FINALS Flashcards
multiple stages of nervous system.
early embryonic stages
childhood
adolescence
adulthood.
Stages of neural development
Neuron growth
Migration
Death
Adult neurogenesis
—the brain’s ability to reorganize in response to intrinsic or extrinsic experiences
neuroplasticity
What stages of development of nervous system is wherein the embryo is initially formed through fertilization, which occurs when a sperm cell and an egg cell unite into a single cell.
Embryonic stage
This fertilized egg cell, or zygote, starts dividing through the process of ____ to generate the cells that make up an entire organism.
mitosis
____ after fertilization, the developing embryo’s cells belong to one of three layers that form into the different tissues in the body (Betts et al., 2022).
Sixteen days
The ____, or inner tissue, is responsible for generating the lining tissues of various spaces within the body, such as the mucosae of the digestive and respiratory systems.
endoderm
The ___, or middle tissue, gives rise to most of the muscle and connective tissues.
mesoderm
the _____, or outer tissue, develops into the body’s outer layer of skin, hair, nails, as well as the nervous system.
ectoderm
As the embryo develops, a portion of the ___ differentiates into a specialized region of _____, which is the precursor for the tissue of the nervous system (Betts et al., 2022).
ectoderm
neuroectoderm
Cells in this region form a neural plate that begins to fold inward to form a neural groove that is lined on each side by a neural fold.
Neural Tube
As the anterior end of the neural tube starts to develop into the brain, it generates
three primary vesicles:
the forebrain (prosencephalon),
the midbrain (mesencephalon), and
the hindbrain (rhombencephalon) (Betts et al., 2022).
By _____ the three primary vesicles differentiate further into five secondary vesicles (Betts et al., 2022) (Figure 2).
week 5,
The forebrain enlarges into two new vesicles called the
telencephalon
diencephalon.
The telencephalon will become the cerebrum—the largest part of the adult brain which contains the lobes of the
cerebral cortex
hippocampus
basal ganglia.
diencephalon will give rise to several structures including the _____ and ______
thalamus
hypothalamus
A third secondary vesicle, the mesencephalon or midbrain, is composed of
tectum,
the cerebral aqueduct,
the tegmentum
cerebral peduncles.
The hindbrain develops into the final secondary vesicles, the ____ and _____
metencephalon
myelencephalon
metencephalon gives rise to the ___ and .____
pons
cerebellum
the myelencephalon gives rise to the adult structure known as the _____
medulla oblongata
Stages of Neural Development
- The brain is made up of neurons and glial cells.
- Neurons, also called nerve cells, are electrically excitable cells that transmit signals called action potentials to other neurons and are considered the fundamental units of the brain and nervous system (Ludwig et al., 2022).
-Glial cells, or neuroglia or simply glia, are the other type of cells found in the nervous system.
considered supporting cells, and help neurons complete their function for communication.
There are six main types of glial cells.
4 of them are found in the CNS and
2 are found in the PNS
Types of neuroglia
Central nervous system
- ependymal cells
- astrocytes
- oligodendrocytes
- microglia
Peripheral nervous system
- Satellite cells
- Schwann cells
____ neurons are generated every hour during this early developmental period (Silbereis et al., 2016).
4.6 million
, the cells being formed are neural stem cells.
neural proliferation
two basic types of stem cells,
pluripotent
totipotent cells.
can give rise to all of the cell types that make up the body,
Pluripotent cells
are more limited than pluripotent cells.
multipotent cells
refers to the process by which neurons travel from their original location to a new target location.
Neuronal migration
migration can be classified into two modes:
1) radial migration,
2) tangential migration.
occurs when neurons are guided by radial glial cells to migrate toward the surface of the brain following the radial pattern of the neural tube and ultimately establish the layered organization of the neocortex (Marin et al., 2003; Wong, 2002).
Radial migration,
second mode of neuronal movement,
tangential migration
Occurs when neurons move to the surface of the central nervous system (or orthogonal to the direction of radial migration).
tangential migration
Mechanisms of migration
Somal translocation
Glial-medicated migration
involves an extension that reaches out from the soma of the immature neuron to lead it on its journey to its target location.
somal translocation
involves the immature neuron “hopping onto” an extended glial cell.
glial-mediated migration.
By the end of migration, neurons are aligned in such a manner that enables them to acquire specific functions, interact with other neurons, and eventually give rise to neural circuits that make up the human nervous system; a process known as _________.
aggregation
_____ is thought to be supported by cell-adhesion molecules, which are located on the surfaces of cells. Cell-adhesion molecules are able to recognize identical or different cell types and subsequently adhere to molecules on other cells (Jaffe et al., 1990; Takeichi, 1988).
Aggregation
____ are clusters of communication channels between neighboring cells that link the cytoplasm of two cells and facilitate the exchange of ions and metabolites such as glucose, which subsequently promotes biochemical coupling between the two cells (Mese et al., 2007).
Gap junctions
which refers to the elimination of neurons in the nervous system, occurs extensively during development and is actually helpful for supporting brain development.
Neuronal cell death,
Neuron death is typically categorized as either
apoptosis or necrosis.
___ refers to active, programmed cell death to maintain appropriate development,
Apoptosis
refers to passive, accidental cell death resulting from environmental perturbations, such as trauma, toxins, or oxygen depletion
Necrosis
excessive necrosis can have detrimental consequences and is known to be associated with pathologies such as
-Alzheimer’s disease
- Parkinson’s disease and
-Stroke
The brain’s ability to reorganize or “rewire” its connections in response to intrinsic or extrinsic experiences is called _____.
neuroplasticity
Our understanding of the rules that govern the networking of neurons goes back to the groundbreaking work by
Donald Hebb over 70 years ago.
“Neurons that fire together, wire together.”
Donal Hebb
