
8. ejaculatory duct
   8 urethra

Question 18

what happens to spermatozoa as they move through the epididymis?

Answer 18

Acquire motility + surface associated proteins that will ultimately be removed in the female reproductive tract

Question 19

what are the parts of male urethra? (3)

Answer 19

1. prostatic
2. membranous
3. penile (spongy)

Question 20

what type of epithelium is found in the seminal vesicles and why does this make sense?

Answer 20

Columnar with goblet cells – produce thick seminal fluid that is rich in fructose, serves as a source of nutrition for sperm

Seminal fluid constitutes about 70% of semen

Question 21

What is the function of the male reproductive structure found immediately inferior to the bladder and immediately superior to the urogenital diaphragm?

Answer 21

prostate gland - contributes essential secretions to semen which maintain sperm viability

urethra passes through the prostate gland and is joined by the ejaculatory ducts

Question 22

what are the three types of cells found in the prostatic epithelium?

Answer 22

1. Secretory cells – vary from cuboidal to columnar and produce prostatic fluid.
2. Basal cells – stem cells to renew secretory epithelium.
3. Neuro endocrine cells – function unknown.

Question 23

what are the three zones of the prostate gland?

Answer 23

1. Transition zone: surrounds the urethra, enlargement commonly gives rise to benign prosthetic hyperplasia and ~20% of prostatic cancers originate here
2. Central zone: contributes about 25% of glandular tissue
3. peripheral zone: ~70% of glandular tissue and ~70% of prostatic cancers arise here

Question 24

From which zone of the prostate do most prosthetic cancer is arise?

Answer 24

peripheral zone – makes up most of the glandular tissue

Question 25

What is the function of the bulbourethral/Cowper’s glands?

Answer 25

paired glands found in the urogenital diaphragm that secrete mucus into the penile urethra at the start of sexual arousal for lubrication

Question 26

what is the function of the urethral glands of Littre?

Answer 26

microscopic glands found in penile/spongy urethra that secrete glycosaminoglycans that protect the epithelium from urine

Can become inflamed (urethritis), site of gonorrhea infections