Chapter 3 Flashcards
Genetics
the functioning and composition of the single gene
Genomics
all genes and their interrelationships that have a combined influence on the growth and development of an organism
autosome
any pair of chromosome that is NOT the sex chromosomes
somatic
body
homolygous
matched
genes
the coded information that makes a person unique
chromosomes
contain genes
DNA
hereditary material in the form of threads of chromosomes
what trait will be present when a dominant and recessive gene are paired?
dominant
what trait will be present when both genes are recessive?
recessive
what trait will be present when both genes are dominant?
dominant
genetic diseases are often related to __
a defective recessive gene
what is it called when there is a dominant and recessive gene paired together?
hybrid
autosomal dominant inheritance: likelihood offspring will be affected?
50%
what does vertical pattern of inheritance mean?
it passes from generation to generation
who is affected by autosomal dominant inheritance?
affects males and females equally
what is an example of autosomal dominant inheritance
Huntington’s
autosomal dominant inheritance
only one gene in the pair of a variant allele is needed for phenotypic expression; no carriers- either have it or don’t
autosomal recessive inheritance
both parents have to be carriers in order for there to be a child that has the disease/trait
autosomal recessive: likelihood offspring will have the disease?
25%
what is horizontal inheritance?
multiple siblings and not in earlier generations
what is an example of an autosomal recessive inheritance?
cystic fibrosis; tay-sachs disease
autosomal recessive: likelihood offspring will carry the disease if only one parent is a carrier?
50%
x-linked recessive inheritance
the abnormal gene is attached to the x-chromosome
what is an example of x-linked recessive inheritance
hemophilia
what is an example of x-linked dominant inheritance
fragile X disorder
who is affected more by x-linked recessive inheritance?
males are affected more; females carry
sickle cell anemia
recessive disorder; African ancestry
cystic fibrosis
recessive disorder; European ancestry
tay-sachs disease
recessive disorder; Jewish ancestry
Phenylkentonuria (PKU)
recessive disorder; lack of enzyme to metabolize the enzyme called phenylalanine
hemophilia
x-linked disorder; lack of factor VIII clotting factor- impairs clotting
huntington’s
autosomal dominant
duschenne’s muscular dystrophy
x-linked recessive
carrier testing
identifies individuals who carry one copy of a gene mutation when there is a family hx of a genetic disorder
preimplantation testing
used to detect genetic changes in embryos created using assisted reproductive techniques
prenatal testing
allows for early detection of genetic disorders
newborn screening
detects genetic disorder that can be treated early in life
what puts couples at a high risk for genetic disorders?
- maternal age >35
- hx of previous pregnancy with a newborn with a genetic disorder
- one or both parents have a genetic disorder
- family hx of genetic disorder
if the fetus is dx with a genetic disorder, couples can ___
elect to continue or terminate the pregnancy
nursing actions for couples at high risk for genetic disorders
- educate about the disorder
- refer to a support group
- explain the stages of grief
- encourage the couple to talk openly about their feelings and concerns
what is a teratogen?
anything that could be harmful to the fetus
what is the period of highest vulnerability against teratogenic effects?
the first 8 weeks of gestation (when major organs are forming)
what are examples of teratogenic agents?
- drugs/medication: prescribed or illicit
- alcohol
- infectious diseases/viruses: TORCH
what is TORCH?
T: toxoplasmosis
O: other agents (syphilis, varicella, listeria, parvovirus)
R: rubella
C: cytomegalovirus
H: herpes simplex virus (HSV-2)
effects of teratogenic agent: alcohol
- fetal alcohol syndrome
- low birth weight
- microcephaly (small head)
- mental retardation
effects of teratogenic agent: cocaine
- heart, face, limb, GI and GU defects
effects of teratogenic agent: varicella
- heart defects
- deafness
- blind
- mental retardation
- fetal demise
syphilis causes __
- skin and bone defects
- fetal demise
puberty
period in life which the reproductive organs mature & one becomes functionally capable of reproduction
- the transitional stage between childhood and sexual maturity
menarche
the first period; onset of menstruation
menstruation (aka menses)
periodic uterine bleeding and vaginal discharge of bloody fluid from the non-pregnant uterus that occurs from the age of puberty to menopause
when does menstruation begin in correlation with ovulation?
approximately 14 days after ovulation
what is the menstrual cycle?
the hormonal process that prepares the body for a possible pregnancy; consists of the ovarian and endometrial cycles
ovarian cycle
28 days divided into three phases: follicular, ovulatory, and luteal
follicular phase: time and hormones
- days 1-14
- LH and FSH mature the follicle
ovulatory phase: time and hormones
- starts when estrogen levels peak and ends with ovulation when the egg is released from the follicle
- LH surges before ovulation and Estrogen is high
luteal phase: time and hormones
- ovulation to menstruation
- high progesterone, low estrogen
in the luteal phase, if the woman is pregnant, then what happens to the hormones associated with this phase?
progesterone and estrogen will continue to be produced
in the luteal phase, when the progesterone level drops, what does this symbolize?
the start of menses
what occurs during/what is ovulation?
the releasing of a human egg
infertile phase
occurs before and after ovulation
fertile phase
5-7 days around the middle of the cycle; includes a few days before, during and one day after ovulation
how many days in a typical cycle?
28 days
what day does ovulation occur
day 14
how many hours does the ovum have to be fertilized before it degenerates?
12-24 hours
how long can sperm live for?
60-72 hours
endometrial cycle consists of what phases?
proliferation, secretory, and menstrual
proliferation phase: time and effect
- follows menstruation, ends with ovulation
- body prepares for implantation; endometrium becomes thicker and vascular
secretory phase: time and effect
-follows ovulation, ends with menstruation
- endometrium continues to thicken
menstrual phase
- only occurs without pregnancy
- hormonal changes cause sloughing off and expulsion of endometrial tissue
vaginal discharge during pre-ovulation
cloudy, yellow/white, sticky
vaginal discharge during ovulation
watery, clear, stretchy; called spinnebarkeet
vaginal discharge during post ovulation
thick, cloudy, sticky
what happens to the basal body temperature (BBT) due to ovulation
increases 24-48 hours after ovulation
mittelschmerz
abdominal pain in the region of the ovary occurring mid-cycle
the sequential process of conception
- gamete
- ovulation
- fertilization
- implantation
conception process: gamete
egg and sperm formation
gamete formation: women
begins during fetal life, but eggs mature once menstruation begins
gamete formation: men
occurs during spermatogensis
conception process: ovulation
release of egg
conception process: fertilization
union of gametes
conception process: implantation
fertilized egg implants into the uterus
where does fertilization usually occur?
the zygote is fertilized in the ampulla (outer third) of the fallopian tube
when does implantation of fertilized ovum occur?
around days 5 or 6 after conception (light spotting may occur)
where does implantation usually occur?
the embryo/blastocyst implants in the upper posterior wall of the uterine mucosa
embryo
implantation to 8 weeks
what happens during the embryo development?
body organ formation
when does the heart form/start beating?
forms: week 3; beats: week 4
fetus
9 weeks to birth
what happens during fetal development?
organ growth and maturation
what is gestation?
280 days or 10 lunar months
- normal timeframe is 37-42 weeks
naegele’s rule
LMP + 7 days - 3 months + fix the year = EDC (estimated date of conception)
what is the placenta?
the means of metabolic and gas exchange
placenta function: endocrine gland
endocrine gland produces hormones that maintain the pregnancy and support embryo/fetus.
placenta function: chorionic villi
projections of the chorion become vascularized, which supports maternal-fetal circulation
can viruses and medications cross the placenta?
yes- causes harm
amniotic fluid
- fluid from the respiratory and GI tracts of fetus enter the amniotic cavity
- fetus swallows fluid, which flows in and out of the fetal lungs
- increases weekly
what is one purpose of amniotic fluid?
help mature fetal lungs
functions of amniotic fluid
- maintain body temp
- infection barrier
- oral fluid source
- waste repository
- maintain fluid/electrolyte balance
- cushion trauma
- musculoskeletal development through freedom of limb movement
polyhydramnios
excessive amount of amniotic fluid
- > 2000 mL
- Amniotic Fluid Index (AFI) of 25
polyhydramnios can indicate:
-chromosomal disorders
- GI disorders
- NTD
- cardiac abnormalities
- pregestational & gestational diabetes
oligohydramnios
decreased amount of amniotic fluid
- <500 mL
- AFI <5
oligohydramnios can indicate:
- placental dysfunction
- renal disorders
- premature rupture of membranes
umbilical cord
- normally arises from the center of the placenta
- appr. 30-90 cm long
- contains 3 vessls
what are the 3 vessels of the umbilical cord?
2 arteries, 1 vein
what kind of blood does the vein of the umbilical cord carry?
oxygenated blood; returns blood to the fetus
what kind of blood do the arteries of the umbilical cord carry?
un-oxygenated blood; from embryo to chorionic villi
if there is only one artery in the umbilical cord, there could be ___
a renal or cardiac defect
warton’s jelly
jelly-like substance that surrounds the vessels and protects them from injury and/or compression
what are the main maternal hormones?
- human chorionic gonadotropin (hCG)
- human chorionic somatomammotropin (hCS)
- progesterone
- estrogen
when is hCG detected (timeframe correlating with conception)?
8-10 days after conception
what does hCG do?
- preserves the fx of the corpus luteum
- controls the corpus luteam’s secretion of estrogen and progesterone until placenta takes over
what hormone is used in pregnancy tests?
hCG
what does hCS do?
- stimulates maternal metabolism
- regulates glucoses available to fetus
- increases insulin resistance
- prepares breasts for lactation
progesterone is referred to as ___
the hormone of pregnancy
decreases uterine contractility & relaxes the muscles
progesterone
what type of hormone is estrogen?
steroid
which female sex characteristics does estrogen affect the development of?
- breast development
- growth of body hair
- widening of the hips
stimulates uterine growth
estrogen
what hormone increases late in pregnancy?
estrogen
what hormone gives uterine sensitivity to oxytocin?
estrogen
assists the cervix to secrete thick viscous mucus (think mucus plug)
progesterone
influences the vaginal epithelium
progesterone
prepares breasts for lactation
progesterone
decreases contractility caused by estrogens
progesterone
prepares uterus for implantation
progesterone
increases breast glandular tissue
progesterone
stimulate uteroplacental blood flow
estrogen
proliferation of breast glandular tissue & vascularity causing vasodilation
estrogen
relaxes joints & pelvic ligaments
estrogen
stimulates myometrial contractility
estrogen
monozygotic twins
- identical twins
- one egg, one fertilization
- zygote splits
- genetically the same
-usually the same sex
dizygotic twins
- fraternal twins
- two eggs (ova), two implantations, two placentas
- just like siblings born at different times
- genetically unique
-same or different sex
causes of infertility in men
- endocrine
- spermatogenesis
- immunological
- transport
- intercourse disorders
causes of infertility in women
- ovulatory dysfunction
- anatomy
- cervical mucus
risk factors for infertility: high risk
- overweight
- diabetes
- lubricants
- smoking
risk factors for infertility: medium risk
- age
- alcohol
- anabolic steroids
- hot tubs
risk factors for infertility: low risk
- drug abuse
- tight clothes
- caffeine
how to diagnose infertility causes
- STI screening
- lab tests (hormone imbalance)
- semen analysis
- ovulatory dysfunction analysis
- endometrial biopsy
- hystero-salpinogram
- laparoscopy
infertility treatments: male
- hormone therapy
- lifestyle changes
- medication to treat antibodies or infections
- repair hernias or varicocele
infertility treatments: female
-hormone therapy to stimulate ovulation
- medications to treat infection/autoimmune
- lifestyle changes
- fibroid removal
what hormones can be used for therapy to stimulate ovualtion?
clomiphene citrate, letrozole
common assisted fertility techniques
- artificial insemination
- IVF
- zift
- gift
- embryo transfer
- testicular sperm aspiration
what is the difference between zift and gift?
- zygote- intrafallopian transfer
- gamete- intrafallopian transfer
what are the emotional and ethical implications of infertility patients?
- lots of varying emotions
- stress and anxiety
- guilt and strain
- lack of support/understanding
- counseling
- art
what is a varicocele
a group of blood vessels in the scrotum that affects sperm production
what is oogenesis/the hormones involved?
the making of the ovum. FSH and LH encourage the maturation
what is spermatogenesis/the hormones involved?
formation of mature sperm.
1. FSH stimulates sperm production
2. LH stimulates testosterone production
3. Testosterone secreted by the testes promotes maturation of sperm
why is cytomegalovirus harmful to the fetus?
1 cause of congenital infection; causes CNS deficits, hearing loss, developmental delays
what does a mother with HSV put their fetus at risk for?
IUGR: intrauterine growth restriction, which can result in premature delivery or death
what medication can be prescribed to mom to decrease the risk of NTDs?
folic acid (600 mcg)
