Histology of Male Reproductive System

Question 1

Which ducts move sperm from the testes out of the body?

Answer 1

• Efferent ductules
• Epididymis
• Vas deferens
• Ejaculatory duct
• Urethra

Question 2

Which exocrine glands secrete fluids into the ducts and add to the sperm to make semen?

Answer 2

• Seminal vesicles
• Prostate gland
• Bulbourethral (Cowper’s) gland

Question 3

What type of epithelium makes up the seminiferous tubules?

Answer 3

Simple columnar epithelium of Sertoli cells

Question 4

Testes are derived from __________.

Answer 4

Intermediate mesoderm

NOTE: This occurs via the surface gonadal ridge. Testes then descend into the scrotum

Question 5

The epididymis is derived from the ________.

Answer 5

Mesonephric duct

Question 6

Primordial germ cells migrate into the testis from the _______.

Answer 6

Yolk sac

Question 7

__________ (warmer/cooler) blood in testicular artery. ________ (warmer/cooler) blood in pampiniform plexus.

Answer 7

Warmer; cooler

NOTE: The pampiniform plexus also plays a role in the temperature regulation of the testes. It acts as a countercurrent heat exchanger, cooling blood in adjacent arteries.

Question 8

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Answer 8

Question 9

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Answer 9

Question 10

The functional unit of spermatogenesis is the __________.

Answer 10

Seminiferous tubule

Question 11

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Answer 11

Question 12

Blood-testes barrier

Question 13

Weismann Barrier

Answer 13

The strict distinction between the “immortal” germ cell lineages producing gametes and “disposable” somatic cells

Question 14

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Answer 14

Question 15

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Answer 15

Question 16

Spermatogonia divide via _________ (mitosis/meoisis). Spermatocytes divide via _________ (mitosis/meoisis).

Answer 16

Mitosis; meoisis

NOTE: Gwem cells remain conencted via intracellular bridges as they complete cell division and migrate upwards

Question 17

Cell type summary

Answer 17

Question 18

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Answer 18

Question 19

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Answer 19

• The primary spermatocytes undergo Meiosis I and divide into two daughter cells, known as secondary spermatocytes, a process which takes 24 days to complete.
• Each secondary spermatocyte will form two spermatids after Meiosis II.

Question 20

Spermatogenesis

Answer 20

Question 21

In spermiogenesis, hapoid spermatids become converted into _________.

Answer 21

Mature Spermatozoa

Question 22

Acrosome formation

Answer 22

Vesicles move from the Golgi stack and adhere to one pole of the nucleus to fuse into a large acrosomal vesicle

NOTE: Acrosome contains hydrolytic enzymes that will later aid in fertilation of an oocyte

Question 23

What happens to the nucleus of the sperm as it becomes more developed? How is this achieved

Answer 23

The nucleus becomes very small. It is achieved by removing histone proteins from nucleosomes and replacing them with a smaller peptide, protamine

Question 24

Aside from the removal of histone, how else is change in the nucleus of sperm changed?

Answer 24

The nucleus passes through a narrow perinuclear ring. The perinuclear ring moves along parallel rows o microtubules comprising the “manchette”

Question 25

\_\_\_\_\_\_\_\_\_\_\_\_\_ form the center of the flagellum.

Answer 25

Centrioles

Question 26

Which cell is the main structural cell of the semineferous tubule?

Answer 26

Sertoli cell

Question 27

Components of sertoli cells

Answer 27

* Irregular **eucromatic nuclei** with prominent nucleoli * Numerous **tight junctions**

Question 28

Functions of sertoli cells

Answer 28

* Tight junctions maintain a blood-testis barrier * Secrete sulfated glycoproteins (**clusterin**) that **transport lipids** to germ cells * Secrete **androgen binding protein** * Secrete **transferrin** * Secrete **inhibin,** a TGF-b molecule that **inhibits** **FSH secretion** * Take up **glucose** from the bloodstream, metabolize it to **lactate**, and export lactate to germ cells as a nutrient fuel * Respond to FSH by **stimulating the development of germ cells**

Question 29

Structure of Leydig cells

Answer 29

* Mitochondria with tubular cristae * Abundant sER * Round, eucromatic nuclei **NOTE:** Leydig cells may also possess cytoplasmic **crystals of Reinke**, composed of an uncharacterized protein aggregate

Question 30

Function of leydig cells

Question 31

Myoid cells (image)

Answer 31

Question 32

What epithelium makes up the rete testis?

Answer 32

Simple cuboidal epithelium

Question 33

What accounts for the irregular lumen of efferent ductules?

Answer 33

* Non-ciliated cells * Tall ciliated cells

Question 34

The _________ is an anastomosing network of channels located in the testicular hilum, that receives the luminal contents of seminiferous tubules and empties them into the efferent ductules.

Answer 34

**Rete testis**

Question 35

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Answer 35

Question 36

Components of epididymis

Answer 36

* Tall **principial** cells * Long microvilli (stereocilia) * Basal cells

Question 37

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Answer 37

Question 38

Functions of epididymis

Answer 38

* Absorb water from seminal fluid and secrete chloride * Stores spermatozoa * Secretes proteins that block the receptors on the plasma membrane of sperm head which renders sperm infertile inside the _male tract_ **NOTE:** In cystic fibrosis, epididymis becomes blocked or fails to develop, causing sterility

Question 39

The _____ propels ehaculated sperm from the epididymis toward the urethra.

Answer 39

Vas deferens **NOTE:** Large amounts of smooth muscle are present in the wall of the vas deferens

Question 40

Sperm and seminal fluid mix in the \_\_\_\_\_\_\_\_\_\_and move towards the urethra.

Answer 40

ejaculatory duct

Question 41

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Answer 41

Question 42

What type of epithelium is found in secretory acini of the prostate gland?

Answer 42

Pseudostratified columnar epithelium **NOTE:** The secretory acini also contain loose connective tissue and smooth muscle.

Question 43

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Answer 43

Question 44

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Answer 44

**NOTE:** Condensed, calcified secretory material is defining feature of histology of the prostate gland

Question 45

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Answer 45

Question 46

Epithelium of prostate gland

Answer 46

* Transitional epithelium in upper part * Stratified columnar in the lower parts

Question 47

Functions of prostate gland

Answer 47

* Secretes proteins that help maintain fluidity of semen *

Question 48

Bulbourethral gland

Answer 48

Question 49

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Answer 49

Question 50

Indictor of prostate carcinoma

Answer 50

* Prostate specific antigen (a serine protease

Question 51

Which component of the penis is being described below? **Paired erectile bodies dorsal to the urethra which are responsible for erection.**

Answer 51

Corpora cavernosa

Question 52

Which component of the penis is being described below? ## Footnote **Surrounds the urethra and prevents the collapse of the urethra during erection.**

Answer 52

Corpus spongiosum

Question 53

The propulsion of semen from the male duct system is coordinated by a __________ nervous system reflex causing the smooth muscle surrounding the reproductive ducts and acessory glans to contract.

Answer 53

Sympathetic

Question 54

What factors control penile erection?

Answer 54

* _Parasympathetic_ nerve active releases **nitric oxide** * NO causes **cGMP formation** in smooth muscle * cGMP causes relaxation and dilation of venous channels **NOTE:** Viagrea blocks cGMP degradation by **PDE5**

Question 55

Viagra is an inhibitor of \_\_\_\_\_\_\_\_, an enzyme that degrades cGMP.

Answer 55

Phosphodiesterase **NOTE:** By **elevating cGMP,** erectile dystfunction can be corrected in spite of sub-optimal levels of circulating testoterone

Question 56

How is prostatic hypertrophy treated?

Answer 56

* Prostatectomy * Trans-urethral resection * Radiation