Male Reproductive System

Question 1

What is a seminiferous tubule?

Answer 1

2-3 seminiferous tubules are found within each lobules, of the testes. Seminiferous tubules contain the sperm, this is also where sperm production happens (“spermatogenesis”).

Question 2

What is the importance of the scrotum?

Answer 2

Scrotum is the supporting structure for the testes, made of loose skin and fat. The scrotum helps with thermal regulation - can lower temperature by pulling them closer to the body - and wrinkling so heat isnt lost. Spermatogenesis can only occur if testes are 1-2 degrees cooler than the body. Cremaster and Dartos are the muscles in the testes, which help with temp control.

Question 3

What are the Cremaster and Dartos?

Answer 3

Cremaster and Dartos are the muscles, within the testes, which help control temperature.

Question 4

What is produced in the testes?

Answer 4

Testes develop sperm and testosterone.

Question 5

Spermatogenic cells

Answer 5

Spermatogonium (2n - stem cells) > Primary spermatocyte (2n) > Secondary spermatocyte (n) > Early spermatid (n) > Late spermatid (n) > Sperm cell (n - spermatozoon) > lumen of seminiferous tubule.

Question 6

What am I:

• am present in testes (seminiferous tubules)
• form blood testes barrier
• support developing sperm cells
• produces fluid, controls movement of spermatogeneic cells and release of sperm into lumen
• secreet ihibin > slows sperm production by inhibiting FSH

Answer 6

Sertoli Cells

Question 7

Spermatogenesis - each day 300M sperm complete this

Answer 7

MITOSIS: Spermatogonium (2n - stem cells) > Primary spermatocyte (2n)

MEIOSIS I: Primary spermatocyte (2n) > Secondary spermatocyte (n) * 2x haploids joined by cytoplasm bridge

MEIOSIS II: Secondary spermatocyte (n) > Early spermatid (n) > Late spermatid (n) * 4 haploids joined

Spermatids > Sperm cell (n - spermatozoon) > sperm goes out into lumen of seminiferous tubule.

Question 8

Importance of cytoplasm bridges between spermocytes / spermatids

Answer 8

Cytoplasm bridges account for synchronisation f sperm so 50% are X chromosomes, 50% are Y chromosomes.

Question 9

Spermiogenesis

Answer 9

Maturation of spermatids into sperm cells

Question 10

Spermiation

Answer 10

Release of sperm cell from sertoli cells

Question 11

Semen

Answer 11

sperm + secretory cells

Question 12

Spermatogenesis (production of sperm) & hormones

Answer 12

• During puberty, hypothalamus releasing hormone (GnRH) which stimulates anterior pituitary for secretion of LH & FSH.
• LH stimulates Leydig cells to secrete testosterone:
  an enzyme in prostate & seminal vesicles converts testosterone into dihydrotestosterone (DHT-more potent)
• FSH stimulates spermatogenesis: with testosterone, stimulating sertoli cells to secrete androgen-binding protein (which keeps hormones levels high). Testosterone stimulates final steps of spermatogenesis

Question 13

Pathway of Sperm Flow through the Ducts of the Testis

Answer 13

Seminiferous tubules 
> Straight tubules
> Rete testis
> Efferent ducts
> Ductus epididymis
> Ductus (vas) deferens

Question 14

___________ is responsible for dilatation of blood vessels during erection

Answer 14

Nitric oxide is responsible for dilatation of blood vessels during erection

Question 15

The ___________ covers the glans penis in an uncircumcised penis

Answer 15

The prepuce (foreskin) covers the glans penis in an uncircumcised penis

Question 16

Erectile tissue in the penis is composed of:
	 A)	blood sinuses 	
	 B)	smooth muscles  	
	 C)	connective tissue  	
	 D)	all of the above

Answer 16

Erectile tissue is composed of numerous blood sinuses lined by endothelial cells and surrounded by smooth muscle and elastic connective tissue.

Question 17

\_\_\_\_\_\_\_\_\_\_\_ help in sperm motility
	 C)	prostaglandins  	
	 A)	fructose  	
	 B)	citric acid  	
	 D)	acid phosphatase

Answer 17

Prostaglandins help in sperm motility

Question 18

The antibiotic that can destroy bacteria in the semen is
Choose one answer.
	 A)	citric acid  	
	 D)	prostate-specific antigen  	
	 C)	acid phosphatase  	
	 B)	seminalplasmin

Answer 18

Seminal plasmin in prostatic fluid is an antibiotic and may help decrease bacteria in semen.

Question 19

Fructose secreted by the seminal vesicles helps in
A) neutralising the acidic environment of the male urethra
B) helps in sperm motility
C) ATP production by the sperm
D) all of the above

Answer 19

Fructose secreted by the seminal vesicles helps in ATP production by the sperm

Question 20

Which accessory sex gland in the males can enlarge with age

Answer 20

Prostate enlarges with age

Question 21

Seminal fluid helps the sperm in all of the following, EXCEPT
Choose one answer.
	 B)	nutrition  	
	 D)	capacitation  	
	 C)	protection  	
	 A)	transportation

Answer 21

Seminal fluid does not help sperm in capacitation. Capacitation happens due to cervical mucus, which helps the sperm fertilise the ovum.
Seminal fluid provides a medium of transport for the sperms. It also contains substances that increase motility and viability of the sperm. It also contains alkaline subtances that neutralise the acidity of the female reproductive tract.

Question 22

After leaving the testes, spermatozoa pass sequentially through the…

Answer 22

After leaving the testes, spermatozoa pass sequentially through the epididymis, ductus deferens, ejaculatory duct, and urethra