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34 Cards in this Set
- Front
- Back
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What factors might contribute to infertility
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pre-gonadal, gonadal, post gonadal factors
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what category do most pregonadal factors come under
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mainly endocrine feedback loop Hypothalamus releases hormones via pituitary gland to gonads, gonads release hormones to signal hypothalamus to stop release of gonadotropin releasing hormones to pituitary. IF THE LOOP BREAKS, INFERTILITY MAY RESULT.
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what % of couples experience difficulty with natural pregnancy?
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25%
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what % of couples are infertile?
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15%
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examples of gonadal factors which may cause infertility?
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abnormalities in numbers of sex chromosomes; space occupying lesions cysts, tumours, scars; environmental agents lead, alcohol, nicotine; testicular dysfunction due to problems with spermatogenesis
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Kleinfelters karyotype
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47XXY (male with extra X chromosome)
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Turners Syndrome karyotype
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45X0
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what is the ideal temperature for spermatogenesis?
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about 2degrees lower than body temp.
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what adaptations help maintain testicular temperature
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dartos/cremaster reflexes, migration of testes from abdomen to scrotum, pampiniform plexus heat-exchanger
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how does the pampiniform plexus work?
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surrounds the testicular artery venous blood returning to the right heart is cooler than the arterial blood incoming. By surrounding the testicular artery with the cooler venous pampiniform plexus, the blood going into the testicle is pre-cooled.
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increased testicular temperatures associated with?
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decreased sperm motility, sperm numbers, and increased numbers of abnormal sperm, all of which mean decreased fertility.
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increased temperatures in testicles due to?
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undescended testicles, environmental factors (clothing/occupation), varicocele (bag of worms varicose veins of the pampiniform plexus)
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demographics that may have varicocele
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truckers/taxidrivers: tighty-whities and driving all day with legs together.
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post gonadal factors may include?
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obstruction of accessory reproductive ducts
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what % of female infertility due to obstruction?
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50%
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types of reproductive tract obstruction?
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atresia (complete obstruction) or stenosis
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what might cause atresia or stenosis
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congenital or acquired masses in walls of reproductive tubes, masses in adjacent structures may press on and occlude tubes, scars from infections or surgery may block tubes or reduce mobility
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what infections may cause scars that occlude tubes?
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lower urinary tract in male, uterine tube in female
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what do cervical glands produce?
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mucin glycoprotein (mucous) which alternates between tightly structured fibrous and loosely structured watery.
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tightly structured mucin glycoprotein cervical mucous
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type G
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loosely structured mucous
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Type E
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effect of glycoproteins
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Type G may be barrier to microorganisms and sperm, and Type E may allow passage of sperm into uterus
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What mucous is found in the cervix during periovulatory period
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type E sperm can get through
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what causes Type G E change
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rising estrogen levels in periovulatory period
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what causes E- G reversion?
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rising progesterone levels after ovulation
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another post gonadal factor
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antibodies to sperm antigens
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what do anti-sperm antibodies cause?
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reduced infertility by reduced motility, sperm agglutination, death of sperm cells
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woman developing antibodies to sperm cells called?
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isoimmunity
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if man develops antibodies to his own sperm cells?
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autoimmunity
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how might a man develop autoimmunity to his own sperm cells?
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damage to blood-sperm barrier.
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what is the blood sperm barrier
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mechanism to isolate cells that dont begin to develop until puberty with onset of spermatogenesis from rest of body.
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example component of blood-sperm barrier?
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continuous tight junctions connecting the sertoli cells together
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why can men develop autoimmunity to their sperm
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because immune responses (against non-self) develop early in life, prior to puberty, when sperm cells (self) first start to develop. immune system thinks sperm are foreign cells and mount an immune response against them as they appear after the development of the immune system.
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what can cause damage to blood sperm barrier?
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through trauma, if sperm gets into blood.
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