PSYC228_Chap2 Flashcards
gene
microscopic structure made of thousands of links of chemical particles that combine to construct all the parts of a living being
how many chromosomes are in every cell nucleus (except sperm + ova)?
46 chromosomes
23 pairs
autosomes
first 22 pairs of a cell’s 23 pairs of chromosomes
shared by both males + females
sex chromosome
23rd chromosome pair of a cell,
XX-f or XY-m
contains genes that determine biological sex characteristics of females and males
genes are in
chromosomes
genes are made of…
dna
DNA
deoxyribonucleic acid
fundamental chemical of all genes that guide construction of cells
adenine, guanine, thymine, + cytosine
nuceleus of cell contains?
chromosomes which carry DNA
in ever cell…
one member of each chromosome pair comes from the mother and one from the father
karyotype
arrangement of chromosomes by size
most basic building blocks of heredity
genes
locus
specific place on chromosome where gene is located
genotype
individua’s collection of genes
genetic potential + limitations
phenotype
observable characteristics of an indiv which result from a gene
allele
normative variation betw genes
1 allele will influence phenotype, the dominant one
a genotype comes a phenotype when?
moment of conception
dominant
quality of an allele that influences the expression of a trait
recessive
allele that can only influence the expression of a trait in the absence of a dominant allele
gametes
ovum + sperm cells
male or female cell that contains 23 chromosomes in their singular form
ocum
female gamete containing 22 autosomes + 1 sex (X) chromosome
sperm cell
male gamete containing 22 autosomes + 1 sex (X or Y) chromosome
ovulation
typically monthly process that causes ovum to ripen + be expelled by ovaries
sex of zygote is determined by
sex chromosome of father’s sperm cell
conception occurs when…
one of the millions of sperm cells released by male manages to penetrate the tough shell of female’s ovum to form zygot
zygot
fertilized ovum/fertilized egg, which male + female gametes have united in one cell
at conception
sperm cell’s 23 chromosomes merge with ovum’s 23 chromosomes to make 46 chromosomes/23 pairs that constitute genetic makeup of zygot/new human being
fertilization typically takes place where?
in outer par of Fallopian tube near ovary
after fertilization…
fertilized ovum/zygote continues down Fallopian tube to uterus, is embeded in uterine lining several days later
fraternal twins
2 eggs, each fertilized, don’t share genetic material
identical twins
single fertilized egg/zygote divides into 2 leading to 2 zygotes
2 major processes underlying conception + prenatal development
meiosis
mitosis
meiosis
process by which cells containing 23 pairs of chromosomes divide into daughter cells containing 1/2 of each chromosome pair
mitosis
process by which cells create an exact copy of themselves, includes all 23 pairs of chromosomes
gametes form thru
meiosis
mitosis occurs when?
after conception
zygot rapidly divides + dna within nucleus of each cell splits + replicates
vital process for prenatal development
oxytocin
released by orgasm, creates pleasurable muscle contractions that facilitate movement of sperm + inc chances of sperm contacting ovum
morula
post-zygote collection of connected cells that continue to divide before forming a more complicated structure
blastocyst
collection of cells arranged as a layer surrounding a central cavity containing fluid, into which an inner cell mass protrudes
morula forms when?
within 30 hrs, zygote splits in 2, and thru the process of mitosis cell division, morula forms
over next 3-4 days, cells in morula cont. to divide as it moves down fallopian tube and enters uterus
when does blastocyst form?
aroudn 6 days after conception, morula has transformed into an arrangement of cells called a blastocyst, which has a central cavity containing fluid and an inner cell mass. It is the blastocyst that may implant in the wall of the uterus and further develop into an embryo.
in some women, what happens when blastocyst implants onto uterine wall?
women may have some light bleeding which can be confused with light menstrual period + lead to miscalculation of pregnancy timeline
ART
assisted reproductive technologies
Assisted Human Reproductive Act
national ethics,
no cloning
no commerce in products for conception + human reproduction
in vitro fertilization
ART procedure where eggs removed from ovaries, exposed to semen for fertilization, then inserted into uterus for implantation
chances of live birth:
41% women <35yrs
30% women >=40yrs
3 stages of prenatal development
germinal stage
embryonic stage
fetal stage
miscarriage
abrupt stop in development of pregnancy + subsequent delivery of the embryo or non-viable fetus before 20th week of pregnancy
cephalocaudal pattern
pattern of physical growth proceeding from the head down thru long axis of body
proximodistal pattern
pattern of physical growth proceeding from center of body thru appendages
organogenesis
early development + differentiation of internal organs such as lungs, heart, gastrointestinal systems
germinal stage of prenatal development
zygote becomes a multicellular organism called blastocyst thru mitosis
blastocyst nourished by secretions in fallopian tube+uterus.
blastocyst differentiates to 2 types of cells: shell-like outer structure that will become fetal support system + multicellular center that will become embryo
estimated that…
30-50% of zygotes are lost before woman knows she’s pregnant
miscarriage stat
~1/5 known pregnancies ends in miscarriage
embryonic stage
further rapid differentiation of cells for many diff purposes.
1st cephalocaudal pattern of differentiation
2nd proximodistal
amniotic sac/support system forms with amniotic fluid around embryo
placenta forms
umbilical cord develops
what does the amniotic sac do?
protects embryo from shocks + abrupt temperature changes
by the end of the embryonic stage…
embryo has features that resemble arms, legs, hands, fingers, facial features like eyelids
The focus of the embryonic period is?
differentiation
placenta
short-lived, multifunctional organ that passes nut.s from mother’s blood to embryo
forms along uterine wall
does work that baby will do after birth - lungs, digestive system, liver, excretory organs
keeps mothers and embryo’s blood seperate.
embryo connects to placenta thru umbilical cord
umbilical cord
vein-filled cord that connects embryo to placenta
plasticity
potential for systematic change within a person
fetal stage of prenatal development
rapid growth of body’s physical systems following cephalocaudal + proximodistal patterns
fetus grows 2.5cm to 50cm and 3.4kg (7.5lbs) by birth
fetus becomes more functional
shortly into fetal stage, urination, swallowing + some reflexes appear
less vulnerable to shocks and outside influences
focus of fetal stage
rapid growth
why is the fetus less vulnerable to outside influences in the fetal stage?
because organ differentiation occurs beforehand, but has not finished in germinal or embryonic stage
plasticity
potential to change
sensitive periods
intervals of heightened plasticity, when environmental influences are most efficient at affecting an organism’s development
potential of environmental influences to have both positive or negative effects on development
critical period
finite window of opportunity for development, outside of which environmental influences are said to have no effect
finite opportunity for. feature to develop, no second chance
germinal stage timeline
conception-2wks
zygote-blastocyst
ends when blastocyst implants on endometrium
embryonic stage timeline
2-8wks (2wk-2months)
embryo
organs develop
critical time in prenatal development bec organs very vulnerable
fetal stage timeline
8wk-birth (2 months-birth)
fetus
rapid growth
first movements - quickening ~ 4months
why are there more sensitive periods than critical
bec plasticity is present thruout lifespan
prenatal sensitive periods
when brain + organs most sensitive to harmful environmental agents/teratogens
teratogen
environmental agen that can adversely affect prenatal development + can have long-lasting effects on subsequent development.
teratology
study of environmental agents that cause birth defects
teratogen
environmental agent that can adversely affect prenatal development + have long lasting effects on subsequent development
Wilson’s 6 principles of teratogenic effects
1 depends on genetic makeup of developing organism
2 timing of exposure crucial
3 dose of teratogen matters
4 interactions of genetics, timing + what is developing
5 growth retardation, functional defect, malformation, death
6 does: response relationship
neural tube
precursor to central nervous system in developing embryo
which period is especially vulnerable?
embryonic (3-8wks)
what is the leading teratogen worldwide + safe in no amound to consume during pregnancy?
alcohol
mutation
abnormality that occurs during genetic transmission that may affect the entire chromosome or specific genes
chromosomal abnormalities
too many or too few
during meiosis
1/2 of cases result in spontaneous miscarriage
mostly likely on sex chromosomes
Trisomy 21
Down syndrome
Trisomy 21
3 chromosomes instead of 2 on 21st pair
rounded face, extra fold over eyelids, intellectual disability, cardiovascular system abnormalities
XXX (triple X syndrome)
extra X chromosome (in females)
XYY (Jacob’s syndrome)
extra Y chromosome in males
Turner syndrome
only 1 sex chromosome, X females only
Klinefelter’s syndrome
2 or more X chromosomes alongside Y chromosome
males only
genetic issues
when repliaction process of a DNA base is omitted or incorrectly copied
autosomal recessive trait
trait that requires presence of paternal + maternal genes from phenotype to be expressed
autosomal dominant trait
trait that requires presence of only 1 parental gene for phenotype to be expressed
sex- linked gene
gene located on one of the sex chromosomes
X or Y
midwifery model of care
woman-centered model of maternity care based on idea that pregnancy + birth are normal, inherently healthy life processes
medical model of care
comparatively new model of maternity care guided by belief that pregnancy + birth are potentially dangerous life processes that must be medically managed
caesarean surgery
medical intervention in which abdomen is cut + fetus removed
ultrasound
use of high-frequency sound waves to visualize embryo or fetus within uterus
informed consent
clinical context
process of explaining purpose of procedure, outlining benefits + risks associated with it, requesting patient’s signature to varify they understand + agree
fundal height
cm
distance from top of uterus to pubic bone
after 12 wks, matches number of wks
amniocentesis
process of removing fluid from amniotic sac of pregnant woman + surveying genome under miscroscope
detect abnormalities/prove father
chorionic villus sampling
process of obtaining a tissue sample form villi of chorion which forms fetal part of placenta
abnormalities, quicker than amniocentesis
co-parenting
extent to which parents are supportive of one another’s parenting
3 categories of prenatal expectations
prepared 27%
fearful 35%
complacent 38%
cervix
powerful ring of muscles that keep uterus tightly shut during pregnancy but then thins + opens during labour
bloody show
plug of thick, blood-tinged mucus discharged from cervix shortly before labour begins
birth doula
specially trained birth companion, who provides physical, emotional, + informational support during labour, birth, + immdediate postpartum
maternal mortality rate
maternal deaths/100000 live births
prostaglandins…
soften + think cervix before labour
oxytocin
stimulates uterine contractions
also inc suddenly when baby passes thru vaginal canal to stimulate bonding
oxytocin ___, but adrenaline ___
ocytocin accelerates birth
adrenaline stalls birth - don’t be scared
endorphins
alter pain perception _ give feeling of pleasure
feeling of love + supported
mothers who feel afraid
tend to secret hormones that delay + impede birth
mothers who feel safe + loved
tend to secrete hormones that make labour + birth easier + less painful
doula-supported women are
28% less likely to have C-section
31% less likely to use drugs
9% less likely to use pain meds
stages of labour
dilation (cervix opening)
descent + birth
delivery of placenta
postpartum period
epidurals
local anaesthetic injected into lower back to numb labour pain
episiotomies
surgical cut in muscles that surround vagina to enlarge the vaginal opening
electronic fetal monitoring
technology for monitoring heart rate of fetus with electrodes attached to mother’s abdomen or placed internally on scalp of fetus
apgar scale
scoring system that assesses health of newborns based on 5 key areas:
activity + muscle tone
heart rate
reflexes
skin colour
respiration
5 key areas of apgar scale
activity + muscle tone
heart rate
relexes
skin colour
respiration
low birth weigth
<2.5 kg
<5.5lbs
very low birth weight
<1.5kg
<3.3lbs
preterm
infant born earlier than full gestational period
< 37wks
small for gestational age
birth weight <2.5kg for infant with gestational age that is normal (37+wks)
postpartum depression
clinical depressive symptoms ~ apathy, sadness, detachment associated with late pregnancy + period of time following birth of infant
postpartum doula
specially trained advisor + helper who provides physical, emotinoa, + informational support to women + families during postpartum period
canadian maternal mortatlity rate is higher than at least
28 other countries
canadian infant mortality rate has remained steady at
5 deaths/1000 live births since 1997
very small minority of women give birth at home though
planned home birth is just as safe as planned hospital birth for low-risk women + associated iwth lower rates of medical interventions
the rate of C-section in Canada
28% 2011
is rising due to electronic fetal monitoring, artificial induction of labour, + maternal choice
newborn health is assessed by tests like
apgar scale
brazelton Neonatal bahavioural assessment scale
the leading cause of infant mortality is
low birth weight
and related to several serious physical problems amon babies who survive
why may babies have low birth weights?
because they are born preterm or small for gestational age
