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Objectives Students should be able to: Draw and label the placenta of the pig at early, middle and late term. Identify the placentomes of the cow and the sheep. Recognise the haemophagous regions of the placenta of the cat or the dog. Identify the endometrial cups of the mare placenta. Distinguish the simple folded placenta of the pig, from the microcotyledonary placentae of the mare, the cotyledonary placenta of the ruminant and the labyrinthine placentae of the dog and cat.

This slide has three sections of pig placenta. SLIDE 185 Pig placenta This slide has three sections of pig placenta. 2.5 mm

This slide has three sections of pig placenta. SLIDE 185 Pig placenta This slide has three sections of pig placenta. Early stage : 22 days gestation. Mid stage : 50 days gestation. Late stage : Near term. This slide has three sections of pig placenta. Duration of pregnancy approx 115 days 2.5 mm

How is the pig placenta classified? SLIDE 185 Pig placenta How is the pig placenta classified?

SLIDE 185 Pig placenta How is the pig placenta classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. DIFFUSE, FOLDED with VILLI. Explain the term in relation to what you see.

SLIDE 185 Pig placenta How is the pig placenta classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. DIFFUSE, FOLDED with VILLI. Explain the term in relation to what you see. There is contact between the maternal epithelium and fetal chorion; but these membranes are not fused. Most of the CAM (chorioallantoic membrane) contributes. Six layers can be identified between maternal and fetal circulation. Maternal endothelium lining blood vessels. Maternal stroma. Maternal epithelium. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels.

SLIDE 185 Pig placenta 1 : early stage Observe the layers and their relationships. Identify: Maternal tissue i). Endometrium. ii). Myometrium. Fetal tissue Chorio-allantoic membrane (CAM). Placental folds 0.5 mm

SLIDE 185 Pig placenta 1 : early stage Observe the layers and their relationships. Identify: Maternal tissue i). Endometrium. ii). Myometrium. Fetal tissue Chorio-allantoic membrane (CAM). Placental folds : F fetal tissue F F endometrium myometrium 0.5 mm

SLIDE 185 Pig placenta 1 : early stage Observe the layers and their relationships. Identify: 1. Endometrium. 2. Maternal blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 200 µm

SLIDE 185 Pig placenta 1 : early stage Observe the layers and their relationships. Identify: 1. Endometrium. 2. Maternal blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 7 5 6 6 4 2 3 1 2 2 200 µm

SLIDE 185 Pig placenta 1 : early stage At higher magnification again identify : 1. Endometrium. 2. Maternal (endometrial) blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 100 µm

SLIDE 185 Pig placenta 1 : early stage At higher magnification again identify : 1. Endometrium. 2. Maternal (endometrial) blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 7 6 6 6 6 5 4 4 2 4 4 1 2 The space seen between the uterine epithelium and the chorion is an artefact produced during processing. 3 100 µm

SLIDE 185 Pig placenta 1 : early stage At high magnification 50 µm

SLIDE 185 Pig placenta 1 : early stage At high magnification allantoic cavity S : space artefact V : villus allantois fetal blood vessel S chorion V uterine epithelium maternal blood vessel maternal crypt Note that red blood cells in the fetal tissue at this very early stage are nucleated. 50 µm

SLIDE 185 Pig placenta 2 : mid stage Observe the layers and their relationships. Identify: Maternal tissue i). Endometrium. ii). Myometrium. Fetal tissue Chorio-allantoic membrane CAM. Placental folds 1.0 mm

SLIDE 185 Pig placenta 2 : mid stage Observe the layers and their relationships. Identify: Maternal tissue i). Endometrium. ii). Myometrium. Fetal tissue Chorio-allantoic membrane CAM. Placental folds : F allantois chorion F F fetal tissue endometrium myometrium 1.0 mm

SLIDE 185 Pig placenta 2 : mid stage Observe the layers and their relationships. Identify: 1. Endometrium. 2. Maternal blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 250 µm

SLIDE 185 Pig placenta 2 : mid stage Observe the layers and their relationships. Identify: 1. Endometrium. 2. Maternal blood vessels. 3. Endometrial glands. 4. Uterine epithelium. 5. Chorion. 6. Fetal blood vessels. 7. Allantois. 7 5 2 6 1 4 2 6 3 250 µm 3

SLIDE 185 Pig placenta 2 : mid stage At higher magnification again identify : 1. Endometrium. 2. Maternal blood vessels. 3. Uterine epithelium. 4. Chorion. 5. Fetal blood vessels. 6. Fetal stroma. 100 µm

SLIDE 185 Pig placenta 2 : mid stage At higher magnification again identify : 1. Endometrium. 2. Maternal blood vessels. 3. Uterine epithelium. 4. Chorion. 5. Fetal blood vessels. 6. Fetal stroma. 2 1 6 3 4 5 100 µm

SLIDE 185 Pig placenta 2 : mid stage At high magnification. 50 µm

SLIDE 185 Pig placenta 2 : mid stage At high magnification. chorion space artefact fetal blood vessels maternal blood vessels villus uterine epithelium maternal crypt 50 µm

SLIDE 185 Pig placenta 3 : late stage In this section of the near term placenta. Note how the development in size of the fetus has stretched the uterine wall, making this the thinnest of the three sections. The proportion of fetal tissue (CAM) has increased with much enlarged folds in the placental barrier. 0.5 mm

SLIDE 185 Pig placenta 3 : late stage In this section of the near term placenta. Note how the development in size of the fetus has stretched the uterine wall, making this the thinnest of the three sections. The proportion of fetal tissue (CAM) has increased with much enlarged folds in the placental barrier. endometrium folds fetal tissue allantoic cavity myometrium 0.5 mm

SLIDE 185 Pig placenta 3 : late stage Observe the layers and their relationships. Identify: 1. Myometrium. 2. Endometrium. 3. Maternal blood vessels. 4. Endometrial glands. 5. Uterine epithelium. 6. Chorion. 7. Fetal blood vessels. 8. Allantois. 250 µm

SLIDE 185 Pig placenta 3 : late stage Observe the layers and their relationships. Identify: 1. Myometrium. 2. Endometrium. 3. Maternal blood vessels. 4. Endometrial glands. 5. Uterine epithelium. 6. Chorion. 7. Fetal blood vessels. 8. Allantois. 8 7 7 6 5 3 2 4 4 1 250 µm

SLIDE 185 Pig placenta 3 : late stage At higher magnification again identify: 1. Maternal blood vessels (capillaries). 2. Uterine epithelium. 3. Chorion. 4. Fetal blood vessels. 5. Allantois. 100 µm

SLIDE 185 Pig placenta 3 : late stage At higher magnification again identify: 1. Maternal blood vessels (capillaries). 2. Uterine epithelium. 3. Chorion. 4. Fetal blood vessels. 5. Allantois. 5 4 3 2 1 1 100 µm

SLIDE 185 Pig placenta 3 : late stage At high magnification : 50 µm

SLIDE 185 Pig placenta 3 : late stage At high magnification : allantois chorion fetal blood vessels villus maternal capillaries maternal crypt uterine epithelium 50 µm

SLIDE 185 Pig placenta areolar region What is the function of the areolar region? 0.5 mm 250 µm

SLIDE 185 Pig placenta areolar region What is the function of the areolar region? What is the function of the areolar region? Areolae develop after about 4 weeks gestation. Uterine glands produce uterine milk. This contains iron rich uteroferrin for the fetus. Chorionic villi extend into these areola regions. chorion areolar folds 0.5 mm uterine milk uterine epithelium endometrial glands myometrium 250 µm

SLIDE 186 Mare placenta Whole section of mare placenta at low magnification. Identify : Maternal i). Endometrium ii). Myometrium Microcotyledons Fetal Chorio-allantoic membrane 1.0 mm

SLIDE 186 Mare placenta Whole section of mare placenta at low magnification. Identify : Maternal i). Endometrium ii). Myometrium Microcotyledons Fetal Chorio-allantoic membrane chorio-allantoic membrane (fetus) microcotyledons allantoic cavity E myometrium E : endometrium 1.0 mm

How is the mare placenta classified? SLIDE 186 Mare placenta How is the mare placenta classified?

SLIDE 186 Mare placenta How is the mare placenta classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. DIFFUSE, VILLOUS with MICROPLACENTOMES (MICROCOTYLEDONS). ENDOMETRIAL CUPS formed by CHORIONIC CELLS. Layers present: Six layers can be identified between the maternal and the fetal circulation.

SLIDE 186 Mare placenta How is the mare placenta classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. DIFFUSE, VILLOUS with MICROPLACENTOMES (MICROCOTYLEDONS). ENDOMETRIAL CUPS formed by CHORIONIC CELLS. Layers present: Six layers can be identified between the maternal and the fetal circulation. Maternal endothelium lining blood vessels. Maternal stroma. Maternal (uterine) epithelium. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels. Duration of pregnancy approx 335 days

Identify a microcotyledon. SLIDE 186 Mare placenta Identify a microcotyledon. 1.0 mm

Identify a microcotyledon. SLIDE 186 Mare placenta Identify a microcotyledon. microcotyledons fetal tissue allantois E : endometrium with uterine glands E myometrium 1.0 mm

SLIDE 186 Mare placenta Follow the connective tissue from both maternal and fetal sides into the cotyledon. 250 µm

SLIDE 186 Mare placenta Follow the connective tissue from both maternal and fetal sides into the cotyledon. allantois fetal blood vessels fetal connective tissue E : endometrium chorion areolar space primary villus secondary villi uterine glands E 250 µm

SLIDE 186 Mare placenta Compare the complexity of the folding of the horse placenta with that of the pig. Histologically, what type of placenta is it? 100 µm

SLIDE 186 Mare placenta Compare the complexity of the folding of the horse placenta with that of the pig. Histologically, what type of placenta is it? Epitheliochorial, non deciduate, diffuse, villous with microcotyledons (microplacentomes). Compare the complexity of the folding of the horse placenta with that of the pig. Histologically, what type of placenta is it? U : uterine gland fetal villi maternal crypts U 100 µm

SLIDE 186 Mare placenta Identify cell layers. Is there any way to determine which are maternal and which are fetal cells? 50 µm

SLIDE 186 Mare placenta Identify cell layers. Is there any way to determine which are maternal and which are fetal cells? The chorionic villi are surrounded by the maternal crypts. Identify cell layers. Is there any way to determine which are maternal and which are fetal cells? maternal blood vessels M : maternal connective tissue fetal connective tissue M fetal blood vessel chorion maternal, uterine epithelium 50 µm

Area at high magnification. SLIDE 186 Mare placenta Area at high magnification. 25 µm

Area at high magnification. SLIDE 186 Mare placenta Area at high magnification. maternal blood vessel fetal (allantoic) blood vessel chorion crypt surrounding villus maternal epithelium chorion 25 µm

DEMONSTRATION SLIDE Mare Endometrial cup What is an endometrial cup? 2.5 mm

DEMONSTRATION SLIDE Mare Endometrial cup What is an endometrial cup? What is an endometrial cup? Found only in the mare endometrial cups develop. Formed by trophoblast cells from the annulate chorionic girdle invading the endometrial stroma. Development starts at about day 35, reaches a maximum at around day 50 and degenerates after day 80. endometrial cup uterine wall 2.5 mm

DEMONSTRATION SLIDE Mare Endometrial cup Area of endometrial cup from previous slide. (stain unknown) 1.0 mm

DEMONSTRATION SLIDE Mare Endometrial cup Area of endometrial cup from previous slide. (stain unknown) Endometrial cups can measure from a few mm across to 5cm in diameter. Area of endometrial cup from previous slide. (stain unknown) invading trophoblast cells band of lymphocytes chorioallantois uterine epithelium 1.0 mm

DEMONSTRATION SLIDE Mare Endometrial cup Another section of an endometrial cup, this slide is stained with H&E. 1.0 mm

DEMONSTRATION SLIDE Mare Endometrial cup Another section of an endometrial cup, this slide is stained with H&E. uterine epithelium absent T : invading trophoblast E : endometrial glands L : band of lymphocytes chorioallantois L E T L L uterine epithelium L E 1.0 mm

DEMONSTRATION SLIDE Mare Endometrial cup Area from previous slide; Large polyhedral trophoblast cells can be identified. A band of lymphocytes is seen surrounding the cup. 250 µm

DEMONSTRATION SLIDE Mare Endometrial cup Area from previous slide; Large polyhedral trophoblast cells can be identified. A band of lymphocytes is seen surrounding the cup. uterine epithelium missing uterine epithelium intact L : lymphocytes L L uterine glands L L invading trophoblast cells 250 µm

DEMONSTRATION SLIDE Mare Endometrial cup What is the appearance and function of the cells of chorionic origin? 50 µm

DEMONSTRATION SLIDE Mare Endometrial cup What is the appearance and function of the cells of chorionic origin? Large polyhedral cells, some bi-nucleate. Produce equine chorionic gonadotropin (ECG) also called PMSG. What is the appearance and function of the cells of chorionic origin? trophoblast cells 50 µm

DEMONSTRATION SLIDE Mare Endometrial cup What are the smaller darker cells around the periphery? What is their function? 100 µm

DEMONSTRATION SLIDE Mare Endometrial cup What are the smaller darker cells around the periphery? Lymphocytes. What is their function? They present a barrier to the trophoblast cells and will eventually invade and destroy the cup cells. What are the smaller darker cells around the periphery? What is their function? cup (trophoblast) cells uterine gland lymphocytes 100 µm

SLIDE 187 Ewe placentome Viewing the whole section; identify the maternal side from the presence of the myometrium. 2.5 mm

SLIDE 187 Ewe placentome Viewing the whole section; identify the maternal side from the presence of the myometrium. chorioallantoic membrane concave maternal caruncle endometrium 2.5 mm myometrium

How is the ewe placentome classified? SLIDE 187 Ewe placentome How is the ewe placentome classified?

SLIDE 187 Ewe placentome How is the ewe placentome classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. VILLOUS COTYLEDONARY with CONCAVE PLACENTOMES. The fetal cotyledon and the maternal caruncle comprise the placentome. Layers present: Six layers can be identified between the maternal and the fetal circulation.

SLIDE 187 Ewe placentome How is the ewe placentome classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. VILLOUS COTYLEDONARY with CONCAVE PLACENTOMES. The fetal cotyledon and the maternal caruncle comprise the placentome. Layers present: Six layers can be identified between the maternal and the fetal circulation. Maternal endothelium lining blood vessels. Maternal stroma. Maternal (uterine) epithelium. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels. Duration of pregnancy approx 150 days

SLIDE 187 Ewe placentome At higher magnification identify : maternal caruncle and the fetal cotyledon. 1.0 mm

SLIDE 187 Ewe placentome At higher magnification identify : maternal caruncle and the fetal cotyledon. fetal villi of cotyledon maternal septa of caruncle endometrium myometrium 1.0 mm

What layers separate the maternal and fetal blood streams? SLIDE 187 Ewe placentome What layers separate the maternal and fetal blood streams? 250 µm

What layers separate the maternal and fetal blood streams? SLIDE 187 Ewe placentome What layers separate the maternal and fetal blood streams? What layers separate the maternal and fetal blood streams? Fetal endothelium, fetal stroma, chorion, uterine epithelium, maternal stroma and endothelium of maternal blood vessels. The uterine epithelium forms syncytia with invading Binucleate trophoblast cells. V : fetal villi in TS section M V M : maternal tissue typically dark staining chorion fetal villi typically pale staining V M uterine epithelium V 250 µm

Identify the layers of the placental barrier. SLIDE 187 Ewe placentome Identify the layers of the placental barrier. 100 µm

SLIDE 187 Ewe placentome Identify the layers of the placental barrier. (The space between the chorionic cells and the maternal epithelial cells lining the crypt is a fixation artefact.) fetal capillary chorion fetal stroma maternal stroma uterine epithelium 100 µm

SLIDE 187 Ewe placentome Again identify the layers from maternal to fetal tissue. Identify binucleate trophoblast cells. 50 µm

SLIDE 187 Ewe placentome Again identify the layers from maternal to fetal tissue. Identify binucleate trophoblast cells. binucleate giant trophoblast cells arrowed BV : fetal blood vessel BV chorion fetal stroma invading binucleate cell in maternal epithelium uterine epithelium maternal stroma 50 µm

Demo Slide Goat placentome A section from goat placenta showing a group of four placentomes. Relate this to the material you see in the dissection room. 5.0 mm

SLIDE 188 Cow placentome Viewing the whole section; identify the maternal side from the presence of the myometrium. Compare the overall shape with that of the ewe. 2.5 mm

SLIDE 188 Cow placentome Viewing the whole section; identify the maternal side from the presence of the myometrium. Compare the overall shape with that of the ewe. chorioallantois convex maternal caruncle P : pedicel P wall of uterus 2.5 mm

Demo Slide cow placentome A section from cow placenta showing a single placentome. Relate this to the material you see in the dissection room.

How is the cow placentome classified? SLIDE 188 Cow placentome How is the cow placentome classified?

SLIDE 188 Cow placentome How is the cow placentome classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. VILLOUS COTYLEDONARY with CONVEX PLACENTOMES. The fetal cotyledon and the maternal caruncle comprise the placentome. Layers present: Six layers can be identified between the maternal and the fetal circulation.

SLIDE 188 Cow placentome How is the cow placentome classified? EPITHELIOCHORIAL. NON DECIDUATE or INDECIDUATE. VILLOUS COTYLEDONARY with CONVEX PLACENTOMES. The fetal cotyledon and the maternal caruncle comprise the placentome. Layers present: Six layers can be identified between the maternal and the fetal circulation. Maternal endothelium lining blood vessels. Maternal stroma. Maternal (uterine) epithelium. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels. Duration of pregnancy approx 280 days

SLIDE 188 Cow placentome This section is stained with with Masson’s trichrome; connective tissue is stained blue/green and cells red. placental area of chorionic villi and maternal crypts pedicel of maternal caruncle endometrial glands 1.0 mm

SLIDE 188 Cow placentome The convex surface of the placentome with interdigitating fetal and maternal tissues. 1.0 mm

SLIDE 188 Cow placentome The convex surface of the placentome with interdigitating fetal and maternal tissues. fetal stroma allantois area of crypts and fetal villi blue staining maternal connective tissue 1.0 mm

The placentome from the fetal side. SLIDE 188 Cow placentome The placentome from the fetal side. 250 µm

The placentome from the fetal side. SLIDE 188 Cow placentome The placentome from the fetal side. maternal tissue forming crypts fetal villi allantois fetal (allantoic) blood vessel fetal connective tissue 250 µm

Identify the main layers forming the placental barrier. SLIDE 188 Cow placentome Identify the main layers forming the placental barrier. 100 µm

Identify the main layers forming the placental barrier. SLIDE 188 Cow placentome Identify the main layers forming the placental barrier. Fetal endothelium, fetal stroma, chorion, uterine epithelium, maternal stroma and maternal endothelium of blood vessels. Identify the main layers forming the placental barrier. C C C : chorionic villi C C M : maternal connective tissue C C uterine epithelium lining crypts M 100 µm

Identify binucleate trophoblast cells. SLIDE 188 Cow placentome Identify binucleate trophoblast cells. 25 µm

Identify binucleate trophoblast cells. SLIDE 188 Cow placentome Identify binucleate trophoblast cells. maternal connective tissue stroma binucleate giant cell (diplokaryocyte) within fetal villus chorion fetal stroma with capillaries maternal epithelium 25 µm

SLIDE 188 Cow placentome Binucleate cells. Are they part of the fetal chorion or the uterine epithelium? 25 µm

SLIDE 188 Cow placentome Binucleate cells. Are they part of the fetal chorion or the uterine epithelium? They are of fetal origin. Binucleate cells. Are they part of the fetal chorion or the uterine epithelium? B : binucleate cells uterine stroma uterine epithelium B chorion cells fetal stroma B B 25 µm

SLIDE 188 Cow placentome Binucleate cells. Can any be identified as part of the other epithelial wall? 25 µm

SLIDE 188 Cow placentome Binucleate cells. Can any be identified as part of the other epithelial wall? Usually only seen amongst the chorionic cells these diplokaryocytes migrate to the crypts and may be seen amongst cells of the maternal epithelium. Binucleate cells. Can any be identified as part of the other epithelial wall? binucleate cells on fetal side arrowed 25 µm

SLIDE 188 Cow placentome Binucleate cells. What function do they perform? binucleate cells on fetal side arrowed B B : apoptopic binucleate cell in maternal epithelium 25 µm

SLIDE 188 Cow placentome Binucleate cells. What function do they perform? These cells secrete prostaglandin, progesterone and proteins including placental lactogen. binucleate cells on fetal side arrowed B B : apoptopic binucleate cell in maternal epithelium 25 µm

Whole section of cat placenta. SLIDE 189 Cat placenta Whole section of cat placenta. 2.0 mm

Whole section of cat placenta. SLIDE 189 Cat placenta Whole section of cat placenta. edge of zonary placenta chorioallantois labyrinthine area uterine wall 2.0 mm

How is the cat placenta classified? SLIDE 189 Cat placenta How is the cat placenta classified?

SLIDE 189 Cat placenta How is the cat placenta classified? ENDOTHELIOCHORIAL. DECIDUATE. LABYRINTHINE. ZONARY. Layers present: Four layers can be identified between the maternal and the fetal circulation.

SLIDE 189 Cat placenta How is the cat placenta classified? ENDOTHELIOCHORIAL. DECIDUATE. LABYRINTHINE. ZONARY. Layers present: Four layers can be identified between the maternal and the fetal circulation. Maternal endothelium lining blood vessels. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels.

Look at the cells of the labyrinthine area. SLIDE 189 Cat placenta Look at the cells of the labyrinthine area. 1.0 mm

Look at the cells of the labyrinthine area. SLIDE 189 Cat placenta Look at the cells of the labyrinthine area. allantois fetal blood vessel chorioallantois labyrinthine area uterine epithelium myometrium 1.0 mm

SLIDE 189 Cat placenta Consider the relationships between the maternal and fetal membranes. Pale fetal lamellae alternating with darker staining maternal lamellae. 250 µm

SLIDE 189 Cat placenta A : pale staining fetal lamellae consisting of fetal stroma and blood vessels. bordered by lines of basophilic syncytial trophoblast cells. B : dark staining lamellae with maternal blood vessels surrounded by decidual cells. 50 µm

SLIDE 189 Cat placenta A : pale staining fetal lamellae consisting of fetal stroma and blood vessels. bordered by lines of basophilic syncytial trophoblast cells. B : dark staining lamellae with maternal blood vessels surrounded by decidual cells. B A A B B B A A 50 µm

SLIDE 189 Cat placenta Identify: Fetal endothelial cells. Maternal endothelium. Cytotrophoblast and Syncytiotrophoblast together making up the chorion. 50 µm

SLIDE 189 Cat placenta Identify: Fetal endothelial cells. Maternal endothelium. Cytotrophoblast and Syncytiotrophoblast together making up the chorion. C A A : fetal blood vessel B : fetal stroma (pale) C : chorionic cells D : giant decidual cells E : maternal blood vessel E B E D B D C 50 µm

SLIDE 184 Dog placenta View at low magnification and identify the main maternal and fetal areas. 2.0 mm

SLIDE 184 Dog placenta View at low magnification and identify the main maternal and fetal areas. chorioallantois fetal blood vessels marginal haematoma placental labyrinth glandular endometrium myometrium 2.0 mm

How is the dog placenta classified? SLIDE 184 Dog placenta How is the dog placenta classified?

SLIDE 184 Dog placenta How is the dog placenta classified? ENDOTHELIOCHORIAL. DECIDUATE. LABYRINTHINE. ZONARY with MARGINAL HAEMATOMA. Layers present: Four layers can be identified between the maternal and the fetal circulation.

SLIDE 184 Dog placenta How is the dog placenta classified? ENDOTHELIOCHORIAL. DECIDUATE. LABYRINTHINE. ZONARY with MARGINAL HAEMATOMA. Layers present: Four layers can be identified between the maternal and the fetal circulation. Maternal endothelium lining blood vessels. Fetal chorion. Fetal stroma. Fetal endothelium lining blood vessels.

SLIDE 184 Dog placenta Fetal stroma and blood vessels can be seen to the left of the labyrinthine placenta. The alternating lamellae do not show up as well as in the previous slide of cat placenta. 250 µm

SLIDE 184 Dog placenta High magnification. 100 µm

SLIDE 184 Dog placenta High magnification. fetal blood vessel fetal stroma M : maternal blood vessels M syncytiotrophoblast cells surrounding maternal blood vessels M 100 µm

What are haemophagous regions? SLIDE 184 Dog placenta What are haemophagous regions? 0.5 mm

SLIDE 184 Dog placenta What are haemophagous regions? Marginal haematomas, from haemorrhaging uterine blood vessels. What is their purpose? marginal haematoma placental labyrinth uterine wall 0.5 mm

SLIDE 184 Dog placenta What are haemophagous regions? Marginal haematomas, from haemorrhaging uterine blood vessels. What is their purpose? Provision of iron for fetal haemopoiesis. marginal haematoma placental labyrinth uterine wall 0.5 mm

Demo Slide Rhesus monkey placenta A section of a discoid placenta from a Rhesus monkey. Relate this to the material you see in the dissection room. discoid placenta uterine wall myometrium

Lectures. Prof DC. Wathes. Second Year Histology. 024. PLACENTATION. J Lectures. Prof DC. Wathes. Second Year Histology. 024. PLACENTATION. J.Bredl. 21-12-04. Gross Anatomy Correlates. Dr S.Frean. Histology slides and stains. Tanya Hopcroft. Compressed version updated. 2006, 2007, 2010