Unit 2 lesson 8 and the rest Flashcards
what is the definition of contraception?
means to prevent pregnancy
- condom
- diaphragm
-IUD
-Vasectomy
-BCP
what is the definition of infertility
is when a couple of reproductive age is unable to become pregnant while not using any form of birth control
- examples…
- surrogate mother another woman carries the baby to term )
- in-vitro fertilization ( fertilization in a lab)
- the fertilized egg is then placed into the mother’s uterus during the luteal phase
-fertility bank
describe how the normal process of conception has been altered by a vasectomy.
sperm cells cannot leave the testicle
-stopping the sperm traveling through the tubes from the testicles (where the sperm are made) to the penis.
describe how the normal process of conception is altered by a condom.
stops sperm from meeting an egg
- cant enter the vagina
describe how the normal process of conception is altered by a diaphragm.
sperm cannot enter the uterus
- prevents the sperm from passing through the cervix
describe how the normal process of conception is altered with tubal ligation.
- prevents the egg from traveling from the ovaries through the fallopian tubes and blocks sperm from traveling up fallopian tubes.
describe how the normal process of conception is altered by an IUD.
not allowing implantation to happen, and not allowing sperm to fertilize
describe how the normal process of conception is altered by a birth control pill.
The pill prevents the ovaries from releasing an egg each month (ovulation). It also: thickens the mucus in the neck of the womb, so it is harder for sperm to penetrate the womb and reach an egg. thins the lining of the womb, so there is less chance of a fertilized egg implanting into the womb and being able to grow.
- full of estrogen and progesterone
- estrogen shuts FSH
- Progesterone shuts off LH
- it also shuts down oogenesis and stops LH and FSH from being released
what is a surrogate mother?
another woman carries the baby to term
how is in-vitro fertilization (IVF) used to produce a successful pregnancy?
fertilization in a lab
- the fertilized egg is then placed into the mother’s uterus during the luteal phase
how is a sperm bank used to produce a successful pregnancy?
female has her ovaries flushed out to obtain an egg, which is then used in vitro-fertilization
- sperm obtained from egg and artificial insemination to get pregnant.
how is intracytoplasmic sperm injection used to produce a successful pregnancy?
-insertion of a single sperm directly into the cytoplasm of a mature egg using a microinjection pipette.
-a treatment to overcome defects in sperm count or motility; an egg is fertilized by microinjection of a single sperm
how is the fertility pill used to produce a successful pregnancy?
-contains FSH
- increase oogenesis in the ovary
How is GIFT (gamete intrafallopian transfer) used to produce a successful pregnancy?
- it happens in the epididymis and uses a mature sperm cell
- sperm and eggs are placed in a fallopian tube to allow fertilization in the natural site. The woman must have at least one normal open fallopian tube.
-A procedure in which sperm and eggs are collected and then inserted together into the fallopian tube
How does artificial insemination produce a successful pregnancy?
- injecting semen into the vagina or uterus
describe how sperm extraction can help produce a successful pregnancy.
- extract sperm and can be used right away to fertilize an egg or frozen to be used later.
Describe how embryo hatching can be used to produce a successful pregnancy.
the developing embryo contains a layer of proteins (egg wall) that must hatch from these proteins before it can successfully implant itself in the lining of the uterus.
what are the legal- rights of individuals that surround assisted reproductive technologies?
what rights should the zygote have?
what rights should gamete donors and surrogate parents have if they’ve donated gametes to or helped an infertile couple?
what is the moral- affecting the individual that surrounds assisted reproductive technologies?
shouldn’t destroy unused zygotes
- a mother who has completed menopause should not have the same access to ASTs as a young woman who wants to start a family
what is the question that needs to be asked to understand the Ethical- affecting society that surrounds assisted reproductive technologies?
ARTs should be funded by the Canadian health system
- we can already screen gametes for genetic diseases. To what extent should people be able to “design” their children?
what is the embryonic period of development?
this period of development takes place over the first eight weeks, or the first two-thirds of the first trimester. During this time, tremendous change takes place. Cells divide and become redistributed. Tissues and organs form, as do structures that support and nourish the developing embryo.
what is the fetal period of development?
this period of development takes place from the start of the ninth week through to birth. It corresponds takes place from the start of the ninth week through to birth. It corresponds to the remaining third of the first trimester and all of the second and third trimesters. During the fetal period, the body grows rapidly and organs begin to function and coordinate to form organ systems.
what is fertilization?
involves the joining of male and female gametes sperm and egg to form a single cell that contains 23 chromosomes from each parent for a total of 46 chromosomes.
how does the process of fertilization look like (just the picture not in-depth yet)
what is the zona pellucida ?
- the plasma membrane of the egg is surrounded by a thin, clear layer of protein and carbohydrates called the zona pellucida.
what is the corona radiata?
- layer surrounded by several jelly-like layers of follicle cells that loosely adhere to one another
- these cells were a source of nourishment for the egg when it was in an ovarian follicle
- when a sperm meets the corona radiata, the sperms enzyme-containing acrosome (the “cap” surrounding the nucleus releases its contents. The enzymes digest a path through the corona and zona pellucida.
explain how the process of fertilization occurs.
step 1: Preparation of sperm
- prostaglandins from the seminal vesicle gland signal the female that sperm are present and guide them to the correct fallopian tube (many ejaculated sperm do not survive step 1. Reach egg in the fallopian tube 4-6 hrs. after intercourse.
step 2: Sperm-egg binding
- about 50 sperm cells are in the egg. Each sperm releases its enzymes from its acrosome cap. One sperm cell does not have enough digestive enzymes to be able to penetrate the egg. Thus, many enzymes from many sperm are needed to digest the egg’s protective zona and corona layers and its cell membrane.
Step 3: Eggs Response:
- when a single sperm penetrates the egg, the egg’s membrane permeability changes immediately. This effort prevents polyspermy; a condition where the egg is fertilized by more than one sperm resulting in zygotes with the incorrect number of chromosomes.
how does cleavage occur in an egg?
immediately after fertilization, rapid cell division changes take place in the zygote. Cleavage is mitotic cell divisions- lots of them to produce a morula which is a ball of cells
- the morula further divides to become a blastula (a ball of cells that has an inner and outer layer of cells).
- All of this change occurs in the span of one week. The structure, morula or blastula, even though it contains many cell divisions, has NOT grown in volume, only surface area. And each of these cells is secreting HCG.
At the end of a week, the blastocyst is ready to implant in the uterus
what happens within 30 hours of being fertilized?
the 0.1 mm zygote divides by mitosis for the first time, giving rise to two new cells. These cells divide, forming four cells then 8, and so on. This process is known as cleavage.
what is happening to the cell when it is a morula?
by the time the zygote is a sphere of 16 cells, it is called a morula.
- the morula reaches the uterus within three to five days after fertilization. During this time, it begins to fill with fluid that diffuses from the uterus. As the fluid-filled space develops, two different groups of cells form.
-blastocyst
- and trophoblast
what is the blastocyst?
A hollow structure - a “pouch” from which new cellular structures can develop.
what is the trophoblast?
forms the outer layer of the blastocyst. The trophoblast will develop into a membrane called the chorion.
what is implantation?
-chorionic cells release HCG which keeps the corpus lustrum viable in the ovary
-chorion releases enzymes to dissolve sections of the endometrial lining
-blastula “nestles” into groove and begins gastrulation (wks2-8)
Explain the importance of secretion of HCG during the time of implantation.
- the trophoblast starts to secrete a hormone called human chorionic gonadotrophin (hcg). HCG has the same effects as luteinizing hormone (LH), so it maintains the corpus lutetium past the time when it would otherwise degenerate. As a result, the secretion of estrogen and progesterone continues, maintaining the endometrium and preventing menstruation. The secretion of hCG continues at a high level for about two months. Then it declines to a low level by the end of four months.
- This is important in the first trimester
what is happening with the number of eggs and sperm involved in fertilization for fraternal twins?
- two eggs released
-both eggs fertilized by two different sperm (therefore zygote) - neither sibling looks the same
- boy/girl
- two brothers
-two sisters
what is happening with the number of eggs and sperm involved in fertilization for identical twins?
- one egg fertilized by one sperm (therefore called monozygotic)
- during cleavage two separate masses of cells completely break off from one another
- share one placenta
- embryo genetically identical
- 2 boys or two girls
what is happening with the number of eggs and sperm involved in fertilization for conjoined twins?
- one egg fertilized by one sperm( monozygotic)
- during cleavage egg separates incompletely
- the shared cells where twins attach
- try to be separated
- were supposed to be identical twins
- girl/girl
- boy/boy
Briefly describe what is meant by gastrulation and state at what time during a female’s gestation period this is occurring.
- second major phase of embryonic development sorting all the cells into distinct cell (germ) layers.
- gastrulation is the formation of three primary germ layers: ectoderm, endoderm, and mesoderm
- occurs after implantation during week 2 of the female’s gestation period.
label the diagram of the blastula/blastocyst
Define all three germ layers of the gastrula…
- ectoderm - outermost germ layer; produces sense organs, nerves, and outer layer of skin
- mesoderm - middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems
- endoderm - the inner germ layer that develops into the lining of the digestive and respiratory systems
label the parts of the layers of the embryo
- chorion
- amniotic cavity
- allantois
what is the amnion?
cells differentiate into a sac that grows to enclose the embryo completely penetrated only by the umbilical cord. The amnion fills with fluid that protects the embryo during gestation.
describe the structure and function of the placenta.
the placenta is formed by wk 8 and consists of tissue from both the embryo and the mother. Chorionic villi from the embryo mesh with the endometrial layer from the mother to make up the placenta.
- umbilical vein is red-oxygenated
- umbilical arteries are blue- deoxygenated
maternal vein blood flow?
deoxygenated as normal
maternal artery blood flow?
oxygenated as normal
maternal artery blood flow?
oxygenated as normal
The levels of HCG peaked at 8 weeks and then declined, yet the levels of estrogen and progesterone continued to increase dramatically. Propose a hypothesis to explain the reason for this
- placenta took over releasing estrogen and progesterone
- HCG dropped
why did the levels of estrogen and progesterone drop drastically after week 36?
the placenta begins to age and becomes less effective at producing estrogen and progesterone
- fetus becomes large and produces its own hormone
- P drops and E drops
when and how is an amniocentesis is done?
- only be done later in pregnancy
- fluid from amnionic fluids
- use ultrasound to see where the baby is located before injecting
- trimester 2
- needle inserted into the amniotic sac
- remove sluffed-off fetal cells in amniotic fluid
- sort chromosomes from cells to see if normal
explain how an ultrasound works.
sends out sound waves into the uterus
- obtain an image analysis, HR,BP, anatomy and length to determine gender, deformities
why is CVS used?
- chorionic villi sampling
- send a suction tube through the vagina and cervix into the uterus
-can happen early on in pregnancy - disadvantage- can damage the placenta
- or cause miscarriage
- uses blood from baby to draw chorionic villi
what is the feedback loop for parturition
- it is a positive feedback loop
what is the dilation stage?
- placenta stops secreting E and P
- relaxin, produced by the placenta prior to labor, causes ligaments in the cervix to loosen
- this enables the cervix to dilate
- uterine contractions push the baby’s head toward the cervix
- once contractions become forceful, the amniotic sac breaks, and the fluid is expelled (“my water broke”)
what is the expulsion stage?
- forceful contractions push the baby through the cervix to the birth canal. As the baby moves through the cervix to the birth canal. As the baby moves through the canal, the head rotates, making it easier for the body to pass through the birth canal
- oxytocin secreted
- pituitary gland causes strong uterine contractions
- these contractions push the baby through the vagina (birth canal)
- the vagina stretches several times its normal size to make way for the head and shoulders
placental stage
-umbilical cord plus placenta and amniotic sac contribute to the after birth
- the final stage of oxytocin causes the final contraction which removes the afterbirth
label the hormonal regulation of parturition.
what is lactation?
- lactation is the production of breast milk
- during pregnancy, high levels of estrogen and progesterone prepared the breasts for milk production
- once the mother has given birth, prolactin, produced by the anterior pituitary, stimulates the mammary glands in the breasts to begin producing milk which is rich in sugars, proteins, and fats.
- Breast feeding is an important source of antibiotics (proteins) for newborns, however, it is a metabolic drain on the mother, and she needs to replenish her calcium levels constantly.
Explain more about what is happening in this process
- when a baby suckles, it stimulates nerve endings in the nipple and areola (circular area of different colored skin around the nipple)
- the nerve impulses travel to the hypothalamus, which, in turn, stimulates the posterior pituitary to release oxytocin.
- Oxytocin causes contractions within the mammary lobules.
- the mammary lobules contain alveoli, which are sacs with cells that produce milk. The lobules end in mammary ducts at the nipple
- contractions within the lobules cause milk to flow to the ducts, where the infant can draw it out by suckling.
- if suckling does not occur, it stops milk production for a few days
