Reproductive System - Female Flashcards
What are ovaries?
solid, egg-shaped structures
attached to the uterus by ligaments
have 2 main functions
- store and release the ova
- produce female sex hormones Estrogen and Progesterone
What is an Ova?
the female reproductive cell
the largest cell in the female body (grain of sand)
female is born with all the ova she will ever have (~200,000)
about 400-500 will mature and are released over a lifetime.
What is progesterone?
a hormone that stimulates the building up of the lining of the uterus in preparation for the fertilized ovum
What is the lining of the uterus called?
endometrium
It is a blood vascular lining
What is estrogen?
the hormone responsible for the secondary sex characteristics and the sex drive in females.
It spurs the onset of puberty and is responsible for ovulation
inhibits the growth of facial hair
What is the uterus?
a hollow, muscular organ
its function is to protect and nourish a fetus
the walls of the uterus have the ability to stretch to the size of a small watermelon
After childbirth, the uterus shrinks back to the original shape in 6-8 weeks but it can take up to 9 months for the uterus to fully recover.
What is a cervix?
The neck or opening of the uterus
It dips down about half an inch into the vagina
It is normally plugged by mucus. It stays tightly closed during pregnancy, but thins and opens for the delivery of the baby.
It dilates up to 10cm for births.
What are the fallopian tubes (oviducts)
2 tubes attached on either side of the uterus
They are about 4 inches long and 3/16 in diameter (the size of a cooked spaghetti noodle)
Carry the egg towards the uterus and sperm cells towards the egg cell
Fertilization takes place in the upper third of the oviduct.
What is Ovulation?
When the egg is released from the ovary
Starts occurring at the age of puberty
The ovum moves to the surface of the ovary and bursts out
The ova falls into the fallopian tube and waits for fertilization
happens at about the 14th day of the cycle
What is the vagina?
Female organ used for intercourse
an empty passageway leading from the vaginal opening to the uterus
The vaginal walls are made of many small folds of membrane that stretch greatly to accommodate a baby during birth.
secrete a fluid that helps to make intercourse easier.
What is the urethra?
The opening to the bladder
What is the clitoris?
a small pea-shaped bump at the front of the labia
It contains a small amount of erectile tissue
the clitoris increases sexual pleasure.
What is the ovarian cycle?
averages about 28 days but can range from 21-25 days.
It is the cycle of releasing an egg for fertilization.
Explain days 1-13 of the ovarian cycle
the follicular stage
follicles are immature eggs
several follicles begin developing (due to FSH - secreted by the anterior pituitary)
The developing follicle begins producing estrogen which stimulates the endometrium to thicken
Explain day 14 of the ovarian cycles
This is ovulation
The most developed follicle bursts from the ovary due to the increased amounts of LH
(LH is secreted by the anterior pituitary because of high levels of estrogen)
Explain days 15-28 of the ovarian cycle
This is the luteal phase
The remaining follicle tissue develops into corpus luteum
The corpus luteum secretes progesterone which causes the endometrium to become mucosal (ready to accept a fertilized egg)
What is implantation?
The process of a fertilized egg embedding into the endometrial layer
What happens if implantation does not occur?
the corpus luteum degenerates leading to LOW progesterone
Low progesterone causes the endometrial tissue to break down (bleeding)
Describe the Uterine Cycle
Day 1 - Menstruation begins - The endometrium is broken down (menses)
Day 5 - Menstruation is usually ended
Day 6-13 - Proliferation phase - Endometrium thickens and becomes more vascular
Day 14 - Ovum has matured and burst out of the ovary
Day 15 - After 24 hours, the egg is done
Day 26 - in the absence of fertilization, estrogen/progesterone levels drop and the endometrium lining breaks down
Day 28 - Menstruation begins again
What happens if fertilization and implantation occur?
The embryo will implant into the endometrium and the placenta begins to develop
The placenta and embryo produce hCG (human chorionic gonadotropin)
hCG prevents the corpus luteum from degenerating (progesterone stays high and the endometrium is NOT shed)
Placenta also produces progesterone and estrogen (this shuts off FSH and LH) - no new follicles develop and no new ovulation.
What happens during birth?
The pressure on the uterus wall causes the pituitary gland to secrete oxytocin
Oxytocin promotes contraction of the uterus wall…which leads to MORE pressure…which leads to MORE oxytocin and contractions = a POSITIVE feedback loop
What is the Corpus Luteum?
It is made up of the follicle cells that remain in the ovary following ovulation.
If pregnancy does not occur then the corpus luteum degenerates in about 10 days.
If pregnancy does occur then the corpus luteum secretes estrogen and progesterone to prevent more eggs from developing
