Female Reproductive System (Pregnancy) Flashcards
State the lifespan of an OVUM and SPERM
OVUM - 12-24 hours after ovulation
SPERM - <72 hours in female genital tract
Define the term ‘FERTILISATION’
fertilisation = fusion of 2 haploid gametes, sperm and ovum, to produce a diploid zygote
State the factors in MALES and FEMALES that determine successful fertilisation
MALES
- production of adequate number of healthy sperm
- successful delivery of sperm into vagina
FEMALES
- ability to ovulate to produce ovum
- ability to provide passage for transport of sperms towards ovum
State the changes that sperms undergo for fertilisation (3)
- transport of sperm (affected by (a) own mobility, (2) assisted by contractions of uterus and oviduct, (3) chemical attraction to ovum)
- capacitation
- acrosome reaction
Regarding CAPACITATION, state
- where this process occurs
- what occurs during this process
CAPACITATION = activation process required for successful fertilisation for sperms to penetrate the egg
- where = after ejaculation in female genital tract
- how = seminal plasma protein contents removed to expose molecules that bind to zona pellucida of oocyte to get ready for acrosome reaction
Regarding ACROSOME REACTION, state
- when this process occurs
- what occurs during this process
ACROSOME REACTION
- when = at the time sperm binds to zona pellucida of ovum
- how = redistribution of membrane constituents –> increase membrane fluidity and permeability (exposing contents of acrosome –> leads to break down of zona pellucida and membrane of the oocyte)
State the changes that ovum undergoes upon/after fertilisation (3)
- cell membrane depolarises –> prevents membrane fusion with other sperm
- cortical/zona reaction - inactivation of sperm receptor and hardening of zona to impair subsequent sperm binding
- resumption of the second meiotic division (oocytes are arrested in metaphase of meisosis II)
State the 2 processes that prevent polyspermy.
- cell membrane depolarises –> prevents membrane fusion with other sperm
- cortical reaction/zona reaction - inactivation of the sperm receptor and hardening of the zona to impair subsequent sperm binding
State the 8 steps in fertilisation
- sperm cell approaches an egg
- contact between the sperm and zona pellucida
- entry of sperm and contact with oolemma (egg membrane)
- resumption of the second meiotic division of the oocyte
- completion of meiosis
- formation of male and female pronuclei
- migration and union of male and female pronuclei
- zygote ready for first mitotic division
PREGNANCY
- Normal human pregnancy: ____ - ____ weeks
- Starts with fertilisation and ends with childbirth
- Calculated from ____ to ____ (____ rule)
- 3 Phases:
PREGNANCY
- Normal human pregnancy: 38 - 40 weeks
- Starts with fertilisation and ends with childbirth
- Calculated from LMP to DATE OF DELIVERY (NAEGELE’S rule)
- 3 Phases:
(1) Pre-embryonic period - first 2 weeks
(2) Embryonic period - 3rd-8th week
(3) Fetal period - 9th-38th week
Arrange the following from start of fertilisation to implantation:
- 1 cell zygote
- 4 cell zygote
- blastomere
- early morula
- late morula
- blastocyst
1 cell zygote –> blastomere –> 4 cell zygote –> early morula –> late morula –> blastocyst
IMPLANTATION OF ____:
- Process in which the ____ buries in the ____
- Timing: ____ - ____ days after ovulation
- ____ cells secrete ____ to digest the ____ cells to invade into the ____
IMPLANTATION OF BLASTOCYST:
- Process in which the BLASTOCYST buries in the ENDOMETRIUM
- Timing: 7 - 10 days after ovulation
- TROPHOBLASTIC cells secrete ENZYMES to digest the UTERINE cells to invade into the ENDOMETRIUM
State the parts of the human body that develop from
- Ectoderm
- Endoderm
- Mesoderm
ECTODERM - epidermis, nervous system
ENDODERM - epithelial lining of GI and organs
MESODERM - connective tissues, muscle, bone, blood, lymph system
State the 2 parts of the placenta.
- fetal part - chorionic plate
- maternal part - decidua basalis
State the functions of placenta (5)
- endocrine roles - production of hormones
- nutritional roles - transports nutrients (glucose, AA, FA, minerals, vitamins) from mother to fetus
- respiratory roles - transportation of oxygen from mother to fetus and carbon dioxide to mother
- immune roles - transportation of maternal Ab (esp IgG) into fetal blood to confer passive immunity to fetus
- excretory roles - transportation of nitrogenous waste (ammonia, urea, uric acid, creatinine) from fetal to maternal blood