Spermatogenesis And Male Infertility

Question 1

What chromosome contains the sex determining region?

Answer 1

The Y chromosome

Question 2

Development of testis occurs from what?

Answer 2

Bipotential gland

Question 3

What does the foetal testes secrete?

Answer 3

Testosterone and mullerian inhibiting factors

Question 4

What are the two primitive genital tracts?

Answer 4

Wolffian

Mullerian

Question 5

What causes development of female genital tract?

Answer 5

Müllerian ducts -> repro tract

Wolffian ducts degenerate

Question 6

What causes male repro tract to develop?

Answer 6

Wolffian ducts -> repro tract

Müllerian ducts degenerate

Question 7

What is androgen insensitivity syndrome?

Answer 7

Testicular feminisation

Question 8

Genetics of androgen insensitivity syndrome?

Answer 8

X linked recessive

46 XY

Question 9

What happens in androgen insensitivity syndrome?

Answer 9

Androgen induction of wolffian duct doesn’t occur but mullerian inhibition does occur.
Testis develop but don’t descend.
Born phenotypically with female external genitalia - absence of ovaries and uterus

Question 10

When does androgen insensitivity syndrome tend to present?

Answer 10

At puberty with primary amenorrhea and lack of public hair

Question 11

How do the testes adapt to external temperature?

Answer 11

Nervous reflexes trigger dartos muscle contraction in scrotal sac to lower/ raise testes according to external temp

Question 12

What is cryptorchidism?

Answer 12

Undescended testes

Question 13

Management of cryptorchidism?

Answer 13

Orchidopexy before age of 14 to reduce risk of testicular germ cell cancer .
If an adult, consider orchidectomy

Question 14

Function of the testis?

Answer 14

Spermatogenesis (seminiferous tubules)

Production of testosterone (leydig cells)

Question 15

What do Sertoli cells do?

Answer 15

Form blood- testis barrier 
Provide nutrients for developing cells
Phagocytosis 
Secrete seminiferous tubule fluid 
Secrete androgen binding globulin 
Secrete inhibit and activin hormones

Question 16

Where is GnRH secreted from?

Answer 16

Hypothalamus, every 2-3 hours

Question 17

What does GnRH do?

Answer 17

Stimulates anterior pituitary to produce LH and FSH

Question 18

Where are LH and FSH secreted from?

Answer 18

Anterior pituitary

Question 19

What does LH do?

Answer 19

Acts on Leydig cells, regulating testosterone secretion

Question 20

What does FSH do?

Answer 20

Acts on Sertoli cells to enhance spermatogensis

Question 21

Where is testosterone produced ?

Answer 21

In leydig cells

Question 22

What is testosterone derived from?

Answer 22

Cholesterol

Question 23

Where is inhibin and activin produced?

Answer 23

Sertoli cells

Question 24

After ejaculation, what do spermatozoa do?

Answer 24

Chemo attraction to oocyte and bind to zone pellucida of oocyte
Acrosome reaction
Hyper activated motility
Penetration and fusion with oocyte membrane
Zonal reaction

Question 25

Function of epididymis and vas deferens?

Answer 25

Exit route from testis to urethra Concentrate and store sperm Site for sperm maturation

Question 26

Function of seminal vesicles?

Answer 26

Produce semen into ejaculatory duct | Secrete fibrinogen

Question 27

Function of prostate gland?

Answer 27

Produces alkaline fluid - neutralises vaginal acidity | Produces clotting enzymes to clot semen within female

Question 28

Function of bulbourethral gland?

Answer 28

Secretes mucous to act as a lubricant

Question 29

Route of sperm?

Answer 29

``` Testes Epididymis Vas deferens Ejaculatory duct Urethra ```

Question 30

Most common cause of male infertility?

Answer 30

Idiopathic

Question 31

Obstructive causes of Male infertility?

Answer 31

CF Vasectomy Infection

Question 32

Congenital causes of male infertility?

Answer 32

Cryptorchidism

Question 33

Infective non obstructive cause of male infertility?

Answer 33

Mumps orchitis

Question 34

Genetic non obstructive cause of male infertility?

Answer 34

Chromosomal- kleinfelters, micro deletions of Y chromosome, robertsonian translocation

Question 35

Endocrine causes of non obstructive infertility?

Answer 35

Pituitary- Acromegaly, customs, hyperprotlactinaemia Hypothalamic- Kallmans, anorexia, tumours Thyroid- hyper/hypothyroidism Diabetes CAH Androgen insensitivity Steroid abuse

Question 36

What is the normal testicular volume of an adult?

Answer 36

12-25ml

Question 37

How do you measure testicular volume?

Answer 37

Orchidometer

Question 38

What is involved in an endocrine profile for infertility?

Answer 38

``` LH FSH testosterone Prolactin TSH ```

Question 39

Findings if obstructive cause of infertility?

Answer 39

Normal testicular volume Normal secondary sexual characteristics Vas deferens may be absent Normal LH, FSH, testosterone

Question 40

Findings if non-obstructive cause of infertility?

Answer 40

Low testicular volume Reduce secondary sexual characteristics Vas deferens present High LH, FSH and low testosterone