Development of the Brain Flashcards
The neural plate (from neuroectoderm) and neural groove develop on the posterior aspect of the trilaminar embryo at _____ weeks. This is induced by the notochord.
3
Neurulation begins at the 4th week (22-23 days). The cranial 2/3 will give rise to the 4th pair of somites, which is the future _______. The caudal 1/3 will give rise to the future ______ ______.
Brain
Spinal Cord
The neural tube first forms at the ______ somite. It proceeds cranially and caudally until only the neuropores remain. The cranial (rostral) neuropore closes at day ______, and the caudal neuropore closes at day _______.
25
27
The brain develops during the 3rd week from the ______ ______, cranial to the 4th pair of somites.
Neural tube
Fusion of neural folds in the cranial region and closure of rostral neuropore form the primary ______ ______.
Brain vesicles
What does the Telencephalon give rise to?
Cerebral hemispheres
Lateral ventricles
What does the Diencephalon give rise to?
Thalamus
Hypothalamus
Epithalamus
3rd ventricle
The forebrain, also called the _________, will give rise to the ________ and ________.
Prosencephalon
Telencephalon
Diencephalon
The midbrain, also called the _________, gives rise to the _______ and _______.
Mesencephalon
Midbrain
Aqueduct
The hindbrain, also called the __________, will give rise to the _________ and _________.
Rhombencephalon
Metencephalon
Myelencephalon
What does the Metencephalon give rise to?
Pons
Cerebellum
Upper part of 4th ventricle
What does the Myelencephalon give rise to?
Medulla
Spinal Cord
Lower part of 4th ventricle
During which week do the secondary brain vesicles form (i.e., forebrain divides into telencephalon and diencephalon, etc.)?
5th week
During the 5th week, the embryonic brain grows rapidly and bends ventrally with the head fold. Bending produces the _______ _______ (midbrain) and the ________ _______ (hindbrain-SC junction). They both fold in the same direction, flexing toward the trunk.
Midbrain Flexure (Mesencephalic Flexure) Cervical Flexure
Unequal growth produces the ________ ________, which folds in the opposite direction, like extension, at the meten-myelencephalon junction.
Pontine Flexure
Brain flexures produce considerable variation position of the…
Gray and white matter
This is what demarcates the hindbrain from the spinal cord, and its junction is arbitrarily defined as the level of superior rootlet of C1 (roughly located at foramen magnum).
Cervical Flexure
This is what divides the hindbrain into the metencephalon (rostral) and myelencephalon (caudal).
Pontine Flexure
***Remember, the myelencephalon gives us the medulla and the metencephalon gives us the pons and cerebellum.
What makes up the cavity of the hindbrain?
4th ventricle and central canal in the medulla
In the caudal myelencephalon, neuroblasts in the alar plates migrate into the marginal zone. This forms the _______ ______ and _______ _______, which are sensory nuclei that associate with their paired, afferent tracts.
Nuclei Gracilus
Nuclei Cuneatus
***Remember, alar = afferent and basal = efferent!
In the myelencephalon, the _________ (ventral) consist of CST fibers.
Pyramids
The rostral myelencephalon is wide and flat. The Pontine Flexure cause the walls of the medulla to move laterally and the roof plate is greatly thinned. This causes the (ALAR/BASAL) plates to become lateral to the (ALAR/BASAL) plates, making motor nuclei develop medial to the sensory nuclei.
Alar
Basal
Neuroblasts (from neuroectoderm) in the basal plate develop into motor neurons. Nuclei organize into cell columns on each side, which have what modalities?
General Somatic Efferent (GSE)
Special Visceral Efferent (SVE - Branchial)
General Visceral Efferent (GVE)
Neuroblasts (from neuroectoderm) in the alar plates of the medulla form neurons that are arranged in columns on each side. What are their modalities?
General Visceral Afferent (GVA)
Special Visceral Afferent (SVA)
General Somatic Afferent (GSA)
Special Somatic Afferent (SSA)
This basal column consists of the nucleus of the hypoglossal nerve in the caudal-most rhombencephalon, that of nerve VI more cranially in the rhombencephalon, that of nerve IV in the most cranial rhombencephalon (later displaced into the caudal midbrain), and that of nerve III in the mesencephalon.
GSE
This basal columns contains three nuclei serving nerves V, VII, and IX through XI and is confined to the rhombencephalon. The nuclei serving nerves V and VII are located cranially in the rhombencephalon and caudally the elongated Nucleus Ambiguus supplies fibers for nerves IX, X, and XI.
SVE (Branchial)
This basal column includes two nuclei located in the rhombencephalon. The salivary nuclei provide preganglionic parasympathetic innervation to the salivary and lacrimal glands via nerves VII and IX. Just caudal to this nucleus is the dorsal parasympathetic neurons innervating the viscera. The Edinger-Westphal nucleus (III) is located in the mesencephalon.
GVE (Parasympathetic)
This alar column consists of the nucleus that receives interoceptive information via the glossopharyngeal nerve (IX) and the vagus nerve (X).
GVA