Ch. 6: Genetics

Question 1

Recent advances in molecular biology and genomics have revolutionized the field of healthcare by providing the tools needed to determine the hereditary component of many diseases as well as improve our ability to predict susceptibility to disease onset and progression of disease and response to medications while genes are the basic physical units of inheritance The genome is the entire set of genetic instructions found in each cell genetic services are rapidly becoming an integral part of routine Healthcare and are super important things like preconception counseling and palliative care for infants and neonatal genetic testing
Provides the tools to determine the hereditary component of many diseases
Improves our ability to predict susceptibility, onset, progression, and response to treatment
Advances in genetic testing and genetically based treatments have altered care
A gradual shift from genetics to genomics
What is the Human Genome Project?

Answer 1

Genetics

Question 2

The Human Genome Project was a publicly funded International effort coordinated by the NIH and the department of energy believe it or not his initiated back in the early 90s with the goal of mapping the entire Human Genome it’s that complete set of genetic instructions in the nucleus of each human cell and through this two key findings from that project were that number one all human beings are 99.9% identical at the level of DNA and number two there’s over 20,000 genes in the human genome the finding that human beings are 99.9% identical at the DNA level should help discourage the use of science as a justification for drawing precise racial boundaries around certain groups of people
All same at molecular level

Answer 2

What is the Human Genome Project?

Question 3

Some of the competencies most relevant to nurses in maternity nursing when it comes to genetics and genomics include pedigrees being able to construct a pedigree collected from family history information developing plans of care that incorporate genetic and genomic assessment information providing patients with credible accurate appropriate and current genetic and genomic information resources services and Technologies recognizing when one’s own attitudes and values related to genetic and genomic science may affect care this is looking more into our implicit bias or even confirmation bias when it comes to genetics and nurses can facilitate referrals for specialized genetic and genomic services for patients as needed
Preconception counseling and testing
Neonatal genetic screening and testing
Palliative care for infants with life-threatening conditions
The identification and care of individuals with genetic conditions
Specialized care of women with genetic conditions during prengnacy

Answer 3

Nursing expertise in genetics and genomics

Question 4

Congenital heart disease
Cystic fibrosis
Factor V Leiden

Answer 4

Specialized care of women with genetic conditions during prengnacy

Question 5

Development from conception to birth of a normal healthy baby occurs without incident in most cases occasionally however anomalies in the genetic code of the embryo can create a birth defect or disorder
Chromosomal abnormalities
Multifactorial

Answer 5

Clinical genetics

Question 6

These are major causes of reproductive loss congenital problems and gynecologic disorders so what that means is that if there is an error at the level of the genetic code during cell division from the very first days after conception then many times the pregnancy will not keep so you’ll end up with an early first trimester lost some of these losses can actually happen before a woman even realizes that she’s pregnant the incidence of abnormalities is approximately 0.6% in newborns 6% and still births and 60% and spontaneous abortions so what we’re saying here is that most of the time the spontaneous abortions/miscarriages are happening 60% of the time because there is a chromosomal abnormality that happens at the time of conception errors resulting in chromosomal abnormalities can occur in either mitosis or meiosis and they can occur in either the autosomes or the sex chromosomes small deviations in chromosomes can cause problems in fetal development
A major cause of reproductive loss, congenital problems, and gynecologic disorders
That when it comes to pregnancy loss and abnormalities and a lot of gynecologic conditions actually that it’s at the level of the DNA
Can occur during mitosis (somatic cell) or meiosis (sex cells)

Answer 6

Chromosomal abnormalities

Question 7

Chromosome number: Down Syndrome
A single gene controlling a trait/disorder/defect
Sex chromosome abnormalities

Answer 7

Can occur during mitosis (somatic cell) or meiosis (sex cells)

Question 8

Patterns of genetic transmission
Most common congenital malformations result from a multifactorial inheritance so this is a combination of genetic and environmental and so I listed for you a couple of examples and these can be mild to severe this can be when it comes to neural tube defects this could be something as spina bifida or it can be something as fatal as anencephaly so we’re looking at environmental factors when it comes to neural tube defects we’re looking at nutrition of the mother and that can absolutely affect fetal development women who drink women who smoke women who are exposed to chemicals so that’s what the environmental Factor comes into that paired with a genetic Factor can cause this list of conditions
Most common genetic malfunction
Combination of environmental and genetic factors

Answer 8

Multifactorial

Question 9

Cleft lip and palate
Congenital heart disease
Neural tube defects
Pyloric stenosis

Answer 9

Combination of environmental and genetic factors

Question 10

The goal of screening is to detect or Define risk for disease and low risk populations and identify those for whom diagnostic testing may be appropriate genetic counseling is a professional service that provides genetics information education and support individuals and families with ongoing or potential genetic health concerns regardless of the setting or the individuals and family stage of Life genetic counseling should be offered and available to all individuals and families who have questions about genetics and their health most families with the history of genetic disease won an answer to the following question what is the chance that our future children will have XYZ disease because the answer to this question may have profound implications for individual family members and the family as a Whole Health Care Professionals must be able to answer this question is accurately as they can in a timely manner
Standard practice in obstetrics
Goal is to identify risk
Genetic hx should be obtained using a questionnaire or checklist
Information
Education
Support

Answer 10

Genetic counseling

Question 11

Not as an isolated event but as part of a sequential process
at ovulation the ovum is released from the ruptured ovarian follicle so when we go back and think about the menstrual cycle this is approximately mid cycle (difference depending on the length of a woman’s cycle as to which day she’s going to be ovulating) so when the ovum is erupts from the follicle the Cilia will capture that in the fallopian tubes because the egg cannot move on its own so it’s relying solely on the motility of the fallopian tube
Ova considered fertile for about 24 hours after ovulation so there’s a very finite period of time that the sperm can fertilize if it is not fertilized within about 24 hours of rupturing from the follicle the ovum will start to degenerate and be reabsorbed into the uterine tissue ejaculation during sexual intercourse normally propels about a teaspoon of semen containing as many as 200 to 500 million sperm into the vagina some sperm can reach the site of fertilization within 5 minutes; some sperm viable for about 2 to 3 days;
most sperm are lost in the vagina within the cervical mucus or in the endometrium or they enter the tube that contains no ovum
fertilization takes place in the ampulla: right inside the outer aspect of that fallopian tube in the in the ampulla
when the sperm successfully penetrates the membrane the membrane becomes impenetrable to any other sperm or anything else to get inside mitotic cellular replication called cleavage begins as the zygote travels the uterine tube into the uterus this is taking days from the time that the sperm penetrates the ovum to the time it actually gets out of the fallopian tube it has traveled into a safe place for item is taking absolute days at least three to four days
a solid ball of cells is produced within three days and you can see that and the figure there when the cavity becomes unracked the blastocyst cavity as we’re starting to continue to divide and divide the cavity becomes unrecognizable or the whole structure of the developing embryo is known as the blastocyst that’s it day four
Fertilization starts doing some cleavage and then marola and then some differentiation into a blastocyst before it implants approximately 6 days from the time that it’s fertilized the time it’s actually starting to implant into the endometrium is almost a week

Answer 11

Conception

Question 12

Zona pellucida degenerates the trophoblast cells displays endometrial cells at the implantation site and the blast assist embeds in the endometrium so from the time that we have a blast assist the blastocyst is going to start to embed into that thick Rich endometrial tissue so think back to the menstrual cycle we’ve had that proliferative that secretive phase of the end where the thickness of the endometrium is at its peak that is where the that’s when the glass assist is going to embed and it’s usually in the anterior posterior funnel so towards the top half of the of the uterus between 6 and 10 days after conception the truth of blast secretes enzymes that enable it to burrow into that endometrium until the entire blast is covered this is implantation chorionic villi develop out of the trophoblast extend into the blood-filled spaces of the endometrium these Villi are vascular processes that obtain oxygen and nutrients from the maternal bloodstream after implantation the endometrium is called the decidua the portion directly under the glasses where the chorionic villi tap into the maternal blood vessels is the decidua solace
Endometrium - becomes thick and vascular
Decidua - after implantation
Morula and blastocyst develops the trophoblast which ultimately becomes the chorion
This layer produces pregnancy hormone HCG. HCG is what causes a pregnancy test to be in both serum and urine
Chronic villi develop out of the trophoblast and extend into the blood - filled spaces of the endometrium (very vascular and rich in glycogen)

Answer 12

Process of implantation

Question 13

Special area of blastocyte called the trophoblasts make contact with the endometrium
Maternal side of placenta develops

Answer 13

Decidua - after implantation

Question 14

3 stages
Ovum or preembryonic stage
Embryonic stage
Fetal stage

Answer 14

Intrauterine development

Question 15

The pre embryonic stage is the period of time that covers cellular replication blastocyst formation the initial development of the embryonic membranes and establishment of that primary germ layer
Conception - 14 days

Answer 15

Ovum or preembryonic stage

Question 16

Lasts from day 15 until approximately 10 weeks gestational age; 8 weeks gestation
Most critical time - teratogens
When the embryo measures approximately 3 cm from Crown to rump this is the most critical time in the development of organ systems and the external features of the embryo

Answer 16

Embryonic stage

Question 17

Lasts from 9-10 weeks (can see human being) until delivery
Changes are not as dramatic because refinement of structure and function is taking place the fetus is less vulnerable to protogens except for those that affect the central nervous system functioning that can affect strategies can affect the central nervous system the entire pregnancy

Answer 17

Fetal stage

Question 18

Amniotic fluid
Yolk sac
Umbilical cord
Placenta
Fetal maturation
Multifetal pregnancy

Answer 18

Embryo and fetus

Question 19

Serves numerous functions
Volume is important to fetal well-being

Answer 19

Amniotic fluid

Question 20

Becomes primitive digestive sys
When the amniotic cavity and amnion are forming another blast is his cavity forms on the other side of the developing embryonic disk this cavity becomes surrounded by a membrane forming the yolk Sac the yolk sack aids in transferring maternal nutrients and oxygen now it does obviously doesn’t persist for the whole pregnancy it’s just early on in that first trimester

Answer 20

Yolk sac

Question 21

Supplies the embryo with maternal nutrients and oxygen
by day 14 after conception the embryonic disc the amniotic sac and the yolk sack are attached back to the chorionic villi by the connecting stock so from the chorionic villi the umbilical cord arises that chorionic villi is going to go on to become the placenta itself is composed of two arteries that carry blood from the embryo to the chorionic Bell ire placenta later on and one vein which returns blood to the embryo so the two arteries are smaller in diameter and have a little bit of a different texture to them and then the vein is much larger than the two arteries cuz it’s what’s giving the blood to the embryo now on occasion a very rare occasion an umbilical cord could have only two they only have two vessels one artery and one vein children that are born with a two vessel cord are thoroughly assessed many times those are associated with congenital malformation somewhere within the child this cord rapidly increases in length and by the time the pregnancy comes to term the cord can be anywhere from 30 to 90 cm in length so hence the the jump rope it twists spirally on itself and it loops around the embryo and fetus there’s connective tissue called Wharton’s jelly that is that surrounds those vessels to help with compression of the blood vessels and to ensure continued nourishment for the embryo and fetus
Because the placenta develops from this chorionic villi the umbilical cord is usually centrally located within the placenta

Answer 21

Umbilical cord

Question 22

The placenta begins to form an implantation during the third week after conception the trophoblast cells of the chorionic villi continue to invade the decidua the Silas as a uterine capillaries are tapped the endometrial spiral arteries fill with maternal blood the chorionic villi grow into the spaces with two layers of cells the outer syntium and the inner cytotrophoblast a third layer develops into anchoring SEPTA dividing the projecting decidua into separate areas of the placenta there is typically anywhere from 15 to 20 of these functional units the maternal placental embryonic circulation is in place
by day 17 after conception when the embryonic heart starts beating
Structure
Func

Answer 22

Placenta

Question 23

Maternal-placental-embryonic circulation by day 17
Functional unit placenta divided into 15-20 cotyledons

Answer 23

Structure - Placenta

Question 24

early functions of the placenta is an endocrine gland: it produces four hormones necessary to maintain a pregnancy in the in the placenta the first one would be human chorionic gonadotropin HCG; another one is called human chorionic somatomotropin or human placental lactogen this substance is similar to a growth hormone and stimulates maternal metabolism to supply needed nutrients for fetal growth; progesterone which maintains the endometrium and decreases contractility of the uterus and stimulates maternal metabolism and development of the breast; estrogen stimulates uterine growth and utero placental blood flow it causes proliferation of the breast glandular tissue and stimulates myometrial contractility
placenta functions are respiration nutrition excretion and storage oxygen diffuses from the maternal blood into the fetal blood carbohydrates proteins calcium and iron are all stored in the placenta for ready access to meet the fetal needs
the fetal concentration of glucose is lower than the glucose level and the maternal blood because of its rapid metabolism by the fetus therefore maternal glucose moves into the fetal circulation by active transport
Mom excrete waste for both of them through kidneys
Endocrine gland (HCG, human placental lactogen and estrogen)
Metabolic func and waste
Nutrient storage

Answer 24

Func - Placenta

Question 25

Viability
Fetal circ sys
Fetal maturation

Answer 25

Fetal maturation

Question 26

Capability of fetus to survivive outside uterus (usually 22-25 weeks gestation)
Limitations based on CNS func and oxygenation capability of lungs
with modern technology and advances in maternal and neonatal care infants who are 22 to 25 weeks of gestation are now considered to be on the threshold of viability the limitations on Survival outside the uterus when an infant is born at this early stage are based on central nervous system function and oxygenation capability of the lungs

Answer 26

Viability

Question 27

The cardiovascular system is the first organ system to function in the developing human blood vessel and blood cell formation begins in a third week and supplies the embryo with oxygen and nutrients from the mother the fetal lungs do not function for gas respiratory gas exchange so a special circulatory pathway the ductus arteriosis bypasses the lungs oxygen rich blood from the placenta flows rapidly through the umbilical vein into the fetal abdomen when the vein reaches the liver it divides into two branches; most of the blood passes through the ductus venosis into the inferior vena cava there it mixes with the deoxygenated blood from the fetal legs on its way to the right atrium most of this Blood passes straight through the right atrium and through the foramen o Valley an opening in that left atrium there mixes with a small amount of deoxygenated blood returning from the fetal veins the blood flows into the left ventricle in a squeezed out into the aorta where the arteries supplying the heart head neck arms received the most The most oxygen rich blood which enhances that cephalocado development of the embryo and fetus
FHR 110-160 bpm
Cephalocaudal: most O2-rich blood circulate heart, head, neck, arms
the following three special characteristics enable the fetus to obtain sufficient oxygen from the maternal blood fetal hemoglobin carries 20% to 30% more oxygen than maternal hemoglobin the hemoglobin concentration of the fetus is about 50% greater than that of the mother and the fetal heart rate is 110 to 160 making the cardiac output per unit of body weight higher than that of an adult so those are the three characteristics that allow the fetus to obtain is what they need as far as oxygenation for Mom

Answer 27

Fetal circ sys

Question 28

Hematopoietic sys (formation of blood occurs in yolk sac)
Respiratory sys
GI sys
Hepatic sys
Renal sys
Neurologic sys
Endocrine sys
Reproductive sys
MS sys
Integumentary sys
Immunologic sys

Answer 28

Fetal maturation

Question 29

Hematopoesis the formation of blood occurs in the yolk Sac beginning in the third week and hepatopoietic stem cells seed the fetal liver during the 5th week and hematopoesis begins there during the sixth week gestation this accounts for the relatively large size of the liver between the 7th and 9th weeks gestation

Answer 29

Hematopoietic sys (formation of blood occurs in yolk sac)

Question 30

The respiratory system begins to development during embryonic life and continues through fetalife and into childhood the development of the respiratory tract begins in week 4 and continues through week 17 with formation of a larynx trachea bronchi and lung butts specialized alveolar cells type 1 and 2 secrete pulmonary surfactants to line the interior of the alveoli after 32 weeks sufficient surfactant is present in developed alveoli to provide infants with a good chance of survival fetal respiratory movements have been seen on ultrasound as early as week 11 these fetal respiratory movements May Aid and development of the chest wall muscles and regulate lung fluid volume shortly before birth secretion of lung fluid decreases the normal birth process squeezes out approximately 1/3 of the fluid the fluid remaining in the lungs at Birth is usually reabsorbed into the infant’s bloodstream within 2 hours of birth
Primary surfactants: prevents lung collapse during exhalation and reduces lung surface tension making breathing easier
Also used to measure fetal lung maturity
L/S ratio: lecithin to sphingomyelin ratio 2:1

Answer 30

Respiratory sys

Question 31

Fetal nutrition and elimination is taken care of by the placenta
During the fourth week the shape of the embryo changes from being almost straight to a c shape as both ends found in fold in toward the ventral surface a portion of the yolk Sac is incorporated into the body from head to tail as the Primitive gut the fetus swallows amniotic fluid beginning in the fifth month gastric emptying intestinal persons occur fetal nutrition and elimination needs are taking care of by the placenta as the fetus accumulate the metabolic rate of the fetus is relatively low but the infant has great growth and development needs beginning in week 9 the fetus synthesizes glycogen for storage in the liver between 26 and 30 weeks the fetus begins to lay down stores around fat in preparation for extra uterine cold stress the GI system is mature by 36 weeks gestation

Answer 31

GI sys

Question 32

Prominent liver for blood production
Liver and biliary track developed from the four gut during the fourth week of gestation hematopoesis begins during the sixth week and requires at the liver be large the embryonic liver is prominent occupying most of the abdominal cavity glycogen is a major source of energy for the fetus and for the neonate stressed by in utero hypoxia extradine loss of the maternal glucose Supply the work of breathing or cold stress iron is also stored in the fetal liver during fetal life delivered does not have to conjugate bilirubin for excretion because the unconjugated bilirubin is cleared by the placenta

Answer 32

Hepatic sys

Question 33

(urine = major constituent of amniotic fluid)
The kidneys formed during the fifth week and begin to function approximately 4 Weeks Later urine is excreted into the amniotic fluid and forms a major part of the amniotic fluid volume at term the fetus has fully developed kidneys however that Glenn Miller filtration rate is low and the kidneys lack the ability to concentrate urine this makes a newborn more susceptible to both over hydration and dehydration

Answer 33

Renal sys

Question 34

Stressors on the fetus and neonate can damage CNS long after embryonic stage
Sensory awareness (taste, sound, purposeful movements)
The nervous system originates from the ectoderm during the third week after fertilization during week five different growth rates cause more flexures in the neural tube delineating three brain areas the four brain the midbrain and the hindbrain the four brain develops into the eyes and cerebral hemispheres the olfactory system and Thalamus also develop from the four brain Pine brain forms the medulla the ponds the cerebellum and the remainder of the cranial nerves the spinal cord develops from the long end of the neural tube term the fetal brain is approximately 1/4 the size of the adult brain neurologic development continues stressors on the fetus and neonate damage the central nervous system long after the vulnerable embryonic time for malformation in other organ systems neurologic insult can result in cerebral palsy neuromuscular impairment intellectual disability and learning disabilities

Answer 34

Neurologic sys

Question 35

Thyroid develops in first few weeks as head develops
Maternal thyroxine not cross placent
Pancreas forms mid-first trimester
The thyroid gland develops along with structures in the head and neck during the third and fourth weeks maternal thyroxine does not readily cross the placenta therefore the fetus that does not produce thyroid hormones will be born with congenital hypothyroidism pancreas forms from the four gut during the fifth through 8 weeks

Answer 35

Endocrine sys

Question 36

Differentiation occurs at 7 weeks
Text differentiation begins in the embryo during the seventh week distinguishing characteristics appear around the 9th week and are fully differentiated by week 12 by week 28 the testes begin descending into the male scrotum at Birth the ovaries of the female fetus contain the lifestyle lifetime supply; most female hormone production is delayed until puberty however the fetal endometrium responds to maternal hormones and withdrawal bleeding or vaginal discharge may occur at Birth when these hormones are lost (psuedomenses)
High level of maternal estrogen also stimulates mammary engorgement and secretion of fluid in newborn infants of both sexes

Answer 36

Reproductive sys

Question 37

Bones and muscles develop by 4th week of embryonic development; ossification occurs throughout childhood
Bones and muscles develop from the mesoderm by the fourth week of embryonic development at that time the cardiac muscle is already beating the flat bones of the skull develop during the embryonic period and ossification continues throughout childhood the bones the long bones appear in the sixth week as a continuous skeleton with no joints differentiation occurs ossification will continue through childhood as well to allow for growth

Answer 37

MS sys

Question 38

By the 7th week there are two layers of cells for the integumentary the cells of the superficial layer a sloft and become mixed with a sebaceous gland secretions to form the white cheesy vernix caseosa the picture that you can see there that thick cream cheese substance on the baby’s head the material that protects the skin of the fetus the vernix is thick at the 24 weeks but thins by term
Vernix caseosa
Fingerprints by 16 wks

Answer 38

Integumentary sys

Question 39

The The only immunoglobulin that crosses the placenta is IGG and it provides passive acquired immunity to specific bacterial toxins the fetus produces IGM by the end of the first trimester IGA is not produced by the fetus however colostrum the precursor to breast milk contains large amounts of IgA
Mom is giving baby IGG through passive immunity the baby is producing IGM and then if the baby nurses they’re getting IGA
IgG crosses placenta
IgA colostrum after birth
Fetus produces IgM

Answer 39

Immunologic sys

Question 40

Twins
Other multifetal pregnancies (3+ fetus)

Answer 40

Multifetal pregnancy

Question 41

partly attributed to the availability of assistive reproductive Technologies and the increasing age
Twinning which women give birth when two mature over or produce in one ovarian cycle both have the potential to be fertilized by separate sperm this results in two zygotes
Dizygotic twins
Monozygotic twins
Conjoined twins

Answer 41

Twins

Question 42

there are always two amnes two corians and two placentas these twins are fraternal twins because they have two separate genetic material two different eggs two different sperms
Fraternal

Answer 42

Dizygotic twins

Question 43

one of them which then divides they are the same sex and have the same genotype if division occurs soon after fertilization to embryos to amnes to coreons and two placentas that may be fused will develop most often division occurs between four and eight days after fertilization so there are two embryos to amnions one corion and one placenta rarely division occurs after the 8th day after fertilization if division occurs very late cleavage may not be complete and conjoined or siamese twins could result
Identical

Answer 43

Monozygotic twins

Question 44

multi-fetal pregnancies with three or more fetuses has increased with the use of fertility drugs and in vitro fertilization
can occur from the division of one zygote into two which one of the two dividing again producing identical triplets
quadruplets quintuplet sextuplets and so on have similar possible derivations

Answer 44

Other multifetal pregnancies (3+ fetus)

Question 45

At the time of implantation two fetal membranes that will surround the developing embryo begin to form Corian develops from the trophoblast and contains the chorionic villi on its surface the Corian becomes the covering of the fetal side of the placenta and contains the major umbilical blood vessels that brown that Branch out over the surface of the placenta the inner cell membrane the amnion develops from the interior cells of the blastocyst as it grows larger the amnion forms on the side opposite the developing blast assist the amnion becomes the covering of the umbilical cord and covers the chorion on the fetal surface of the placenta daniotic cavity initially derives its fluid by diffusion from the maternal blood fluid secreted by the respiratory and gastrointestinal tracts of the fetus also enters the amniotic cavity the amount of fluid increases weekly and $700 to a liter of transparent liquid is normally present at term the volume of amniotic fluid changes constantly during the pregnancy fluid and fluid flows into and out of the fetal lungs
beginning in week 11 beginning urinating into fluid increasing volume
Amniotic fluid serves many functions it helps to maintain a constant body temperature it serves as a source of oral fluid and as a repository for Waste in a system maintenance of fluid and electrolyte homeostasis it cushions the fetus from trauma and it allows freedom of movement for musculoskeletal development it is also a barrier to infection and allows for fetal lung development the fluid keeps the embryo from tangling with the membranes facilitating symmetric growth the
A normal range of AFI is typically 300 to 1500 if there is a decrease in Antioch fluid that’s referred to as oligo hydrangeas so you’ve heard women talk about drivers or not having enough fluid many times we’re concerned about renal abnormalities because if there is less fluid around the baby that means that the baby is not excreting that volume so it’s taking it in through the digestive system and through its but it’s not excreting it through it’s renal system it’s not avoiding it so there may be an issue with the kidneys conversely if there’s too much volume then the concern is a some some anomaly in the GI tract that’s not allowing for the fetus to consume the amniotic fluid into their bodies
Membrane consists of two layers
Increases during pregnancy and peaks at 38 weeks
Important factor in assessing fetal well-being
Normal range AFI = 5-20 cm on U/S
300-1500 mL

Answer 45

Amniotic sac and fluid

Question 46

Chorion
Amnion
Functions:

Answer 46

Membrane consists of two layers

Question 47

Provides space for movement and growth
Maintains consistent temperature
Protects from pressure, impact
Barrier against ascending infection
Cushions the umbilical cord
Composed of water secreted by the amnion and fetal urine

Answer 47

Functions:

Question 48

Less than 5cm = oligohydraminos
Greater than 20 = polyhydramnios
Both oligo and poly have implications

Answer 48

300-1500 mL

Question 49

Teratogens
Maternal nutrition
Continental disorders may be inherited or maybe caused by environmental factors or by an adequate maternal nutrition which he spoke of previously congenital means that the condition was present at birth some congenital malformations may be the result of teratogens that is environmental substances or exposures that result in functional or structural disability known human teratogens are drugs and chemicals infections exposure to radiation and certain maternal conditions such as diabetes and PKU during its periods of rapid growth and differentiation during the first two weeks of development teratogens either have no effect on the embryo or have effects so severe that they can cause miscarriage brain growth and development continue during the fetal period and teratogens can severely affect mental development throughout the gestation malnutrition during pregnancy produces low birth weight newborns who are susceptible to infection malnutrition also affects brain development during the latter half of gestation and can result in learning disabilities in the child inadequate folic acid is associated with neural tube defects so that’s part of the teaching points
Prevention of neural tube defects

Answer 49

Nongentic factors influencing development

Question 50

Drugs
Chemicals
Infection
Exposure to radiation
Maternal conditions

Answer 50

Teratogens

Question 51

Malnutrition
Folic acid
Especially important to consider before conception
Prevention neural tube defects

Answer 51

Maternal nutrition

Question 52

Needed for the normal formation of the SC

Answer 52

Prevention of neural tube defects