Maternal Adaptations to Pregnancy II Flashcards

1
Q

What changes occur to ADH secretion during pregnancy?

A

Osmolarity set point for ADH release is lower

Pregnancy does not interfere with the capacity of the pregnancy woman to respond to the normal physiological stimuli that affect ADH release

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2
Q

What occurs to the residual volume, functional residual capacity, total volume, and vital capacity of the lungs during pregnancy?

A

Both RV and FRC are decreased as a result of the uterus forcing the diaphragm upward

Total volume is decreased slightly

Vital capacity is unchanged

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3
Q

What occurs to alveolar ventilation during pregnancy?

A

Increases due to an increase in tidal volume

Respiration rate does not increase

Progesterone increases ventilation by increasing the sensitivity of the central chemoreceptors to CO2

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4
Q

What occurs to oxygen consumption during pregnancy?

A

Oxygen consumption increases in proportion to increasing fetal mass

Alveolar PCO2 decreases because alveolar ventilation exceeds the metabolic rate

The resulting respiratory alkalosis is compensated by the excretion of bicarbonate by the kidney

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5
Q

What occurs to the anterior pituitary during pregnancy?

A

Increases in size

Hyperplasia of lactotropes, causing an increase in serum PRL levels

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6
Q

What occurs to ACTH, GH, TSH, FSH, and LH during pregnancy?

A

ACTH - increase 4-5 fold

GH - remains the same, source changes to placenta

TSH - lower in 1st trimerster than 2nd or 3rd

FSH/LH - fall to very low levels

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7
Q

What changes to the thyroid are associated with pregnancy?

A

Becomes enlarged during the 1st trimester

May be caused by the thyrotropic effect of hCG

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8
Q

What changes occur to the pancreas during pregnancy?

A

Hypertrophy and hyperplasia of beta cells

Increase in peripheral resistance to the metabolic effects of insulin due to increased levels of maternal hPL and cortisol

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9
Q

What changes occur to the adrenal cortex during pregnancy?

A

Increase in maternal total cortisol levels

Placenta expresses HSD-II, protecting the fetus from maternal cortisol

RAA increase

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10
Q

What are the changes in the GI system associated with pregnancy?

A

GI motility, absorption and lower esophageal sphincter tone decrease

Intragastric pressur increases

Gall bladder function and emptying are impaired

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11
Q

What hormone are required for breast development during pregnancy?

A

Prolactin

human placental lactogen

estrogens

progesterone

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12
Q

What hormone have permissive effects on breast development?

A

GH

IGF-1

Insulin

Cortisol

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13
Q

How is PRL release controlled in the pituitary?

A

Under tonic inhibition by dopamine through Gi protein

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14
Q

What occurs to circulating PRL levels during pregnancy?

A

Steadily rise during pregnancy

Due to lacotrope hypertorphy and hyperlasia

High levels of estrogens promote lactotrope proliferation and prolacting release

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15
Q

How is prolactin released following parturition?

A

Suckling is the most potent postpartum stimulus for PRL release

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16
Q

What is the mechanism of PRL action?

A

Tyrosine kinase receptor activates JAK/STAT pathway

17
Q

Describe lactation during pregnancy

A

Lactation is inhibited during pregnancy by high progesterone levels

18
Q

How is lactation initiated?

A

Secretory activity is triggered by fall in progesterone and estrogen levels

Elevated PRL levels promote lactation

19
Q

What are the specific actions of PRL pertaining to milk production?

A

Induces transcription of milk protein

Promotes the secretion of milk into the alveoli

20
Q

How is milk ejection stimulated?

A

Oxytocin acts on myoepithelial cells to promote ejection

Suckling is principal stimulus

Psychic stimuli can also promote oxytocin release

21
Q

What is Lactational Amenorrhea?

A

Lactation suppresses ovarian cycles

GnRH release is inhibited by PRL or afferent neural pathway activated by suckling

22
Q

What are the target tissues of oxytocin?

A

Myoepithelial cells of the breast

Uterine smooth muscle

23
Q

What pathway does oxytocin activate?

A

G-protein coupled receptor

IP3/diacylglycerol signaling pathway

24
Q

What are the effects of oxytocin on uterine contractions?

A

During first 2 trimesters, uterus is resistant to oxytocin because it produces oxytocinases

Does NOT initiate labor

25
Q

What is oxytocin used clinically for?

A

Induce labor

Enhance contractions

Decrease postpartum bleeding