N303 - Ch 13 Ob

Front 1

How long does pregnancy approximately last?

Back 1

1. TEN lunar months
2. NINE calendar months
3. FORTY weeks
4. TWO HUNDRED & EIGHTY days

Front 2

When does conception occur?

Back 2

Approximately two weeks after the first day of the last menstrual period, even though pregnancy is computed from the first day of the last LMP

Front 3

What are the stages of intrauterine development?

Back 3

1. Ovum or preembryonic
2. Embryo
3. Fetus

Front 4

How long is the ovum stage?

Back 4

Conception until day 14

Front 5

What are the steps of the ovum stage?

Back 5

1. Cellular replication
2. Blastocyst formation
3. Initial development of the embryonic membranes
4. Establishment of the primary germ layers

Front 6

When do the primary germ layers differentiate?

Back 6

During the third week after conception (the third week of the ovum stage)

Front 7

What are the primary germ layers?

Back 7

1. Ectoderm
2. Mesoderm
3. Endoderm (entoderm)

Front 8

What is the ectoderm?

Back 8

The upper layer of the embryonic disk that gives rise to the epidermis, the glands (anterior pituitary, cutaneous, and mammary), the nails and hair, CNS & PNS, the lens of the eye, the tooth enamel, and the floor of the amniotic cavity

Front 9

What is the mesoderm?

Back 9

The middle layer of the embryonic disk that develops into the bones and teeth, the muscles (skeletal, smooth, cardiac), the dermis and connective tissue, the cardiovascular system and spleen, and the urogenital system

Front 10

What is the endoderm?

Back 10

The lower layer of the embryonic disk that gives rise to the epithelium lining the respiratory and digestive tracts, and the glandular cells of associated organs, including the oropharynx, the liver and pancreas, the urethra, the bladder, and the vagina

Front 11

What forms the roof of the yolk sac?

Back 11

The endoderm

Front 12

When is the stage of the embryo?

Back 12

From day 15 until approximately 8 weeks after conception, when the embryo measures 3 cm from crown and rump

Front 13

When is the most critical time in the development of organ systems and the main external features?

Back 13

The embryonic stage

Front 14

What occurs at the end of the eighth week?

Back 14

All organ systems and external structures are present, and the embryo is unmistakably human

Front 15

What membranes form at the time of implantation?

Back 15

1. Chorion
2. Amnion

Front 16

What does the chorion become?

Back 16

The covering of the fetal side of the placenta

Front 17

What does the amnion become?

Back 17

The covering of the umbilical cord and covers the chorion on the fetal surface of the placenta

Front 18

What does the fetus breath?

Back 18

The amniotic fluid

Front 19

Where does the fetus urinate?

Back 19

Into the amniotic fluid

Front 20

What are the functions of the amniotic fluid?

Back 20

1. Helps maintain a constant body temperature
2. Serves as a source of oral fluid and a repository for waste
3. Cushions the fetus from trauma or blunting and dispersing outside forces
4. Allows freedom of movement for musculoskeletal development
5. Keeps the embryo from tangling with the membranes, facilitating symmetric growth

Front 21

What complications can occur if the embryo does become tangled with the membranes?

Back 21

Amputations of the extremities or other deformities can occur due to constricting amniotic bands

Front 22

What is the normal amount of amniotic fluid necessary for normal fetal development?

Back 22

About 800 to 1200 mL

Front 23

What is oligohydramnios?

Back 23

Having less than 300 mL of amniotic fluid

Front 24

What is associated with oligohydramnios?

Back 24

Fetal renal abnormalities

Front 25

What is (poly)hydramnios?

Back 25

Having more than 2 L (2000 mL) of amniotic fluid

Front 26

What is associated with (poly)hydramnios?

Back 26

Gastrointestinal and other malformations

Front 27

What does amniotic fluid contain?

Back 27

Albumin, urea, uric acid, creatinine, lecithin, sphingomyelin, bilirubin, fructose, fat, leukocytes, proteins, epithelial cells, enzymes, and lanugo hair

Front 28

What is the function of the yolk sac?

Back 28

1. Aids in transferring maternal nutrients and oxygen, which have diffused through the chorion, to the embryo. Blood vessels form to aid transport.

2. Manufacture blood cells and plasma.

Front 29

What vessels make up the umbilical cord?

Back 29

Two arteries and one vein

Front 30

What do the two arteries of the umbilical cord carry?

Back 30

Blood from the embryo to the chorionic villi

(therefore, DEOXYGENATED blood)

Front 31

What does the vein of the umbilical cord carry?

Back 31

OXYGENATED blood to the embryo

Front 32

What is a nuchal cord?

Back 32

An umbilical cord wrapped around the fetal neck

Front 33

What does the placenta develop from?

Back 33

Chorionic villi

Front 34

What are the two layers of cells of the chorionic villi (placenta)?

Back 34

1. The outer syncytium
2. The inner cytotrophoblast

Front 35

What is the function of the placenta?

Back 35

As a means of metabolic exchange between the mother and fetus

Front 36

What is the functional layer of the placenta?

Back 36

Syncytium

Front 37

When is the placenta completely developed?

Back 37

By the 12th week of gestation

Front 38

What hormones are produced by the placenta?

Back 38

1. Human chorionic gonadotropin (hCG)
2. Human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)

Front 39

When can the hormone human chorionic gonadotropin (hCG) be detected in the maternal serum?

Back 39

8 to 10 days after conception, shortly after implantation

Front 40

What is the purpose of human chorionic gonadotropin (hCG)?

Back 40

Ensure the continued supply of estrogen and progesterone needed to maintain the pregnancy

Front 41

When does human chorionic gonadotropin (hCG) reach is maximal level?

Back 41

At 50 to 70 days, then begins to decrease

Front 42

What can cause miscarriage?

Back 42

If the corpus luteum stops functioning before the placenta is producing sufficient estrogen and progesterone

Front 43

What is the hormone human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)?

Back 43

A substance similar to a growth hormone and stimulates the maternal metabolism to supply nutrients needed for fetal growth.

Front 44

What is the function of human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)?

Back 44

1. Increases resistance to insulin
2. Facilitates glucose transport across the placental membrane
3. Stimulates breast development to prepare for lactation

Front 45

When does the placenta begin to produce most of the maternal estrogens?

Back 45

By 7 weeks after fertilization

Front 46

What is the major estrogen produced by the placenta?

Back 46

Estriol

Front 47

What is the major estrogen produced by the ovaries?

Back 47

Estradiol

Front 48

What is the purpose of measuring estriol levels?

Back 48

To determine placental functioning

Front 49

What does estrogen do?

Back 49

1. Stimulates uterine growth and uteroplacental blood flow

2. Causes proliferation of the breast glandular tissue and stimulates myometrial contractility

Front 50

What are the metabolic functions of the placenta?

Back 50

1. Respiration
2. Nutrition
3. Excretion
4. Storage

Front 51

How does the placenta function as lungs for the fetus?

Back 51

Oxygen diffuses from the maternal blood across the placental membrane into the fetal blood, and carbon dioxide diffuses in the opposite direction

Front 52

What is stored in the placenta for ready access to meet fetal needs?

Back 52

Carbohydrates, proteins, calcium, and iron

Front 53

What nutrients are transferred to the fetus via the placenta?

Back 53

Water, inorganic salts, carbohydrates, proteins, fats, and vitamins

Front 54

What nutrients are transferred by facilitated and active transport?

Back 54

Glucose, amino acids, calcium, iron, and molecules with higher molecular weights

Front 55

Which direction are calcium and amino acids transported?

Back 55

Against the concentration gradient between the maternal blood and fetal blood

Front 56

Why does glucose need to be transported by active transport?

Back 56

Because:
1. The fetal glucose concentration is lower than the glucose level in the maternal blood
2. Rapid metabolism by the fetus
3. Fetal glucose requirement demands larger concentrations of glucose than simple diffusion can provide

Front 57

What is pinocytosis?

Back 57

A mechanism used for transferring large molecules, such as albumin and gamma globulins, across the placental membrane

Front 58

What is transported by pinocytosis?

Back 58

The maternal immunoglobulins that provide early passive immunity to the fetus

Front 59

How are fetal metabolic wastes excreted?

Back 59

The waste products cross the placental membrane from the fetal blood to the maternal blood, and are then excreted by maternal kidneys

Front 60

What does placental function depend on?

Back 60

Maternal blood pressure supplying circulation

Front 61

What substances are developmentally toxic to humans?

Back 61

1. Lead
2. Aminopterin
3. Adrogens
4. Angiotensin-converting enzyme inhibitors
5. Cigarette smoking
6. Cocaine
7. Phenytoin
8. Rubella, syphilis, varicella

etc...

Front 62

How is optimal circulation achieved?

Back 62

With the woman lying at rest on her side

Front 63

What do Braxton Hicks contractions appear to do?

Back 63

Enhance the movement of blood through the intervillous spaces, aiding placental circulation

Front 64

What do prolonged or too-short Braxton Hicks contractions do?

Back 64

Reduce blood flow to the placenta during labor

Front 65

How long is the fetus stage?

Back 65

From week 9 (when the fetus becomes recognizable as a human being) until the end of the pregnancy

Front 66

What is viability?

Back 66

Refers to the capability of the fetus to survive outside the uterus

Front 67

What are the limitations on survival outside the uterus?

Back 67

Central nervous system function and the oxygenation capability of the lungs

Front 68

How is blood transported to the fetal lungs?

Back 68

Via the ductus arteriosus

Front 69

How is blood transported to the fetal lower extremities?

Back 69

Via the ductus venosus into the inferior vena cava

Front 70

How is blood pumped between the right and left sides of the heart?

Back 70

Via the foramen ovale

Front 71

What special characteristics enable the fetus to obtain sufficient oxygen from the maternal blood?

Back 71

1. Fetal hemoglobin carries 20% to 30% more oxygen than maternal hemoglobin

2. The Hgb concentration of the fetus is about 50% greater than that of the mother

3. The fetal heart rate is 110 to 160 BPM, making the cardiac output per unit of body weight higher than that of an adult

Front 72

What is hematopoiesis?

Back 72

The formation of blood, which occurs in the yolk sac

Front 73

What is the most common malformation of the midgut?

Back 73

Meckel diverticulum

Front 74

What causes Meckel diverticulum?

Back 74

When a remnant of the yolk stalk that has failed to degenerate attaches to the ileum, leaving a blind sac

Front 75

Why is vitamin K injected into the newborn?

Back 75

To help coagulate

Front 76

What is the most critical alveolar surfactant required for postnatal lung expansion?

Back 76

Lecithin

Front 77

When is the infant's lung considered mature?

Back 77

When the lecithin/sphingomyelin (L/S) ratio is 2:1

Front 78

What can retard fetal lung maturity?

Back 78

Gestational diabetes or chronic glomerulonephritis

Front 79

What are general fetal movements?

Back 79

Slow gross movements that involve the whole body, with durations varying from several seconds to a minute

Front 80

What are startle movements?

Back 80

Quick (less than 1 second), generalized movements that always start in the limbs and may spread to the trunk and neck

Front 81

What are hiccups?

Back 81

Repetitive phasic contractions of the diaphragm that may last for several minutes

Front 82

What are fetal breathing movements?

Back 82

Paradoxic movements in which the thorax moves inward and the abdomen outward with each contraction of the diaphragm

Front 83

What are isolated arm or leg movements?

Back 83

Movements of the extremities that occur without movement of the trunk

Front 84

What is hand-face contact?

Back 84

Any movement in which the hand makes contact with the face or mouth

Front 85

What is retroflexion of the head?

Back 85

A slow-to-jerky backward bending of the head

Front 86

What is lateral rotation of the head?

Back 86

Isolated turning of the head from side to side

Front 87

What is anteflexion of the head?

Back 87

A normally slow forward bending of the head

Front 88

What is opening of the mouth?

Back 88

Isolated movement that may be accompanied by protrusion of the tongue

Front 89

What is a yawn?

Back 89

Slow opening of the mouth followed by rapid closure after a few seconds

Front 90

What is sucking?

Back 90

Burst of rhythmic jaw movements, sometimes followed by swallowing. With this movement, fetus may be drinking amniotic fluid.

Front 91

What is stretch?

Back 91

Complex movement that involves overextension of the spine, retroflexion of the head, and elevation of the arms

Front 92

When is hearing developed fully?

Back 92

At birth

Front 93

What can cause fetal hiccups?

Back 93

A cold solution placed into the amniotic fluid

Front 94

What is dizygotic twinning?

Back 94

Fertilization of two eggs, two implantations, two placentas, two chorions, and two amnions

Front 95

What are the different formations of monozygotic twins?

Back 95

1. One fertilization: blastomeres separate, resulting in two implanations, two placentas, and two sets of membranes

2. One blastomere with two inner cell masses, one fused placenta, one chorion, two separate amnions

3. One blastomere with incomplete separation of cell mass, resulting in conjoined twins