Female reproductive system Flashcards
FRS diagram
Ovary Ovarian ligament Funnel Fallopian tube (oviduct) Wall of uterus (womb) Lining of uterus (endometrium) Cervix Vagina Vulva
Ovary function
Produce the eggs (ova/ovum),
produce oestrogen and progesterone
Fallopian tube function
Fertilisation
Transports egg from the ovary to the uterus
Vagina function
Allows entry of sperm
Is the birth canal for the exit of the baby
Cervix function
Opening of the uterus, separates the uterus from the vagina
Uterus function
Embryo implants here
Holds the embryo during pregnancy
Nourishes the embryo
Endometrium function
Inner lining of the womb
Lining with blood vessels to nourish the embryo
Female hormones
FSH->Oestrogen->LH-> Progesterone
Each causes the production of the hormone after it and inhibits the one before it.
FSH
Stands for
Produced
Function
Stands for: Follicle stimulating hormone
Produced: Pituitary
Function: Causes graffian follicles to be produced in the ovary.
Stimulates the production of a few potential eggs to develop in the GF.
Stimulates production of oestrogen
Oestrogen
Stimulated
Produced
Functions
Stimulated: FSH Produced: graffian follicle in ovary Functions: causes endometrium to develop- prepare for pregnancy Inhibits FSH Stimulates release of LH
LH Stands for Stimulated Produced Functions
Stands for: Luteinising hormone Stimulated: Oestrogen Produced: Pituitary Functions: Causes ovulation (GF releases egg into the fallopian tube), The empty follicle fills with yellow cells and becomes the corpus luteum (yellow body) Stimulates release of progesterone
Progesterone
Stimulated
Produced
Functions
Stimulated: LH
Produced: Corpus luteum in the ovary
Functions: Prepares for pregnancy- maintains structure of endometrium
Inhibits FSH and LH
Egg production (before meiosis)
Ovaries produce the eggs, they are not yet divided by meiosis and are diploid. After puberty a number of eggs are produced by meiosis every month. (haploid) Only one egg continues to grow, the rest die.
Egg production (after meiosis)
- Once meiosis is complete, the egg is surrounded within the graffian follicle.
- GF produces oestrogen
- When mature the follicle bursts at ovulation to release the egg from the ovary. (LH)
- After ovulation the follicle fills with yellow cells and becomes the corpus luteum (yellow body)
- CL produces progesterone
- CL degenerates after a few days, so no progesterone, and cycle restarts
Menstrual cycle def.
The menstrual cycle is a 28 day sequence of events that produces an egg and prepares the body for pregnancy.
Menstruation
Start and end (during life)
Starts during puberty
Ends during menopause
Menstrual cycle day 1-5
Old lining breaks down and is shed from body. Loss of blood and tissue called menstraution.
New egg produced in ovary by meiosis, surrounded by graffian follicle
Hormone: FSH
Menstrual cycle day 6-14
Oestrogen produced by GF
Causes lining to build up to prepare for implantation
Stimulates release of LH
Menstrual cycle day 14
LH causes ovulation, GF bursts to release egg into fallopian tube.
Menstrual cycle day 14-28
- GF develops into corpus luteum (secretes progesterone which thickens endometrium)
- Released egg dies by day 16 if unfertilised.
- If unfertilised, corpus luteum degenerates on day 22
- Results in reduction of progesterone levels , and lining breaks down. Cycle restarts.
Fertile period def.
Days in the menstrual cycle when a woman has the highest chance of becoming pregnant if she has intercourse.
When is the fertile period?
Why?
Day 12-16
Egg released day 14, it can remain alive for 2 days after ovulation so if she has intercourse 2 days after ovulation it may become fertilised. The sperm can live for 2 days in the female so if the female has intercourse 2 days before ovulation, the sperm may still be alive when the egg is released and will fertilise it.
Which hormones cause development of secondary sexual characteristics
Oestrogen and progesterone
Fertilisation def.
The fusion of the egg and the sperm nuclei to form a diploid zygote. Occurs in the fallopian tube (oviduct)
What happens during fertilisation
Many sperm reach the egg at the same time. The acrosome releases enzymes to digest the egg membrane. The sperm loses its tail and the head enters the egg. The egg and sperm head fuse to form a zygote. A chemical reaction at the membrane prevents other sperm cells entering.
Implantation def.
the embedding of the fertilised egg (zygote) into the endometrium. Occurs 6-9 days after fertilisation.
Stages of the fertilised egg between fertilisation and implantation
Zygote—divides by mitosis by day 3—->Clump of solid cells called a morula —day5—>Blastocyst/blastula (hollow ball of cells) —travels down fallopian tube to uterus and implants–> Embryo
When is the beginning of pregnancy
Once embryo implants in the endometrium
Development of fertilised egg
Zygote
Fertilised egg
Development of fertilised egg
Morula
Solid ball of cells
day 3 after fertilisation
Development of fertilised egg
Blastocyst
Hollow ball of cells
day 5
Development of fertilised egg
Embryo
Implanted blastocyst
How does the egg move in the fallopian tube
Due to hair like structures called cilia
Difference between identical and non identical twins
Identical: One egg fertilised and then splits
Not Identical: Two eggs are fertilised
Outer layer of blastocyst and function
Called trophoblast
Develops into the amnion and placenta
Inner layer of blastocyst
name and what it develops into
Called inner cell mass
develops into embryonic disc which develop into features of the embryo.
Germ layers
def.
and what they develop into
Def: Layers in the blastocyst that form specific parts of a developing embryo.
Ectoderm: skin, hair, nails (Ecto and endo like amoeba)
Mesoderm: Muscles, Skeleton (M-middle-muscles)
Endoderm: Inner lining of digestive system, lungs, liver (Ls)
Development of Embryo into a Foetus
Week 4
“Vital organs”-brain, heart, limbs
Development of Embryo into a Foetus
Week 6
“senses”-eyes, ears, nose,
skeleton
Development of Embryo into a Foetus
Week 8
Sex organs,
Cartilage replaced by bone
Known as a foetus
Development of Embryo into a Foetus
Week 12
Sex of baby can be determined
Nerves and muscles develop so limbs move.
Foetus sucks thumb and urinates
Amnion and amniotic fluid
Amnion: develops once embryo implants.
Amniotic fluid: Amnion fills with liquid
Function: Protects the embryo during pregnancy and acts a shock absorber
Placenta
When operational
Forms from
Forms early in pregnancy
Becomes fully operational about 3 months into the pregnancy.
Forms from the trophoblast of blastocyst.
Links the baby and the mother
Placenta function
- Passes food and oxygen and also harmful substances from mother to baby.
- Passes wastes from baby to mother (CO2, Urea, Salts)
- Placenta makes progesterone to keep the endometrium built up.
How does the placenta form
Forms from the tissues of the embryo and endometrium.
- After implantation the embryo forms an outer membrane called a chorion which surrounds the amnion.
- The chorion develops finger like projections-chorionic villi
- The chorionic villi invade the endometrium forming the placenta.
Why is it important that the mothers and babies blood doesnt mix
- The blood groups of mother and baby might not be compatible.
- The blood pressure of the mothers system may cause damage to the embryo.
Gestation def.
The length of time spent in the uterus from fertilisation to birth
9 months in humans
Beginning of labour
- Placenta stops making progesterone. The walls of the uterus begins to contract as a result.
- Pituitary releases oxytocin causing further contractions.
Stage 1 of birth
Uterus contracts and pushes the foetus towards the cervix.
The cervix opens (dilates)
The contractions cause the amnion to break releasing the amniotic fluid through the vagina. (waters breaking)
Lasts 12 hours
Stage 2 of birth
The foetus passes through the cervix and the birth canal head first.
The umbilical cord is tied and cut. This leaves a scar which becomes a navel (belly button)
Lasts 20 mins to 1 hour
Stage 3 of birth
The baby is now born.
The uterus now contracts again and expels the afterbirth- umbilical cord and placenta
Lasts 10-15 mins
What is Lactation?
Caused by
The secretion of milk from the mammary glands.
Caused by secretion of prolactin by the pituitary.
What is produced at first in the mammary glands
Colostrum is produced. It is highly beneficial milk.
Why does milk continue to be produced as long as the woman breastfeeds
Prolactin continues to be produced as long as it continues, stimulating the production of milk.
Why breastfeeding is more beneficial than bottle feeding
Colostrum and breastmilk provides the baby with essential antibodies to protect against infection.
It has the ideal balance of nutrients for the baby.
Has little fat making it easier to digest.
Allows mother and baby to bond.
Helps mother recover and lose excess fat.
