Male Infertility and Spermatogenesis Flashcards Preview

Y3 OBS AND GYNAE > Male Infertility and Spermatogenesis > Flashcards

Flashcards in Male Infertility and Spermatogenesis Deck (50)
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1
Q

What determines our gender?

A

Chromosomes (XY or XX)
Sex hormones secreted
External + internal genitalia
Psychological factor

2
Q

Which chromosome has the sex-defining region?

A

Y-chromosome

3
Q

Which 2 hormones/factors contribute to the development of the internal genital tract in the male?

A

Testosterone (dihydrotestosterone)

Mullerian inhibiting factor

4
Q

There are 2 primitive genital tracts: Wolffian and Mullerian ducts. Which duct contributes to male and female genital tracts respectively?

A
Males = Wolffian
Females = Mullerian
5
Q

Without stimulation by testosterone + Mullerian inhibiting factor, what develops in the male?

A

Internal genital tract resembling that of a female

6
Q

The testes develop in the ________ but descend into the ______ before birth. Why?

A

Abdominal cavity
Scrotal sac
Lower temperature outside the body facilitates spermatogenesis

7
Q

What is cryptorchidism? How is it managed?

A

Undescended testes, resulting in reduced sperm count and increased risk of testicular cancer
Orchidectomy

8
Q

What does testicular descent depend on?

A

Androgenic drive

9
Q

Where does spermatogenesis occur?

A

Seminiferous tubules

10
Q

Where is testosterone secreted from?

A

Leydig cells

11
Q

List the function of Sertoli cells

A
Form blood-testis barrier (protection)
Provide nutrients for developing cells
Phagocytosis
Secrete seminiferous tubule fluid
Secrete androgen-binding globulin
Regulate FSH levels through inhibin
12
Q

Where does LH act in the male?

A

Leydig cells - regulate testosterone levels

13
Q

Where does FSH act in males?

A

Sertoli cells - enhances spermatogenesis

14
Q

What are the 3 main categories of causes of male infertility?

A

Idiopathic (most common cause)
Obstructive
Non-obstructive

15
Q

List some obstructive causes of male infertility

A

Cystic fibrosis (vas deferens defect)
Vasectomy
Infection

16
Q

List some non-obstructive causes of male infertility

A
Cryptorchidism
Infection
Radiation (chemo/radiotherapy)
Testicular tumour
Genetic (Klinefelter's, microdeletetion of Y ch., robertsonian translocation)
Semen structure abnormality
Systemic/endocrine disorders
17
Q

List some pituitary causes of male infertility

A

Tumours
Acromegaly
Cushing’s disease
Hyperprolactinaemia

18
Q

List some hypothalamic causes of male infertility

A

Tumour
Increased exercise
Kallmann’s syndrome
Anorexia

19
Q

Which drug when abused is notorious for causing male infertility?

A

Steroids

20
Q

What would be assessed on genital examination in a male with infertility?

A
Testicular volume (normal = 12-25ml)
Presence of vas deferens + epidydimis
Penis
Urethral orifice
Presence of swellings/varicocele
21
Q

What 5 domains are assessed on semen analysis?

A
Volume
Density (number of sperm)
Motility (how many are moving)
Progression (how well they move)
Morphology
22
Q

What extrinsic factors may cause abnormality in semen analysis?

A
Completeness of sample
Period of abstinence from sex
Conditions during transport e.g. cold
Time delay 
Health of the man
23
Q

How would testicular volume, secondary sexual characteristics, endocrine hormones and structure of vas deferens be affected in obstructive male infertility?

A

All normal

Vas deferens may be absent

24
Q

How would testicular volume, secondary sexual characteristics, endocrine hormones and structure of vas deferens be affected in non-obstructive male infertility?

A

Low testicular volume
Reduced secondary sexual characteristics
High endocrine hormones
Vas deferens present

25
Q

List some lifestyle improvements that can help male infertility

A
Frequent sex, 2-3x a week
Avoid lubricants (toxic to sperm)
Less than 4 units of alcohol a week
Stop smoking
BMI less than 30
Avoid tight underwear, saunas/hot baths
26
Q

When is ICSI indicated over IUI?

A

IUI - low sperm count

ICSI - very low sperm count

27
Q

What is the success (pregnancy) rate of IUI and ICSI?

A
IUI = 15%
ICSI = 30%
28
Q

When is surgical sperm aspiration indicated?

A

Azoospermia (very low sperm count)

when sperm cannot be prepared from semen (ICSI)

29
Q

What is the success (pregnancy) rate of surgical sperm aspiration?

A

95% in obstructive

50% in non-obstructive

30
Q

If IUI, ICSI and sperm aspiration fail, what is the next option?

A

Donor sperm

31
Q

What is androgen insensitivity syndrome? How does it present

A

Congenital insensitivity to androgens (46XY) causing no androgen induction of wolfian duct (therefore female genitalia) but mullerian inhibition does occur
(no uterus/ovaries)
Primary amenorrhea and a lack of pubic hair in puberty

32
Q

Where is sperm stored?

A

Epididymis

33
Q

The testis is encased within the…

A

Tunica vaginalis

34
Q

List the three sets of erectile tissue within the penis

A

2 x corpus cavernosum

1 x corpus spongiosum

35
Q

How does spermatozoa penetrate the ovum?

A

Acrosome reaction via the release of enzymes which help to penetrate the egg

36
Q

What is the action of inhibin in the menstrual cycle?

A

Reduces secretion of FSH

37
Q

Why can GnRH not be measured?

A

It is released in a pulsatile fashion from the hypothalamus

38
Q

Negative feedback of the hypothalamus and pituitary gland is controlled by…

A

Testosterone

39
Q

Production of FSH and LH is cyclical in males and females. True/False?

A

False

It is non-cyclical in males

40
Q

List the stages by which spermatozoa undergo to reach the egg

A
  1. Capacitation reactions
  2. Chemoattraction to ZP of oocye
  3. Acrosome reaction
  4. Hyperactivated motility
  5. Penetration and fusion with oocyte membrane
  6. Zonal reaction
41
Q

What is the role of the seminal vesicles?

A

Produce semen into ejaculatory duct

42
Q

What is the role of the prostate gland in fertilisation?

A

Alkalises fluid and neutralises vaginal acidity

Produce clotting enzymes to clot semen in the female

43
Q

What is the role of the bulbourethral gland in fertilisation?

A

Secrete mucous to act as a lubricant

44
Q

What is the role of the vas deferens?

A

Transport sperm from testis to urethra

45
Q

What is male infertility?

A

Failure of sperm to normally fertilise egg causing infertility

46
Q

Male factor is a common cause of infertility. True/ False?

A

True

1/3 of infertility problems due to male factor

47
Q

What would be assessed in a history of a male with infertility?

A

Duration of infertility, primary or secondary, libido, sexual function, sexual activity

PMHx (health of man - DM, respiratory disease, recent illness, GU/testicular infection or inflammation)
Surgery or reproductive tract or any treatments
FHx (genetic disease)
DHx (steroids, antibiotics, alpha blockers, recreational)
SHx (environmental exposure to pesticides, heat)

48
Q

What is the main diagnostic procedure which shows abnormality in male infertility?

A

Semen analysis

49
Q

List further investigations that may be indicated in male infertility

A
6 week repeat semen analysis
Endocrine profile
Chromosome analysis
CF screening
Testicular biopsy, scrotal scan
50
Q

List management options for male infertility

A

General lifestyle advice

Treatment of specific disease e.g. reversal of vasectomy