Spermatogenesis and Male Infertility Flashcards

1
Q

What determines the development of the internal reproductive tract in the embryo?

A

SRY on Y chromosome result in the development of testes, and the degeneration of the mullerian ducts

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2
Q

What will the foetal testes secrete?

A

Testosterone

AMH

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3
Q

What are the 2 primitive genital tracts?

A

Wolffian

Mullerian

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4
Q

What duct is present in males?

A

Wolffian

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5
Q

What duct is present in females?

A

Mullerian

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6
Q

When can you distinguish sex on a USS?

A

Week 16

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7
Q

What is androgen insensitivity syndrome (testicular feminisation)?

A

Congenital insensitivity to androgens
Testis develop but do not descend
Androgen induction of wolffian duct does not occur, but mullerian inhibition occurs

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8
Q

What internal sex organs will those with testicular feminisation have?

A

Externally female genitalia
Absence of uterus and ovaries
Short vagina

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9
Q

How will those with androgen sensitivity present?

A

Puberty with primary amenorrhoea and a lack of pubic hair

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10
Q

What is the function of the testis?

A

Spermatogenesis (seminiferous tubules)

Production of testosterone (leydig cells)

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11
Q

What covers the testis?

A

Double layer of tunical vaginalis

White fibrous tunica albingia

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12
Q

Why is the descent of the testis important?

A

Lower temp outside body to facilitate spermatogenesis

Nervous reflex triggers dartos muscle contraction in scrotal sac to lower/ raise testes according to the external temp

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13
Q

How common is cryptorchidism?

A

1:25

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14
Q

When should an orchiopexy be performed in cryptorchidism?

A

By 12 months due to strong assoc with azoospermia
12 years to minimize risk of testicular germ cell ca
If undescended as adult - consider orchidectomy

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15
Q

What are the venous drainage of the testes?

A

Left testicular joins left renal

Right drains directly to IVC

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16
Q

What gonadotropin drives sertoli cell function?

A

FSH

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17
Q

What gonadotropin drives testosterone production?

A

LH - leydig cells

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18
Q

What is present in the head of a sperm?

A

Acrosome - enzymes required for penetration of ovum

Nucleus

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19
Q

What is present in the midpiece of the sperm?

A

Mitochondria

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20
Q

What is present in the tail of the sperm?

A

Microtubules

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21
Q

What is the function of the sertoli cells?

A
Blood-testes barrier 
Nutrientes
Phagocytosis 
Secrete seminiferous tubule fluid
Secrete ABG 
Secretes inhibin and activin
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22
Q

Describe the GnRH release in men?

A

Every 2-3 hours

Begins age 8-12

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23
Q

What is testosterone?

A

Steroid hormone derived from cholesterol

Secreted into blood and seminiferous tubules for sperm production

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24
Q

Effect of testosterone before birth?

A

Masculinises reproductive tract and promotes descent of testes and generation of external genitalia

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25
Q

Role of testosterone in puberty?

A

Puberty and male characteristics (growth and maturation male reproductive system)

26
Q

Role of testosterone in the adult?

A

Spermatogenesis
Secondary sexual characteristics (male body shape, deep voice, thickening of skin), libido, penile erection, aggressive behaviour

27
Q

What is capacitation?

A

A series of biochemical and electrical events before fertilisation (hyperactive motility, ability to bind ZP and AR)

28
Q

How are spermatozoa attracted to oocytes?

A

Chemoattraction; binds to zona pellucida

29
Q

What liquefies the spermatozoa?

A

Enzymes in prostate

30
Q

Function of the epididymis and vas deferens?

A

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

31
Q

Function of the seminal vesicles?

A

Produce semen into ejaculatory duct, supply fructose, secrete prostaglandins (motility), secretes fibrinogen (clot precursor)

32
Q

Function of the prostate gland?

A

Alkaline fluid (neutralizes vaginal acidity), produces clotting enzymes to clot semen within female

33
Q

Function of the bulbourethral gland?

A

Mucus to act as lubricant

34
Q

What is erection under control from?

A

Parasymp system

35
Q

What % of infertility is due to male factor?

A

30% - biggest portion

36
Q

What causes obstructive male infertility?

A

CF - mutation in one gene can result in bilateral absence of vas
Vasectomy
Infection

37
Q

What causes non-obstructive male infertility?

A
Cryptorchidism
Mumps orchitis 
Chemo/radiotherapy 
Testicular tumour
Klinefelter's syndrome 
Globozoospermia
Systemic disorder
Endocrine
38
Q

What pituitary tumours can cause male infertility?

A

ACromegaly
Cushing’s disease
Hyperprolacinaemia

39
Q

What hypothalamic causes can result in male infertility?

A

Idiopathic
Tumours
Kallmann syndrome
Anorexia

40
Q

What are the endocrine causes of male infertility?

A
Pituitary tumours
Hypothalamic
Thyroid 
Diabetes
CAH
Androgen insensitivity
Steroid abuse
41
Q

How is male infertility assessed?

A
See as couple
Infertility history
Andrology history 
Examination; general and genital 
Ix; semen analysis
42
Q

What are the best questions to ask about testosterone?

A

Facial hair; will be reduced in low testosterone

Early morning erection

43
Q

What are you examining in a genital male examination?

A

Testicular volume
Presence of vas and epididymis
Penis; urethral orifice (hypospadia)
Presence of any varicocele or other scrotal swellings

44
Q

What are the normal testicular volumes?

A

Pre-pubertal; 1-3mls

Adults; 12-25 mls

45
Q

How do you measure testicular volume?

A

Orchidometer

46
Q

What testicular volume is likely to be infertile?

A

Less than 5ml

47
Q

What do you assess in semen analysis?

A
Volume
Density 
Motility
Progression 
Morphology
48
Q

What is a normal semen volume?

A

1.5ml

49
Q

What is the normal sperm concentration?

A

15 million sperm per ml

50
Q

What is normal motility of sperm?

A

40

51
Q

What is normal morphology of sperm?

A

4% morphologically normal

52
Q

What are factors that can affect semen analysis?

A

Completeness of sample
Period of abstinence; less than 3 days or over 7 day
Cold condition whilst travelling
Time between production and assessment over 1 hour
Natural variations between samples
Health of man 3 months prior

53
Q

What are the clinical and endocrine features of obstructive infertility?

A

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

54
Q

What are the clinical and endocrine features of non-obstructive infertility?

A

Low testicular vol
Reduced secondary sexual characteristics
Vas deferens present
High LH, FSH +/- low testosterone

55
Q

What is the treatment of male infertility?

A

Treat any specific cause e.g. reversal of vasectomy, cabergoline if hyperprolactinemia
ICSI +/- surgical sperm aspiration
Donor insemination

56
Q

General advice for male infertility?

A
Frequent sexual inercourse; 2-3x a week
Less than 4 units of alcohol per day
Stop smoking
BMI <30 
Avoid tight fitting underwear and prolonged hot baths
Certain occupations
Complementary therapies 
Possible benefits of anti-oxidants
57
Q

Treatment for anejaculation conditions?

A

Psychosexual treatment

58
Q

What is ICSI?

A
Sperm prepared from semen
Egg stripped
Sperm immobilised
Single sperm injected
Success rate 35%
59
Q

What is the indication for surgical sperm aspiration?

A

Azoospermia

60
Q

What is surgical sperm aspiration?

A

Sperm aspirated surgically then injected into oocyte (ICSI_

61
Q

What are the indications for donor sperm insemination?

A

Azoospermia or v low count, failed ICSI, genetic conditions, infective conditions

62
Q

What is the pregnancy rate of donor sperm insemination?

A

15% per cycle