EMBRYOLOGY-6

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Questions and Answers

Which hormone does the placenta produce to maintain the functionality of the corpus luteum initially?

Human chorionic gonadotropin (hCG) (correct)

Progesterone

Human chorionic somatotropin

Estrogens

What role does human chorionic somatotropin (placental lactogen) serve during pregnancy?

It directly stimulates fetal growth.

It aids in the formation of the placenta.

It regulates maternal metabolism of glucose. (correct)

It suppresses the immune response in the mother.

Which decidual region is located between the implanted embryo and the myometrium?

Decidua Basalis (correct)

Decidua Reciprocalis

Decidua Parietalis

Decidua Capsularis

What is the role of the decidua capsularis during pregnancy?

It covers the embryo and degenerates at the 3rd month. Signup and view all the answers

Which of the following infectious agents can cross the placenta?

Toxoplasma gondii Signup and view all the answers

Which statement accurately describes the function of the chorion frondosum?

It harbors the placenta's connections to maternal tissue. Signup and view all the answers

How does the placenta protect the embryo from the mother’s immune system?

By lacking major histocompatibility complex (MHC) in specific cell types. Signup and view all the answers

What changes occur in hormone production related to the corpus luteum by the third trimester?

The corpus luteum ceases its hormone production. Signup and view all the answers

What happens to the decidua capsularis by the end of the third month?

It disappears. Signup and view all the answers

How do the amnion and chorion interact during pregnancy?

They fuse to create the amniochorionic membrane. Signup and view all the answers

What is a potential consequence of vasa previa during pregnancy?

Fetal bradycardia Signup and view all the answers

Which condition is characterized by the presence of only paternal chromosomes and no fetal tissue?

Complete hydatiform mole Signup and view all the answers

What type of twins are formed when two oocytes are fertilized at the same time?

Dizygotic twins Signup and view all the answers

What is a serious potential condition that can develop from a complete hydatiform mole?

Choriocarcinoma Signup and view all the answers

What is a common symptom of hyperemesis gravidarum associated with hydatiform mole?

Acute nausea and vomiting Signup and view all the answers

Which of the following is NOT a complication associated with placental abruptio?

Excessive emotional disturbances Signup and view all the answers

What characteristic differentiates monozygotic twins from dizygotic twins?

Same genetic material Signup and view all the answers

During which pregnancy complication might a hematoma form with no external bleeding?

Placental abruptio Signup and view all the answers

What is the main reason for conducting amniocentesis after the 15th week of pregnancy?

To minimize risks of harming the fetus Signup and view all the answers

Which of the following is NOT a complication associated with oligohydramnios?

Excessive fetal movement Signup and view all the answers

What primarily composes amniotic fluid during the second trimester?

Water, proteins, electrolytes, and fetal epithelial cells Signup and view all the answers

Which condition is caused by renal agenesis resulting in oligohydramnios?

Potter syndrome Signup and view all the answers

What factors may contribute to the development of polyhydramnios?

Maternal infections and cardiac issues Signup and view all the answers

How frequently is amniotic fluid turned over in the third trimester?

Every 3 hours Signup and view all the answers

What is the primary mechanism through which amniotic fluid is reabsorbed?

Through the amniochorionic membrane Signup and view all the answers

Which abnormality is indicated by elevated levels of alpha-fetoprotein in the amniotic fluid?

Esophageal atresia Signup and view all the answers

What is the primary characteristic of the fetal side of a mature placenta?

It is shiny due to the amnion. Signup and view all the answers

Which of the following complications is associated with the abnormal adherence of chorionic villi to the myometrium?

Placenta accreta Signup and view all the answers

What condition is described as the complete penetration of the myometrium, often reaching nearby organs?

Placenta percreta Signup and view all the answers

What could potentially cause placenta abruption?

Maternal hypertension Signup and view all the answers

Which of the following statements about placenta previa is true?

It occurs when the placenta attaches at the internal uterine os. Signup and view all the answers

What is the primary risk associated with placenta that digs too deep into the uterine wall?

Severe hemorrhaging during delivery Signup and view all the answers

What is the thickness of a mature placenta?

Around 3 cm Signup and view all the answers

What is the primary function of the vitelline stalk or canal during embryonic development?

To facilitate communication between the midgut and the vitelline sac Signup and view all the answers

What condition involves a premature separation of the placenta from the uterine wall?

Placenta abruption Signup and view all the answers

During which week of embryonic development does extraembryonic hematopoiesis occur in the yolk sac?

Sixth week Signup and view all the answers

What is the fate of the allantois in human embryonic development?

It degenerates and becomes a ligament of the urinary bladder Signup and view all the answers

Which structures contribute to the formation of the umbilical cord?

Body stalk and vitelline duct Signup and view all the answers

What happens to the intestinal loop during the early stages of embryonic development?

It is absorbed back into the abdominal cavity Signup and view all the answers

What is the approximate length and diameter of the umbilical cord at term?

55-60 cm long and 2-2.5 cm in diameter Signup and view all the answers

What is contained within the umbilical cord at its initial stage of development?

Body stalk, allantois, umbilical vessels and vitelline duct Signup and view all the answers

What is the role of Wharton’s jelly in the umbilical cord?

To protect the blood vessels Signup and view all the answers

Study Notes

Embryonic Development and Support Systems

The embryo establishes a parasitic relationship with the mother for oxygen, nutrients, and waste removal. It must avoid rejection as a foreign body.
The placenta and extraembryonic membranes facilitate communication with the mother.
The placenta and chorion originate from the trophoblast, while the amnion, yolk sac, allantois, and extraembryonic mesoderm originate from the inner cell mass.

Amniotic Membrane and Cavity

The amniotic sac completely covers the embryo.
Functions of the amniotic sac include: buffering against mechanical injury, accommodating growth, allowing fetal movements, protecting the fetus from adhesion, acting as a barrier to infections (bacteriostatic properties), maintaining a constant temperature, and assisting in fluid and electrolyte homeostasis.

Amniotic Membrane Functions

Contains significant cytokines and essential growth factors.
Reduces pain when applied to wounds.
Increases and enhances wound healing.
Has antibacterial properties.
Is non-immunogenic.
Provides a biological barrier.
Provides a matrix for cell migration and proliferation.
Reduces inflammation and scar tissue formation.
Stem cells are present within the amniotic membrane, which are of significant research interest.

Amniotic Fluid Composition

Amniotic fluid is primarily composed of the embryo's urine after the 11th week, though lung secretions are also a component.
Fetal urine lacks waste products, as these are secreted by the placenta.

Disorders in Amniotic Fluid Volume

Oligohydramnios: reduced amniotic fluid volume, potentially caused by diminished placental blood flow, premature amniochorionic membrane rupture, renal agenesis, or urinary tract obstruction.
Polyhydramnios: increased amniotic fluid volume; causes are often unknown but potentially linked to maternal factors like diabetes, and/or fetal issues such as esophageal or duodenal atresia, anencephaly, or congenital diaphragmatic hernia.

Placenta and Chorion

The placenta and chorion cooperate.
The placenta is formed by cytotrophoblast, syncytiotrophoblast, and extraembryonic mesoderm.
The placenta is an endocrine organ, producing human chorionic gonadotropin (hCG) to maintain the corpus luteum, and estrogen and progesterone later in pregnancy .

Further Development

The chorionic villi help with maternal blood circulation within the intervillous space.
Cytotrophoblast from anchoring villi invades spiral arteries within the uterine wall.
Oxygen levels in fetal blood are different from maternal oxygens.
Inadequate placental perfusion can affect fetus.

Other Developmental Aspects

The allantois and umbilical cord are involved in embryonic development.
Amniotic bands can cause fetal abnormalities.
Placental attachment types (eccentric, marginal, membranous) exist
Hydatiform moles and choriocarcinomas are abnormal placental conditions.
Twins (monozygotic and dizygotic) result from different developmental processes.

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Description

This quiz covers embryonic development, emphasizing the roles of various support structures such as the placenta and amniotic sac. Each component's function, origin, and importance for fetal development are highlighted, along with their unique properties. Explore how these systems maintain a healthy environment for the embryo during development.