Embryonic Development and Organogenesis

Flashcards covering key vocabulary related to embryonic development, fertilization, and organogenesis.

Acrosome

Digestive enzymes released to penetrate the oocyte's jelly coat.

Fertilization Membrane

A structure that prevents additional sperm from injecting their nucleus into the oocyte post-fertilization.

Haploid

Having one set of chromosomes (23 in humans).

Diploid

Having two sets of chromosomes (46 in humans).

Embryonic Cleavage

Early cell divisions after fertilization where the overall size of the embryo remains the same.

HCG (Human Chorionic Gonadotropin)

A hormone released by the blastocyst to maintain the corpus luteum.

Trophoblast

The outer layer of the blastocyst that will become the placenta.

Inner Cell Mass

The inner cell mass of the blastocyst that will become the embryo.

Extraembryonic Membranes

Membranes that support embryonic development but are not part of the actual embryo.

ELISA Test

A type of test used in pregnancy tests that detects hCG.

Chorionic Villi

Finger-like projections that develop from the trophoblast and invade the endometrium to increase surface area for nutrient and waste exchange.

Chorion

The embryonic version of the placenta, responsible for nutrient and waste exchange.

Simple Squamous Epithelium

A tissue with thin, flat cells used for efficient diffusion, found in chorionic villi.

Umbilical Artery

Carries deoxygenated blood from the embryo to the chorionic villi.

Umbilical Vein

Carries oxygenated blood from the chorionic villi back to the embryo.

Placenta Previa

A condition where the placenta covers the cervix, obstructing delivery.

Gastrulation

The process after the blastocyst stage where two tissue layers form.

Ectoderm

Outermost primary germ layer; gives rise to the epidermis and nervous system.

Mesoderm

Middle primary germ layer; gives rise to connective tissues, muscles, and cardiovascular system.

Endoderm

Innermost primary germ layer; gives rise to the gastrointestinal tract, lungs, and parts of the renal system.

Morphogenesis

The process where primary germ layers change in structure, folding in on themselves.

Yolk Sac

An extraembryonic membrane, a vestigial structure in humans.

Amniotic Sac

A sac filled with fluid that surrounds and cushions the embryo, allowing for three-dimensional development.

Ontogeny Recapitulates Phylogeny

Embryonic development retells the story of evolution

Organogenesis

The production and maturation of organs.

Differentiation

The specialization of cells during development; cells mature into specific types.

Totipotent Stem Cell

A stem cell capable of differentiating into any cell type in the body.

Pluripotent Stem Cell

A stem cell having limits; can turn into many cells but not all.

Chemical Gradients

The influence on stem cell differentiation based on the chemicals present in the stem cell's region.

Induction

The influence on stem cell differentiation due to physical contact with other cells.

Neurulation

The morphogenesis of the nervous system.

Neural Tube

A tube-like structure formed from the ectoderm that runs from the anterior to the posterior end of the embryo; becomes the spinal cord and brain.

Spina Bifida

A defect where the neural tube does not close on the posterior side, leading to incomplete formation of the spinal cord and nerves.

Anencephaly

A defect where the neural tube does not close anteriorly, resulting in the absence of a cerebrum.

Neural Crest

Cells that migrate out during development and become the peripheral nervous system.

Somites

Cubes of mesoderm that develop into segmented patterns like ribs, vertebrae, and intercostal muscles.