Placental Structure and Function
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Questions and Answers

What condition is characterized by necrosis of mucous membranes in fetuses?

  • Fetal tension (correct)
  • Agalactia
  • Trichomonal infection
  • Mild placentitis

Which test is used for diagnosis related to agglutination in bovine milk?

  • Western blot test
  • Fluorescent antibody test
  • Milk Ring test (correct)
  • PCR assay

What is defined as the expulsion of a living fetus before it reaches a viable age?

  • Premature birth
  • Still birth
  • Early embryonic death
  • Abortion (correct)

Which condition involves the expulsion of a dead fetus at the time of parturition?

<p>Still birth (A)</p> Signup and view all the answers

What indicates embryonic death with post-abortus necrosis?

<p>Hemorrhagic cotyledons (B)</p> Signup and view all the answers

What is commonly observed in a serological test for fetal infections?

<p>Macrated fetal stomach (B)</p> Signup and view all the answers

Which of the following describes the phenomenon of repeated abortions at a particular month of gestation?

<p>Habitual abortion (D)</p> Signup and view all the answers

What type of infection is indicated by post-abortus symptoms like slight placentitis?

<p>Trichomoniasis (A)</p> Signup and view all the answers

What is the typical period during which a fetus dies in the uterus before being expelled?

<p>24-72 hours (C)</p> Signup and view all the answers

What impact does abortion have on the productivity of a farm animal?

<p>Creates unproductive animals (B)</p> Signup and view all the answers

What chemical is essential for the growth of the organism mentioned?

<p>Erythritol (C)</p> Signup and view all the answers

What is a premonitory sign observed in cases of infection in adult cows?

<p>Vulvar edema (C)</p> Signup and view all the answers

Which of the following is NOT a sequelae of the infection?

<p>Abscess formation (D)</p> Signup and view all the answers

What is the suspicious reaction titer for non-vaccinated cows in agglutination tests?

<p>1:50 (A)</p> Signup and view all the answers

Which serological test is commonly performed to identify infected cattle?

<p>Tube agglutination test (D)</p> Signup and view all the answers

Which of the following organs is NOT part of the anatomical sites affected in adult male cattle?

<p>Lungs (D)</p> Signup and view all the answers

What is the characteristic feature of foetal membranes in infected cases?

<p>Edematous and hemorrhagic (A)</p> Signup and view all the answers

What kind of test is the Milk Ring Test categorized as?

<p>A method for brucellosis screening (B)</p> Signup and view all the answers

When can hCG be first detected in blood during gestation?

<p>Day 8 to 10 (C)</p> Signup and view all the answers

What is the primary role of hCG during early pregnancy?

<p>Provide a luteotrophic stimulus for the ovulatory corpus luteum (A)</p> Signup and view all the answers

Which hormone is secreted by the placenta to stimulate ovarian function?

<p>hCG (A)</p> Signup and view all the answers

After which day of gestation does the placenta assume progesterone production in the mare?

<p>Day 100 (B)</p> Signup and view all the answers

Which animal's progesterone source includes the CL and accessory CL throughout gestation?

<p>Sheep (D)</p> Signup and view all the answers

What effect does high progesterone have during pregnancy?

<p>Inhibits myometrial contraction (B)</p> Signup and view all the answers

Which hormone is specifically mentioned as being produced by the placenta during the last part of gestation?

<p>Estrogens (B)</p> Signup and view all the answers

What effect does the removal of the CL have in sows during gestation?

<p>Causes abortion (D)</p> Signup and view all the answers

What is the primary role of chorionic villi in the placenta?

<p>They provide a region for nutrient and metabolic waste exchange. (C)</p> Signup and view all the answers

In which type of placenta is the endometrial epithelium completely intact on both maternal and fetal sides?

<p>Epitheliochorial placenta (A)</p> Signup and view all the answers

What happens to the endometrial epithelium in ruminants during placentation?

<p>It experiences transient erosion and regrowth. (C)</p> Signup and view all the answers

What type of cells are nucleate giant cells, and when do they appear in sheep?

<p>They are binucleate cells that appear around day 14. (C)</p> Signup and view all the answers

Which of the following features characterizes the placenta of pigs and horses?

<p>It features an epitheliochorial type of placenta. (B)</p> Signup and view all the answers

What substances are believed to be secreted by binucleate giant cells in ruminants?

<p>Placental lactogen and pregnancy specific protein B (A)</p> Signup and view all the answers

How many layers can fetal and maternal blood supplies exchange through in the placenta?

<p>As many as 6 layers and as few as 3 layers (A)</p> Signup and view all the answers

Where do nucleate giant cells originate from during the gestation process?

<p>From trophoblast cells (C)</p> Signup and view all the answers

Study Notes

Placental Structure and Function

  • Chorionic villi interface with the endometrium, facilitating nutrient and metabolic waste exchange.
  • Classification based on separation of fetal and maternal blood supplies; described with maternal tissue as prefix and fetal tissue as suffix.

Epitheliochorial Placenta

  • Both maternal endometrial epithelium and chorionic villi epithelium are intact.
  • Found in species such as pigs, horses, and ruminants; ruminants exhibit transient erosion of endometrial epithelium, termed syndesmochorial.
  • Nucleate giant cells, large with two nuclei, originate from trophoblast cells and secrete placental lactogen and pregnancy-specific protein B (PSPB).

Hormonal Functions of the Placenta

  • Hormones secreted by the placenta support ovarian function, maintain pregnancy, influence fetal growth, stimulate mammary function, and assist in parturition.
  • Key placental hormones include:
    • Progesterone
    • Human chorionic gonadotropin (hCG)
    • Relaxin
    • Placental lactogen
    • Pregnancy-specific protein B (PSPB)
    • Prostaglandins

Progesterone Sources During Gestation

  • Sheep: Source transitions from corpus luteum (CL) to placenta after day 50 of a 150-day gestation.
  • Mare: CL supports progesterone production up to day 100; placenta takes over, with gestation lasting around 330 days.
  • Cow: CL maintains progesterone until ~day 215; placenta and adrenal glands produce sufficient progesterone during a 280-day gestation.
  • Sow: CL supports progesterone production throughout a 114-day gestation; removal of CL induces abortion.

Definition and Types of Abortion

  • Abortion: Expulsion of a fetus before it reaches a viable age; can involve live or dead fetuses.
  • Premature birth: Delivery of a viable fetus 15-30 days before expected parturition.
  • Stillbirth: Dead fetus expelled at the time of parturition.
  • Habitual abortion: Repeated abortions during a specific gestation month.
  • Threatened abortion: Symptoms of potential abortion at any stage, not always leading to actual abortion.
  • Early embryonic death: Unseen expulsion of ova, embryos, or fetuses.

Significance of Abortion in Cattle

  • Abortions after four months often lead to retained placenta; earlier abortions typically do not.
  • Common causes include infections affecting the fetus or membranes.
  • Economic implications: Loss of fetus, prolonged uterine disease, infertility, and potential herd threats from infectious causes.

Clinical Diagnosis of Abortion

  • History of abortion storms in herds may indicate brucellosis.
  • Diagnostic methods include:
    • Isolation of organisms from fetal tissues (lungs, stomach, placenta).
    • Serological tests: tube agglutination, plate agglutination, heat inactivation, complement fixation, and card tests.
  • Test results help identify infection status in cows, with specific reacting titers indicating suspicion or positivity.

Other Considerations

  • Miscellaneous factors affecting fetal health, including peroxide exposure and lesions in the adult cow.
  • Fetal complications may arise from maternal conditions, necessitating careful diagnosis and management strategies.

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Description

This quiz explores the anatomy and function of the placenta, focusing on the interaction between chorionic villi and the endometrium. It covers the classification of placentas based on their intimacy and the separation of fetal and maternal blood supplies. Test your knowledge on this essential aspect of reproductive biology.

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