Male Reproductive System

Question 1

3 functions of male reproductive system

Answer 1

1 - production of spermatazoa
2 - delivery of semen into the female reproductive tract
3 - production of androgens, chiefly testosterone

Question 2

What are the 3 layers of the scrotum lining?

Answer 2

Mesothelium
Tunica Albuginea
Tunica Vasculosa

Question 3

What is the function of the tunica albuginea in the testis?

Answer 3

Tough fibrous capsule

Question 4

What is the function of the tunica vasculosa in the testis?

Answer 4

Sends septa into the testis to divide it into lobules

Question 5

Excretory tubules of the testes

Answer 5

Seminiferous tubules connected to the rete testis by straight tubules.
Rete testis carry sperm out of the testis connecting to a series of efferent ductules forming the head of the epididymis
Body and tail of epididymis forms a single coiled tube where sperm mature and are temporarily stored.
Epididymis continuous with vas deferens which takes sperm away from scrotum and along spermatic cord during ejaculation.

Question 6

What are seminiferous tubules lined by?

Answer 6

Seminiferous epithelium consisting of various germ cells and a support cell called a Sertoli cell

Question 7

What is seminiferous epithelium bound by?

Answer 7

A basal lamina and lamina propria of connective tissue and myofibroblasts.

Question 8

What are leydig cells and where are they found?

Answer 8

Found in connective tissue between seminiferous tubules.

Endocrine cells which produce testosterone

Question 9

What is spermatogenesis?

Answer 9

The process of proliferation and maturation that transforms diploid spermatagonia into haploid spermatazoa.

Question 10

What is the journey of spermatagonia to spermatazoa during spermataogenesis?

Answer 10

Spermatagonia 
(mitosis)
Primary Spermatocytes
(meiosis 1 - slow process)
Secondary spermatocytes
(meiosis 2 - rapid process)
Spermatids
(spermiogenesis)
Spermatozoa

Question 11

What is the structure of sertoli cells?

Answer 11

They extend from the basal lamina to the lumen of their tubule.
Their cytoplasm ramifies and surrounds all of the developing cells.

Question 12

5 functions of sertoli cells

Answer 12

1 - secrete factors that regulate spermatogenesis and spermiogenesis
2 - secrete factors that control Leydig cells
3 - secrete tubular fluid
4 - phagocytose discarded spermatid cytoplasm
5 - divide the tubule epithelium into two compartments via tight junctions

Question 13

What does the basal compartment contain?

Answer 13

spermatagonia and early primary spermatocytes

Question 14

What does the adluminal compartment contain?

Answer 14

All other developing cells (not spermatagonia or primary spermatocytes)

Question 15

What is spermiogenesis?

Answer 15

The maturation of the spermatid into a spermatozoa

Question 16

Key steps of spermiogenesis

Answer 16

1 - production of acrosomal cap from acrosomal vesicle. Has enzymes that allow penetration of corona radiata and zona pellucida during fertilisation.
2 - elongation of nucleus and centriole to form flagellum
3 - release of excess cytoplasm (residual body) which is phagocytosed by sertoli cell

Question 17

What is spermiation?

Answer 17

Release of the spermatazoa by sertoli cells into the lumen

Question 18

How do spermatozoa get to the rete testis and epididymis?

Answer 18

Because they are immotile and incapable of fertilisation at spermiation, they are swept into the rete testis and epididymis by fluid flow and peristalsis.
They become fertile and motile during their passage through the epididymis.

Question 19

What do Leydig cells respond to?

Answer 19

LH from the pituitary gland releasing testosterone which acts locally on seminiferous tubules and enters circulation

Question 20

What are the rete testis lined by?

Answer 20

Simple cuboidal ciliated epithelium

Question 21

What are the efferent ducts lined by?

Answer 21

Ciliated epithelium that varies from cuboidal to pseudostratified columnar - gives surface of tubules a “scalloped” appearance

Question 22

What happens in the efferent ducts?

Answer 22

Most of the fluid that comes from the testis is absorbed here

Question 23

What is the epididymis lined by?

Answer 23

Pseudostratified columnar epithelium with stereocilia

Question 24

What happens in the epididymis?

Answer 24

Sperm are stored for about a week and mature, becoming motile and capable of fertilisation

Question 25

What are the vas deferens lined by?

Answer 25

Pseudostratified columnar epithelium with stereocilia

Question 26

What happens in the vas deferens?

Answer 26

3 layers of smooth muscle innervated by sympathetic nervous system producing strong peristalsis during ejaculation

Question 27

What is most of the ejaculate derived from?

Answer 27

Seminal vesicles and prostate gland

Question 28

What do the bulbourethral glands contribute?

Answer 28

A clear fluid that is released before ejaculation which helps lubricate the urethra.

Question 29

What are the 3 segments of the urethra?

Answer 29

Prostatic urethra Membranous urethra Penile urethra

Question 30

What are the seminal vesicles?

Answer 30

A sac with a complex array of folds lined by pseudostratified columnar epithelium with smooth muscle surrounding the folds

Question 31

What does the duct from the seminal vesicle join and then form?

Answer 31

Joins the vas deferens to form the ejaculatory duct which pierces the prostate gland and empties into the urethra

Question 32

Structure of the prostate

Answer 32

Surrounded by a thin fibromuscular capsule and defined by fibromuscular septa forming spaces lined by heterogeneous secretory epithelium.

Question 33

What passes through the prostate and where?

Answer 33

Urethra and ejaculatory ducts pass through fibrous stromal tissue at the centre of the gland

Question 34

What does the prostate gland produce?

Answer 34

A watery fluid that makes up about a third of the ejaculate

Question 35

What are the three zones of the prostate?

Answer 35

Transitional zone - around urethra Central zone - posterior to transitional zone Peripheral zone - lateral to other zones, makes up most of gland

Question 36

What is the structure of the penis?

Answer 36

``` Richly vascularised subcutaneous layer Fibrocollagenous capsule (tunica albuginea) containing 3 erectile columns - 2 corpora cavernosa and corpus spongiosum which has urethra running through ```

Question 37

Why does the spongiosum have less erectile function than the cavernosa?

Answer 37

Contains more connective tissue which aids passage of semen through the urethra

Question 38

What is the penile urethra lined by?

Answer 38

Stratified columnar epithelium, changing to non-keratinised stratified squamous near the tip

Question 39

Structure of erectile tissue

Answer 39

Consists of blood sinuses surrounded by fibromuscular tissue containing smooth muscle

Question 40

What are the blood sinuses in erectile tissue supplied by?

Answer 40

Helicine arteries which are spiral in shape

Question 41

What does parasympathetic stimulation of the penis lead to?

Answer 41

Dilation of the helicine arteries which causes the sinuses to become engorged with blood and press on the veins, restricting venous outflow