Male Reproductive System

Question 1

What are the functions of the male reproductive system?

Answer 1

• make and support male gametes(sperm)
• transfer sperm to female genital tract
• produces hormones

Question 2

What are the components of the male reproductive system?

Answer 2

Testes—> makes sperm

Penis—> transfer of sperm and urinary functions

Genital ducts: epididymis, ductus deferens, efferent ducts, ejaculatory ducts —> transport semen

Glands: prostate, seminal vesicles, bulbourethral glands—> make seminal fluid

Question 3

Describe the root of the penis

Answer 3

Attached to perineal membrane

Unattached parts of the corpus cavernousa and spongiosum

• Right and left Crus
• bulb

Question 4

Describe the body of the penis

Answer 4

Not attached

• Two corpora cavernosa (dorsal)
• One corpus spongiosum(ventral)
  - forms glans penis
  - contains the penile (spongy) urethra

Question 5

The muscles of the perineum …

Answer 5

Surrounds the erectile tissues and openings in the perineum

Question 6

What is the scrotum?

Answer 6

-supporting structure for the Testes

• Dartos muscle
  - subcutaneous layer of smooth muscle
  - contraction tightens the scrotum

Question 7

Describe the spermatic cord

Answer 7

-fascia

• Cremaster muscle
  
  • Skeletal muscle from internal oblique
    
    • Contraction moves Testes closer to the body
• Nerve; a branch of genitofemoral
• esticular artery
• Pampiniform plexus of testicular veins
• Ductus deferens
  
  • transports spermatozoa from epididymis to ejaculatory duct

Question 8

What are the Testes?

Answer 8

Paired oval glands
-approximately 2 inch long x 1 inch diameter

Develop in the posterior abdomen & descend into the scrotum through the inguinal canals @ 7-8 months

Question 9

Describe the structure of Testes

Answer 9

Tunica vaginalis
- serous membrane derived from peritoneum during descent of Testes

Tunica albuginea

• thick connective tissue capsule
• extends inward to form septa

Lobules

• 200-300 internal compartments
• each lobule contains 1-4 seminiferous tubules

Seminiferous tubules

• seminiferous epithelium
  
  • produce spermatozoa

Question 10

Seminiferous tubules has two cell populations…

Answer 10

1. Sertoli cells are supporting cells

2. Spermatogonic cells replicate & differentiate into mature sperm

Question 11

Explain the structure and function of Sertoli cells

Answer 11

• supporting cells
• extend from basement membrane to lumen
• tight junctions join adjacent Sertoli cells
  
  • blood-testis barrier
• secrete inhibin
  
  • hormone that inhibits FSH secretion
• secrete androgen-binding protein
  
  • binds testosterone to keep concentration high

Question 12

What are the types of spermatogonia cells?

Answer 12

• spermatogonia(2n)
  
  • stem cells
• primary spermatocytes(2n,4d)
• secondary spermatpcytes (1n, 2d)
• spermatides( 1n, 1D)
• spermatozoa( 1n, 1d)

Question 13

What are the Leydig cells?

Answer 13

Also known as interstitial cells

• located in spaces between adjacent seminiferous tubules
• secrete testosterone

Question 14

Summarize spermatogenesis

Answer 14

Development of spermatogonia into sperm

-Include meiosis and spermiogenesis
Lasts 65-75 days

Spermatogonia
Stem cells
2n,2d

Primary spermatocyte
2n,4d

Secondary spermatocyte
1n, 2d

4 spermatids
1n, 1d

4 spermatozoa

• 1n,1d
• mature sperm

Question 15

Describe sperm

Answer 15

Head

• acrosome
  
  • vesicle contains enzymes required for penetration of the zona pelucida of the oocyte
• nucleus
  
  • 23 condensed chromosomes (22, X or Y)

Tail (flagellum)
1. Neck

2. Middle piece
   
   • mitochondria provide ATP for sperm motility
3. Principal piece
4. End piece
   
   • core of microtubules & dynein motor proteins

Question 16

What is Cryptorchidism?

Answer 16

Condition when Testes do not descend into the scrotum

• 3% full-term infants
• 30% premature infants
• Most (80%) will descend spontaneously during the first year of life
• Untreated & bilateral results in sterility
• 30-50x greater risk of testicular cancer

Question 17

What are the types of ducts in the reproductive system?

Answer 17

Intra-testicular ducts & excurrent ducts

Question 18

What are the intra-testicular ducts?

Answer 18

• seminiferous tubules
  
  • seminiferous epithelium

Straight tubules (tubuli recti)
   -short terminal portion of the seminiferous tubule

Rete testis

• network of channnels
• simple cuboidal to low columnar

Question 19

What are the excurrent ducts?

Answer 19

• efferent ducts
• epididymis
• Ductus deferens
  
  • pseudostratified columnar epithelium with stereocilia
• Ejaculatory ducts
  
  • union of the duct of seminal vesicle and ampulla of Ductus deferens

Question 20

What are the efferent ducts made of ?

Answer 20

Pseudostratified columnar epithelium

Question 21

What are the parts of epididymis ?

Answer 21

Head, body, tail

Psuedostratified columnar epithelium with stereocilia

Question 22

What are the Ductus deferens made of?

Answer 22

Ductus deferens have a pseudostratified columnar epithelium with stereocilia and a thick muscular wall

Question 23

What is a vasectomy?

Answer 23

Is the interruption of the Ductus deferens usually at the scrotum

Question 24

What are the accessory sex glands?

Answer 24

1. Seminal vesicles
2. Prostate
3. Bulbourethral glands

Question 25

What is the function of a prostate?

Answer 25

• Single gland inferior to bladder
• typically the size of a golf ball
• surrounds the prostatic urethra

Secretes a milky, slightly acidic fluid into the prostatic urethra

• Citric acid
  
  • ATP production
• Proteolytic enzymes
  
  • prostate-specific antigen(PSA)
• Acid phosphatase
• Seminalplasmin
  - antibiotic

Produces about 25% of volume of semen

Question 26

Describe the Bulbourethral glands(Cowper’s glands)

Answer 26

• Paired glands inferior to prostate on either side of the membranous urethra
  
  • Ducts open into the penile (spongy) urethra

-Secrete clear, mucus-like fluid into the urethra

Question 27

Describe the ejaculatory ducts

Answer 27

Union of the duct of seminal vesicle and ampulla of Ductus deferens

Question 28

Give the function of seminal vesicle

Answer 28

Paired glands posterior to bladder duct joins Ductus deferens to form ejaculatory duct

Secrete an alkaline, viscous fluid

- Fructose needed for ATP production by sperm
- Prostaglandins & clotting proteins

Question 29

Describe the structure-function of prostate

Answer 29

Single gland inferior to bladder and surrounds the prostatic urethra

Produces about 25% of volume of semen

Secretes a milky, slightly acidic fluid

- citric acid for ATP production
- prostate-specific antigen (PSA)
- enzymes
- acid phosphatase
- seminalplasmin —> antibiotic

Question 30

What are the symptoms of benign prostatic hypertrophy ?

Answer 30

• enlarged prostate gland
• relatively common in men by age 80
• numerous nodules compress the prostatic urethra
  
  • weak urination
  • difficulty starting & stopping
  • urge or feeling to urinate

Question 31

How does semen get to the female genital tract?

Answer 31

• Semen is a mixture of sperm cells and glandular secretions
• Volume of 2.5-3 ml
• 50-150 million sperm per ml
• low sperm count : 20 million or less sperm per ml
  
  • higher risk of infertility

Question 32

What is erection? What Causes it?

Answer 32

-enlargement & stiffening of the penis

How?- parasympathetic fibers initiate and maintain the erection

  - Nitrous oxide(NO) released
  - smooth muscle of arterioles relax 
  - blood vessels dilate
  - large amounts of blood enter the erectile tissues
  - veins become compressed blocking outflow.

Question 33

What is ejaculation? What causes it?

Answer 33

Release of semen

Caused by the sympathetic reflex

Peristaltic contractions propel semen into the urethra

• Contraction of smooth muscle
• decrease blood flow and blood pressure
• Veins open and drain blood