Prenancy & Development Flashcards
(140 cards)
1
Q
Events that occur from fertilization until infant is born
A
Pregnancy
2
Q
Developing offspring
A
conceptus
3
Q
time from last menstrual period until birth
A
gestation period
4
Q
How long does gestation period usually last?
A
~280 days
5
Q
Conceptus from fertilization through week 8
A
embryo
6
Q
conceptus from week 8 until birth
A
fetus
7
Q
What must happen before fertilization can occur?
A
Sperm must reach secondary oocyte
8
Q
How long is oocyte viable? How long is sperm viable?
A
Oocyte - 12-24 hours; sperm 24-48 hours after ejaculation
9
Q
For fertilization to occur, coitus must occur no more than ____ days before and at least ___ hours after ovulation
A
2 days; 24 hours
10
Q
Sperm’s chromosomes combine with those of secondary oocyte to form fertilized egg
A
Fertilization
11
Q
Fertilized egg; combined sperm and egg
A
zygote
12
Q
How far do ejaculated sperm have to travel to join with egg?
A
12 cm (5 inches)
13
Q
Why do most sperm not make the trip to join egg?
A
- some leak out immediately after deposition
- some destroyed by acidic vaginal environment
- some fail to make it through cervix
- some are dispersed in uterine cavity or destroyed by phagocytes
14
Q
How many sperm reach uterine tubes?
A
Only a few thousands out of millions
15
Q
Sperm must be ______ before they can penetrate oocyte
A
capacitated
16
Q
What must happen r/t motility so sperm can penetrate oocyte?
A
Motility must be enhanced and cell membranes must become fragile enough to release hydrolytic enzymes
17
Q
What do secretions of female tract help to do?
A
Help to weaken and thin out acrosome membrane of sperm
18
Q
How do sperm find oocyte?
A
They “sniff” their way to oocyte; sperm have olfactory receptors that can follow chemical trail released by egg or surrounding sperm
19
Q
What are the steps for sperm to reach oocyte?
A
- approach
- acrosomal reaction
- binding
- fusion of membranes
20
Q
What are two mechanisms to ensure monospermy in humans?
A
- oocyte membranes block
2. zona reaction
21
Q
What triggers acrosomal reaction?
A
Calcium flowing into each sperm
22
Q
What happens when sperm approach oocyte?
A
- Aided by enzymes, sperm weaves through corona radiata
- Hyaluronidase causes granulosa cells to separate
- Sperm membrane calcium channels open
23
Q
What does hyaluronidase on cell surface of sperm do?
A
Acts to digest connection between granulosa cells, causing them to separate
24
Q
What causes sperm membrane calcium channels to open?
A
sperm heads bind to sperm-binding receptors in zona pellucida, causing them to open
25
What happens during acrosomal reaction?
1. When triggered by calcium influx, enzymes from many sperm are released that digests holes in zona pellucida
2. Hundreds of acrosomes in region all release enzymes at the same time to digest zona pellucida
26
What enzymes are released that digest holes in zona pellucida during acrosomal reaction?
Aluronidase, acrosin, proteases, etc.
27
What happens during binding?
1. After path has been cleared in zona pellucida, a single sperm forcibly swims toward oocyte membrane
2. acrosomal collar on rear portion of acrosomal membrane binds to oocyte plasma membrane sperm-binding receptor
28
What does binding cause?
1. Causes oocyte to form microvilli that wrap around the sperm head
2. Triggers fusion of oocyte and sperm membranes
29
What happens during membrane fusion?
1. Oocyte and sperm membranes fuse
| 2. Cytoplasmic contents of sperm enter oocyte
30
What parts of sperm remain after cytoplasmic contents of sperm enter oocyte?
Tail and other parts, such as sperm cell membrane and mitochondria, are left behind on oocyte cell membrane surface
31
Condition in which one sperm penetrates oocyte
Monospermy
32
Condition in which multiple sperm penetrate oocyte
Polyspermy
33
What happens with oocyte membrane block after sperm binds to oocyte?
When a sperm binds to sperm-binding receptor on oocyte, it causes oocyte to shed all other sperm-binding receptors, so other sperm can no longer bind to oocyte plasma membrane
34
What is another name for slow to block polyspermy?
Zona reaction
35
What does entry of sperm into oocyte trigger?
Triggers calcium surge from oocyte endoplasmic reticulum
36
Granules located just inside oocyte plasma membrane release zonal inhibiting proteins (ZIP) into extracellular space below zona pellucida
Cortical reaction
37
What do zonal inhibiting proteins do?
ZIPs destroy zona pellucida sperm-binding receptors; fragments bind water and swell, detaching any other sperm still around
38
What is assisted reproductive technology (ART)?
Various technologies and processes that may help an infertile couple's ability to have offspring
39
How do assisted reproductive technologies work?
1. Hormone therapy can increase sperm and egg production
| 2. Surgery can open blocked uterine tubes
40
What are disadvantages of assisted reproductive technology (ART)?
Costly, emotionally draining, and painful for oocyte donor
41
What are some examples of ART?
1. In vitro fertilization (IVF) - most common
2. Zygote intrafallopian transfer (ZIFT)
3. Gamete intrafallopian transfer (GIFT)
42
What do ART procedures include?
Surgical removal of oocytes following hormone stimulation, fertilizing oocytes, and then returning fertilized oocytes to woman's body
43
ART procedure in which oocytes and sperm are incubated in culture dishes for several days, then embryos at 2-cell to blastocyte phase are then transferred to uterus in hopes of implantation
In vitro fertilization (IVF)
44
ART procedure in which IVF oocytes are transferred to uterine tubes, so natural implantation can occur
Zygote intrafallopian transfer (ZIFT)
45
ART procedure that does use IVF; sperm and oocytes are transferred together into uterine tubes so natural fertilization can take place
Gamete intrafallopian transfer (GIFT)
46
What happens to parathyroid hormones and vitamin D levels throughout pregnancy?
They stay high throughout pregnancy
47
Why do parathyroid hormones and vitamin D levels stay high throughout pregnancy?
To ensure adequate development of calcium for fetal bone mineralization
48
Hormone that stimulates maturation of breasts, fetal growth, and glucose sparing in the mother
Human Placental Lactogen (hPL)
49
What is another name for Human Placental Lactogen (hPL)?
Human Chorionic Somatomammotropin (hCS)
50
What could glucose sparing (reserving glucose for fetus) cause in the mother?
May cause Gestational Diabetes
51
Physiological changes for GI system in mother during pregnancy
Morning sickness; heartburn and constipation are common
52
What is thought to cause morning sickness?
Believed to be due to elevated hCG levels, estrogen and progesterone
53
Physiological changes for urinary system in mother during pregnancy
Increased urine production
54
What causes increased urine production in mother during pregnancy?
Due to increased maternal metabolism and fetal wastes
55
What may occur during pregnancy as bladder is compressed?
Frequent/urgent urination and stress incontinence
56
Physiological changes of respiratory system in mother during pregnancy
1. Estrogens may cause nasal edema and congestion
| 2. Tidal volume increases and dyspnea may occur later in pregnancy
57
Physiological changes of cardiovascular system in mother during pregnancy
1. Blood volume increases
2. Cardiac output rises
3. Venous return from lower limbs may be impaired
58
How much does blood volume increase during pregnancy? Why?
Increases 25-40% to safeguard against blood loss during childbirth
59
How much does cardiac output rise during pregnancy? Why?
35-40% to propel greater blood volume around the body
60
What results from impaired venous return from lower limbs of body?
May result in varicose veins
61
Factors that may cause severe congenital abnormalities or even fetal death if potentially harmful substances cross placental barriers and enter fetal blood
Teratogens
62
What happens to fetus if mother drinks?
Pregnant women who drink alcohol cause fetus to also become inebriated, but fetal consequences may be much longer lasting and result in Fetal Alcohol Syndrome (FAS)
63
What characteristics of fetus occur with fetal alcohol syndrome (FAS)?
Typified by microencephaly (small head), intellectual disability, and abnormal growth
64
How does nicotine use affect fetus?
Nicotine hinders oxygen deliver to fetus, impairing normal growth and development
65
What type of drugs/infections can cross placenta?
1. Drugs - anticoagulants, antihypertensives, sedatives, and many others
2. Infections - rubella (German measles)
66
Dangerous complication of pregnancy that can result in deterioration of placenta and insufficient blood supply
Preeclampsia
67
What condition can lead to fetus being starved of oxygen?
Preeclampsia
68
What happens to mother during preeclampsia? How often does it occur?
Woman becomes edematous and hypertensive, and proteinuria occurs; occurs in 1 out of 10 pregnant women
69
What may cause preeclampsia?
May be due to immunological abnormalities
70
Culmination of pregnancy; giving birth to baby
Parturition
71
Series of events that expel infant from uterus
Labor
72
When does estrogen levels reach their highest level in mother's blood?
During last few weeks of pregnancy
73
What initiates labor?
Fetal secretion of cortisol stimulates placenta to secrete more estrogen
74
What are the 3 effects of increased estrogen?
1. Causes production of oxytocin receptors by myometrium
2. Causes formation of gap junctions between uterine smooth muscle cells
3. Antagonizes calming effects of progesterone, leading to Braxton Hicks contractions in uterus
75
What is another name for Braxton Hicks contractions?
False labor
76
Weeks before delivery, _______ produce ______
fetal lungs; surfactant protein A (SP-A)
77
What may surfactant protein A trigger?
Inflammatory response in cervix, causing it to soften in preparation for labor
78
Fetal ____ causes placenta to produce _____
oxytocin; prostaglandins
79
What do prostaglandins stimulate?
Stimulate synthesis of gap junctions in uterine smooth muscle
80
What are 2 of the powerful uterine muscle stimulants?
oxytocin and prostaglandins
81
What does prostaglandins do r/t labor?
Initiate contractions; also help to thin and soften cervix
82
What does oxytocin do related to labor?
Makes contractions more frequent and vigorous
83
Explain positive feedback mechanism that occurs during labor
Greater distension of cervix causes more oxytocin to release, causing grater contractile force, leading to greater distention of cervix, causing release of more oxytocin
84
What does increasing cervical distension initially activate?
Activates hypothalamus, causing release from posterior pituitary
85
What are the 3 stages of labor?
Dilation, expulsion, and placental stages
86
What is the longest stage of labor? How long does it last?
Dilation stage is longest; usually lasts 6-12 hours
87
Stage of labor that lasts from labor's onset to fully dilated cervix (10 cm)
Dilation stage
88
What happens with contractions through dilation stage?
Initially contractions are weak and 15-30 minutes apart and last 10-30 seconds, but become more rapid and vigorous as dilation stage progresses
89
What happens during dilation stage with cervix?
Cervix effaces and dilates fully to 10 cm
90
What happens with amnion during dilation stage?
Amnion ruptures, releasing amniotic fluids
91
What is engagement and when does it occur?
Engagement happens when baby's head enters true pelvis; occurs during dilation stage
92
Stage of labor that lasts from full dilation to delivery of infant
Expulsion stage
93
What happens to contractions during expulsion stage??
Strong contractions occur every 2-3 minutes, each lasting about 1 minute; urge to push increases in absence of local anesthesia
94
Incision made to widen vagina orifice; may be done to reduce tearing
Episiotomy
95
Occurs during expulsion stage when largest dimension of head distends vulva
Crowning
96
What happens to baby's neck as head exits perineum?
Neck extends
97
Usual, head first presentation of baby; skull dilates cervix
Vertex
98
Buttock first position
Breech
99
What happens when baby is in breech position?
Delivery is more difficult; often forceps or C-section required
100
Stage of labor when placenta is delivered; occurs within 30 mins after birth
Placental stage
101
Definition of afterbirth
Delivery of placenta and membranes
102
Purpose of strong contractions during placental stage
1. Cause detachment of placenta and compression of uterine blood vessels
2. Contractions limit bleeding and shear placenta from uterine wall, causing detachment
103
Why must all placental fragments be removed from uterus?
To prevent post-partum bleeding
104
Deformed or narrow, male-like pelvis that makes labor prolonged or difficult
Dystocia
105
What can result from dystocia?
Maternal fatigue and/or fetal brain damage (such as cerebral palsy)
106
What is treatment for dystocia?
C-section
107
How long does neonatal period last?
4 week period immediately after birth
108
Birth is a shock to baby, so physical status is assessed within 1-5 minutes after birth by _____ score
Apgar score
109
What does Apgar score assess?
1. Heart rate
2. Muscle tone
3. Respiration
4. Reflexes
5. Color
110
When does Apgar score assessment occur? How many points for each characteristic assessed?
At 1-5 minutes; can score 0-2 points for each
111
Score of __ to __ on Apgar score usually indicates a healthy baby
8-10
112
What stimulates respiratory control center to trigger first inspiration?
Once CO2 is no longer being removed by placenta, levels rise causing central acidosis
113
_____ in alveolar fluid helps reduce surface tension
Surfactant
114
What is respiratory rate in newborn?
~45 breaths/min for first 2 week, then declines
115
What is considered a premature baby?
<2500 grams, of 5.5 lbs, at birth
116
When does surfactant production occur?
During last months of prenatal life, so infants usually requires respiratory assistance until lungs mature
117
Unstable period lasting 6-8 hours after birth
Transitional period
118
Why does baby gag frequently after birth?
D/t regurgitation of mucus and debris
119
_____ period consists of alternating periods of activity and sleep, in which vitals may be unstable during active periods; usually stabilizes with ____ periods occurring every 3-4 hours
Transitional period; waking
120
What happens to umbilical arteries and vein during newborn period?
They constrict and become fibrosed
121
Proximal umbilical arteries persist as _______ to urinary bladder
Superior vesical arteries
122
Distal umbilical arteries become ______
medial umbilical ligaments
123
Umbilical vein becomes _____
round ligament of liver; ligamentum teres
124
What is ductus venosus converted to?
Ligamentum venosum
125
What causes pulmonary shunts to close?
Pressure changes from infant breathing
126
_______ becomes ______ up to a year after birth
Foramen ovale; fossa ovalis
127
________ arteriosis becomes ______ arteriosum
Ductus arteriosis, ligamentum arteriosum
128
All shunts, except for ______, close within ____ minutes after birth
Foramen ovale; 30 mins
129
How long does it usually take for foramen ovale to close?
Up to a year
130
Failure of ______ or ______ to close leads to congenital heart defects
Ductus arteriosus; foramen ovale
131
Production of milk by mammary glands
lactation
132
What triggers lactation?
Toward end of pregnancy, hypothalamus is stimulated to release prolactin-releasing factors (PRFs)
133
What stimulates hypothalamus to release prolactin-releasing factors (PRFs)?
1. placental estrogens
2. progesterone
3. human placental lactogen
134
What does PRFs stimulate to release prolactin?
anterior pituitary
135
During 2-3 day delay until true milk comes in, mammaries secrete ______
Colostrum
136
Yellowish fluid that has less lactose, but more protein, vitamin A, and minerals than true milk, and almost no fat
Colostrum
137
What type of antibody is colostrum rich in?
IgA
138
What does IgA protect infant against?
It is resistant to digestion, so may protect infant against bacterial infection; some may be absorbed into bloodstream to provide broader immunity
139
Prolactin release wanes after birth, so lactation is sustained by _____
Stimulation of nipples during suckling
140
How is lactation sustained?
Suckling stimulates mechanoreceptors in nipple, causing afferent impulses to be sent to hypothalamus, triggering release of PRFs
