Physiology: Pregnancy and such Flashcards

1
Q

Fertilization

A

process by which sperm and egg fuse to form a zygote

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

Process of Fertilization

A

400 million sperm deposited in cervix, 50-200 reach ampullary-isthmus junction
sperm undergo capacitation in uterus
fertilization occurs in ampulla
zygote - divides to from a blastocyst - inner cell mass (fetal zone) and outer trophectoderm (placental zone)

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

Blastocyst divisions - Trophectoderm

A

placental zone

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

Blastocyst division - Inner Cell Mass

A

fetal zone

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

Implantation

A

process by which blastocyst attaches itself on the endometrial surface and invades the uterine decidua

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

Process of Implantation

A

takes 6-7 days
uterine endometrium at site differentiates into decidual cells
embryo development and uterus must be synchornized

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

Trohpectoderm Differentiation

A

6-7 days after fertilization

outer: Syncticotrophoblast
inner: Cytotrophoblast

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

Syncticotrophoblast secrete

A
Chorionic Gonadotropin (hCG)
hCG stimulates corpus luteum to secrete progesterone until placenta is fully mature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Placenta Functions

A

supply nutrients and oxygen
remove metabolic by-products and CO2
provide endocrine support to maintain pregnancy and for fetal development

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

Placenta is composed of:

A

chorionic villi and uterine endometrium

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

Functions of Synctiotrophoblast layer in placenta

A

separates maternal blood form fetal blood
hormones secreted: hCG, placental lactogen (hPL), chorionic somatotropin (hCS), progesterone (P), estrogens and prostaglandins

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

Human Chorionic Gonadotropin

A

functionally similar to: LH, longer half-life

urinary, B-fragment serves as diagnostic tool for onset and progression of pregnancy

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

Functions of hCG

A

induces progesterone synthesis and secretion by syncytiotrophoblast cells
7th week “Luteal-Placental Shift” - placenta takes over steroid functions of corpus luteum

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

Placental Synthesis of Estrogen - Feto-Placental Unit

A

+: hcG on placenta cause cholesterol to be converted to progesterone
+: ACTH on fetal adrenal, causes CYP 17 to convert progesterone to DHEA-Sulfate and DHEA
DHEA in adrenal gland is converted to estrone (E1) by aromatase in the placenta
estrone (E1) can be converted to estradiol (E2)
Fetal liver: DHEA-Sulfate is converted to 16a-DHEA-Sulfate which in the placenta is converted to estriol (E3)

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

Placental membrane is permeable to:

A
glucose
oxygen
amino acids
fatty acids
Na, K, Cl
ketone bodies
vitamins
viruses
lipid soluble narcotics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Placental membrane is impermeable to:

A

immunoglobulins

chemicals that are embryo toxic

17
Q

Maternal adjustments during gestation: blood volume and hemodynamics

A
  • 30% increase in plasma volume
  • 20-30% increase in RBC mass
  • 2nd half: plasma renin, aldosterone and angiotensin 2 levels increase (increase: electrolytes, ECF, -> plasma volume)
  • placental prostacyclin increases - maintains vascular tone, and normal blood pressure
  • by 10 weeks - 40% increase in cardiac output
18
Q

Maternal adjustments during gestation: respiration

A

-increase rate of respiration

19
Q

Maternal adjustments during gestation: metabolism

A
  • average weight gain: 24lb
  • average extra daily calorie: 250-300; protein 30 g/day
  • 1st half: glycogen and fat stores increase )anabolism
  • 2nd half: fetal growth removes stored maternal nutrients, increases mothers appetite (Accelerated starvation), maternal insulin resistance: allows free flow of glucose, amino acid and fatty acid to fetus (maternal insulin resistance)
20
Q

accelerated starvation

A

increased maternal appetite due to quick removal of storage nutrients by fetus

21
Q

maternal insulin resistance

A

free flow of glucose, amino acid and fatty acid to fetus

22
Q

Fetal adjustments during gestation: Respiration

A
  • 24-28 weeks Type 2 alveolar cells - synthesize and secrete surfactant
  • surfactant essential for inflation after birth
  • asphyxia during birth stimulates the respiratory centers, diaphragm descends, creates 40 mm H2O negative pressure, opens up alveoli - 40cc of air flow in (Onset of breathing)
  • air in lungs prevents collapse - process continue until breathing rate is 40/min
23
Q

Onset of breathing

A
  • asphyxia stimulates respiratory centers
  • diaphragm descends - creating negative intrapleural pressure (40 mm H20)
  • alveoli open and 40 cc of air flows in
24
Q

Parturition

A

process by which uterus expels the mature fetus and placenta, and reverts back to pregravid size

25
Q

Phases of Parturition

A

1st phase: initiation of labor
2nd phase: delivery of fetus and placenta
3rd phase: uterine contractions to revert to pregravid size

26
Q

Factors responsible for parturition

A

Estradiol: produces PGE2 in placenta and decidua, oxytocin receptors in myometrium
PGE2: initiates myometrium contractions
Oxytocin: sustain of myometrial contractions

27
Q

Labor pains

A

-massive contractions, activate pain fibers of myometrium - intense pain

28
Q

Onset of Labor

A

PGE2 -> uterine contractions -> stretch of cervix -> oxytocin release -> uterine contractions

29
Q

Parturition Process

A

contractions push fetus into cervical canal and vagina

10-45 min later - uterus contracts separating placenta - small blood loss (350 mL)

30
Q

lactation

A

process by which milk is synthesized and EJECTED from the mammary glands (combined process of hormones and baby)

31
Q

hormones for: ductal development

A

Estradiol
Growth hormone
Prolactin

32
Q

ESTRADIOL functions on development of mammary glands

A

oxytocin receptors in alveolar and ductal smooth muscle cells

33
Q

hormones for: Lobuloaveolar Development

A
progesterone
estradiol
prolactin
GH
insulin
IGF-1
thyroxine
cortisol
34
Q

hormones for: milk synthesis

A

prolactin & cortisol

35
Q

During gestation milk synthesis does not occur because:

A

Estradiol inhibits prolactin binding
Progesterone inhibits cortisol induces milk synthesis

after delivery estradiol and progesterone levels fall, withdrawing the inhibition

36
Q

Milk Let Down reflex

A

suckling stimulates areola and nipples -> oxytocin release -> contraction of myoepthelial cells in alveoli and ducts -> milk flows through duct and nipple

37
Q

First Milk

A

Colostrum
high protein
low amounts carbohydrate
regular amount of fat

38
Q

Compostiion of Milk

A

Protein 0.8 - 1.2 %
Carbohydrate 6.8 - 7.2%
Fat 3 - 5 %
Mineral 0.2%