midterm 2 Flashcards
(200 cards)
1
Q
what is the amniotic cavity?
A
Cells of ICM form two-layered Embryonic disk and a space called the amniotic cavity
2
Q
what do Trophoblast form?
A
Trophoblast forms cytotrophoblast, syncytiotrophoblast, & chorion
3
Q
what are the 2 layers of the Embryonic disc ?
A
Epiblast, Hypoblast
4
Q
what is the Epiblast?
A
will become the embryo proper
5
Q
what is the Hypoblast?
A
forms extraembryonic membrane: yolk sac
6
Q
what does the Cytotrophoblast do?
A
1) adheres to endometrium
& burrows through uterine wall
2) secretes factors to attract maternal blood vessels
3) remodels the maternal blood vessels
7
Q
what does the Syncytiotrophoblast do?
A
multinucleated body that digests uterine tissue
8
Q
what does the Chorion
do?
A
1 - embryonic contribution to the placenta
2 - membrane that surrounds all others
9
Q
what is the Amniotic cavity filled with ?
A
amniotic fluid
10
Q
Functions of amnion ?
A
1) cushion and shock absorber
2) temperature regulator
11
Q
Functions of the yolk sac ?
A
1) supplies some nutrients absorbed from trophoblast
2) primitive blood circulation for 2nd and 3rd week
3) after week 4 greatly reduces in size as placenta takes over nourishment function
4) source of blood cells and primordial germ cells
12
Q
what is the allantois?
A
allantois is outpocketing that serves as primitive excretory duct that eventually become part of urinary bladder
13
Q
what happens in Embryogenesis and gastrulation?
A
1) two layers to three layers via gastrulation
2) pluripotency to multipotency
3) primitive streak or indentation visible on dorsal surface of embryo
4) cells migrate toward and thru primitive streak and form two layers
14
Q
what are the 2 layers formed in Embryogenesis and gastrulation?
A
Endoderm , Mesoderm
15
Q
what is the endoderm?
A
displaces hypoblast
16
Q
what is the Mesoderm?
A
second layer to migrate in fills middle layer and becomes
17
Q
What is the ectoderm?
A
cells of epiblast that did not migrate thru become ectoderm
18
Q
what does the endoderm layer become ?
A
1) digestive system
2) Liver
3) Pancreas
4) Lungs inner layers
19
Q
what does the mesoderm layer become ?
A
it becomes the dermis of the skin
- circulatory system
- Lungs (epithelial layers)
- Skeletal System
- Muscular System
20
Q
what does the ectoderm layer become ?
A
1) Hair
2) nails
3) skin (epidermis)
4) nervous system (CNS)
21
Q
How does the placenta connect to the embryo?
A
umbilical cord
22
Q
Umbilical cord
A
- two arteries that carry deoxygenated blood and waste from the fetus
- single vein that carries nutrients and oxygen from mom to fetus
23
Q
what are tissues from the embryo called?
A
chorion
24
Q
what is the chorion?
A
- chorionic membrane with finger-like villi
- burrow into endometrium and remodel maternal blood vessels
- fetal mesenchymal cells derived from mesoderm fill villi and differentiate into blood vessels, including those of the cord
25
what tissue comes from the mom?
decidua basalis portion of endometrium
26
A
27
B
28
Label
29
A
30
A
31
3 main functions of the placenta ?
Nutrition & digestion, respiration, endocrine function
32
Nutrition & digestion functions of the placenta ?
- Mediates diffusion of maternal glucose, amino acids, fatty acids, vitamins and minerals
- stores nutrients during early pregnancy to accommodate for increased fetal demand later in pregnancy
- excretes and filters fetal nitrogenous wastes into maternal blood
33
Respiration functions of the placenta ?
Mediates maternal to fetal oxygen transport and fetal to maternal CO2 transport
34
endocrine functions of the placenta ?
- secretes several hormones; hCG, estrogens, progesterone, to maintain pregnancy and stimulate maternal and fetal development
- mediates the transmission of maternal hormones into fetal blood and vice versa
35
how does maternal blood get to fetal blood?
maternal blood -> chorionic epithelial cells -> fetal connective tissue -> fetal endothelial cells -> fetal blood
36
does maternal blood interact with fetal flood?
NO, there is no direct intermingling
37
what substances use simple diffusion in the placenta?
O2, CO2, lipid-soluble
38
what substances use facilitated diffusion in the placenta?
carbohydrates, vitamins
39
what substances use active transport in the placenta?
Amino acids, iron
40
Benefit of the separation of maternal and fetal blood?
prevents the mother’s cytotoxic T cells from reaching and subsequently destroying the fetus, which bears “non-self”
antigens. Further, it ensures the fetal red blood cells do not enter the mother’s circulation and trigger antibody development
(if they carry “non-self” antigens)—at least until the final stages of pregnancy or birth.
41
what percentage of identical have separate chorions, amnions
33
42
what percentage of identical have common chorion, separate amnions
66
43
what is Placenta previa?
Placenta previa can result if an embryo implants close to the internal
os of the uterus (the internal opening of the cervix). As the fetus grows, the placenta can partially or completely cover
the opening of the cervix (Figure 28.7). Although it occurs in only 0.5 percent of pregnancies, placenta previa is the
leading cause of antepartum hemorrhage (profuse vaginal bleeding after week 24 of pregnancy but prior to childbirth).
44
when does Organogenesis occur ?
during Embryonic Period
45
What are the 2 pain processes that occur?
Neurulation, Somitogenesis
46
What is Neurulation?
formation of neural tube
47
What is Somitogenesis?
segmentation of meswodermal cells in developing trunk axial skeleton/muscles
48
where do the brain structures form?
At the anterior end of the neural tube
49
how is Tube-within-tube gut produced ?
through folding
50
Formation of heart?
formation of the heart starts with the tube
51
what other systems are produced?
urogenital, rudiments of pulmonary, limb bud, eye pits, facial structures
52
which cells help with the development of the nervous system?
neuroectodermal cells
53
what are 3 important features?
Notochord, neural plate, neural tube
54
what is the function of the Notochord?
signals the overlying ectoderm in dorsal midline to thicken and form neural plate
55
what happens to the neural plate?
Edges of the neural plate, the neural folds, bend toward each other (due to cytoskeletal changes in cells). The ends meet and neural tube disconnects
56
what are frees special cells called ?
Neural Crest
- Sometimes called 4th Germ Layer
- Migrate all over to form many important structures
57
what develops from the neural tube?
brain and spinal chord
58
59
60
61
62
Explain the stages of neurulation
1) Neuroectodermal tissues differentiate from the ectoderm and thicken to form the neural plate. the border of the neural plate separates it from the ectoderm.
2) The neural plate then bends dorsally with the two ends joining together to form the neural crest
3) the closure of the neural tube disconnects the neural crest from the epidermis. The neural crest cells will differentiate to form most of the PNS
4) The notochord degenerates and only persists as the nucleus pulposus. Other mesodermal cells differentiate into somites, these are precursors of the axial skeleton and skeletal muscle.
63
what can cause neural tube defects?
- Deficiency in maternal folate (folic acid) in the 1st weeks of pregnancy can cause neural tube defects
64
list some neural tube defects
1) Spina Bifida - Failure of posterior neuropore closure
2) Anencephaly: Failure of anterior neuropore closure
65
what is the Neural Crest?
Population of migratory cells left over from neurulation
66
what does the neural crest contribute to?
- peripheral nervous system
- septum that partitions the outflow tracts of heart into two major vessels that separate systemic and pulmonary circulation
67
what are Somites?
One either side of neural tube, the mesoderm splits into temporary segmented structures called somites.
68
What do somites form?
- vertebral column
- muscles of ribs, vertebral column, and limbs
- dermis of skin
69
how does embryonic folding occur?
- From a flat disc to 3-d cylinder by end of week 4
- Tube-within-tube body plan
- Expansion, folding, and fusion of edges of embryo
- Inner tube is future gastrointestinal tract
70
which system is the first fully-functional system to develop?
Circulatory system
71
at how many weeks does the heart start beating?
4
72
how is the heart formed?
- Cranial mesodermal cells condense into paired tubes that fuse to form single heart tube connected via capillaries to chorionic villi
- Rudimentary Tube loops upon itself
- Begins to beat and pump blood
> Initially RBCs produced in liver, eventually will come from bone marrow
- Partitions to form 4 rudimentary chambers
> right and left atria
> right and left ventricles
73
what happens to the embryo at 7 weeks?
- GI system develops too rapidly for abdomen, intestines temporarily loop into umbilical cord
- the Webbing removed between digits on paddle-shaped hands and feet
- Facial structure includes nostrils, outer ears, and lenses on eyes
- Major brain structures in place
- External genitalia ambiguous
74
what happens to the embryo at 8 weeks?
- All major organs and external body structures have begun to form.
- The embryos's heart beats with a regular rhythm.
- The arms and legs grow longer, and fingers and toes have begun to form.
- The sex organs begin to form.
- The eyes have moved forward on the face and eyelids have formed.
- The embryo is 3 cm long and weighs 8 g.
- At the end of eight weeks, the embryo looks more like a human and is now called a fetus.
75
what happens to the embryo at 9 weeks?
- Continued cell proliferation and differentiation in immature organ systems
- Sexual Differentiation
- Fetal circulatory system and shunts
76
when do secondary sexual characteristics develop?
During Puberty
77
Factors biological sex is based on
- Presence or absence of Y chromosome
- Type of gonads
- Sex Hormones
- Internal reproductive anatomy
- External genitalia
78
what is Sex determination ?
Specification of the gonads as either testes or ovaries
79
XY
SRY gene on Y chromosome directs development of testes
80
NO SRY gene?
Ovaries development
81
what is the Cloaca?
Cloaca is extension of primitive gut
- Ducts connect bipotential gonads to cloaca
82
what connect bipotential gonads to cloaca?
Ducts
83
cloaca divides into what for males?
Urethra & rectum
84
cloaca divides into what for females?
lower part of vagina, urethra, & rectum
85
what are the different sex chromosomes?
XXX, XXY, XYY
86
Factors that affect differences in hormone levels
- Congenital Adrenal Hyperplasia
- Androgen Insensitivity
- Mutations in genes for enzymes that convert sex hormones from one form to the other
87
Differences of Sexual Differentiation
- Differences in internal reproductive anatomy
- Differences in external genitalia
- Due to these variations cannot assign a binary sex of male or female intersex
- Prevalence of intersex may be as high as 2% of population
- Biological Sex is on a Spectrum
88
Differences of Sexual Differentiation? what are the characteristics of androgen insensitivity (XY)
- Develop testes
- Lack internal genitalia
- Develop “female”-like external genitalia
- Depends on whether complete AIS
- At puberty get breast tissue as circulating testosterone is converted to estrogen
89
what is fetal circulation?
1- Circulatory “shunts” divert blood flow and bypass immature organs such as liver and lungs until after birth
2- Oxygenated blood from umbilical vein flows toward the inferior vena cava
3- Mostly bypasses immature liver, via the ductus venosus shunt.
4- Enters Right atrium
5- Immature Lungs mostly bypassed via foramen ovale shunt that connects right and left atria.
6- Rest of blood pumped to RV then to pulmonary trunk
7- shunt in pulmonary artery, ductus arteriosus, diverts some of this blood to the aorta
8- Oxygenated blood moves thru foramen ovale into LA to mix with deoxygenated blood returning from pulmonary circuit
9- This blood moves thru LV and is pumped into aorta
- Some moves thru coronary arteries into myocardium
-some moves thru carotid arteries to brain
10 - Descending aorta carries “mixed” blood to lower regions of body
11 - Deoxygenated blood carrying wastes and high carbon dioxide eventually passes into umbilical arteries and is filtered thru placenta to maternal circulation
90
characteristics of mutation in 5 (alpha) reductase?
-dihydrotestosterone (DHT) needed for
-penis development/enlargement
-prostate growth
-fusion of tissues to form scrotum
-at puberty large surge in testosterone
-penis enlargement
-male secondary sexual characteristics
91
what happens in weeks 9-12?
- End of first trimester
- Major neuronal proliferation
starts
- Swallowing and rhythmic “breathing” of amniotic fluid
- Urine production
- Jerky, uncontrolled movements
facial expressions, grasping reflex
- Bone marrow takes over RBC production
92
what happens in weeks 13-16?
- Beginning of second trimester
- Major neuronal migration starts
form synapses once they reach destination
- Major sensory organ development
- Hair follicles develop
- Meconium (fetal feces) accumulate in intestines
- Fetus “responds” to mother’s voice and loud sounds
- Sucking reflex
93
what are some potential health complications with meconium that can occur at birth?
- In 5-20% of births the fetus passed meconium in utero (> 34 weeks when GI system matures)
- Signal of fetal distress
- O2 deprivation, maternal high BP, maternal drug abuse, long labor or difficult birth
- If gasping reflex occurs, may be “inhaled” into fetal lungs
- Staining of amniotic fluid at birth greenish/yellow
94
what must be done as soon as the infant is born?
MUST aspirate infant’s airways as soon as head is delivered
95
what happens in weeks 16-20?
- Fetal movements felt
by mother – “quickening”
- Space restrictions forces
growing fetus into the “fetal position”
- Sebaceous glands coat skin with waxy vernix caseosa
- Silky lanugo hair appears
- Eyes respond to light introduced to womb
96
what happens in weeks 21-30?
- Rapid weight gain
- Myelination of axons in spinal cord begins
- Lungs start to produce surfactant
- Vital for respiratory function after birth
- Testes descend into scrotum if male
- Viability becomes possible if born
Good chance of survival btw 25-28 weeks
97
what happens in week 31?
- Fetus lays down subcutaneous fat
- Shedding of lanugo hair
- Average crown-to-rump length just before birth is 35.5 – 40.5 cm (14-16- in)
- Average weight is 2.5-4 kg (5.5 – 8.8 lbs)
- Further maturation of systems (lungs, nervous)
- Preparation for birth
98
What is teratology?
the study of monsters
- science dealing with developmental deviations
99
1941?
- Opthalmologist Norman Gregg
- Rubella virus causes syndrome of abnormal development
- defects in eyes, ears, heart
100
1950s?
- Fraser group in Montreal
- cortisone effects on cleft palate in mice varied with strain teratogenetics
101
1960s?
Thalidomide, a sedative used widely in West Germany, linked to phocomelia and amelia (missing limb)
102
what is rubella?
- This is a respiratory disease caused by a virus
- Mild disease in children and young adults: rash and fever for 2-3 days
103
what could an Exposed fetus develop?
- congenital rubella syndrome (CRS)
Resulting in:
- cardiovascular defects
- skin rash
- Intellectual disability
- Deafness
- Cataracts, glaucoma
- abnormally small eyes & head
- liver and spleen damage
104
what is the risk of rubella?
85% in the 1st trimester
105
Explain Thalidomide
- Highly teratogenic during days 25-50
- Inhibits angiogenesis
- Gross malformations of limbs, facial and systemic abnormalities
106
what are developmental disorders?
Birth defects, congenital anomalies, or congenital malformations
107
Give some examples of malformations
- heart defects
- incomplete closure of neural tube: anencephaly or spina bifida
- failure of fusion in face to form lips: cleft lip
-failure of palatal shelves to meet at midline and fuse: cleft palate
- malformations in limbs: phocomelia, amelia
- improper placement of urethral opening in penis: hypospadia
- failure of tissues between toes to breakdown: syndactyly
- extra fingers & toes:
polydactyly
108
what is the prevalence of birth defects?
- 2-4% of all living newborns have at least 1 birth defect
- Doubles in 1st few years after birth
109
what % of congenital disorders are fatal?
25
110
what are teratogens?
Agents/factors that cause congenital malformations or raise the incidence of the malformations in the population
111
what are some causative agents?
- infectious agents (rubella, syphilis)
- physical agents (ionizing radiation, hyperthermia)
- drugs (prescription, over-the-counter, recreational)
- environmental chemicals (methylmercury, PCBs, pesticides, herbicides)
- maternal health factors (diabetes, malnutrition)
112
what are the factors that determine the capacity of an agent to produce birth defects?
1) Developmental stage at the time of exposure
2) Dose and duration of exposure
3) Genotype of the embryo
4) Mechanisms of action is specific and may involve inhibition of specific biochemical or molecular process; cell death; decreased cell proliferation or other cellular phenomena.
5) Manifestation of abnormal development are death, malformation, growth retardation and functional disorders.
113
what are the critical periods of susceptibility?
- insults during the !st 3 weeks are less likely to lead to defects
- Maximal susceptibility during weeks 3 to 8 when most major organs and body regions are being established
- Anomalies from 3rd to 9th month tend to be functional (i.e. intellectual disability) or involve disturbances in growth (or destruction) of already formed parts
- Some teratogenic substances have specific window of influence thalidomide (4 to 6 weeks)
114
give some examples of prenatal exposures that have long term effects?
- Extended period of vulnerability: 1st trimester thru adolescence
- Developmental neurotoxic effects
- Mercury
- Heavy metals
- Prescription drugs
- Retinoic acid (Accutane for acne)
- Anticonvulsant drugs (Valproate)
- Recreational drugs
- alcohol
- cigarette smoking
- Illegal drugs
115
Explain the mercury contamination
- Minamata Bay, Japan, 1956
- “cat dancing disease”
- Bioacccumulation in food chain
- Prenatally exposed children
= most severely affected.
Intellectual disability, cerebral palsy, blindness, other CNS impairments.
116
Anticonvulsants?
- Prescribed to control seizure disorders
- Many neural, facial, and liver abnormalities
- Fetal Valproate syndrome:
> impaired intellectual development
> behavioral problems
117
what are the facial features of children with fetal valproate syndrome
- short nose
- anteverted nostrils
- long philthrum
- small mouth
- epicanthel folds
118
describe alcohol as a teratogen
- Prevelance is 0.2- 0.7%
- Fetal alcohol syndrome:
> growth deficiency
> facial dysmorphogenesis
> CNS effects: changes in brain structure, behavioral abnormalities
- Leading cause of intellectual disability
119
describe illegal drugs as a teratogen
- These drugs easily cross the placenta
- No obvious congenital malformations
> IQ reductions
> Attention problems, behavioural problems
- Animal studies with cocaine
alteration of dopamine systems (attention)
- Methamphetamine
> Animal exposure changes in brain structure, behaviour & neurotransmitters, and impaired spatial memory
120
Most common class of birth defects?
congenital heart defects with a prevalence of 30%
- presence of a heart murmur
- Defects can involve:
- interior walls of the heart: ASD, VSD
- valves inside heart
- Arteries and veins: Truncus
- Arteriosus
- Various causes, many unknown
121
Congenital disorders are caused by chromosomal abberations like?
- Aneuploidy
( Down syndrome, Trisomy 13, 18)
- Structural errors
> reciprocal translocations, deletions, duplications
> breakages caused by environmental factors, such as radiation and chemical teratogens
122
what are some Congenital disorders caused by genetic mutations ?
- Autosomal dominant
>Achondroplasia short-limbed dwarfism
>Apert’s syndrome Cranio-facial abnormalities
- Autosomal recessive
>Sickle cell anemia. Mutation in hemoglobin gene
>Congenital phocomelia limb deformities
- X-linked recessive
> Hemophilia Blood clotting disorder
> AIS Androgen insensitivity
123
how do you get nutritional deficiencies?
Extreme calorie restriction
124
what can iodine deficiency in pregnancy cause?
fetal death, severe growth restriction, cretinism
125
what can B vitamin or Folic Acid deficiencies cause?
neural tube defects
126
what can vitamin A deficiency cause?
- blindness
- Excess: abnormal development throws off control of expression of genes responsible for establishing the embryonic body plan
127
what is the risk of birth defects in liveborn babies?
2-4%
128
what kind of tests could be used to investigate defects?
- Screening tests identify those in general population with a higher risk of birth defect
- Diagnostic test (more invasive) looks at whether a particular individual is affected
- Looking for the following
>neural tube defects
>aneuploidies (Trisomy 21, 13, 18)
>mutated genes or structural errors in chromosomes
129
types of screening
130
what is an ultra sound ?
Uses sound-wave reflections to make highly-detailed images of tissue interfaces.
131
in pregnancy when are the ultrasound scans done?
- 1st scan in 1st trimester (11-14 weeks)
> to confirm gestational age and number of fetuses
> nuchal translucency screening
- 2nd scan in 2nd trimester at 18-20 weeks
> detailed anatomic survey to identify half of structural malformations >Can be diagnostic for some
132
What is nuchal translucency screening ?
This is a screening for risk of aneuploidies. It measures the thickness of fluid compartment in the embryo’s neck.
- Used along with Maternal Serum Blood Testing for
Enhanced first trimester screening (eFTS) for measuring risk of Trisomy 18 or 21
133
what does AFP stand for?
Maternal Serum alpha-fetoprotein
134
what is AFP secreted and excreted by?
secreted by fetal liver and excreted in fetal urine
135
when is AFP measured?
Measured in both 1st trimester (eFTS) screening and 2nd trimester screening (14-21 weeks)
136
what could cause abnormal high levels of AFP ?
- open neural tube defect
- abdominal wall defect
- abnormal maternal-placental interface
- inaccurate gestational age
- multiple gestations
137
what does MSS stand for?
Maternal Serum Quadruple Screen
138
is AFP part of MSS?
yes
139
disadvantage of diagnostic testing?
Invasive and risk of miscarriage
140
when should diagnostic testing be conducted?
- advanced maternal age
- family history of birth defects
141
what are the types pf diagnostic tests?
- Chorionic villus sampling (CVS) btw 10-12 weeks
- Amniocentesis btw 14-16 weeks
- Fetal blood sample from umbilical vein after 18 weeks
142
If an anomaly is detected what could be done?
- Complete pregnancy and take precautions at birth
- Terminate pregnancy
- Fetal surgery?
> spina bifida, in which surgeon tries to close off the neural tube
> fixing heart defects
143
what occurs in fetal heart surgery?
- Hypoplastic left heart syndrome
- Blockage of aortic valve prevents proper growth of left ventricle
- Fatal if untreated
- Fetal operation may allow child to be born with healthy heart
144
145
what is the most fatal type of spina bifida?
Fetal myelomeningocele
146
when is full term for pregnancy?
- 38.5 weeks from conception
- 40.5 weeks since LMP
147
what is the size of the uterus pre pregnancy?
Fist size
148
what are the main hormones in pregnancy?
Estrogens, progesterone, and hCG
149
what kind of organ does the placenta become in pregnancy?
Endocrine
- It converts weak androgens secreted by maternal and fetal adrenal glands to estrogens
- ovulation prevention
- fetal tissue growth, maturation of lungs and liver
- maternal tissue growth: uterus and mammary glands
150
when is hcg highest?
first 30 days of pregnancy
151
when is estrogen and progesterone highest?
4 - 9 months. Estrogen is the highest at 9 months. Both are at peak at 9 months
152
role of progesterones?
- ovulation prevention
- inhibition of uterine contractions
> drop in progesterone during late gestation allows uterine contractions to increase
153
role of hCG
stimulates testosterone production in male fetal gonads
154
role of relaxin
increases elasticity in joints and ligaments in pelvis
155
where does majority of the weight gain come from in pregnancy?
from the fetus about 3.2- 3.6 kgs
156
what changes occur to the digestive and urinary system during pregnacy?
- 1st trimester: “morning sickness”
> decreased intestinal peristalsis
> pregnancy-related hormones
- mid-pregnancy
> kidneys become highly efficient to process fetal and maternal wastes
> high urine production
- 3rd trimester
> gastric reflux: upward constriction of growing uterus on stomach
> frequent urination: downward pressing on bladder
157
what changes occur to the circulatory system during pregnancy?
- 30% increase in blood volume
- moderate rise in pulse
- moderate rise in blood pressure
158
Give examples of dangerous complications that can occur in pregnancy
1) Gestational Diabetes
2) Pre-eclampsia
159
what is Gestational Diabetes?
Pregnancy-related hormones cause insulin resistance which cannot be overcome by pancreas
- it occurs in 4% of all women during pregnancy
- Increased risk of pre-term labor, development of Type II diabetes later in life
160
If Gestational Diabetes is not treated what can it lead to?
- pre-eclampsia
- polyhydramnios (too much amniotic fluid)
- large fetuses
- birth trauma
- C-sections
- perinatal mortality
- neonatal metabolic complications
161
what are the 2 main indicators of Pre-Eclampsia?
- Elevated blood pressure
- Protein in urine
162
What are the symptoms of Pre-Eclampsia?
headache, right upper-quadrant abdominal pain, visions changes, abnormal swelling
163
what is the incidence rate of Pre-Eclampsia?
5%
164
Potential complications and treatment of Pre-Eclampsia?
Potential complications
- liver & kidney damage, bleeding, fetal growth restriction, fetal death
Treatment
- mild cases: monitoring and bed rest
- severe cases: hospitalization and pre-term delivery
165
what is Eclampsia?
Untreated Pre-Eclampsia which can lead to seizures, coma and renal failure
166
What are some respiratory changes that occur on pregnancy?
- volume of gas inhaled or exhaled by lungs increases by 50%
- upward pressure on diaphragm causes shortness of breath
- respiratory mucosa swell
167
What are some Integumentary
changes that occur on pregnancy?
- stretch marks
- increase in melanocyte-stimulating hormone and estrogens
- darkens areolae
- linea nigra from belly button to pubis
- “mask of pregnancy” on face
168
At what month do progesterone levels plateau?
7
169
what does increase in estrogen and progesterone cause?
makes uterine myometrium more sensitive to stimuli which promote contractions.
170
How are Uterine contractions stimulated?
- Positive feedback loop of: Oxytocin Protaglandins.
- Pain due to myometrial hypoxia during uterine contractions
171
Which hormone induces Labor?
Pitocin
172
What is the 1st stage of Labor?
1) Cervical Dilation ( +ve feedback in which the uterus contracts and the cervix stimulates more Ut contractions)
- 10 cm is full dilation
- longest stage of labor
- sharp reduction in O2 to fetus during each contraction
- rupture of amniotic membranes
(green / yellow colour)
173
What are some complications that can occur with the Meconium at Birth?
1) Signal of fetal distress
- O2 deprivation, maternal high BP, maternal drug abuse, long labor or difficult birth
2) If gasping reflex occurs, may be “inhaled” into fetal lungs
3) Staining of amniotic fluid at birth greenish/yellow
174
What % of births pass meconium in utero?
5-20
175
176
What must be done as soon as the baby is born?
aspirate infant’s airways as soon as head is delivered
177
What occurs in the Expulsion stage of Labor?
The orientation of the fetus affects the length of this stage
- Tearing in perineum versus episiotomy
- Presentation of newborn head
aspiration of mucus from mouth and nose
178
What is the Breech Position?
Buttocks or lower limbs presented to birth canal rather than head-first position
- occurs in 3% of pregnancies
- the risks are perinatal morbidity and mortality
179
What occurs in the After Birth stage of Labor?
- After expulsion the myometrium contracts to shear placenta from back of uterine wall
- Continued contractions reduce blood loss
- If placenta not expelled after 30 minutes must be manually removed
- if not removed can lead to infection or bleeding otherwise
- Involution
180
what is Caesarean Delivery?
Baby is removed via
surgical incision in the
abdominal wall and
uterus
181
Reasons to do a Caesarean Delivery?
- Breech position
- Pre-eclampsia/ Eclampsia
- Fetal distress
- Maternal STIs
-Placenta Previa
182
What respiratory adjustment is made after birth?
- Stimulation of the first breath ( during uterine contractions there is constriction of the blood vessels due to which there is less O2 and more CO2)
183
When does the infant take its first breath after birth?
In the first 10 seconds
184
How is the respiratory adjustment made?
- Lungs are inflated to near full capacity
- Lung alveoli open and capillaries fill with blood
- Amniotic fluid drains or is absorbed
185
What circulatory adjustment is made after birth?
- Shunts are closed
- Umbilical chord is cut
- ductus venosus becomes ligamentum venosum
- ductus arteriosus constricts due to increased O2 concentration becomes ligamentum arteriosum
186
What does the temporary reversal of blood flow from LA to RA do?
blocks foramen ovale shunt with tissue flaps becomes fossa ovalis
187
What thermoregulatory adjustments made after birth?
- New borns produce heat slowly and lose it quickly.
- brown fat is broken down
- Homeostasis in newborns is determined based on the APGAR score
188
What does APGAR stand for?
Appearance, Pulse, Grimace, Activity, Respiration
189
What kind of process is growth and development ?
Dynamic. They are inter-related and inter-dependent
190
Difference between growth and development ?
Growth is an increase in size while development is an increase in complexity
191
Gives examples of cellular level of growth
1) Hyperplasia or Multiplicative Growth: increase in cell number via cell division
2) Hypertrophy or Auxetic: increase in size of cells w/o division
e.g. increases
3) Apoptosis: programmed cell death
192
What is Accretionary growth?
increase in Extracellular matrix btw cells
e.g. bone & cartilage
193
What is Appositional growth?
hyperplasia and accretionary growth at surface of tissue
194
What is Interstitial growth?
hyperplasia and accretionary growth throughout thickness of tissue
195
What tissue grows even during maturity?
Ovarian follicles
196
Describe bone formation
- Bone is a replacement tissue
- By birth most cartilage is replaced with bone but some remains in adult skeleton
197
What is cartilage?
Cartilage template for endochondral ossification
198
What are the 2 types of ossification
Intramembranous
Endochondral
199
Describe Intramembranous ossification?
- Compact and spongy bone develop directly from sheets of mesenchymal (undifferentiated) connective tissue
- Flat bones of face, most cranial bones, clavicles
- At birthskull and clavicles not fully ossified yet sutures in skull not closed
- End of pubertal growth spurt
last bones to ossify are flat bones of face
200
