Embryology

• What are the cells in the bilaminar disc?

  Epiblast and hypoblast
• The paraxial mesoderm forms somites
• Hyaluronidase is involved in penetrating the zona pellucida during fertilization.

  False
• How many blastomeres are in a morula?

  16
• The ectoderm becomes the neural tube.
• What does the hypoblast become?

  Yolk sac
• The epiblast is also known as the inner cell mass (ICM).
• Which neuropore closes first?

  Cranial
• Steps in fertilization

  1️⃣ Sperm capacitation

  2️⃣ Penetration of corona radiata

  3️⃣ Penetration of zona pellucida

  4️⃣ Formation of female pronucleus

  5️⃣ Formation of male pronucleus

  6️⃣ Fusion of pronuclei
• Which part of the sperm is left behind during fertilization?

  Tail
• On day 3, the embryo becomes a 16-cell morula.
• The blastocyst separates into the embryoblast and trophoblast.
• What do primary chorionic villi allow exchange of?

  Foetal waste and maternal nutrients
• Match the cell type with its function or description:

  Blastocyst ↔️ Stage of early embryo

  Embryoblast ↔️ Becomes foetus

  Trophoblast ↔️ Forms placenta

  Epiblast ↔️ Forms embryo proper
• The gastrulation process begins with the formation of the primitive streak.
• Gastrulation results in the formation of three germ layers.
• Order the layers formed during gastrulation:

  1️⃣ Endoderm

  2️⃣ Mesoderm

  3️⃣ Ectoderm
• Which germ layer becomes the digestive system?

  Endoderm
• Which germ layer becomes the neural tube?

  Ectoderm
• Match the mesoderm derivative with its description:

  Notochord ↔️ Stimulates axial skeleton

  Paraxial mesoderm ↔️ Forms somites

  Intermediate mesoderm ↔️ Forms UG system

  Lateral plate mesoderm ↔️ Forms body wall
• The neural tube forms from the ectoderm lying over the mesoderm.
• Which neuropore closes on day 28?

  Caudal
• Order the derivatives of the paraxial mesoderm:

  1️⃣ Somitomeres

  2️⃣ Somites

  3️⃣ Sclerotome

  4️⃣ Dermamyotome

  5️⃣ Dermatome and myotome
• Which pharyngeal arch is innervated by the trigeminal nerve?

  PA1
• Match the pharyngeal arch with its main structure:

  PA1 ↔️ Mandible and maxilla

  PA2 ↔️ Hyoid bone

  PA3 ↔️ Larynx (thyroid cartilage)

  PA4&6 ↔️ Larynx (cricoid cartilage)