Ovulatory Cycle, Conception, and Fertility Flashcards
Hormones
regulatory substances in an organism and transported into tissue fluids such as blood to stimulate specific cells or tissues into action
A woman’s monthly cycles are controlled by the release of what hormones?
Estrogen, progesterone, Follicle-stimulating hormone (FSH), and lutenizing hormone (LH)
What does FSH do?
It triggers ovarian follicle development.
What does LH do?
It triggers the release of the egg from the most mature follicle
Hypothalamus
Dominant factor in controlling the anterior pituitary gland which in turn controls the ovaries. It releases gonadotrophin-releasing hormone (GnRH), which stimulates the pituitary gland to release the sex hormones called gonadotrophins (FSH and LH)
What hormones do the overlies release back to the brain?
Estrogen and Progesterone
What is Estrogen responsible for?
The secondary sex characteristics: growth of the breasts, female body shape, distribution of body hair, stimulates the growth of the bacteria that increases the acidity in the vagina, causes fluid retention.
How long does the Ovarian cycle last?
About 28 days. It begins with menstruation. Under the influence of estrogen the endometrium is then rebuilt.
When do the follicles begin to develop?
About day 25 of the previous cycle.
When does the egg begin to develop and mature?
ABout day 5 of the cycle.
What group of cells surrounds each egg?
Follicle
How many follicles ripen each month?
About 20 of these fluid filled sacs, one outgrows the others.
When does the peak fertile period occur?
When the egg is released from the ovary, about 14 days before the end of the cycle, regardless of the total length of the cycle.
Middleschmertz
pain experienced when the egg bursts from the ovary.
What happens after the egg leaves the ovary?
It travels down the fallopian tube where it awaits fertilization by a sperm (drawn in by the fimbria)
How long can the e.g. live if fertilization does not occur?
12-24 hours
Corpus Luteum
Site where the egg was released from the ovary, it becomes a yellow body that produces progesterone until about 10 weeks when the placenta takes over; lasts for 12-14 days unless it begins receiving HCG
Luteal phase
named after the corpus luteum and is the second half of a woman’s menstrual cycle, beginning after ovulation and continuing until menstruation occurs
What does progesterone do after ovulation?
Makes the lining of the uterus thick for implantation, causes changes to the uterine lining, increases blood supply to the uterus, causes increase of temperature in ovulation, gives sensation of fulness of breasts before menstruation.
What are the three phases of the menstrual cycle?
The Menstrual phase, the proliferative phase, the secretory phase
Menstrual phase
Lasts for 3-7 days; endometrium is shed since it is not needed to develop an embryo
Proliferative phase
Proceeds from menstruation through to ovulation; the endometrium is reforming and thickening
SEcretory phase
Following ovulation and is controlled by the estrogen and progesterone released by the corpus luteum. The endometrium thickens and becomes spongy. If an egg has been fertilized it will proceed to the uterus where it will embed in the endometrium and grow to form an embryo.
What three factors must be present for conception?
A healthy egg, a healthy sperm, and a healthy medium in which the pserm can travel and thrive. This medium is fertile quality cervical fluid
Fertile Quality cervical fluid
acts as a living conduit to direct the sperm through the cervix. Produced under the influence of increasing levels of estrogen in the first half of the cycle.
Where does fertilization take place?
The outer 3rd of the fallopian tubes, within just a few hours of ovulation
Peristalsis
Moves the fertilized egg toward the uterus
Penetration
The sperm penetrates the outer membrane of the egg by releasing enzymes taht create a hole in it. Oocyte penetration (innermost part of the egg); chromosome transfer
What is the moment of conception?
Conception occurs when one sperm penetrates one egg. The membrane of the ovum is sealed and no more sperm an enter
Zygote
Fertilized egg; journey to the uterus takes about 3-4 days; splits first into two identical cells, then continues to divide slowly as it travels down the fallopian tubes.
Morula
Cluster of 32 cells, a fluid filled cavity will appear in this cluster
Blastocyst
A single layer of cells, the trophoblast, surround the blastocyst. The inner cells clumped together will develop the fetus, umbilical cord, and the amnion
Trophoblast
Single layer of cells surrounding blastocyst; develops into the placenta and the chorion; becomes sticky and attaches itself to the endometrium
Implantation
Occurs a week after fertilization; Blastocyst starts development into an embryo and starts releasing a pregnancy hormone called HCG (Human chorionic gonadotrophin)
HCG
Sends message to corpus luteum to remain alive, releases progesterone long enough to sustain the nourishing lining
Implantation bleeding
Light pink or dark brown spotting around 8 days after ovulation and/or/ around the time of their expected period.
Chromosomes
A sperm and ova have 23 each; threadlike structures that carry their genetic information
Twins
More than one egg at a time results in fraternal twins; identical come from a single egg fertilized by a single sperm.
