Male Infertility and Spermatogenesis

Question 1

how does the internal reproductive tract of a male develop

Answer 1

wolffian ducts develop the reproductive tract

mullerian ducts degenerate

Question 2

how does internal reproductive tract of females form

Answer 2

wolffian ducts degenerate, mullerian ducts form the reproductive tract

Question 3

what does lack of mullerian inhibiting factor in females cause

Answer 3

mullerian ducts to develop into femal reproductive tract

Question 4

what does testosterone in males cause

Answer 4

transforms wolffian ducts into male reproductive tract and testosterone converted to dihydrotestosterone which causes undifferentiated external genitalia to develop-penis scrotum

Question 5

describe androgen insensitivity syndrome

Answer 5

male karyotype
x linked recessive disorder
testes develop but do not descend
external female genitalia

Question 6

why in androgen insensitivity syndrome do you get external female and internal male

Answer 6

androgen induction of wolffian duct does not occur but mullerian inhibition does occu-born with phenotypically external genitalia female

Question 7

what do testes secrete in males which causes development of internal and external sex organs

Answer 7

testes secrete testosterone and mullerian inhibiting factor

Question 8

in ovaries what is secreted

Answer 8

no Y chromosome so no SRY(sex determining region), undifferentiated gonads develop into ovaries, no testosterone or Mullerian inhibiting factor

Question 9

what is cryptorchidism

Answer 9

undescended testes

Question 10

what are the clinical implications of cryptorchidism

Answer 10

increasingly common

reduces sperm count but if unilateral usually fertile

Question 11

if cryptorchidism what can reduce chance of germ cell cancer

Answer 11

orchidopexy if below age 14 to minimise risk testicular germ cell cancer
if undescended as adult, consider orchidectomy

Question 12

what is the function of the testis

Answer 12

spermatogenesis and production of testosterone

Question 13

what is contained in the acrosome

Answer 13

enzymes for penetrating the ovum

Question 14

what is the role of the sertoli cells

Answer 14

forms a blood-testes barrier
provides nutrients for the developing cells 
phagocytosis 
secrete seminiferous tubule fluid 
secrete androgen binding globulin 
secrete inhibin and activin hormones

Question 15

where are leydig cells in the testis

Answer 15

in the intersitium

Question 16

what does LH stimulate

Answer 16

testosterone secretion

Question 17

what does testosterone do via negative feedback

Answer 17

decrease release of GnRH and LH

Question 18

what does FSH stimulate

Answer 18

FSH and testosterone stimulate spermatogenesis

Question 19

what decreases secretion of FSH

Answer 19

inhibin

Question 20

where is GnRH released from

Answer 20

hypothalamus

Question 21

what does GnRH stimulate

Answer 21

the anterior pituitary to produce LH and FSH

Question 22

production of testosterone and spermatogenesis is cyclical or non-cyclical

Answer 22

non cyclical (cyclical in females)

Question 23

when testosterone is produced where is it secreted

Answer 23

into blood and seminiferous tubules for sperm production

Question 24

what is the effect of testosterone before birth

Answer 24

masculinises reproductive tract and promotes descent of testes

Question 25

where are inhibin and activin secreted from

Answer 25

sertoli cell

Question 26

what does inhibin do

Answer 26

feedback of FSH to decrease release

Question 27

what does activin do

Answer 27

stimulate FSH release

Question 28

what are the steps of capacitation

Answer 28

``` cehmoattraction docking(specific recognition acrosomal exocytosis hyperactivity penetration of egg coat and membrane fusion zonal reaction ```

Question 29

what is capacitation

Answer 29

series biochemical and electrical events before fertilisation (hyperactivited motility, ability to bind to zona pellucida and AR)

Question 30

what is the function of the epididymis and vas deferens

Answer 30

exit route from testes to urethra, concentrate and store sperm, site for sperm maturation

Question 31

what is the function of seminal vesicles

Answer 31

produce semen into ejaculatory duct, supply fructose, secrete prostaglandins (stimulates motility), secrete fibrinogen (clot precursor)

Question 32

what is the function of the prostate gland

Answer 32

produce alkaline fluid (neutralises vaginal acidity), produces clotting enzymes to clot semen within female

Question 33

what is the most common cause for male infertility

Answer 33

idiopathic

Question 34

name some obstructive causes for male infertility

Answer 34

cystic fibrosis, vasectomy, infection

Question 35

name some non-obstructive causes of male infertility

Answer 35

``` cryptorchidism infection: mumps orchitis iatrogenic-chemo/radiotherapy pathological eg tumour genetic ```

Question 36

describe some endocrine causes of male infertility

Answer 36

``` pituitary tumours-acromegaly, cushings disease, hyperprolactinaemia hypothalamic causes thyroid disorders diabetes CAH androgen insensitivity steroid abuse ```

Question 37

what is the normal testicular volume

Answer 37

12-25 mls

Question 38

what is looked at in semen analysis

Answer 38

volume, density, motility, progression, morphology

Question 39

what are some of the xtrinisc factors which may affect semen analysis

Answer 39

``` completeness of sample period of abstinence condition during transport time between production and assessment natural variations between samples health of man 3 months before production ```

Question 40

if semen analysis found to be abnormal what would you do

Answer 40

repeat semen analysis 6 weeks later endocrine profile (LH, FSH, testosterone, PRL, TSH) chromosome analysis (including Y chromosome microdeletions), cf screening depending on results-testicular biopsy, scrotal scan

Question 41

what are the clinical features of an obstructive cause

Answer 41

normal testiucalr volume, normal secondary sexual characteristics vas deferens may be absent endocrine features-normal LH, FSH and testosterone

Question 42

what are the clinical features of non-obstructive

Answer 42

low testicular volume, reduced secondary sexual characteristics vas deferens present endocrine features-high LH, FSH and low testosterone

Question 43

what is the indication for surgical sperm aspiration

Answer 43

azoospermia

Question 44

what is the success rate at obtaining sperm from obstructed vs non-obstructed azoospermia

Answer 44

95% obstructed and 50% non-obstructive