Male Reproductive Physiology P1+2 Flashcards by Isla Anderson

describe key parts male reproductive organs

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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

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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

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function of testes

sperm and testosterone production

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sprem production

Millions of viable sperm per day
Average time from production to ejaculation 64 days

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testosterone production

Male secondary sexual characters
Controls spermatogenesis

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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

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pituitary hormone effects

LH and FSH stimlate spermatogenesis and testosterone secretion by the testes

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testes hormone effects

testosterone and inhibin inhibit the secretion of gnrh bythe hypothalamus and lh and fsh by the pituitary

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what is spermatogenesis

Sperm production from the primordial germ cells.

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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

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what are two distinct phases of spermatogenesis

Spermatocytogenesis
Spermiogenesis

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Spermatocytogenesis

Clonal expansion and maturation through mitotic and meiotic process

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Spermiogenesis

Differentiation into mature sperm cells

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when does spermatogenesis start

Process starts at puberty and continues lifelong

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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