1. Pregnancy and Human Development: Part B28
Pregnancy and Human Development: Part B

2. Gastrulation sets stage for organogenesis At eighth week
Formation of body organs and systems
At eighth week
All organ systems recognizable
End of embryonic period
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3. Embryo begins as flat plate 
Organogenesis
Embryo begins as flat plate 
Cylindrical body resembling three stacked sheets of paper folding laterally into tube, and at both ends
© 2013 Pearson Education, Inc.

4. Figure 28.10 Folding of the embryonic body, lateral views.
Tail
Head
Amnion
Yolk sac
Ectoderm
Mesoderm
Trilaminar
embryonic
disc
Endoderm
Future gut
(digestive
tube)
Lateral
fold
Somites
(seen
through
ectoderm)
Tail
fold
Head
fold
Yolk sac
Neural
tube
Notochord
Primitive
gut
Hindgut
Yolk
sac
Foregut
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5. Specialization of Endoderm
Primitive gut formed from endodermal folding
Forms epithelial lining of GI tract
Organs of GI tract become apparent, and oral and anal openings perforate
Mucosal lining of respiratory tract forms from pharyngeal endoderm (foregut)
Glands arise further along tract
© 2013 Pearson Education, Inc.

6. Figure 28.10a Folding of the embryonic body, lateral views.
Tail
Head
Amnion
Yolk sac
Ectoderm
Mesoderm
Trilaminar
embryonic
disc
Endoderm
© 2013 Pearson Education, Inc.

7. Figure 28.10b Folding of the embryonic body, lateral views.
Future gut
(digestive
tube)
Lateral
fold
© 2013 Pearson Education, Inc.

8. Figure 28.10c Folding of the embryonic body, lateral views.
Somites
(seen
through
ectoderm)
Tail
fold
Head
fold
Yolk sac
© 2013 Pearson Education, Inc.

9. Figure 28.10d Folding of the embryonic body, lateral views.
Neural
tube
Notochord
Primitive
gut
Hindgut
Foregut
Yolk
sac
© 2013 Pearson Education, Inc.

10. Figure 28.11 Endodermal differentiation.
Pharynx
Parathyroid
glands and
thymus
Thyroid
gland
Esophagus
Trachea
Connection
to yolk sac
Right and
left lungs
Stomach
Liver
Umbilical
cord
Pancreas
Gallbladder
Small intestine
Allantois
Large intestine
5-week embryo
© 2013 Pearson Education, Inc.

11. Specialization of Ectoderm
Neurulation
First major event of organogenesis
Gives rise to brain and spinal cord
Induced by chemical signals from notochord
Ectoderm over notochord thickens, forming neural plate
Neural plate folds inward as neural groove with neural folds
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12. Specialization of Ectoderm
By 22nd day, neural folds fuse into neural tube
Anterior end  brain; rest  spinal cord
Neural crest cells migrate widely  cranial, spinal, and sympathetic ganglia and nerves; adrenal medulla; pigment cells of skin; contribute to some connective tissues
Brain waves recorded by end of second month
© 2013 Pearson Education, Inc.

13. Figure 28.12a Neurulation and early mesodermal differentiation.
Head
Amnion
Amniotic cavity
Left
Right
Neural plate
Cut
edge of
amnion
Primitive
streak
Ectoderm
17 days. The flat three-layered
embryo has completed
gastrulation. Notochord and
neural plate are present.
Tail
Mesoderm
Notochord
Endoderm
Yolk sac
© 2013 Pearson Education, Inc.

14. Figure 28.12b Neurulation and early mesodermal differentiation.
Neural
groove
Somite
Neural
fold
Neural
crest
Intermediate
mesoderm
20 days. The neural folds form
by folding of the neural plate, which
then deepens, producing the
neural groove. Three mesodermal
aggregates form on each side of
the notochord (somite,
intermediate mesoderm, and
lateral plate mesoderm).
Lateral plate
mesoderm
Coelom
© 2013 Pearson Education, Inc.

15. Figure 28.12c Neurulation and early mesodermal differentiation.
Surface
ectoderm
Neural
crest
22 days. The neural folds have
closed, forming the neural tube
which has detached from the
surface ectoderm and lies
between the surface ectoderm
and the notochord. Embryonic
body is beginning to undercut.
Neural
tube
Somite
Notochord
© 2013 Pearson Education, Inc.

16. Figure 28.12d Neurulation and early mesodermal differentiation.
Neural tube
(ectoderm)
Dermatome
Myotome
Sclerotome
Epidermis
(ectoderm)
Somite
Gut lining
(endoderm)
End of week 4. Embryo
undercutting is complete. Somites
have subdivided into sclerotome,
myotome, and dermatome, which
form the vertebrae, skeletal
muscles, and dermis respectively.
Body coelom present.
Kidney and gonads
(intermediate
mesoderm)
Lateral plate
mesoderm
Limb bud
Smooth
muscle of gut
Visceral serosa
Peritoneal cavity
(coelom)
Parietal serosa
Dermis
© 2013 Pearson Education, Inc.

17. Specialization of Mesoderm
First evidence - appearance of notochord
Eventually replaced by vertebral column
Three mesoderm aggregates appear lateral to notochord
Somites, intermediate mesoderm, and double sheets of lateral plate mesoderm
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18. Specialization of Mesoderm
Somites (40 pairs) each have three functional parts
Sclerotome cells - produce vertebra and rib at each level
Dermatome cells - form dermis of skin on dorsal part of body
Myotome cells - form skeletal muscles of neck, trunk, and limbs (via limb buds)
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19. Specialization of Mesoderm
Intermediate mesoderm forms gonads and kidneys
Lateral plate mesoderm consists of somatic and splanchnic mesoderm
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20. Specialization of the Mesoderm
Somatic mesoderm forms
Dermis of skin in ventral region
Parietal serosa of ventral body cavity
Most tissues of limbs
Splanchnic mesoderm forms
Heart and blood vessels
Most connective tissues of body
~ Entire wall of digestive & respiratory organs
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21. Specialization of the Mesoderm
At end of embryonic period
Bones have begun to ossify; skeletal muscles well formed, contracting; metanephric kidneys developing; gonads formed
Lungs, digestive organs attaining final shape and body position
Blood delivery to/from placenta constant & efficient
Heart and liver bulge on ventral surface
© 2013 Pearson Education, Inc.

22. Figure 28.12a Neurulation and early mesodermal differentiation.
Head
Amnion
Amniotic cavity
Left
Right
Neural plate
Cut
edge of
amnion
Primitive
streak
Ectoderm
17 days. The flat three-layered
embryo has completed
gastrulation. Notochord and
neural plate are present.
Tail
Mesoderm
Notochord
Endoderm
Yolk sac
© 2013 Pearson Education, Inc.

23. Figure 28.12b Neurulation and early mesodermal differentiation.
Neural
groove
Somite
Neural
fold
Neural
crest
Intermediate
mesoderm
20 days. The neural folds form
by folding of the neural plate, which
then deepens, producing the
neural groove. Three mesodermal
aggregates form on each side of
the notochord (somite,
intermediate mesoderm, and
lateral plate mesoderm).
Lateral plate
mesoderm
Coelom
© 2013 Pearson Education, Inc.

24. Figure 28.12c Neurulation and early mesodermal differentiation.
Surface
ectoderm
Neural
crest
22 days. The neural folds have
closed, forming the neural tube
which has detached from the
surface ectoderm and lies
between the surface ectoderm
and the notochord. Embryonic
body is beginning to undercut.
Neural
tube
Somite
Notochord
© 2013 Pearson Education, Inc.

25. Figure 28.12d Neurulation and early mesodermal differentiation.
Neural tube
(ectoderm)
Dermatome
Myotome
Sclerotome
Epidermis
(ectoderm)
Somite
Gut lining
(endoderm)
End of week 4. Embryo
undercutting is complete. Somites
have subdivided into sclerotome,
myotome, and dermatome, which
form the vertebrae, skeletal
muscles, and dermis respectively.
Body coelom present.
Kidney and gonads
(intermediate
mesoderm)
Lateral plate
mesoderm
Limb bud
Smooth
muscle of gut
Visceral serosa
Peritoneal cavity
(coelom)
Parietal serosa
Dermis
© 2013 Pearson Education, Inc.

26. Figure 28.13 Flowchart showing major derivatives of the embryonic germ layers.
Epiblast
ECTODERM
MESODERM
ENDODERM
Notochord
Somite
Intermediate
mesoderm
Lateral plate
mesoderm
Somatic
mesoderm
Splanchnic
mesoderm
• Epidermis, hair,
nails, glands of skin
Nucleus
pulposus of
intervertebral
discs
• Sclerotome:
vertebrae and
ribs
• Kidneys
• Parietal serosa
• Wall of
digestive and
respiratory
tracts (except
epithelial
lining)
Epithelial lining
and glands of
digestive and
respiratory
tracts
• Gonads
• Dermis of ventral
body region
• Brain and spinal
cord
• Dermatome:
dermis of
dorsal body
region
• Connective
tissues of limbs
(bones, joints,
and ligaments)
• Neural crest and
derivatives (e.g.,
cranial, spinal, and
sympathetic
ganglia and
associated nerves;
chromaffin cells of
the adrenal
medulla; pigment
cells of the skin)
• Visceral serosa
• Myotome:
trunk and limb
musculature
• Heart
• Blood vessels
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27. Development of Fetal Circulation
First blood cells arise in yolk sac
By end of third week
Embryo has system of paired vessels
Two vessels forming heart have fused; bent into "S" shape
Heart beats by 3½ weeks
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28. Development of Fetal Circulation
Unique vascular modifications
Umbilical arteries and umbilical vein
Three vascular shunts
All occluded at birth
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29. Development of Fetal Circulation
Vascular shunts
Ductus venosus - bypasses liver (umbilical vein  ductus venosus  IVC)
Foramen ovale - opening in interatrial septum; bypasses pulmonary circulation
Ductus arteriosus - bypasses pulmonary circulation (pulmonary trunk  ductus arteriosus  aorta)
© 2013 Pearson Education, Inc.

30. Figure 28.14a Circulation in fetus and newborn.
Aortic arch
Superior vena cava
Ductus arteriosus
Ligamentum arteriosum
Pulmonary artery
Pulmonary veins
Heart
Lung
Foramen ovale
Fossa ovalis
Liver
Ductus venosus
Ligamentum venosum
Hepatic portal vein
Umbilical vein
Ligamentum teres
Inferior vena cava
Umbilicus
Abdominal aorta
Common iliac artery
Umbilical arteries
Medial umbilical ligaments
Urinary bladder
Umbilical cord
Placenta
High oxygenation
Moderate oxygenation
Low oxygenation
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Very low oxygenation

31. Figure 28.14b Circulation in fetus and newborn.
Aortic arch
Newborn
Superior vena cava
Ductus arteriosus
Ligamentum arteriosum
Pulmonary artery
Pulmonary veins
Heart
Lung
Foramen ovale
Fossa ovalis
Liver
Ductus venosus
Ligamentum venosum
Hepatic portal vein
Umbilical vein
Ligamentum teres
Inferior vena cava
Umbilicus
Abdominal aorta
Common iliac artery
Umbilical arteries
Medial umbilical ligaments
Urinary bladder
High oxygenation
Moderate oxygenation
Low oxygenation
Very low oxygenation
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32. Events of Fetal Development
Fetal period - weeks 9 through 38
Time of rapid growth of body structures established in embryo
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33. Figure 28.15a Photographs of a developing fetus.
Amniotic sac
Umbilical cord
Umbilical vein
Chorionic
villi
Yolk sac
Cut edge
of chorion
Embryo at week 7, about 17 mm long.
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34. Figure 28.15b Photographs of a developing fetus.
Fetus in month 3, about 6 cm long.
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35. Figure 28.15c Photographs of a developing fetus.
Fetus late in month 5, about 19 cm long.
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36. Table 28.1 Developmental Events of the Fetal Period (1 of 3)
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37. Table 28.1 Developmental Events of the Fetal Period (2 of 3)
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38. Table 28.1 Developmental Events of the Fetal Period (3 of 3)
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39. Effects of Pregnancy on the Mother: Anatomical Changes
Reproductive organs become engorged with blood
Chadwick's sign - vagina develops purplish hue
Breasts enlarge and areolae darken
Pigmentation of facial skin many increase (chloasma)
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40. Effects of Pregnancy: Anatomical Changes
Uterus expands, occupying most of abdominal cavity
Ribs flare  thorax widens
Lordosis occurs with change in center of gravity
Relaxin causes pelvic ligaments and pubic symphysis to relax to ease birth passage
Weight gain of ~13 kg (28 lb)
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41. Effects of Pregnancy: Anatomical Changes
Good nutrition vital
300 additional daily calories
Multivitamins with folic acid reduce fetal risk of neurological problems, e.g., spina bifida, anencephaly, and spontaneous preterm birth
© 2013 Pearson Education, Inc.

42. (Uterus the size of a fist and resides in the pelvis.) 4 months
Figure Relative size of the uterus before conception and during pregnancy.
Before conception
(Uterus the size of a fist and resides in the pelvis.)
4 months
(Fundus of the uterus is halfway between the pubic symphysis and
the umbilicus.)
7 months
(Fundus is well
above the
umbilicus.)
9 months
(Fundus reaches the
xiphoid process.)
© 2013 Pearson Education, Inc.

43. Effects of Pregnancy: Metabolic Changes
Placental hormones
Human placental lactogen (hPL) (human chorionic somatomammotropin (hCS))
 maturation of breasts, fetal growth, and glucose sparing in mother (reserving glucose for fetus)
Parathyroid hormone and vitamin D levels high throughout pregnancy  adequate calcium for fetal bone mineralization
© 2013 Pearson Education, Inc.

44. Effects of Pregnancy: Physiological Changes
GI tract
Morning sickness believed due to elevated levels of hCG, estrogen and progesterone
Heartburn and constipation are common
Urinary system
 Urine production due to  maternal metabolism and fetal wastes
Frequent, urgent urination; stress incontinence may occur as bladder compressed
© 2013 Pearson Education, Inc.

45. Effects of Pregnancy: Physiological Changes
Respiratory system
Estrogens may cause nasal edema and congestion
Tidal volume increases
Dyspnea (difficult breathing) may occur later in pregnancy
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46. Effects of Pregnancy: Physiological Changes
Cardiovascular system
Blood volume increases 25–40%
Safeguards against blood loss during childbirth
Cardiac output rises as much as 35-40%
Propels greater volume around body
Venous return from lower limbs may be impaired, resulting in varicose veins
© 2013 Pearson Education, Inc.

47. Homeostatic Imbalance
Preeclampsia
Insufficient placental blood supply  fetus starved of oxygen
Woman  edematous, hypertensive, proteinuria
Believed due to immunological abnormalities
Correlated with number of fetal cells that enter maternal circulation
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48. Parturition Giving birth to baby Labor
Events that expel infant from uterus
Increased production of surfactant protein A (SP-A) in weeks before delivery  inflammatory response in cervix  softening in preparation for labor
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49. Fetus determines own birth date During last few weeks of pregnancy
Initiation of Labor
Fetus determines own birth date
During last few weeks of pregnancy
Fetal secretion of cortisol stimulates placenta to secrete more estrogen
Causes production of oxytocin receptors by myometrium
Causes formation of gap junctions between uterine smooth muscle cells
Antagonizes calming effects of progesterone, leading to Braxton Hicks contractions in uterus
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50. Fetal oxytocin causes placenta to produce prostaglandins
Initiation of Labor
Surfactant protein A (SP-A) from fetal lungs causes softening of cervix
Fetal oxytocin causes placenta to produce prostaglandins
Oxytocin and prostaglandins - powerful uterine muscle stimulants
Due especially to prostaglandins, contractions  more frequent and vigorous
Anti-prostaglandins contraindicated during labor
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51. Increasing cervical distension
Initiation of Labor
Increasing cervical distension
Activates hypothalamus, causing oxytocin release from posterior pituitary
Positive feedback mechanism occurs
Greater distension of cervix  more oxytocin release  greater contractile force  greater distension of cervix  etc.
© 2013 Pearson Education, Inc.

52. Figure 28.17 Hormonal induction of labor.
Start
Estrogen
Oxytocin
(+)
from
placenta
from fetus
and mother's
posterior pituitary
Induces oxytocin
receptors on uterus
Positive feedback
Stimulates uterus
to contract
Stimulates
placenta to release
(+)
Prostaglandins
Stimulate more
vigorous contractions
of uterus
© 2013 Pearson Education, Inc.

53. Stages of Labor: Dilation Stage
From labor's onset to fully dilated cervix (10 cm)
Longest stage of labor - 6–12 hours or more
Initial weak contractions:
15–30 minutes apart, 10–30 seconds long
Become more vigorous and rapid
Cervix effaces and dilates fully to 10 cm
Amnion ruptures, releasing amniotic fluid
Engagement occurs - head enters true pelvis
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54. Umbilical cord Placenta Uterus Cervix Vagina Sacrum Perineum Uterus
Figure Parturition.
Umbilical cord
Slide 1 1a
Placenta
Early dilation. Baby’s head engaged; widest dimension Is along left-right axis.
Uterus
Cervix
Vagina 1b
Late dilation.
Baby’s head rotates so
widest dimension is in anteroposterior axis
(of pelvic outlet). Dilation nearly complete
Pubic
symphysis
Sacrum 2
Expulsion.
Baby’s head extends
as it is delivered
Perineum 3
Placental stage. After baby is delivered, the placenta detaches and is removed.
Uterus
Placenta (detaching)
Umbilical cord
© 2013 Pearson Education, Inc.

55. Umbilical cord Placenta Uterus Cervix Vagina
Figure Parturition.
Umbilical cord
Slide 2 1a
Placenta
Early dilation. Baby’s head engaged; widest dimension Is along left-right axis.
Uterus
Cervix
Vagina
© 2013 Pearson Education, Inc.

56. Umbilical cord Placenta Uterus Cervix Vagina Sacrum
Figure Parturition.
Umbilical cord
Slide 3 1a
Placenta
Early dilation. Baby’s head engaged; widest dimension Is along left-right axis.
Uterus
Cervix
Vagina 1b
Late dilation.
Baby’s head rotates so
widest dimension is in anteroposterior axis
(of pelvic outlet). Dilation nearly complete
Pubic
symphysis
Sacrum
© 2013 Pearson Education, Inc.

57. Stages of Labor: Expulsion Stage
From full dilation to delivery of infant
Strong contractions every 2–3 minutes, about 1 minute long
Urge to push increases (in absence of local anesthesia)
Crowning occurs when largest dimension of head distends vulva
Episiotomy may be done to reduce tearing
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58. Umbilical cord Placenta Uterus Cervix Vagina Sacrum Perineum
Figure Parturition.
Umbilical cord
Slide 4 1a
Placenta
Early dilation. Baby’s head engaged; widest dimension Is along left-right axis.
Uterus
Cervix
Vagina 1b
Late dilation.
Baby’s head rotates so
widest dimension is in anteroposterior axis
(of pelvic outlet). Dilation nearly complete
Pubic
symphysis
Sacrum 2
Expulsion.
Baby’s head extends
as it is delivered
Perineum
© 2013 Pearson Education, Inc.

59. Stages of Labor: Expulsion Stage
Vertex position – head-first
Skull dilates cervix; early suctioning allows breathing prior to complete delivery
Breech position – buttock-first
Delivery more difficult; often forceps required, or C-section (delivery through abdominal and uterine wall incision)
© 2013 Pearson Education, Inc.

60. Umbilical cord Placenta Uterus Cervix Vagina Sacrum Perineum Uterus
Figure Parturition.
Umbilical cord
Slide 5 1a
Placenta
Early dilation. Baby’s head engaged; widest dimension Is along left-right axis.
Uterus
Cervix
Vagina 1b
Late dilation.
Baby’s head rotates so
widest dimension is in anteroposterior axis
(of pelvic outlet). Dilation nearly complete
Pubic
symphysis
Sacrum 2
Expulsion.
Baby’s head extends
as it is delivered
Perineum 3
Placental stage. After baby is delivered, the placenta detaches and is removed.
Uterus
Placenta (detaching)
Umbilical cord
© 2013 Pearson Education, Inc.

61. Stages of Labor: Placental Stage
Strong contractions continue, causing detachment of placenta and compression of uterine blood vessels
Limit bleeding; cause placental detachment
Delivery of afterbirth (placenta and membranes) occurs ~30 minutes after birth
All placenta fragments must be removed to prevent postpartum bleeding
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62. Adjustments of the Infant to Extrauterine Life
Neonatal period - four-week period immediately after birth
Physical status assessed 1–5 minutes after birth
Apgar score - 0–2 points each for
Heart rate • Muscle tone
Respiration • Reflexes
Color
Score of 8–10 - healthy
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63. Respiratory rate ~45 per minute first two weeks, then declines
First Breath
 CO2  central acidosis  stimulates respiratory control centers to trigger first inspiration
Requires tremendous effort – airways tiny; lungs collapsed
Surfactant in alveolar fluid helps reduce surface tension
Respiratory rate ~45 per minute first two weeks, then declines
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64. First Breath
Keeping lungs inflated difficult for premature infant (< 2500 g, or 5.5 pounds, at birth)
Surfactant production in last months of prenatal life
Preemies usually on respiratory assistance until lungs mature
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65. Unstable period lasting 6–8 hours after birth
Transitional Period
Unstable period lasting 6–8 hours after birth
Alternating periods of activity and sleep
Vital signs may be irregular during activity
Baby gags frequently as regurgitates mucus and debris
Stabilizes with waking periods occurring every 3–4 hours
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66. Occlusion of Fetal Blood Vessels
Umbilical arteries and vein constrict and become fibrosed
Proximal umbilical arteries  superior vesical arteries to urinary bladder
Distal umbilical arteries  medial umbilical ligaments
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67. Occlusion of Fetal Blood Vessels
Umbilical vein becomes round ligament of liver (ligamentum teres)
Ductus venosus  ligamentum venosum about 30 minutes after birth
Pressure changes from infant breathing cause pulmonary shunts to close
Foramen ovale  fossa ovalis up to a year after birth
Ductus arteriosus  ligamentum arteriosum about 30 minutes after birth
© 2013 Pearson Education, Inc.

68. Production of milk by mammary glands Toward end of pregnancy
Lactation
Production of milk by mammary glands
Toward end of pregnancy
Placental estrogens, progesterone, and human placental lactogen stimulate hypothalamus to release prolactin-releasing factors (PRFs) 
Anterior pituitary releases prolactin
2-3 days later true milk production begins
© 2013 Pearson Education, Inc.

69. Lactation
Colostrum
Less lactose but more protein, vitamin A, minerals than true milk; almost no fat
Yellowish secretion rich in IgA antibodies
IgA resistant to digestion; may protect infant against bacterial infection; absorbed into bloodstream for immunity
Released first 2–3 days
Followed by true milk production
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70. Prolactin release wanes after birth
Lactation
Prolactin release wanes after birth
Lactation sustained by mechanical stimulation of nipples - suckling
Suckling causes afferent impulses to hypothalamus  prolactin  stimulates milk production for next feeding
Hypothalamus also  oxytocin from posterior pituitary  let-down reflex
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71. Hypothalamus releases prolactin releasing factors (PRF)
Figure Milk production and the positive feedback mechanism of the milk let-down reflex.
Hypothalamus releases prolactin
releasing factors (PRF)
to portal circulation.
Start
Stimulation of
mechanoreceptors in
nipples by suckling
infant sends afferent
impulses to the
hypothalamus.
Hypothalamus
sends efferent
impulses to the
posterior
pituitary where
oxytocin is stored.
Anterior pituitary
secretes prolactin
to blood.
Oxytocin is
released from the
posterior pituitary
and stimulates
myoepithelial cells
of breasts to contract.
Prolactin targets
mammary glands
of breasts.
Positive feedback
Milk production
Let-down reflex.
Milk is ejected
through ducts
of nipples.
© 2013 Pearson Education, Inc.

72. Advantages of Breast Milk
Fats and iron better absorbed; amino acids more easily metabolized, compared with cow's milk
Beneficial chemicals
IgA, complement, lysozyme, interferon, and lactoperoxidase (protect from infections)
Interleukins and prostaglandins prevent overzealous inflammatory responses
Glycoprotein deters ulcer-causing bacterium from attaching to stomach mucosa
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73. Advantages of Breast Milk
Natural laxative effect helps eliminate bile-rich meconium, helping to prevent physiological jaundice
Encourages bacterial colonization of large intestine
Women nursing 6 months lose bone calcium; replaced after weaning if healthy diet
Women may ovulate when nursing despite inhibition of GnRH and gonadotropins
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74. Assisted Reproductive Technology
Surgical removal of oocytes following hormone stimulation
Fertilization of oocytes
Return of fertilized oocytes to woman's body
Disadvantages
Costly, emotionally draining, painful for oocyte donor
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75. Assisted Reproductive Technology
In vitro fertilization (IVF)
Oocytes and sperm incubated in culture dishes for several days
Embryos (two-cell to blastocyst stage) transferred to uterus for possible implantation
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76. Assisted Reproductive Technology
Zygote intrafallopian transfer (ZIFT)
Fertilized oocytes transferred to uterine tubes
Gamete intrafallopian transfer (GIFT)
Sperm and harvested oocytes are transferred together into the uterine tubes
Cloning
Legal, moral, ethical, political roadblocks
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