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Human reproduction and fertility > Jones - reading > Flashcards

Jones - reading Flashcards

1
Q

What is fitness?

A

Survivors selected by ability to reproduce

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2
Q

What is the gene pool constantly doing?

A

Adapting

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3
Q

What is the purpose of reproduction?

A

Pass genes to next generation

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4
Q

How do most organisms reproduce?

A

asexually

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5
Q

How do unicellular organisms reproduce?

A

mitotically - produce two identical offspring

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6
Q

how do complex vertebrates reproduce?

A

Partenogenesis - egg cell doesn’t need sperm to become an embryo

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7
Q

How do mammals reproduce?

A

sexually

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8
Q

what is produced at fertilisation?

A

zygote

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9
Q

what is the function of meiosis?

A

halves genetic material

produces germ cells

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10
Q

How do mammals increase genetic diversity?

A

exchanging pieces of homologous chromosomes

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11
Q

What is a mechanism of recognising fitness in mammals?

A

sexual selection

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12
Q

Negatives of sexual selection

A

Energy expenditure in finding, attracting and keeping a partner
exposure of both partners to death

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13
Q

Why do mammals reproduce by internal fertilisation?

A

Reduced number of eggs - energy expenditure

women undergo egg loss but mainly before egg growth

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14
Q

What is viviparity?

A

production of smaller eggs
development in vivo
birthing live young

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15
Q

Positives of viiparity?

A

reduces pressure to develop quickly

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16
Q

negatives of viviparity?

A

long gestation is demanding on females

there is a selective pressure on birthing as it can go wrong

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17
Q

How long do mammals display parental care for?

A

An extended period

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18
Q

What is fercundity?

A

reproductive capacity

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19
Q

How does fercundity differ in males and females?

A

Males - persists throughout life, slowly declines

Females - declines steeply at 35, ends at 50, due to loss of egg quality

20
Q

Male contraception using testosterone levels

A

High testosterone leads to FSH stimulating spermatogenesis
could suppress endogenous testosterone production and therefore spermatogenesis
Shown as effective in some people - less in others
took a long time to get a low sperm count in some people

21
Q

Male contraception using small molecule inhibitors of BRDT

A

BRDT= testes specific epigenetic reader protein
JQ1 = BRDT inhibitor - targets bromodomain and prevents recognition of acetylated H4
reduces sperm number and motility without altering hormones
reversible withing 1 month

22
Q

Male contraception PLC3

A

Potential to inhibit PLC3 and prevent oocyte activation

no specific molecules found yet

23
Q

female contraception Target the zona pellucida

A

immuniation of zona pellucida

this may cause abnormal cycles

24
Q

Male contraception

Binding to the androgen and progesterone receptors

A

reduces testosterone conc in blood
effective and reversible
no serious side effects
weight gain

25
Q

Male contraception

Adjudin

A

disrupts spermatid adhesion to sertoli cells

premature spermiation - not mature enough to fertilise

26
Q

Male contraception

Retinoic acid receptor antagonists

A

Aldehyde dehydrogenase in setoli cells synthesises retanoic acid
this is required for spermatageneis

27
Q

Male contraception

Synthetic androgens

A

Supress gonadorophins and sperm production
reversible
may be incomplete suppression

28
Q

Male contraception

Nestorone and testosterone gel

A

Progestin compound
blocks testosterone production and reduces sperm production
targets sertoli germ cell adhesion or sperm motility

29
Q

Male contraception

Vasalgel

A

Reversibly blocks vas deferens
prevents passage of sperm
impairs sperm function
reversible

30
Q

Male contraception

Block to sperm delivery

A

100% efficacy after 15 days
attaches to cells in vas deferens and blocks sperm passage
leads to morpholically different sperm

31
Q

Female contraception

Combined pill

A

Supresses secretion of progestogen and estrogen
prevents ovulation as no LH surge
inhibition of follicle maturation

32
Q

Female contraception

Mini pill

A

progesterone only
estetrol - produced during pregnancy
less side effects

33
Q

Femal contraception

Vaginal rings

A

Release haormones to prevent follicle development and ovuation
does not need an trained proffessional but is longer lasting

34
Q

female contraception

emergancy contraception

A

same hormones as normal pill
delays ovulation
needs to be 1 day befor LH surge - sometimes too late
needs to be taken within 24 hours

35
Q

IUDs

A

Copper or hormonal

36
Q

Implants

A

Long lasting

hormonal

37
Q

Injections

38
Q

new female contraception

A

COX2 inhibitors: less prostaglandin production and failure to ovulate
Rofecoxib: delayed follicle rupture
Meloxicam: interfers with ovulation

39
Q

Are developmental abnormalities

more likely in babies generated via ART?

A 
Different types of ART: do they all have the same level
of risk?
 Cancer risk?
 Vitrification
 ICSI vs IVF?
 Imprinting disorders
 Cardiometabolic problems
 Low birth weight
 Urogenital issues
40
Q

Why are the results from different studies at odds

with one another?

A

 Underlying infertility/subfertility
 Multiple births
 Confounding variables e.g. maternal age, follow-up (closer
scrutiny following ART), genetic origin, sample size
 Differences in procedures over time and in different places
(e.g. types of medication; day of transfer; oocyte/sperm
selection criteria/culture media)
 Risk behaviours (smoking, alcohol)
 Importance of long-term follow-up

41
Q

Are developmental abnormalities
more likely in babies generated via ART?
conclusion

A

The risks do seem to be slightly higher for
some conditions.
 BUT, don’t forget that these ART procedures
result in the birth of thousands/millions of
healthy (and desperately wanted) babies.
 Additionally, the techniques are constantly
being monitored, adapted and improved.

42
Q

What methods are used to create ‘three-parent babies’? How do they work?

A

Cytoplasmic (ooplasmic transfer)
 Mitochondrial replacement therapy (MRT) via Spindle transfer (ST) or Pronuclear
transfer (PNT or PT)
 Could also consider standard Nuclear Transfer

43
Q

Are the techniques safe and effective?

A

ST appears safe in monkeys
33% effective - better than current rate
no detectable heteroplasmy
later study on humans showed abnormal separation of the second polar body

44
Q

What are the benefits?

A

Couples able to conceive via CT despite poor-quality oocytes

 Couples able to conceive via ST and PNT despite maternal mtDNA disease

45
Q

What problems can arise in offspring/future generations?

A

MtDNA heteroplasmy/persistence of donor or mutant mtDNA
 Reversion of mtDNA population due to genetic drift
 Developmental abnormalities

Human reproduction and fertility (4 decks)

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