biol30001 reproductive physiology placentation geoff shaw reading: essrep7 ch 13 (+ ch 14,15)...
TRANSCRIPT
![Page 1: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/1.jpg)
BIOL30001 Reproductive Physiology
PlacentationGeoff Shaw
Reading:EssRep7 Ch 13 (+ Ch 14,15)Johnson & Everitt 6 Chapter 10, 11, 12Stevens DH (1975) “Comparative Placentation”Renfree MB (1982) Implantation and placentation.
In Austin & Short: Reproduction in mammals, Book 2.
Mossmann HW (1987) “Vertebrate fetal membranes”
This illustration was made by Luc Viatour http://commons.wikimedia.org/wiki/File:Da_Vinci_Studies_of_Embryos_Luc_Viatour.jpg
![Page 2: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/2.jpg)
Viviparity - birth of live-young• advantages - fetal development & survival
• requires specialised maternal-fetal interface - placenta
– fetal and maternal components
– exchange of gases, nutrients & wastes
– hormones
– limits fetal invasion
– immunological interface
euth
erian
s
mar
supia
ls
mon
otre
mes
rept
iles
amph
ibian
s
fish
multiple evolution
inver
teb.
![Page 3: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/3.jpg)
Role of placenta• Nutritive exchange
– histotrophic vs haemotrophic– gas: O2 and CO2
– sugars, amino acids, lipids etc– waste products, eg. urea
• Hormones– maternal recognition of pregnancy– uterine contractility and secretion– modulation of maternal and fetal physiology
• Immunological interface– fetus has “foreign” paternal genes MHC etc so
fetus is an allograft. Why isn’t it rejected by an immune response?
![Page 4: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/4.jpg)
fetal membranes and placentation - complex endpoint …
… but really arises from a series of simple steps, like origami
![Page 5: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/5.jpg)
Formation of extra-embryonic membranes (mouse/human)
trophectoderm
trophectoderm chorionic ectoderm
extraembryonic ectoderm
extraembryonic mesoderminner cell mass extraembryonic endoderm (pluriblast) embryonicectoderm
mesoderm
endoderm
chorion and placenta
amnion
yolk sac and allantois
embryo and fetus
also see EssRep7 13.1
mesoderm
epiblast
hypoblast
![Page 6: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/6.jpg)
Formation of extra-embryonic membranes
EssRep7 13.1
extra-embryonic coelom
pro-amniotic cavity
pro-embryonic disc
yolk sac cavity
![Page 7: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/7.jpg)
Formation of extra-embryonic membranes
extra-embryoniccoelom
embryonic disc(embryonic ecto-, meso- and endo-derm
amniotic cavity
amnion
chorion
developing chorio-vitelline placenta
yolk sac
EssRep7 13.1
![Page 8: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/8.jpg)
Formation of extra-embryonic membranes
J&E – 10.8
chorio-allantois
allantoisallantoic mesoderm
chorion
regressing yolk sac
primitive umbilical cordextra-embryoniccoelom
amnioticcavity
embryo
EssRep7 13.1
![Page 9: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/9.jpg)
Classification of placentation
• Tissues– chorio-vitelline– chorio-allantoic
• macroscopic structure• microscopic relationship between fetal and
maternal tissues - invasiveness– non-invasive eg pig, horse, sheep, cow– invasive - eccentric eg. dog, rat, rabbit– invasive - interstitial eg. human
![Page 10: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/10.jpg)
Major placenta types
discoid,eg. human, mouse
zonary,eg dog
cotyledonary,eg sheep, cow
diffuseeg. pig, horse, camel
see J&E6 - 10.5
![Page 11: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/11.jpg)
Grosser’s classification: placental typesFetal
Maternal
epithelio-chorial
synepithelio-chorial
endothelio-chorial
haemo-chorial
humandoghorse sheep
see J&E6 – 10.6
![Page 12: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/12.jpg)
Placental blood flow -- human
EssRep7 13.4
haemochorial
![Page 13: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/13.jpg)
EssRep7 13.3
basal decidua
![Page 14: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/14.jpg)
Cast of fetal placental capillary bed
see EssRep7 13.5
![Page 15: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/15.jpg)
Placenta of sheep
EssRep7 13.3
synepithelio-chorial
![Page 16: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/16.jpg)
EssRep7 13.3
fetal chorionic epithelium
binucleate cellmicrovillus junctional zonematernal syncytium
maternal capillary
![Page 17: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/17.jpg)
Placental Hormones• hCG
– LH activity - maintains CL– immune suppression
• hPL (hCS) – prolactin / growth hormone activity– increased breakdown of adipose tissues
• Progesterone & oestrogen- – modulates endometrium: MRP; implantation;
secretory activity; immunological modulation; etc.– suppresses gonadotrophins– myometrium; mammary development– maternal amino acid metabolism
see also EssRep7 13.7
![Page 18: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/18.jpg)
placental oestrogens
oestrone
oestradiol
oestriol
testosterone
![Page 19: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/19.jpg)
placental steroidogenesis – e2
Johnson & Everitt 6, Fig 11.3
steroidogenesis in pregnancy is a combination of maternal, placental and fetal activity
![Page 20: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/20.jpg)
see Johnson & Everitt Table 12.1
pH 7.4
pH 7.3 pH 7.2
pH 7.4
consumes 30% of O2 supplied
![Page 21: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/21.jpg)
Placenta• Placental transfer
– main energy from glucose and lactate in humans– active transfer of specific materials - amino acids, lipids,
vitamins etc.
• placental metabolism– uses 30% of glucose and oxygen supplied by mother– highly active in protein synthesis– conjugation and inactivation of maternal hormones
![Page 22: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/22.jpg)
EssRep7 14.5
Ut Art
Ut Vein
Umb Vein
Umb Art
pH 7.43
pH 7.2 pH 7.26
pH 7.35
• Fetal haemoglobin• Bohr effect – pH
change as CO2 ex-changed increases O2 transfer
note: placenta highly metabolically active – uses 30% of O2 supplied
![Page 23: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/23.jpg)
BODY
FO
LUNG
PLACENTA
DA
Lung is fluid filled and has low O2. It has constricted arterioles restricting blood flow
Most blood shunts through foramen ovale and ductus arteriosus.
oxygenated blood draining from placenta mixes with depleted blood from body
Circulation before birth
![Page 24: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/24.jpg)
BODY
FO closes
LUNG
DA closes
Oxygen opens capillaries in lung increasing blood flow
increased oxygenation of blood in ductus arteriosus causes contraction and closure
increased flow into Left Atrium closes flap over Foramen ovale
Circulation after birth
![Page 25: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/25.jpg)
Johnson & Everitt Fig 12.5
indicator of lung surfactant production
![Page 26: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/26.jpg)
Actions of fetal adrenal glucocorticoids
lung surfactant; water resorptioncentral respiratory mechanisms
metabolism glucose storage and gluconeogenesis
endocrine induced insulin secretioninduced adrenaline secretionconversion of T3 to T4placental steroidogenesis
blood switch from fetal to adult haemoglobinswitch haematopoiesis to bone marrow
salt balance stimulation of GFR and Na+ resorption?activation of ANF
lactogenesis ductal-lobule-alveolar growth in pregnancy
![Page 27: BIOL30001 Reproductive Physiology Placentation Geoff Shaw Reading: EssRep7 Ch 13 (+ Ch 14,15) Johnson & Everitt 6 Chapter 10, 11, 12 Stevens DH (1975)](https://reader036.vdocuments.site/reader036/viewer/2022070400/56649f155503460f94c2a1a8/html5/thumbnails/27.jpg)
Summary – Placenta structure and function
• nutrition, gas exchange, hormones, immune control• folding and budding yolk sac (choriovitelline)
allantois (chorioallantoic)• morphology: discoid, zonary, cotyledonary, diffuse• Grosser’s classification by degree of invasion:
epitheliochorial haemochorial• sophisticated countercurrent blood flow mechanisms• hormones – gonadotrophins, lactogens,
progesterone, oestrogens• fetal gas exchange – fetal haemoglobin• shift of circulation at birth from placental to lung gas
exchange• role of glucocorticoids in fetal ot neonatal transition