Anatomy/Physiology of Labor & Birth Flashcards Preview

NM704 Labor & Birth > Anatomy/Physiology of Labor & Birth > Flashcards

Flashcards in Anatomy/Physiology of Labor & Birth Deck (110)
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1

primary cause is collagen rearrangement. Modulated by inflammatory and hormonal influences accompanied by increase in water content. Triggered by increase in inflammation, oxytocin, and prostaglandin activity. Traction on the cervix from uterine contractions may contribute prior to onset of labor.

cervical ripening

2

"cephalic, breech, shoulder" are fetal __________

presentations

3

flexion of fetal head in labor results in:

the presentation of a smaller diameter

4

restitution occurs as a result of:

untwisting of the neck

5

An inlet with a short anteroposterior diameter and a wide transverse diameter is characteristic of which pelvic type?

plattypeloid

6

The positional changes the fetus undergoes to accommodate itself to the maternal pelvis

mechanisms of labor

7

-->lowest level of the presenting part has reached the level of the ischial spines
-->Biparietal diameter has reached the inlet

engagement

8

The sagittal suture of the fetal head lies between:

the parietal bones

9

to deterimine position of the fetus, the midwife identifies:

the sagittal suture

10

to determine the attitude of the fetus, the midwife identifies:

the cephalic prominence

11

to determine station of the fetus, the midwife would:

palpate the ischial spines

12

flexion is a fetal __________

attitude

13

Extension of the fetal head during labor results in:

Pivoting of the head under the symphysis pubis

14

Pivoting of the head under the symphysis pubis

effacement

15

Cervical os widens. Force of contraction plus hydrostatic action of amniotic fluid or pressure from presenting fetal part promotes dilation on the softened/low resistance cervix

dilatation

16

hormone that inhibits contractions

progesterone

17

Uterotropin that causes uterine myometrial cells to express receptors for prostaglandins and oxytocin and develop gap junctions

estrogen

18

Uterotropin and uterotonin that facilitate contractions, increase myometrial sensitivity to oxytocin, and stimulates formation of gap junctions.

prostaglandins

19

Uterotonin that is released in pulsatile fashion, peaks with fetal ejection reflex.

oxytocin

20

receptors in the myometrium that stimulate smooth muscle contractions. The binding of these receptors results in Prostaglandin production in decidua

oxytocin receptors

21

transmembrane proteins that create a line of communication between two adjacent myocytes. Action potentials that initiate contractions travel through these to create a synchronized contraction

gap junctions

22

middle layer of the uterine wall, consisting mainly of uterine smooth muscle cells (also called uterine myocytes), but also of supporting stromal and vascular tissue. Its main function is to induce uterine contractions.

Myometrium

23

phase with increased myometrial excitability and responsiveness to substances that stimulate ctx due to estrogen influence, cells express receptors for prostaglandin and oxytocin and develop gap junctions.

activation phase

24

Changes in oxytocin receptor _____________ (rather than production and release of oxytocin) is the primary influence on the strength and frequency of contractions. Prolonged or repeated stimulation of receptors contribute to downregulation, reducing number of receptors available -> less forceful/less frequent contractions

number and sensitivity

25

contractions start in the __________

fundus

26

contractions 1) start in the fundus, 2) last longer in the fundus, 3) progress from fundus to isthmus. Muscle bundles in fundus shorten w/ contractions, upper portion of uterus thickens. Reduced fundal capacity promotes descent of the fetus. Lower segment muscles become longer and more flexible to accommodate the fetus.

Triple descending gradient

27

contractions last longer in the __________

fundus

28

contractions progress from _________ to ________

fundus to isthmus

29

period in late pregnancy of uterine inactivity. Inhibitors of uterine contractions include progesterone, prostacyclin, relaxin, nitric oxide, and other hormones

Quiescence

30

period of pregnancy where uterotropins (estrogen) stimulate upregulation of myometrial receptors for oxytocin and prostaglandins, and turning on of gap junctions between myometrial cells

activation