Anatomy/Physiology of Labor & Birth

Question 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.

Answer 1

cervical ripening

Question 2

“cephalic, breech, shoulder” are fetal __________

Answer 2

presentations

Question 3

flexion of fetal head in labor results in:

Answer 3

the presentation of a smaller diameter

Question 4

restitution occurs as a result of:

Answer 4

untwisting of the neck

Question 5

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

Answer 5

plattypeloid

Question 6

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

Answer 6

mechanisms of labor

Question 7

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

Answer 7

engagement

Question 8

The sagittal suture of the fetal head lies between:

Answer 8

the parietal bones

Question 9

to deterimine position of the fetus, the midwife identifies:

Answer 9

the sagittal suture

Question 10

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

Answer 10

the cephalic prominence

Question 11

to determine station of the fetus, the midwife would:

Answer 11

palpate the ischial spines

Question 12

flexion is a fetal __________

Answer 12

attitude

Question 13

Extension of the fetal head during labor results in:

Answer 13

Pivoting of the head under the symphysis pubis

Question 14

Pivoting of the head under the symphysis pubis

Answer 14

effacement

Question 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

Answer 15

dilatation

Question 16

hormone that inhibits contractions

Answer 16

progesterone

Question 17

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

Answer 17

estrogen

Question 18

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

Answer 18

prostaglandins

Question 19

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

Answer 19

oxytocin

Question 20

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

Answer 20

oxytocin receptors

Question 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

Answer 21

gap junctions

Question 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.

Answer 22

Myometrium

Question 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.

Answer 23

activation phase

Question 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

Answer 24

number and sensitivity

Question 25

contractions start in the __________

Answer 25

fundus

Question 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.

Answer 26

Triple descending gradient

Question 27

contractions last longer in the __________

Answer 27

fundus

Question 28

contractions progress from _________ to ________

Answer 28

fundus to isthmus

Question 29

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

Answer 29

Quiescence

Question 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

Answer 30

activation

Question 31

period of pregnancy where uterotonins (oxytocin and prostaglandins) promote labor progression

Answer 31

stimulation

Question 32

during labor, maternal BP:

Answer 32

increases during ctx and returns to baseline in between

Question 33

_______ increases an additional 10-15% in first stage labor and as much as 50% in secod stage

Answer 33

cardiac output

Question 34

____________ decreases as contraction intensity and duration increases

Answer 34

placental blood flow

Question 35

Increase in _____________ in second stage due to pushing, prompting PNS stimulation during Valsalva.

Answer 35

central venous pressure

Question 36

joint that connects the sacrum with the coccyx

Answer 36

sacrococcygeal symphysis

Question 37

the bony passageway through which the fetus must maneuver to be born vaginally...below the linea terminalis

Answer 37

true pelvis

Question 38

above the linea terminalis, includes iliac fossa and iliac crests

Answer 38

false pelvis

Question 39

invisible line that runs along the pelvic brim from the top of the symphysis pubis around to the sacral promontory

Answer 39

linea terminalis

Question 40

primary portion of the levantor ani. Originates at posterior border of the symphysis pubis and sweeps back to insert on lateral margins of coccyx.

Answer 40

pubococcoygeus

Question 41

Attach posteriorly to central tendinous point on perineum, anteriorily inters to corpus cavernous of the clitoris, laterally surround orifice of the vagina and cover vestibular bulbs and Bartholin glands on either side

Answer 41

Bulbocavernosus (2)

Question 42

Arise from inner and anterior surfaces of the ischial tuberosity of the superior ramus of the ischium by a small tendon. They insert into the central tendinous point of the perineum.

Answer 42

Superficial transverse perineal (2)

Question 43

Midline between vagina and anus. Point of fusion for both superior and inferior fascia of the urogenital diaphragm. Common point of attachment for Bulbocavernosus, superficial transverse perineal, and pubococcoygeus.

Answer 43

Central tendinous point of the perineum (a fibromuscular structure)

Question 44

Perineal innervation occurs via the _____________ and its branches

Answer 44

pudendal nerve

Question 45

pudendal nerve originates from:

Answer 45

S2, S3, and S4.

Question 46

__________ nerve also innervates the levator ani, rectal sphincter, skin of the vulva and lower portion of the vagina, and muscles of the urogenital diaphragm

Answer 46

pudendal nerve

Question 47

obstetric conjugate (what the fetus must pass through) is 11 cm

Answer 47

pelvic inlet

Question 48

least amount of room, where arrest of labor usually occurs. Extends from apex of suprapubic arch, through ischial spines, to the junction of the 4th and 5th sacral vertebrae.

Answer 48

midplane

Question 49

obstetric diameter is 11.5 cm. Flexibility of the coccyx allows it to be pushed out of the way by the presenting part.

Answer 49

pelvic outlet

Question 50

type of pelvis that is commonly known as the "female pelvis" because inlet and midplane are adeqate in all diameters, the posterior segment is broad and roomy, forepelvis is well-rounded, AP is long, transverse is adequate, pelvic arch is 90 degrees, and capacity is adequate

Answer 50

gynecoid

Question 51

type of pelvis inlet: Android Adequate anterorposterior and transverse diameters. Very short and inadequate posterior sagittal diameter. Long anterior sagittal diameter. Shallow posterior segment w/ reduced capacity. Narrow, sharply angled forepelvis. Reduced in all diameters. Short AP, narrow transeverse. 70 degree pelvic arch. Reduced capacity.

Answer 51

android

Question 52

type of pelvis inlet: Long anteroposterior, posterior sagittal, and anterior sagittal diameters. Adequate but short transverse. Deep posterior and anterior segments.

Answer 52

anthropoid

Question 53

type of pelvis midplane: | Long AP diameter, all other adequate. Overall capacity adequate.

Answer 53

anthropoid

Question 54

type of pelvis midplane: | Reduced in all diameters.

Answer 54

android

Question 55

type of pelvis midplane: | Adequate in all diameters.

Answer 55

gynecoid

Question 56

type of pelvis inlet: Short anteropsterior, posterior and anterior sagittal diameters. Long transverse. Shallow posterior and anterior segments.

Answer 56

platypelloid

Question 57

type of pelvis midplane: | Short AP, AS, and AS diameters. Wide transverse. Overall capacity reduced

Answer 57

platypelloid

Question 58

type of pelvis outlet: | Short AP, wide transverse. Very wide arch. Inadequate capacity.

Answer 58

platypelloid

Question 59

type of pelvis outlet: | Short AP, narrow transeverse. 70 degree pelvic arch. Reduced capacity.

Answer 59

android

Question 60

type of pelvis outlet: | Long AP, adequate transverse. Normal or narrow arch. Adequate capacity.

Answer 60

anthropoid

Question 61

two types of pelvis that are adequate for vaginal birth

Answer 61

gynecoid, anthropoid

Question 62

relationship of the long axis on the fetus to the long axis of the pregnant person. "longitudinal, transverse, oblique"

Answer 62

lie

Question 63

The part of the fetus that lies over the pelvic inlet - cephalic or head first - breech or pelvis first - shoulder.

Answer 63

presentation

Question 64

the posture of the fetus, specifically the degree of flexion or extension of the head.

Answer 64

attitude

Question 65

relationship of the denominator to the front, back, or sides of the pregnant pelvis

Answer 65

position

Question 66

sagittal suture is located midway between the symphysis pubis and the sacral promontory

Answer 66

synclitism

Question 67

fetal neck is tilted so that so that the fetal head leans laterally toward the fetal shoulder

Answer 67

asynclitism

Question 68

when the anterior parietal bone (the one closest to the symphysis) becomes the lowest/leading part due to the flexion of the head toward the sacral promontory

Answer 68

anterior asynclitism

Question 69

when the posterior parietal bone (the one closest to the sacral promontory) becomes the lowest/leading part as a result of lateral flexion toward the symphysis

Answer 69

posterior asynclitism

Question 70

Ways that ___________ assists in labor: during normal labor, the head enters the pelvis with a moderate degree of posterior asynclitism and then changes to anterior as it descends farther into the pelvis before the mechanism of internal rotation occurs. This is an accommodation by the fetus to take advantage of the roomiest parts of the true pelvis.

Answer 70

asynclitism

Question 71

How ___________ impedes labor; | if the head remains asynclitic as it continues to descend in the pelvis internal rotation may be prevented.

Answer 71

asynclitism

Question 72

portion of the fetal head that is first encountered on 4th leopold maneuver

Answer 72

cephalic prominence

Question 73

``` engagement descent flexion internal rotation extension restitution external rotation ```

Answer 73

mechanisms of labor for birth in the *occiput anterior* position

Question 74

``` engagement descent flexion internal rotation 8flexion followed by extension* restitution external rotation ```

Answer 74

mechanisms of labor for birth in the *occiput posterior* position

Question 75

long arc from LOP to ROP/ OA=

Answer 75

135 deg

Question 76

short arc from LOP to ROP/ OP=

Answer 76

45 deg

Question 77

occurs when the biparietal diameter passes through the pelvic inlet

Answer 77

engagement

Question 78

Allows the smaller suboccipitobregmatic diameter to be the widest fetal head diameter that transverses the pelvis

Answer 78

flexion

Question 79

brings anteroposterior diameterof the fetal head into alignment with the anteroposterior diameter of the pelvis

Answer 79

internal rotation

Question 80

allows the head to follow the curve of Carus and move under the symphysis pubis

Answer 80

extension

Question 81

neck turns back so head is at a right angle with shoulders. Sagittal suture is in one oblique diameter of pelvis, shoulders in the other

Answer 81

restitution

Question 82

shoulders rotate 45 degrees, bringing shoulders into alignment with AP diameter of pelvic outlet

Answer 82

external rotation

Question 83

birth of shoulders by lateral flexion

Answer 83

expulsion

Question 84

change in shape of the fetal head d/t the soft skull bones overriding/overlapping one another so that movement is possible at the location of the sutures

Answer 84

molding

Question 85

formation of an edematous swelling over the most dependent portion of the presenting fetal head. Crosses sutures lines as generalized swelling (different than hematoma)

Answer 85

caput succadaneum

Question 86

bleeding beneath the periosteum. May occur over more than one cranial bone but is limited to each individual bone and does not cross sutures.

Answer 86

Cephalohematoma

Question 87

how to determine ____________: | 2nd leopold maneuver. Firm, convex, continuously smooth and resistant mass extending from breech to neck.

Answer 87

fetal back

Question 88

a neutral fetal head and spine. The head is neither extended nor flexed, and the spine is neither arched nor curved (This is a fetus with excellent posture!). This attitude features the top of the head, the middle part of the vertex, as the presenting part.

Answer 88

military attitude

Question 89

cardinal movement that occurs at the mid-plane of the pelvis

Answer 89

internal rotation

Question 90

corresponds with the internal rotation of the shoulders

Answer 90

external rotation

Question 91

plane of the pelvis where engagement occurs

Answer 91

inlet

Question 92

the head negotiates this during extension

Answer 92

outlet

Question 93

when the sagittal suture is closer to the sacrum

Answer 93

anterior asynclitism

Question 94

when the posterior parietal bone enters the pelvis first

Answer 94

posterior asynclitism

Question 95

when the sagittal suture is closer to the symphysis pubis

Answer 95

posterior asynclitism

Question 96

asynclitism interferes with this cardinal movement

Answer 96

internal rotation

Question 97

this makes the diameter of the fetal head smaller at the inlet

Answer 97

asynclitism

Question 98

central hormone leading to uterine quiescence. When progesterone dominates, labor onset it prevented.

Answer 98

progesterone

Question 99

Plays a central role in activation of labor (phase 1). It is a uterotropin-a hormone that facilitates initiation of labor.

Answer 99

estrogen

Question 100

under influence of this, uterine myometrial cells express receptors for prostaglandins and oxytocin and is necessary for development of gap junctions.

Answer 100

estrogen

Question 101

Plays a role in labor activitation and acts as a uterotropin by increasing myometrial sensitivity to oxytocin and stimulating the formation of gap junctions

Answer 101

prostaglandins

Question 102

Promotes decreased collagen content in the cervix leading to cervical softening and effacement

Answer 102

prostaglandins

Question 103

produces by uterine decidua and promotes uterine contractions

Answer 103

prostaglandins

Question 104

when bound to receptors in the uterus causes contractions. It also leads to production of prostaglandins in the uterine decidua

Answer 104

oxytocin

Question 105

Increase dramatically in last weeks of pregnancy. Changes in number and sensitivity are the primary influence on the strength and frequency of contractions in active labor-not the production and release of oxytocin

Answer 105

oxytocin receptors

Question 106

allow communication between muscle fibers that allows for effective coordination of contractions

Answer 106

Gap junctions

Question 107

thing needed for both onset of labor and effective progress of labor

Answer 107

Gap junctions

Question 108

quiescence active hormones

Answer 108

progesterone, nitric oxide, relaxin, prostacyclin

Question 109

activation phase hormones

Answer 109

estrogen, prostaglandins

Question 110

stimulation phase hormones

Answer 110

oxytocin, prostaglandins