Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Phys II Unit III > 4 Fertilization, Pregnancy, Parturition, & Lactation > Flashcards

4 Fertilization, Pregnancy, Parturition, & Lactation Flashcards

1
Q

What are the four stages of pregnancy?

A
  1. Initiation (Fertilization—>Implantation—>Secretion of hCG to rescue the corpus luteum)
  2. Gestation
  3. Parturition
  4. Lactation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

________ is the usual site of fertilization

A

Oviduct, usually in the upper third (ampulla)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When must fertilization occur?

A

Within 24 hours of ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Sperm usually survive about _______ but can survive up to _______ in the female reproductive tract

A

48 hours

5 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do sperm deposited in the vagina reach the ovum for fertilization?

A

Travel through cervical canal, uterus, and oviduct to the ampulla (upper third)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the female reproductive tract aid sperm in their migration?

A

Contractions of the myometrium

Upward contractions of oviduct smooth muscle

Allurin released by mature eggs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Chemoattractant for sperms to reach egg in ampulla of oviduct

A

Allurin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Upon sperm passage through female reproductive tract, the process of __________ occurs

A

Capacitation or “activation”

Surface characteristics of the sperm are altered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Sperm motility in the cervical canal requires _________ pH

A

Alkaline

Alkaline secretions from prostate gland elevate pH

Estrogen makes mucus watery, facilitating sperm motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the uterus assist with sperm transport?

A

Myometrial contractions
• Prostaglandins in the ejaculate
• Estrogen-primed tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sperm capacitation involves what processes?

A

Cholesterol withdrawal
Redistribution of surface proteins
Calcium influx to increase motility (whiplashing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Once a capacitated sperm reaches an ovum, what has to happen in order for fertilization to occur?

A

Penetration of the corona radiate —> binding of membrane head to ZP3 proteins of the zona pellucida

Acrosome hydrolytic enzymes digest zona pellucida, creating pathway to the ovum membrane

When the sperm reaches the ovum, the two membranes fuse and the sperm head with its DNA enters the cytoplasm

ZP3 proteins are inactivated and harden the zona pellucida to block polyspermy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sperm contains receptors that bind to _________ in the zona pellucida

A

Protein ZP3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

An enzyme released from the sperm to allow it to penetrate the zona pellucida

A

Acrosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Fusion of the sperm to the ovum’s membrane is mediated by….

A

Binding of fertilin on the sperm head to integrin receptor on ovum’s membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is polyspermy prevented?

A

Structural changes in zona pellucida following sperm’s fusion with the ovum’s membrane

Release of cortical granules containing enzymes that degrade ZP3 proteins and harden glycoproteins on the zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The zona reaction signals the ovum to do what?

A

Complete 2nd meoitic division and extrusion of 2nd polar body

Allows for formation of female pronucleus and its fusion to male pronucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The fertilized ovum divides in what manner?

A

Mitotically

Within a week it grows and differentiates into blastocyst capable of implantation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Blastocyst implants into endometrial lining by means of…

A

Enzymes that digest endometrial tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Due to progesterone action days ______ of a regular 28-day cycle are the optimal period for implantation

A

20-24

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When is hCG detectable in maternal serum?

A

Only after implantation is completed, 8-11 days after conception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Placenetal hCG will rescue the ________.

A

Corpus luteum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When the free-floating blastocyst adheres to the endometrial lining, ______________ begin to penetrate the endometrium.

A

Cords of trophoblastic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens as advancing cords of trophoblastic cells tunnel deeper into the endometrium?

A

They carve out a hole for the blastocyst —> boundaries between the cells in the advancing trophoblastic tissue disintegrate

When implantation is finished, the blastocyst is completely buried in the endometrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
The placenta is well established and operational by ________
5 weeks after implantation
26
Organ of exchange between maternal and fetal blood that performs the functions of the digestive system, the respiratory system, and the kidneys for the fetus
Placenta!!!!
27
The placenta prevents....
Immunologic rejection
28
The placenta acts as a transient endocrine organ that secretes what essential pregnancy hormones?
Human chorionic gonadotropin (hCG) - maintains corpus luteum until placenta takes over function in last two trimesters Estrogen Progesterone
29
______ is what most pregnancy tests detect
hCG
30
______ may be the causative agent of morning sickness
hCG
31
The action of hCG is similar to LH in that it...
Stimulates the corpus luteum to secrete progesterone and estrogen
32
Once the placenta secretes estrogen and progesterone, the hCG levels _______ and the corpus luteum _______
Decline Regresses hCG levels in maternal plasma peak between 9 and 12 weeks gestation and then decline to a stable plateau
33
Describe normal levels of hCG in pregnancy
Steep rise in hCG starting after implantation, with peak around 9-12 weeks, plateauing at ~10^3 or 10^4
34
If there is fetal death, what happens to hCG levels?
Levels rise normally, then fall with a half-life of 24 hours after death of the fetus
35
In cases of ectopic pregnancy, what happens to hCG levels?
Rise more slowly
36
When hCG levels rise slowly but continue to rise after week 9-12, this is called...
Hydatidiform mole
37
______ levels increase during pregnancy and require __________ for synthesis
Increase | Both fetus and placenta
38
What is the most important estrogen of pregnancy
Estriol Levels in maternal urine may be used as an index of fetal health
39
What are the functions of estrogen during pregnancy?
Increased growth of myometrium (muscles for labor) Development of ductile system of breasts Stimulates prolactin release by anterior pituitary Relax and soften pelvic ligaments Inhibits lactation by antagonizing prolactin effect on the best and inhibiting lactalbumin (required for lactose synthesis)
40
For the first 6-12 weeks of pregnancy, progesterone is secreted by ________, but after 12 weeks, the major source is ________
Corpus luteum —> placenta
41
Synthesis of progesterone requires...
Maternal cholesterol
42
What are the functions of progesterone in pregnancy?
Conversion of uterus to secretory gland, readying it for implantation FOrmation of cervical plug Inhibition of myometrial contraction Inhibition of prostaglandin synthesis from uterus Development of alveolus and lobule in breast Inhibition of lactose synthesis
43
How long is gestation?
About 38 weeks from conception
44
What are the physical changes within the mother to meet the demands of pregnancy?
``` Uterine enlargement Breasts enlarge and develop ability to produce milk Volume of blood increases 30% Weight gain Respiratory activity increases about 20% Urinary output increases Kidneys excrete added wastes from fetus Nutritional requirements increase ```
45
During the first two trimesters, the uterus remains quiet due to ...
Inhibitory effects of high levels of progesterone
46
During the last trimester, uterus becomes progressively __________
More excitable (Braxton-Hicks contractions)
47
Throughout gestation, the uterus remains sealed by ...
The rigid, tightly closed cervix
48
What hormone, produced by corpus luteum of pregnancy and by the placenta, relaxes pelvic ligaments and softens the uterine cervix by loosening the connective tissue between pelvic bones
Relaxin
49
What are the three parts of parturition?
Labor, delivery, and birth
50
What changes are required in order for parturition to occur?
Dilation of cervical canal to accommodate passage of fetus from uterus through vagina and to the outside Contraction of uterine myometrium that are sufficiently strong to expel fetus
51
Exact factors triggering increase in uterine contract ability and initiation of parturition are...
Not fully established
52
What is the role of high estrogen levels in parturition?
Promotes synthesis of connexons for gap junctions within uterine smooth muscle cells —> coordinated uterine contraction Increased concentration of myometrial receptors for oxytocin —> increased responsiveness to oxytocin Increased production of prostaglandins —> stimulates enzymes to degrade collagen fibers (cervical softening) and increases oxytocin receptors in myometrium
53
What is the role of Oxytocin during labor?
Produced in the hypothalamus and stored in posterior pituitary Circulating blood levels of oxytocin remains constant prior to onset of labor Uterine responsiveness to oxytocin is 100x greater at term than in nonpregnant women Profound effect of oxytocin at term due to INCREASED CONCENTRATION of RECEPTORS in MYOMETRIUM
54
Labor is initiated when the _____________ concentration reaches a critical threshold
Oxytocin receptor concentration Permits the onset of strong, coordinated contractions in response to ordinary levels of circulating oxytocin
55
________ levels in _____________ act as a “placental clock” for parturition
CRH levels in maternal plasma (corticotrophin-releasing hormone)
56
What is the role of CRH in induction of labor?
Fetal portion of placenta secretes CRH into fetal circulation —> increased fetal ACTH Increased ACTH —> DHEA from fetal adrenal cortex —> increases availability for placental conversion into estrogen Increased ACTH stimulates fetal cortisol production —> fetal lung maturation (ensures infant is ready to live outside the womb)
57
High CRH levels are associated with ....
Premature deliveries
58
Low CRH levels are associated with...
Late deliveries
59
What is the role of inflammation in labor?
Activation of nuclear factor (NF-kB) in the uterus (caused by uterine stretching and increased production of macrophages as a result of increased pulmonary surfactant) NF-kB stimulates production of inflammatory cytokines (IL-8) and prostaglandins —> promotes cervical softening
60
What else could activate NF-kB and result in premature labor?
Bacterial infections Allergic reactions Multiple fetus pregnancy (due to increased uterine stretching)
61
Labor is a _________ cycle that progressively increases until....
Positive-feedback cycle Until cervical dilation and delivery are complete
62
_______ is a pharmacological synthetic form of oxytoxin
Pitocin
63
What are the three stages of labor?
Cervical dilation - lasts from several hours to as long as 24 hours in a first pregnancy Delivery of baby - begins when cervical dilation is complete (usually 30 to 90 minutes) Delivery of placenta - second series of uterine contractions separates placenta from uterus (usually 15-30 min)
64
Which stage of labor is the longest?
Cervical dilation
65
Which stage of labor is the shortest?
Delivery of placenta
66
What is involution?
After delivery, shrinkage of uterus to presentational size
67
________ and ________ promote development of mammary glands during gestation
Estrogen and progesterone
68
During gestation, ______ stimulates synthesis of milk enzymes
Prolactin
69
Lactation does not occur during pregnancy due to ....
Inhibition from estrogen and progesterone Withdrawal of placental steroids at parturition initiates lactation
70
Lactation is sustained by _______.
Suckling Oxytocin —> milk ejection Prolactin —> secretion (production) of more milk
71
What are the hormones of lactation?
ESTROGENS stimulate ductal growth PROGESTERONE, PROLACTIN, and hCS (human chorionic somatomammotropin) stimulate development of lobules and alveoli PROLACTIN and hCS stimulate milk enzymes INSULIN and CORTISOL also promote lactation
72
After parturition, estrogen and progesterone ______, so lactation can occur
Decrease
73
How does the sucking reflex occur?
(+) signal = infant’s cry or smell (-) signal = psychological stress (+) signal to POSTERIOR pituitary —> increased Oxytocin release —> contraction of myoepithelial cells surrounding alveoli —> milk ejection Suckling of infant —> mechanoreceptors in nipple —> signal hypothalamus to release prolactin from ANTERIOR pituitary —> secretion by alveolar epithelial cells —> increased milk synthesis
74
Major hormone responsible for lactogenesis
Prolactin Synthesized/secreted by lactotrophs in pituitary
75
Release of prolactin is controlled by what two hormones?
Thyrotropin-releasing hormone (stimulatory) Dopamine (inhibitory)
76
Prolactin inhibits _______ release, preventing ________.
GnRH | Ovulation
77
Ovulation is suppressed as long as _______ continues
Lactation Because prolactin inhibits GnRH —> inhibition of LH and FSH release It also antagonizes the action of LH and FSH on ovaries
78
In non-lactating women, ovulation resumes in ________ postpartum
7-10 weeks
79
In lactating women, ovulation resumes within _______ postpartum
27 weeks (7 months)
80
In order to get full ovulation suppression, you must...
Breast feed regularly BUT not recommended as a contraceptive method

Phys II Unit III (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions