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Unit 7: Physiology > pregnancy & lactation (3) > Flashcards

pregnancy & lactation (3) Flashcards

1
Q

what is the acrosome? what is the acrosomal reaction?

A
  • the acrosomal is a large organelle in the head of the sperm
  • reaction is the exocytosis of the acrosome from the sperm cell
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2
Q

what is the cortical reaction

A

it is the exocytosis of granules that previously lay immediately beneath the plasma membrane. The enzymes released lead to changes in the zona pellucida proteins cause the zona to harden to prevent the re entry of other sperm cells

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3
Q

what two things make up the zygote?

A

the male pronucleus and the female pronucleus

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4
Q

what hormones stimulates the uterine endometrium to proliferate?

A

estradiol

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5
Q

what produces the estradiol?

A

the follicles

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6
Q

during mid-cycle the estradiol levels rise, what does this lead to/

A

positive feedback so that there is a surge in LH and FSH release from a. pituitary causing ovulation

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7
Q

what maintains the blastocyte until the placenta forms? at what age does the placenta form?

A

the corpus lutetium maintains it

8 weeks

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8
Q

from point of fertilization, how long usually until fertilization?

A

about 7 days

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9
Q

how long does it usually take for the blastocyte to go from fallopian tubes to uterus?

A

3-5 days

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10
Q

how does sperm get transported?

A
  • flagellar motility
  • sperm transport is facilitated by contractions of the uterus, cervix & fallopian tubes in response to oxytocin released during the female orgasm, and prostaglandins in the male seminal fluid
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11
Q

what produces hCG?

A

syncytiotrophoblasts in the blastocyte

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12
Q

where is fetal nutrition derived from before the placental formation?

A

from endomtrial decidua

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13
Q

where is the placenta formed from?

A

trohoblasts & adjacent cells

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14
Q

what are somatomammotropins?

A

related to growth hormones. They coordinate fuel economy by contributing to the conversion of glucose to fatty acids & ketones. These also promote mammary gland development in pregnant mother w

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15
Q

at 8 weeks pregnancy, after the placenta has been formed, what type of estrogen is seen to increase?

A

estriol (E3)

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16
Q

what two enzymes does the fetus lack? why is this beneficial?

A

3-beta hydroxysteroid dehydrogenase & aromatase
beneficial because otherwise the fetus would be able to produce estrogen and high levels of estrogen in the baby can be fatal

17
Q

what 3 enzymes does the placenta lack? where are these enzymes supplied from then?

A

17 alpha hydroxylase and 17,20 desmolase activity and 16 alpha hydroxylase
these enzymes are supplied from the fetal liver & adrenal gland

18
Q

if blood volume increases a lot during pregnancy, why does the MAP decrease?

A

because other organs (like kidneys) will make adaptive changes
also speculated that the steroid hormones present can have vasodilatory effects

19
Q

tell me about the increased cardiac output during the 1st trimester?

A

due mostly to an increase in stroke volume. Kidney & uterus see the greatest increase in blood supply and some increase to the heart, skin & breast

20
Q

explain how there is increased alveolar ventilation during pregnancy

A

steroid effects on medullary respiratory centers; increased alveolar ventilation results in decreased maternal arterial pCO2

21
Q

tell me about the increased nutritional demands during pregnancy

A

Increased demand for dietary protein (add 30 grams/dy) as well as iron & folic acid reflecting the increased production of blood cells

22
Q

what is the average weight gain during pregnancy?

A

25-35 lbs

23
Q

how much does the BMR increase by during the latter part of pregnancy?

A

15%

24
Q

what’s the mean duration of pregnancy?

A
  • 38 weeks from time of ovulation
  • 40 weeks from the 1st day of the last menstrual period

aka WAYYY to long

25
Q

what triggers parturition?

A

increase in fetal production of cortisol near term which increases the ratio of estrogen/progesterone and thus the sensitivity of the uterus to contractile stimuli

26
Q

what two hormones will keep the uterus quiet during pregnancy?

A

progesterons and relaxin

27
Q

what organs produce the prostaglandins? what are the two most common prostaglandins? what is their function?

A
  • the uterus, fetal membranes and placenta produce prostaglandins
  • PGE2 and PGF2a
  • stimulate the uterine smooth muscle cells, promote formation of gap junctions between uterine smooth muscle cells which potentiates their response to oxytocin causing softening/thinning/dilation or “effacement” of the cervix
28
Q

what is the function of oxytocin?

A

promotes milk let down & uterine contractility

29
Q

what is the function of mammogenic hormones?

example?

A

promote cell proliferation

ex. progesterone

30
Q

what is the function of lactogenic hormones?

example?

A

promote initiation of milk production

ex. prolactin

31
Q

what is the function of galactokinetic hormones?

A

promote milk ejection or let down

32
Q

what is the function of galactopoietic hormones?

example?

A

maintain milk production

ex. prolactin

33
Q

what is the function secretory unit of the breast?

A

alveolus

34
Q

what is the function of the myoepithelial cells of the alveolus?

A

surround each alveolus & adipose cells and promote milk let down in response to oxytocin

35
Q

what cells in the alveolous secrete milk? in response to what?

A

secretory epithelial cells in response to prolactin & permissive hormones (ie cortisol)

36
Q

what is colostrum? what are some of its characteristics?

A
  • high in protein, has immunologic protection.
  • Provides a low volume form of nutrition for neonate’s immature GI tract during the first few days of life.
  • Has little or no fat compared to mature human milk
37
Q

what is the effect of suckling on the arcuate nucleus in the hypothalamus?

A

afferent input from the nipple inhibits neurons that release dopamine (DA). DA normally travels via the hypothalamic portal system to the a. pituitary where it inhibits prolactin (PRL) release by lactotrophs. Inhibition of DA release leads to increase in PRL release

38
Q

what is the result of suckling on the supraoptic & paraventricular nuclei of the hypothalamus?

A

the afferent input from the nipple triggers the production & release of oxytocin from the posterior pituitary

39
Q

how does suckling affect ovulation?

A

-In the preoptic area & arcuate nucleus, the afferent input from the nipple inhibits GnRH release. -by Inhibiting GnRH/LH and FSH will inhibit the ovarian cycle in lactating females

Unit 7: Physiology (19 decks)

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