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Physiology II Final > Lecture 22 Pregnancy and Lactation > Flashcards

Lecture 22 Pregnancy and Lactation Flashcards

(80 cards)

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1
Q

What is the oocyte surrounded by?

A

Corona radiata + zona pellucida

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2
Q

The corna radiata consists of how many granulosa cells?

A

100+

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3
Q

How does the oocyte enter the fallopian tube?

A

Ciliated epithelium of fimbriae is activated by estrogen from ovaries
Causes cilia to beat towards ostium

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4
Q

Where does fertilization take place?

A

in the ampulla of the fallopian tube

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5
Q

Sperm transport is aided by what?

A

by contractions of uterus and fallopian tubes
Contractions activated by:
Prostaglandins from male seminal fluid
Oxytocin from posterior pituitary

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6
Q

When the sperm penetrates the barriers surrounding oocyte what does it release?

A

Hyaluronidase from acrosome: dissolves material holding together corona radiata cells
Zona lysin: penetrates zona pellucida

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7
Q

The completion of meiosis of the egg is activated by what?

A

When there is a fusion of sperm cell membrane and oocyte cell membrane and the femal and male nuclei fuses

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8
Q

How long does the fertilized ovum travel for down the fallopian tube?

A

3-5 days

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9
Q

What is the migrations of the fertilized ovum aided by?

A

ciliated epithelium of fallopian tube and contractions of the fallopian tube

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10
Q

What causes relaxation of the uterus to allow entry of blastocyst into uterine lumen?

A

Progesterone produced by corpus luteum

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11
Q

Nourishment for developing embryo is provided via what?

A

fallopian tube secretory cells and uterine endometrium

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12
Q

Fertilized egg undergoes several mitotic divisions while in Fallopian tube to produce what?

A

Blastocyst = 100 cells

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13
Q

How many cleavages include equal cell divisions?

A

The first two, after several cleavages, however, two distinct cell populations begin to appear

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14
Q

What are the two distinct cell populations that begin to appear after several cleavages?

A

One population consists of many small outer cells surrounding a large single inner cell

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15
Q

What do the outer, smaller cells form in a blastocyst?

A

Smaller cells divide more rapidly than the larger, inner cells and form the trophoblast

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16
Q

What are the cells within the trophoblast collectively called?

A

inner cell mass

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17
Q

What will the inner cell mass give rise to?

A

Not only the embryo proper but also the yolk sac, amnion, and allantoic stalk

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18
Q

As cleavage continues, a cavity develops within the trophoblast. This cavity is located eccentrically with the inner cell mass located opposite the cavity. What is this “hollow ball” structure called?

A

Blastocyst

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19
Q

What is the outer wall of the blastocyst ?

A

The trophoblast

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20
Q

The side of the blastocyst where the inner cell mass is located is reffered to what?

A

The embryonic pole

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21
Q

What is on the opposite side to the embryonic pole, where the cavity is found?

A

Abembryonic pole

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22
Q

How many days after fertilization does the blastocyst attach to the inner wall of the uterus and begins to implant?

A

7 days

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23
Q

What pole of the blastocyst becomes sticky and so this is the pole that normally attaches to the endometrium?

A

Embryonic pole

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24
Q

What is implantation?

A

After the blastocyst attaches to the endometrium it begins to embed itself into the wall of the uterus.

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25
At the time of implantation, the trophoblast forms what two kinds of tissues?
An inner cytotrophoblas that is composed of cells separated from one another by cell membranes. and outer syncytiotrophoblast: a syncytium of cells which forms on the side of the blastocyst that has initiated the implantation process
26
As the syncytiotrophoblast erodes its way into the endometrium, it develops cavities called what?
trophoblastic lacunae
27
What do the trophoblastic lacunae become?
Filled with maternal blood and represent the potential source of oxygen and nutrients for the developing embryo
28
What are the actions of the syncytiotrophoblast?
Secrete proteolytic enzymes - digest/liquefy adjacent cells of uterine endometrium - releases some fluids from digestion that help provide nourishment for the blastocyst.
29
The cytotrophoblast forms solid tubular thickenings called what?
primary villi
30
At about fourteen days following fertilization, primary villi become what?
hollow and acquire a mesodermal core and these projections are called secondary villi
31
Several days later the secondary villi will form what?
branched, hollow structures containing fetal blood vessels and these are the tertiary villi
32
What taps into the maternal blood in the trophoblastic lacunae?
tertiary villi
33
The blood vessels within the tertiary villi dump into vessels running through what?
Allantoic stalk
34
Note that in mammals there is no allantoic membrane, but the stalk of the allantois develops to contain the vessels connecting the chorion with the embryo. What is this vessel-filled stalk called?
the umbilical cord
35
What is collectively called the placenta?
The chorion plus the portion of the uterine endometrium with the trophoblastic lacunae
36
Influence of progesterone from corpus luteum causes endometrial cells to become enlarged and store large quantities of what during latter half of menstrual cycle.
glycogen, proteins, lipids, and minerals during latter half of menstrual cycle
37
What does progesterone from corpus luteum cause endometrial cells to become following implantation?
Enlarged and store more nutrients
38
Endometrial cells that are enlarged and store more nutrients after implantation under the influence of progesterone are now referred to as what?
Decidual cells
39
What do decidual cells provide?
All nutrients to early embryo for first week after implantation and continue to provide some nutrients up through 8 weeks following implantation
40
What do decidual cells provide?
All nutrients to early embryo for first week after implantation and continue to provide some nutrients up through 8 weeks following implantation
41
What is the Oxygen diffusion of mother and fetus?
PO2 of mother - 50 mm Hg | PO2 of fetus - 30 mm Hg
42
Why does adequate oxygenation occur with such a low pressure gradient (mean diffusion gradient pressure = 20 mm Hg)?
Fetal hemoglobin Fetal blood hemoglobin concentration is about 50% greater than maternal Bohr effect
43
Describe the early placenta
Thick; permeability low | Small surface area
44
Describe late placenta
Thin; permeability high | Large surface area
45
When can hemogloblin carry more oxygen?
At low PCO2
46
Fetal blood coming into the placenta carries more what?
CO2 | -Excess CO2 diffuses into maternal blood
47
Excess CO2 diffuses into maternal blood can causes the fetal blood to become _____. and maternal blood to become _______.
More alkaline | More acidic
48
The changes in maternal and fetal blood causes what?
increase capacity of fetal blood to combine with oxygen Decreases in capacity of maternal blood to combine with oxygen Double bohr effect
49
The carbon dioxide diffusion causes PCO2 of fetal blood to be how much higher than maternal blood?
2-3x
50
Describe diffusion of foodstuffs
Facilitated diffusion of glucose via trophoblast cells | Slower diffusion of fatty acids into fetal blood
51
What are the excreted waste products from the fetus?
urea, uric acid, and creatinine diffuse from fetus to mother
52
Describe the changes in the levels of HCG
Secreted by the syncytial trophoblast cells into maternal fluids Measurable secretion 8-9 days after ovulation Maximal secretion during 10th - 12th week of pregnancy Lower levels secreted 16th through 20th weeks
53
What are the functions of HCG?
prevents involution of corpus luteum Causes CL to increase secretion of progesterone and estrogens Causes increased growth in CL Exerts interstitial cell-stimulating effect on testes of male fetus: results in production of testosterone until birht
54
What are estrogens secreted by?
syncytiotrophoblast cells of the placenta
55
Towards the end of the pregnancy, what is the secretion level of estrogens
30x mothers normal level
56
Placental estrogens are formed almost entirely from what?
androgenic steroid compounds Formed in mother's and fetal adrenal glands Converted by trophoblast cells into estradiol, estrone and estriol
57
What are the functions of estrogens?
Uterine enlargement Breast enlargement Growth of breast ductal structure enlargement of maternal external genitalia Relaxation of pelvic ligaments May also affect aspects of fetal development
58
What is progesterone secreted by?
in small quantities by corpus luteum early | in large quantities by placenta
59
What are the functions of progesterone?
causes decidual cells to develop in the endometrium Decreases contractility of pregnant uterus Increases secretions of fallopian tubes and uterus May work with estrogen to prepare breasts for lactation
60
What secretes human chorionic somatomammotropin?
placenta beginning in 5th week of pregnancy
61
What are the functions of human chorionic somatomammotropin?
Causes decreased insulin sensitivity and decreased utilization of glucose by mother Promotes release of free fatty acids from mother's fat stores allowing this to be used as alternate source of energy by the mother General metabolic hormone providing for nutritional needs for both mother and fetus
62
What are the responses of the maternal body?
``` increased size of sexual organs Weight gain changes in metabolism nutritional needs: -mineral deficiencies -iron deficiency -vitamin deficiencies Hypochromic anemai ```
63
Describe the changes in maternal circulation
increase in cardiac output until 27th week but return to almost normal during last 8 weeks Increase in blood volume by 30% during latter half of pregnancy Increase in minute respiration: progesterone increases sensitivity of respiratory center to CO2
64
What increases sensitivity of respiratory center to CO2?
progesterone
65
What are the changes in maternal renal function?
increase in salt and water reabsorption: due to steroid hormones by placenta and adrenal glands 50% increase in renal blood flow and glomerular filtration
66
What is preclampsia?
Hypertension during last few months of preg associated with leakage of large amounts of protein into urine Excess salt and water retention by kidneys Weight gain and edema (hypertension) Renal blood flow and filtration are decreased
67
What are the possible causes of preclampsia?
Excess secretion of placental/adrenal hormones Autoimmunity Insufficient blood supply to placenta
68
What is eclampsia?
``` extreme degree of preclampsia Vascular spasm Clonic seizures Coma decreased kidney and liver function High death rate if not treated ```
69
What is parturition?
increased excitability of uterine musculature; birth
70
What are the progressive hormonal changes with parturition?
increased ration of estrogens to progesterone Oxytocin from posterior pituitary (both from mother and fetus) Cortisol from fetal adrenal glands
71
What are the progressive mechanical changes with parturition?
Stretching of smooth muscle of uterus | Stretching or irritating of cervix
72
Describe the positive feedback cycle during pregnancy
Baby's head stretches cervix cervical stretch excites fundic contractions Fundic contractions pushes baby down and stretches cervix some more cycle repeats over and over again
73
What is the high-estrogen state of pregnancy responsible for?
growth of breasts during pregnancy | Growth and branching of ductal system
74
Progesterone works with estrogen towards the end of pregnancy to do what?
complete final development of ductal system and development of secretory cells (analogous to effect on endometrium)
75
What secretes prolactin?
anterior pituitary
76
What are the functions of prolactin?
promotes milk secretion (counteracts estrogen and progesterone) Has full effects after birth when estrogen and progesterone effects of placenta have been eliminated
77
Human chroionic somatomammotropin may have some ________ properties.
lactogenic
78
What is colostrum?
Secreted just before and after parturition: similar to milk without fat antibodies from mother
79
What is prolactin inhibitory factor?
dopamine
80
Describe the pathway of milk to the nipple
``` milk secreting epithelial cells produce milk in alveoli in the lobules goes through duct lactiferous sinus (ampulla) lactiferous duct nipple ```

Physiology II Final (4 decks)

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