Transcript
Page 1: John J. Parrish - University of Wisconsin · 1 Lecture 20 Pregnancy and Fetal Development John J. Parrish Placental Functions Placenta Chemical Protection Physical Protection Exchange

1

Lecture 20Pregnancy and Fetal Development

John J. Parrish

Placental Functions

Placenta

Chemical Protection Physical Protection

EndocrineExchange

Placental Functions

Placenta

Chemical Protection Physical Protection

EndocrineExchange•Gas

•Nutrients•Waste products

•Immunosupression

•Prevents infiltration bymaternal defenses•Filters toxins

•Shock Absorber

•Transient•Estrogen•Progesterone•HCG•eCG•PL

Similarities in Early Development

MAN PIG BIRD

Developmental Horizons Mare Cow Ewe Sow Woman

Germ layers 13-14 14 10-14 7-8 10-14Open neural tube 20 15-21 13Fusion of chorioamniontic folds 18 17 16Heart beat apparent 24 21-22 20 16 25Limb buds visible 24 25 28-35 17-18 28Cotelydons first appear 30Eye differentiation 40 30-45 42-49 21-28Birth 340 280 147-155 112 266

Developmental Features

Critical Organ Systems Develop Early!Critical Organ Systems Develop Early!

Fetal Development in the Human

0 4 8 12 16 20 24 28 32 36 40

OvulationOvulation

Leng

th (c

m)

Leng

th (c

m)

0

10

20

30

40

50

Age of Fetus (weeks since last menstruation)

1

2

3

0

Wei

ght (

kg)

Wei

ght (

kg)

Partu

ritio

nPa

rturit

ion

Page 2: John J. Parrish - University of Wisconsin · 1 Lecture 20 Pregnancy and Fetal Development John J. Parrish Placental Functions Placenta Chemical Protection Physical Protection Exchange

2

Crown

Rump

Estimates of Age• Crown rump length• Length femur, radius or tibia

• Circumference of head

Factors Influencing Fetal Growth

Genetics

Species

Breed

Litter size

Genotype

Fetal Hormones

Thyroid

Insulin

Growth hormone

Environment

Mother Nutrition Size, Parity

Placenta Blood flow Size

Factors Influencing Fetal Growth

Genetics

Species

Breed

Litter size

Genotype

Factors Influencing Fetal Growth

Genetics

Species

Breed

Litter size

Genotype

Genetics

Species

Breed

Litter size

Genotype

Factors Influencing Fetal Growth

Genetics

Species

Breed

Litter size

Genotype

Factors Influencing Fetal Growth

Certains lines of animals maygrow faster.

Page 3: John J. Parrish - University of Wisconsin · 1 Lecture 20 Pregnancy and Fetal Development John J. Parrish Placental Functions Placenta Chemical Protection Physical Protection Exchange

3

Factors Influencing Fetal Growth

Environment

Mother Nutrition Size, Parity

Placenta Blood flow Size

Factors Influencing Fetal Growth

Environment

Mother Nutrition Size, Parity

Placenta Blood flow Size

Factors Influencing Fetal Growth

Fetal Hormones

Thyroid

Insulin

Growth hormone

Skeletal and muscular developmentSkeletal and muscular development

Increased energy substrate availabilityand stimulates placental growthIncreased energy substrate availabilityand stimulates placental growth

Stimulates fetal growthStimulates fetal growth

Uterine Size Changes During Pregnancy

Hyperplasia» Increase in # of cells

Hypertrophy» Increase in size of cells

Stretching

Placenta

Liver

Left Atrium Lungs Right Atrium

ForamenOvale

ForamenOvale

DuctusVenosusDuctus

Venosus

DuctusArteriosus

DuctusArteriosusAorta

Umbilical Arteries

Umbilical Vein

Portal VeinPortal Vein

Vena CavaVena Cava

Headand Heart Tissues

Rela

tive

P 4 a

nd E

2

Weeks of GestationOvulation

Page 4: John J. Parrish - University of Wisconsin · 1 Lecture 20 Pregnancy and Fetal Development John J. Parrish Placental Functions Placenta Chemical Protection Physical Protection Exchange

4

Rela

tive

P 4 a

nd E

2

Rela

tive

P 4 a

nd E

2

Weeks of GestationOvulation

Rela

tive

P 4 a

nd E

2

Weeks of GestationOvulation

Page 5: John J. Parrish - University of Wisconsin · 1 Lecture 20 Pregnancy and Fetal Development John J. Parrish Placental Functions Placenta Chemical Protection Physical Protection Exchange

5

ProgesteroneMaintains

Pregnancy!

ProgesteroneMaintains

Pregnancy!

Progesterone is Essential To Maintain Pregnancy

Corpus Luteum Placenta

Sow 3.8 mo 3.8 mo(none)Cow 9 mo 6 - 8 moEwe 5 mo 50 dMare 11 mo 70 dHuman 9 mo 60-70 d

Species Gestation PlacentalLength Takeover

Other Species in Which Placenta Doesnot Take-over Progesterone

Production

Bitch Queen Alpaca, Llama, Camel Rabbit Goat


Top Related