H18- Male Reproductive System

Question 1

Consists of

Answer 1

Gonads (testes) and their excretory ducts, accessory sex glands and the penis

Question 2

Excretory ducts (associated parts)

Answer 2

tubuli recti, rete testis, ductuli efferentes, ductus deferens,, ejaculatory duct, urethra)

Question 3

Accessory sex glands (associated parts)

Answer 3

seminal vesicles, prostate, and bulbourethral glands)

Question 4

Function of male reproductive system

Answer 4

production of male gametes (spermatozoa), components of semen, and male hormones

Question 5

Testes

Answer 5

Compound tubular glands
Exocrine- produce holocrine secretion (spermatozoa)
Endocrine- produce male hormone (testosterone)

Question 6

3 layers of testicular capsule

Answer 6

Tunica Vaginalis (outer layer)- mesothelium
Tunica Albuginea (middle layer)- dense fibroelastic CT 
Tunica Vasculosa (inner layer)- blood vessels in loose CT
(continuous with intestinal tissue of testis)

Question 7

Tunica Albuginea

Answer 7

• Thickens posteriorly to form mediastium testis
• Septa radiate into testis and divide it into 200-300 pyramidal compartments- testicular lobes
• Each lobule has 1-4 seminiferous tubules

Question 8

Parenchyma of testis

Answer 8

Interstitial tissue and seminiferous tubules

Question 9

Interstitial tissue (of parenchyma of testis)

Answer 9

• Macrophages
• Blood and lymph vessels
• nerves and miscellaneous cells
• Most important cell type: Interstitial cell (of Leydig)

Question 10

Interstitial Cells of Leydig

Answer 10

Large polyhedral cell lying between seminiferous tubules
Spherical nucleus
Binucleate, distinct nucleus

Question 11

Interstitial Cells of Leydig secrete:

Answer 11

Testosterone

Question 12

Testosterone (3 facts)

Answer 12

• From Interstitial cells of Leydig
• Released by endocrine mode of secretion
• Production is controlled by LH (luteinizing hormone) from basophils of the adenohypophysis (pituitary gland)

Question 13

Testosterone is responsible for

Answer 13

the proliferation and differentiation of germ cells, the development and maintenance of excretory ducts and accessory sex glands, and the development and maintenance of secondary sex characteristics

Question 14

Seminiferous Tubules

Answer 14

400-600 per testis
Coiled Tubes
0.2mm in diameter, and 30-70 cm long, 250 m/testis

Question 15

Seminiferous Tubule epithelium and basement membrane

Answer 15

germinal epithelium, rests on a basement membrane

BM covered externally by fibrous lamina propria which contains fibroblasts, collagen and myoid cells (myoid cells are contractile and aid in sperm movement)

Question 16

Seminiferous (germinal) epithelium has 2 cell types:

Answer 16

1) Sustentacular cells of Sertoil (supporting or nurse cells)
2) Spermatogenic cells

Question 17

Sustentacular cells of sertoli (Sertoli cells)

Answer 17

Spaced along the seminiferous tubule, extend fro basal lamina to lumen of tubule

1) Tall, pillar-like cells; pale ovoid nucleus with prominent nucleolus
2) Adjacent Sertoli cells are connected by tight junctions

Question 18

Adjacent Sertoil cells form:

Answer 18

Blood-testis barrier, which prevents contents of tubule from freely interacting with vascular system and divides tubule into 2 compartments:

Basal compartment (between cell junctions and basal lamina)
Adluminal compartment (between cell junctions and lumen)

Question 19

Basal compartment

Answer 19

between cell junctions and basal lamina
contains spermatogenic cells
area of free exchange

Question 20

Adluminal compartment

Answer 20

between cell junctions and lumen
Contains more differentiated germ cells
Isolated from blood vessels, receive nutrition from Sertoli cells
Prevents protein from lumen from reaching the blood and causing formation of antibodies to sperm

Question 21

During differentiation, spermatogenic cells attached to and nourished by

Answer 21

Sertoli Cells

Question 22

Sertoli cells produce 3 compounds

Answer 22

Androgen Binding Protein (ABP)- concentrates testosteron in adluminal compartment

Inhibin- regulates follicle stimulating hormone (FSH) levels from the pituitary gland and so the number of cells entering spermatogenesis

Mullerian Inhibiting Hormone (Anti-Mullerian)- secreted prenatally, suppresses development of Mullerian duct (of females) and promotes development of the Wolffian duct (of males) RAWWWR (wolf)

Question 23

Spermatogenic cells (germ cells of DA BOYZ) describe em’

Answer 23

1) Differentiate as they move from basal compartment to lumen
2) Differentiate by process known as spermatogenesis, consisting of cell multiplication (meiotic division) and cell differentiation (spermiogenesis)

Question 24

Takes ______ days to form mature spermatozoon

Answer 24

64 days

Question 25

Line of differentiation

Answer 25

spermatogonia--> primary spermatocyte --> secondary spermatocyte --> spermatids --> mature spermatozoon

Question 26

Spermatogonia

Answer 26

lie in basal compartment round cells, diploid divide to produce primary spermatocytes

Question 27

Primary Spermatocytes

Answer 27

``` Largest germ cell; spherical or ovoid Moves from basal compartment to adluminal compartment (passes through Sertoli-Sertoli tight junctions) Undergo first meiotic division to produce secondary spermatocytes Cell division (cytokinesis) is incomplete so secondary spermatocytes are connected by cytoplasmic bridges ```

Question 28

Secondary Spermatocytes

Answer 28

half the size of primary spermatocytes Lie near the lumen Rarely seen in section because they divide rapidly (second meiotic division) to produce haploid spermatids

Question 29

Spermatids

Answer 29

Lie close to lumen | Early and late spermatids are 2 types

Question 30

Early spermatids

Answer 30

spherical, 6 micrometers in diameter

Question 31

Late spermatids

Answer 31

resemble spermatozoa 4 daughter spermatids are in cytoplasmic continuity with one another Lie in deep recesses on apical surface of Sertoli cells Become mature spermatozoa by a process called Spermiogenesis

Question 32

Spermiogenesis

Answer 32

differentiation of spermatids to mature spermatozoa - Centrioles migrate to opposite poles of nucleus - One forms flagellum (axoneme) with 9+2 arragement - Cytoplasm shed as residual body - Spermatozoon realsed from Sertoli cell - Morphologically mature but functionally immature (non-motile and limited capacity for fertilization)

Question 33

Spermatozoa

Answer 33

Lie in lumen of tubule Consist of head and tail Head= condensed nucleus and acrosome cap Final maturation of sperm is called capacitation (takes place in female reproductive tract)

Question 34

Excretory Ducts consist of

Answer 34

``` tubuli recti rete testis ductuli efferentes ductus epididymis ductus deferens ejaculatory duct urethra ```

Question 35

Tubuli Recti

Answer 35

From seminiferous tubules to rete testis | Short, straight tubule lined with Sertoli cells

Question 36

Rete Testis

Answer 36

Anastomosing channels in the mediastinum testis connecting tubuli recti and ductuli efferentes Simple cuboidal epithelium with single cilium and scattered microvilli

Question 37

Ductuli Efferentes

Answer 37

- form part of head of epididymis; 10-15 tubules connecting rete testis and ductus epididymis - Each ductule is 6-8 cm long, 0.5 mm in diameter - Lined by simple columnar epithelium - Tall columnar cells with cilia alternate with shorter cuboidal cells that reabsorb fluid to produce characteristic "up and down" appearance - Cells ciliated, cilia beat toward epididymis; help transport non-motile spermatozoa - Bound by CT; surrounded by circular smooth muscle layer which increases in thickness as it courses toward the epididymis

Question 38

Ductus Epididymis

Answer 38

- ductuli efferents unite to form a single ductus epididymis connecting ductuli efferents and ducts deferens - tortuous coiled duct 5-6 m long; forms part of head, body and tail of the epididymis - sperm acquire motility in the epididymis - Pseudostratified columnar epithelium with stereocilia - Cells absorb excess fluid produced by seminiferous tubulues - Thin lamina propria - Outside lamina propria, thin layer of circular smooth muscle (muscularis) increases in thickness as it approaches ductus deferens

Question 39

Ductus deferens

Answer 39

- continuation of epididymis - enters inguinal canal and course retroperitoneal to join with duct of seminal vesicle to form ejaculatory duct - Thick wall, narrow lumen - Usually seen as part of the spermatic cord - Terminal portion of ductus deferens dilates to form ampulla of ductus deferens which has a wider lumen and branching folds

Question 40

Mucosa of Ductus Deferens

Answer 40

epithelium + lamina propria Rises into folds (causes stellate appearance of lumen in a cross section) Epithelium- psuedostratified columnar epithelium with stereocilia Lamina propria is thin

Question 41

Muscularis of Ductus Deferens

Answer 41

Has 3 layers: Inner and outer longitudinal, middle circular Middle and outer layers are well developed Smooth muscle is innervated by autonomic nerve fibers Outer adventitia

Question 42

Ejaculatory duct

Answer 42

formed by the union of the ampulla of the ductus deferens and duct of the seminal vesicle

Question 43

Seminal vesicles (accessory sex glands)

Answer 43

Paired, elongated, sac-like structures lying on posterior surface of bladder A single long tubule Ends join ductus deferens to form ejaculatory ducts Testosterone-dependent

Question 44

Mucosa of Seminal vesicles

Answer 44

Thrown into numerous folds that give lumen a "honeycomb" appearance Epithelium varies- pseudostratified columnar, simple columnar or cuboidal -Secretes yellow viscous secretion that forms substantial part of semen (70%) Rich in fructose and prostaglandins Energy source for spermatozoa Epithelium rests on loose lamina propria with many blood vessels and elastic fibers (surrounded by a muscular wall)

Question 45

Muscularis of Seminal Vesicles

Answer 45

Inner circular and outer longitudinal smooth muscle fibers | Surrounded by Adventitia

Question 46

Prostate

Answer 46

Surrounds urethra Largest accessory sex organ Testosterone dependent Aggregate of 30-50 compound tubuloalveolar glands that drain into prostatic sinus via 15-30 prostatic ducts Glands have wide lumens and branch extensively

Question 47

Epithelium of Prostate

Answer 47

Varies from simple squamous, cuboidal, columnar, or pseudo stratified columnar Rests on fibroelastic connective tissue layer containing smooth muscle cells Gland is surrounded by fibroelastic capsule that also contains smooth muscle cells (fibromuscular stroma) Septa enter into gland

Question 48

Prostatic secretion:

Answer 48

thin, milky fluid rich in proteolytic enzymes and acid phosphatase Secretory material may condense to form spherical bodies called prostatic concretions Although prostate specific antigen (PSA) secreted by the prostate normally enters the prostatic secretions, elevated serum PSA associated with prostate cancer (affects 1 in 20 men) is due to increased activity by prostate cancer cells

Question 49

Bulbourethral glands (Glands of Cowper)

Answer 49

Paired, pea sized glands in the UG diaphragm Compound tubuloalveolar gland that drains via duct into urethra Gland secretes clear viscous fluid rich in amino acids and sialoproteins Lubricates the urethra