Exam 3

Von Baer’s laws

Generalizations concerning vertebrate development, indicating that general features appear before specialized ones.

Germ Layers

Three distinct regions formed during gastrulation that give rise to different organ systems: ectoderm, mesoderm, and endoderm.

Ectoderm

The outer germ layer that develops into skin, brain, and neural crest.

Mesoderm

The middle germ layer that gives rise to blood, heart, kidneys, gonads, bones, muscles, and connective tissues.

Endoderm

The inner germ layer that forms the digestive tube and associated organs, including the lungs.

Induction

The process by which one cell population influences the development of neighboring cells through close-range interactions.

Specification

The initial stage of commitment of cell fate where the cell can differentiate autonomously, but that commitment can be reversed.

Differentiation

The process by which an unspecialized cell becomes specialized into specific cell types.

Primary Neurulation

The process where cells surrounding the neural plate direct plate cells to proliferate and pinch off, forming a hollow neural tube.

BMP (Bone Morphogenetic Protein)

A factor secreted by the mesoderm that induces ectoderm to develop into epidermis and inhibits neuroectoderm formation.

Wnt signaling

A pathway involved in nervous system patterning, where Wnt binds to receptors allowing transcription activation by B-catenin.

Neurulation defects

Birth defects related to incomplete or improper neurulation, often due to nutritional deficiencies like lack of folic acid.

Hensen’s Node

An organizer in chick and human embryos responsible for nervous system patterning.

Pyramidal Decussation

The crossing of corticospinal tract axons from one side of the body to the other, explaining contralateral control of movement.

Neural crest

A group of cells that arises from the ectoderm and gives rise to various structures including neurons and glia of the PNS.

Fate mapping studies

Methods used to track individual cells over time to determine their developmental fate in embryology.

Spemann-Mangold Organizer

A powerful embryonic tissue that can program surrounding cells to form the body axis.

Differentiation of the Telencephalon

The process where this brain region develops into cerebral hemispheres, olfactory bulbs, and basal telencephalon.

Cerebellum

A brain region critical for movement control, communicating between the cerebral cortex and other brain structures.

Medulla oblongata

The hindbrain structure responsible for autonomic functions such as heart rate and respiration.

Nervous system inducing factor

Although the nervous system is the 'default' state, BMP inhibition is necessary for ectoderm to differentiate into neural tissue.

Gastrulation

The process during embryonic development that leads to the formation of the three germ layers.

Organogenesis

The phase of development in which the three germ layers form organs.

Neural Tube

The embryonic structure that develops into the central nervous system, including the brain and spinal cord.

Neural Patterning

The process by which cells in the developing neural tube acquire specific identities.

Somites

Segments of mesoderm that give rise to vertebrae, muscles, and dermis.

Apoptosis

Programmed cell death that plays a critical role in shaping developing tissues.

Morphogens

Substances that dictate the fate of cells based on their concentration gradient.

Cell Signaling

The communication process between cells that directs cell growth, differentiation, and function.

Extracellular Matrix (ECM)

A network of proteins and molecules outside the cell that provides structural and biochemical support.

Endoderm-derived organs

Organs such as the liver, pancreas, and lungs that arise from the endoderm germ layer.

Neural Stem Cells

Undifferentiated cells in the nervous system that can differentiate into neurons and glial cells.

Cell Fate Determination

The process by which a cell becomes committed