5.1.2

Question 1

what r the 5 main structures in the vagina for fertilisation

Answer 1

-fallopian tube
-ovary
-endometrium
-uterus
-vagina

Question 2

how long does the menstrual cycle go?

Answer 2

28 days on average

Question 3

what occurs on day 14 of the menstrual cycle

Answer 3

ovulation cycle begins, if there has been mating, fertilisation occurs 1-2 days later

Question 4

illustrate when a baby is a zygote, embryo, foetus, newborn

Answer 4

zygote : 1-5 days
embryo : day 5- week12
foetus : week 12+
born : newborn

Question 5

when does implantation occur

Answer 5

day 7 of pregnancy

Question 6

how does fertilisation occur ?

Answer 6

1.the ovary releases an egg in ovulation and it is taken to the middle of the fallopian tube
2. when sexual intercourse takes place, a male release semen which is comprised of sperm
3. the sperm swims into the vagina then through the cervix and uterus to the fallopian tube where the egg lays
4. sperm fuses with egg to create zygote
5. zygote then travels down the oviduct to the uterus where it is implanted

Question 7

where does fertilisation occur specifically in the vagina

Answer 7

outer 1/3 of the fallopian tube

Question 8

when the sperm reaches the egg cell, it must cross 3 layers, what r they?

Answer 8

1. first membrane, the sperm physically pushes thro
2. zygote creates a strong membrane which prevents any other sperm fertilising the egg
3. surface protrins allows only one sperm 2 penetraste pass the plasma membrane

Question 9

what is implantation?

Answer 9

its around day 8 of pregnancy, and the embryo attaches to uterus lining, the endometrium section

• the myometrium muscle underneath endometrium
• • The blastocyst/zygote is implanted on the walls of the reproductive tract (uterine wall).
• Successfully implantation means pregnancy.
• This implantation process onto the walls establishes blastocyst’s access to nutrients (glucose, proteins, oxygen) to develop into a grown fetus (blood vessels surrounding the blastocyst carries blood which has dissolved nutrients)

Implantation is the process of adhering the fertilised egg to stick to the walls of the reproductive tract, providing the most suitable environment for zygote development.

Question 10

what r hormones?

Answer 10

• chemical messengers that travel in the bloodstream
• hormones r released by glands (endocrine system)

Question 11

what r the three types of hormones?

Answer 11

lipids (testerone, estrogen)
proteins (insulin)
amino acids (adrenaline)

Question 12

what r the three hormone classes

Answer 12

amine, peptide and steriod hormones

Question 13

what are the two most important hormones in the body generally, located in the brain

Answer 13

• hypothalamus ; releases hormones
• pituitary gland ; hormones r transported from here to the other glands

Question 14

where r hormones released for pregnancy

Answer 14

hormones r released from the ovarian follicle outer cells

e.g, estrogen

Question 15

how r hormones controlled in pregnancy

Answer 15

1. hypothalamus releases hormones
2. the gonadtropin GNRH releases the hormones to the pituitary
3. this this leads to LH and FSH acting upon the estrogen and progesterone

Question 16

what is a negative feedback loop

Answer 16

it ensures homeostasis stability so not too many hormones (FSH, LH, GnRH) are produced, so once estrogen levels rise, they exert negative feedback, causing less levels of GnRH being produced.

Fluctuations should always be curved as shown in the graph due to negative feedback.

Question 17

what does FSH and LH do n link it together

Answer 17

FSH = allow the release of follicle by the ovaries
* initiates the ripening of follicle and egg in the ovary. this stimulates secretion of estrogen

by day 14, a surge in luteinising hormone takes place, causing ovulation

Causes follicle to release egg also known as ovulation, allows empty follicle to grow into corpus luteum and inhibits secretion of estrogen.

Question 18

what is the corpus luteum

Answer 18

The hormones are then all produced by this structure called corpus luteum until the placenta can take over around week 8 of pregnancy

pool of hormone

Question 19

what is estrogen’s role in the early stage of pregnancy?

Answer 19

It will travel through the blood stream and cause the development, repair and thickening of the endometrium, and it increases the nutrients and glucose with it

• It comes from the outer lining cells of the follicle
• It thickens the endometrium to prepare it for implantation for the clump of cells in the embryo

Question 20

what is progestrone role in the beginning of pregnancy?

Answer 20

Maintains the wall of the uterus to ensure its not contracting against the embryo

• Maintains pregnancy by ensuring the muscle walls of the uterus don’t crush the embryo

That’s why when women give birth, they’re given anti progesterone drugs sometimes to contract the uterus, pushing the baby out

Question 21

whats Beta HCG ?? what is it released in ?

Answer 21

Hormone that determines ones pregnancy as it is released through urine

• It is released through the outer cells of the implanted embryo – implantation
• Chorionic = placenta
• It acts on the gonads
• It allows the ovary to continuously release the hormones of progesterone and estrogen

Question 22

what is the link between corupus luteum and placenta

Answer 22

The corpus luteum continuously produces estrogen and progesterone until the placenta can take over. About week 8 of pregnancy, the placenta begins to produce the nutrients and hormones necessary for the embryo

Question 23

what r the two things that can occur after day 14 of the menstrual cycle?

Answer 23

fertilisation or no fertilisation

Question 24

what happens if ovulation occurs and no sperm makes its way to the egg in the fallopian tube

Answer 24

no implantation occurs after the hypothetical 7th day of pregnancy . this will lead to the decreased level of estrogen and progestrone as theyre not needed.

• Decrease in estrogen breaks down the thickening of the endometrium
• The uterine muscles contract due to no progesterone control

There are blood vessel within the uterus as uterine walls contract upon them, the blood vessel are squished to the point where they’re thin and stop blood flow

• Stopped Blood flow would cause a stroke to the brain the uterine lining will die as if it has had a heart attack

-The shedding of the dead cells are what is referred to as the first day of menstruation (menses) for a female as it leaves the body

Question 25

why does LH stimulate the beginning of ovulation?

Answer 25

By day 13, like there is a negative feedback loop, there is also a positive one which tends to occur at around day 13 of the reproductive cycle for a female which causes instead of a decrease an increase in LH. This increase causes in LH is primarily what begins implantation and release of hormones. The decrease however in the graph shows how fertilisation doesn’t occur because LH and the hormones drops

Question 26

whatll happen after week 12 with the corpus luteum

Answer 26

The corpus luteum produces high levels of hCG in the first ten weeks of pregnancy as seen below, but then it drops. this is because the placenta has taken over, a new organism, getting rid of b-hcg

Question 27

what r the four main roles of the placenta

Answer 27

1. nutrient exchange, glucose mainly (takes blood sugar from mommy bloodstream thro the umbilical vein)
2. interface - ensures mama and embryo blood never mix
3. protects the baby as it is 50% foreign so mamas immune system will naturally want to destory it.
4. it ensures the baby can breathe. umbilical cord provides oxygen fo rbaby to breathe while it is swimming in amniotic fluid.
5. releases the hormones estrogen and progesterone

Question 28

what are the hormonal changes when giving birth at 37 weeks? whats the main hormone utilised

Answer 28

• The muscles in the uterus must contract to expel the baby.
• The tissue of the cervix must soften so that the cervix can dilate (widen) to allow the passage of the baby.

oxytocin - *

Causes contractions of the uterine muscle caused by the nerves surrounding the cervix
* A positive feedback loop is occurring where everything continues to increase until the fetus has been deliver
o The nerves surrounding the cervix is increasing
o The baby’s head is getting pushed harder against the cervix
o Oxytocin levels are increasing
o The contractions increasing
 Until finally resulting in the fetus delivery