VETS2008 Lecture 17 - Placenta (Specific) PDF

VETS2008 – Placenta (specific) Dr Kate Dutton-Regester BASc, MPhil, PhD [email protected] Learning outcomes for this lecture 1. Describe the classifications of placentae based on distribution of attachment sites, and identify classification of each species 2. Describe the microscopic...

VETS2008 – Placenta (specific) Dr Kate Dutton-Regester BASc, MPhil, PhD [email protected] Learning outcomes for this lecture 1. Describe the classifications of placentae based on distribution of attachment sites, and identify classification of each species 2. Describe the microscopic structure of the maternal-fetal interface, specifically describing the separation of maternal and fetal circulation, and compare differences between species 3. Describe the histological appearance of the placenta and indicators of pathology 2 Active learning links UQ Active eLearning Wordcloud apps.elearning.uq.edu.au/wordcloud/71644 MCQs apps.elearning.uq.edu.au/poll/71644 Active learn ID = 71644 Padlet padletuq.padlet.org/tpini/ao61tbyw6sqqmb01 3 The repro life cycle – where are we today? MALE FEMALE Copulation Estrus Puberty Puberty Fertilisation/preg Male repro tract establishment Female repro tract Embryo/fetal Hormone development Hormone signalling signalling Parturition & Spermato- lactation genesis Oogenesis Post birth 4 Placental types by chorionic villi distribution Placentae (plural) can be classified by the distribution of villi on the surface of the chorion DIFFUSE Even distribution of villi across the entire chorionic surface COTYLEDONARY Discrete round patches of villi form cotyledons on the chorion Connect to endometrial caruncles ZONARY Prominent round transfer zone of villi as a central band Edges of band form pigmented zone, containing haemorrhage and necrotic tissue DISCOID Discrete disc of villi on one side 5 Pick the placenta type 7 Placental types by fetal/maternal separation Placentae can also be classified by their invasiveness (i.e. how many tissue layers there are between fetal and maternal circulation) 6 layers: 5 layers: 1. Maternal capillary 1. Maternal capillary 3 layers: 2. Endometrial CT 2. Endometrial CT 1. Chorionic epithelium 3. Endometrial epithelium 3. Chorionic epithelium 2. Chorionic CT 4. Chorionic epithelium 4. Chorionic CT 3. Fetal capillary 5. Chorionic CT 5. Fetal capillary 6. Fetal capillary No endometrial epithelium, CT or No endometrial epithelium maternal capillary 8 Separation of circulation In all placentae, fetal and maternal blood NEVER directly mix! If fetal blood gets into maternal circulation (e.g. placental haemorrhage), it is treated as a foreign antigen – can lead to sensitisation and downstream issues for offspring (e.g. neonatal isoerythrolysis) 9  A definitive Placentation – Cattle (cow) sign of pregnancy in Placenta classification rectal Cotyledonary palpation! Epitheliochorial Unique features: o Convex caruncles 70-120 cotyledons, significantly increase in size through gestation Placentome = fetal cotyledon + maternal caruncle 10 The bovine placenta 11 Placentation – Sheep (ewe) 90-100 cotyledons, significantly increase in size through gestation Placenta classification Cotyledonary Epitheliochorial Unique features: o Concave caruncles 12  Placentation – Horse (mare) Placenta classification Diffuse Epitheliochorial Unique features: o ‘F’ shaped placenta o Microcotyledons (microscopic), evenly distributed over surface o Endometrial cups o Placental cells which invade into endometrium o 5-10 transient structures (~d40-150) that secrete eCG o Cervical star o Large, white avillous region overlying cervix (no endometrial attachment) 13 Placentation – Horse (mare) 14  Placentation – Pig (sow) Placenta classification Diffuse Epitheliochorial Unique features: o Simple chorionic villi o Smooth surface 15  Placentation – Dog (bitch) Placenta classification Zonary Endotheliochorial Unique features: o Highly invasive villi in transfer zone o Marginal band of haematoma o Remainder of chorioallantois relatively avascular 16  Placentation – Cat (Queen) Placenta classification Zonary Endotheliochorial Unique features: o Highly invasive villi in transfer zone o Relatively small marginal band of haematoma o Remainder of chorioallantois relatively avascular 17 Test your knowledge Placentas can be classified as epitheliochorial, endotheliochorial or haemochorial A. Felines, canines and ruminants Which species have an B. Ruminants and primates epitheliochorial placenta? C. Equids, suids and ruminants D. Primates, suids and rodents Use UQ poll to answer: apps.elearning.uq.edu.au/poll/71644 E. Equids, ruminants and primates 18 Histology of the placenta Ruminants have both regular mononucleated and binucleated trophoblasts o Invade endometrium o Produce placental lactogen and PAGs Chorionic trophoblast cells are typically cuboidal~columnar 19 Histopathology of the placenta Necrosis (debris) and fungal hyphae Congestion in the chorioallantois 20 Histopathology of the placenta Fibrinous exudate Neutrophilic infiltrate Gram +ve bacteria 21 What do you notice? What do you wonder? 22 Take home points Placenta types by villi distribution: o Cotyledonary = cow, ewe o Diffuse = mare, sow o Zonary = bitch, queen o Discoid = human, primate, rodent Placenta types by circ separation: o Epitheliochorial = 6 layers, cow, ewe, mare, sow o Endotheliochorial = 5 layers, bitch, queen o Hemochorial = 3 layers, human, primate, rodent Unique placental features by sp o Ruminants = placentomes, cow = convex, ewe = concave o Mare = endometrial cups, cervical star o Bitch = prominent marginal band of hematoma Histology Cuboidal/columnar trophoblast cells Ruminants have binucleated trophoblast cells 23 Thanks! Questions? [email protected] 24