Sperm Use During Egg Fertilization in the Honeybee (Apis ...
When Egg Meets Sperm…. Life Spans Unfertilized egg can only live for 24 hours Sperm usually live...
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Transcript of When Egg Meets Sperm…. Life Spans Unfertilized egg can only live for 24 hours Sperm usually live...
When Egg Meets Sperm…
Life Spans
Unfertilized egg can only live for 24 hours
Sperm usually live for 48 hours (can live up to 7 days) in a women’s body
Fertilization
The fusion of a sperm and eggMillions of Sperm are released in the vagina
move up uterus & to the fallopian tubes
if there is an egg, fertilization occurs
ONLY 1 sperm can fertilize an egg! Once this occurs, a protective shield forms
(fertilization envelope) around the eggFertilized egg = Zygote
What’s Next?
Zygote divides into many cells moves into uterus
Ball of cells = blastocyst
Cells travel for 7-8 days
Attach to uterine lining & continue developing Called implantation
The Pathway
Implantation
Occurs when the embryo attaches to the wall of the uterus
Some women can feel this occur (feel light cramps)
Causes a hormone called hcG to be released Supports pregnancy what pregnancy tests use
After implantation: Pregnancy
Membranes develop around the embryo to protect & nourish it = placenta
More on pregnancy…
Umbilical cord: connects embryo to mom Transports oxygen & nutrients to embryo Removes waste products
At 8 weeks, embryo is called a fetus
Pregnancy lasts about 266 days 40 weeks or 9 months
Giving Birth
Oxytocin (hormone) triggers uterine wall to contract
Labor beginsCervix expandsBaby starts to emerge, head first cut cord
Cord will dry up/fall off becomes your belly buttonPlacenta must be delivered after baby
Miscarriages
Spontaneous end of a pregnancy Occurs when a fetus can NOT survive out of the womb
Types: Embryo stops growing very early no fetus forms Fetal heartbeat has stopped fetus has died
Causes: Genetic Uterine abnormalities, hormonal abnormalities Reproductive tract infections Tissue rejection
Risk Factors: diabetes, smoking, drugs, fertility issues, etc
Stillbirth
Baby has died during delivery or prior to birth
Causes: (many) Umbilical cord Diabetes Trauma Drugs, smoking Birth defects infections
Ectopic Pregnancies
Implantation occurs outside the uterus in: In fallopian tube *most common 95%* Cervix Abdomen Ovary
Pregnancy has to be terminatedSymptoms similar to pregnancy
Additional symptoms: bleeding, lower back pain, low blood pressure, dizziness, sharp stabbing pain in back/neck
Infertility
Inability to conceive Can be female or male
Options: Fertility drugs: side effects include multiples IVF (invitro fertilization): fertilization happens outside
the body Very expensive, possible multiples
Egg Donors/Sperm Donors Expensive, invasive for egg donors Would you want it?
Adoption Can be expensive, heartbreaking, and joyful
Why do Birth Control Pills Work?
Estrogen & progesterone pills fool your body into thinking you are pregnant Hence, you don’t ovulate (or shouldn’t), FSH & LH
stay low Effectiveness also depends on following directions