Flashcards: Embryology and Anatomy of Development — 24 cards

Embryonic development — definition?

Process from fertilization to organ formation.

Embryonic period — focus?

Major organ systems are established.

Fertilization site — main location?

Ampullary region of the oviduct.

Zona pellucida — role?

Sperm interacts with it during fertilization.

Polyspermy block — purpose?

Prevents multiple sperm entry into oocyte.

First division — time after ovulation?

Approximately 24 hours.

Cleavage — process?

Cell division without growth.

Zygote — formation?

Fertilized egg with maternal and paternal pronuclei.

Morula — definition?

Solid ball of 16 blastomeres.

Gastrulation — key event?

Formation of bilaminar disc and primitive streak.

Notochord — derivative?

Nucleus pulposus of intervertebral discs.

Neurulation — outcome?

Neural tube formation.

Pharyngeal arches — number?

Initially six, fifth rudimentary, six fuses with four.

First pharyngeal cleft — develops into?

External auditory meatus.

Tongue development — origin?

Fusion of lingual septum and swellings.

Placenta formation — requires?

Synchronization of uterine receptivity and embryo stage.

Chorioallantoic placenta — type?

Formed by chorion and allantois contributions.

Placental barrier layers — define?

Maternal and fetal tissue strata separating blood.

Epitheliochorial placenta — barrier?

No maternal tissue loss, intact epithelium.

Synepitheliochorial placenta — feature?

Trophoblast fusion with endometrial epithelium.

Endotheliochorial placenta — characteristic?

Maternal epithelium and connective tissue lost.

Haemochorial placenta — barrier?

Maternal barrier is fully reduced.

Thoracic cavity — parts?

Pectoral and intrathoracic abdominal regions.

Pleura layers — define?

Parietal and visceral pleura.