Male Reproductive Physiology P1+2 Flashcards
describe key parts male reproductive organs
normal process ejaculation
sperm created in testes
sperm travels through vas deferens
seminal vesicles and prostaye creae semen carried along with sperm to urethra
sperm and semen travel through urethra ejaculated out of penis
what three types of cells are within the seminiforous tubules
Germ cells- produce sperm
Sertoli/sustentacular cells- support sperm producing cell, produce inhibin
Interstitial(Leydig) cells- produce testosterone
function of testes
sperm and testosterone production
sprem production
Millions of viable sperm per day
Average time from production to ejaculation 64 days
testosterone production
Male secondary sexual characters
Controls spermatogenesis
endocrine control of testicular function
Reproductive hormones
GnRH- Gonadotrophin releasing hormone, produced from hypothalamus
Gonadotrophins- FSH and LH, released from anterior pituitary
Testosterone- released from testicles
pituitary hormone effects
LH and FSH stimlate spermatogenesis and testosterone secretion by the testes
testes hormone effects
testosterone and inhibin inhibit the secretion of gnrh bythe hypothalamus and lh and fsh by the pituitary
what is spermatogenesis
Sperm production from the primordial germ cells.
how long is the average cycle of spermatogenesis
Average cycle of spermatogenesis is 64 days in which the germ cells pass through different developmental stages
what are two distinct phases of spermatogenesis
Spermatocytogenesis
Spermiogenesis
Spermatocytogenesis
Clonal expansion and maturation through mitotic and meiotic process
Spermiogenesis
Differentiation into mature sperm cells
when does spermatogenesis start
Process starts at puberty and continues lifelong
spermatocytogenesis phases
A - mitosis 16 days
B
1- meiosis 1 24 days
2 - meiosis 2 some hours
[clonal expansion/maturation]
spermiogenesis phases
differentiation
spermatid –> sperm
mitotic division of spermatogenesis
Spermatogonium to primary spermatocyte-duplication, diploid chromosomes number(46)
first meiotic division
primary spermatocyte to secondary spermatocyte, two cells with haploid chromosome number(23)
second meiotic division
secondary spermatocyte to spermatid, two cells with haploid chromosome number(23)
spermiogenesis chromosomal division
maturation of spermatids into functional sperm cells
what factors affect spermatogenesis
lifestyle
medical
combination
= infertility
medical factors that affect spermatogenesis
Pretesticular-Problem with the hormonal control
Testicular- Problem at the site of production
pretesticular medical factors
Functional- excessive weight loss, gain
Intracranial tumours, cysts, bleed
Prolactinoma
Medications- opiates, external testosterone, steroids(body building)
Genetic- Kallmann’s syndrome
testicular medical factors
Surgery- orchidectomy, orchidopexy
STI
Mumps orchitis
Testicular trauma or torsion
Radiotherapy or chemotherapy
Genetic- Klinefelter’s (46 XXY), Y-chromosome microdeletion
lifestyle factors
sperm from factor - reversible
mother - irreversible
SMOKING
Steps to reduce the impact of factors affecting fertility
Improve lifestyle- normal BMI, stop smoking, alcohol in recommended limits, healthy diet, exercise, adjustments to occupational exposure
Optimise underlying medical condition
Stop medications or switch to alternative pregnancy compatible medications
Reduce STI risk and treat promptly if diagnosed.
Fertility preservation- sperm freezing prior to surgery or cancer treatment
how would you take a history
A 30 years old man attends the fertility clinic with his 28 year old partner. The couple are trying to conceive for 18 months without any success. Initial investigations organised by the GP are reviewed. Female results are normal. Semen analysis report for the man shows very low sperm count of 2million/ml (oligospermia) and reduced sperm motility.
[normal 15 million or more]
Past fertility- puberty, personal or family history of genetic problems, previous fertility treatment
Androgen deficiency symptoms- Infrequent shaving, unable to grow a beard, low libido, erection/ejaculation difficulty
Medical problems current or past- systemic disease, malignancy, prolactinoma
Genitourinary history- STI, mumps orchitis, testicular trauma/ torsion, undescended testicle, recurrent UTI
Past surgery- inguinal hernia repair, orchidepexy, orchidectomy
Medications- high dose steroid, testosterone replacement,
Supplements- body building products(exogenous steroids)
Occupation
Lifestyle- sedentary, food habits, smoking, obesity, alcohol, recreational drug use
what are pretesticular clues
Past fertility- puberty, personal or family history of genetic problems, previous fertility treatment
Androgen deficiency symptoms- Infrequent shaving, unable to grow a beard, low libido, erection/ejaculation difficulty
Medical problems current or past- systemic disease, malignancy, prolactinoma
Genitourinary history- STI, mumps orchitis, testicular trauma/ torsion, undescended testicle, recurrent UTI
Past surgery- inguinal hernia repair, orchidepexy, orchidectomy
Medications- high dose steroid, testosterone replacement,
Supplements- body building products(exogenous steroids)
Occupation
Lifestyle- sedentary, food habits, smoking, obesity, alcohol, recreational drug use
Systemic illness, local malignancy
Chemoradiotherapy, prolactinoma, Kallman’s(GnRH deficiency, genetic),
Steroid/testosterone/medication use
Extreme exercise, weight gain or loss(functional hypothalamic)
what are testicular clues
STI
Testes trauma or torsion,
Surgery- orchidopexy, orchidectomy, inguinal hernia repair
Varicocoele
Genetic(Klinefelter, cystic fibrosis, Kartangener’s syndrome)
what are lifestyle clues
Heat affecting testicles
Smoking
High BMI
Excessive alcohol
Recreational drug use
Occupation- exposure to
chemicals/ heavy metal/radiation
what examinations/investigations should be done on this man
BMI
Genital examination- external genitalia, testicular size, palpation of vas deferens, inguinal hernia, varicocoele
USS testis
Hormonal profile- FSH, LH, Testosterone, Prolactin
Genetic test- Karyotype, Y-chromosome microdeletion
diagnosis of this man
Oligospermia
Hormonal
Lifestyle
No cause
(Idiopathic)
Genetic
