Development of the Brain Flashcards
During week 3 the development of the neural plate, comprised of the neural folds found laterally, and the neural groove found medially, is induced by what structure?
Notochord
The neural tube forms at which of the following somites?
A. 1st
B. 2nd
C. 3rd
D. 4th
E. 5th
5th Somite
Neuralation begins at the 4th week, and grows both cranially (rostrally) and caudally. These cranial and caudal neuropores eventually close off, but at different times. What day does the cranial and caudal neuropore close?
Cranial Neuropore: Day 25
Caudal Neuropore: Day 27
The 4th pair of somites and the superior somites, or the cranial 2/3rds of the neural tube forms what structure?
The caudal 1/3 of the neural tube forms what structure?
Cranial 2/3rds= Brain
Caudal 1/3: Spinal cord
The fusion of the neural folds causes the rostral/cranial neropore to close and form the primary brain vesicles.
What are the 3 primary vesicles?
Prosencephalon
Mesencephalon
Rhomboencephalon
During week 5 the 3 primary brain vesicles give become 5 secondary vesicles. What are these 5 secondary vesicles, and which primary vesicles do they come from?
Prosencephalon: Telencephalon and Diencephalon
Mesencephalon
Rhombencephalon: Metencephalon and Myelencephalon
What do the walls of the Telencephalon become?
What do the cavities of the Telencephalon become?
Cerebral Hemisphere
Lateral Ventricles and part of 3rd ventricles
What do the walls of the Diencephalon become (3)?
What do the cavities of the Diencephalon become?
Epithalamus, Thalamus, Hypothalamus
3rd Ventricle
What do the walls of the Mesencephalonbecome?
What do the cavities of the Mesencephalon become?
Midbrain
Cerebral aqueduct
What do the walls of the Metencephalon become?
What do the cavities of the Metencephalon become ?
Pons and Cerebellum
Upper part of 4th Ventricle
What do the walls of the Meyelencephalon become?
What do the cavities of the Meyelencephalon become?
Medulla Oblongata
Lower part of the 4th Ventricle
During week 5, the brain bends and grows rapidly producing the flexures of the brain. All of the following flexures create a fold on the anterior portion, except for which of the following that forms on the posterior portion and is ultimately responsible for putting the cerebellum over and posterior to the pons?
A. Midbrain Flexure
B. Cervical Flexure
C. Pontine Flexure
Pontine Flexure
Metencephalon and meyelencephalon junction
Brain flexures produce a considereable amount of variation thats seen in the postiioning of gray and white matter. Indicate where each of the following flexures are found?
Midbrain Flexure:
Cervical Flexure:
Pontine Flexure:
Midbrain Flexure: at the mesencephalon
Cervical Flexure: between the hindbrain and spinal cord
Pontine Flexure: at metencephalon and myelencephalon junction
The Cavity of the hindbrain is responsible for forming what two structures?
Fourth Ventricle
Central Canal in the medulla
The alar plates are located more laterally and give rise to __________, while the basal plates are located more medially and gives rise to __________
Alar plates: AFFERENT inputs
Basal Plates: EFFERENT outputs
Neuroblasts in the alar plates found in the caudal portion of the meylencephalon go into the marginzal zone and become what two sensory nuclei?
Gracile Nucleus
Cuneate Nucleus
The rostral portion of the myelencephalon is wide and flat due to the movement of what flexure?
What structure does the roof plate of the myelencephalon’s cavity give rise to?
Pontine Flexure
inferior portion of the 4th ventricle
The metencephalon forms the pons and the cerebellum, as well as the superior portion of the 4th ventricle. Which of these develops from the dorsal part of the alar plates?
Cerebellum
What flexure is responsible for forcing the walls of the pons laterally in the metencephalon?
Pontine Flexure
Explain how we get the formation of the choroid plexus in the 4th ventricle? Include the involvement of the Tela Choroidea
The pia mater and the ependymal roof of the 4th ventricle come together to form the Tela Choroidea. The Tela Choroidea than invaginates and forms the choroid plexus
NOTE: Plexuses develop similarly in the roof of the 3rd Ventricle and medial walls of lateral ventricles
The epithelial lining of the choroid plexus is derived from which of the following?
A. Mesenchyme
B. Neuroepithelium
C. Mesoderm
D. None of the above
Neuroepithelium
CSF needs to be able to enter the subarachnoid space from ventricles. To do this apertures, foramen, etc need to form. Explain how this occurs in the 4th ventricle, and what apertures specifically develop.
The roof of the Tela Choroidea invaginates again and forms the median and lateral apertures
In the Mesencephalon (Midbrain), neuorblasts of the alar plate migrate to form what structure?
This structure formed from the alar plate eventually forms what other 2 structures that also make up the quadrigemina?
Tectum
Superior and Inferior Colliculi
In the mesencaphalon, neuroblasts from the basal plate form what structure that relates to the red nuclei, reticular nuclei, CN III nuclei, and CN IV nuclei?
Tegmental Nuclei
In the midbrain, extensions of white matter from the cerebral cortex come down and form what strucutre? What’s another name for this structure?
A. Superior Colliculi
B. Inferior Colliculi
C. Cerebral Peduncles
D. Tegmental nuclei
Cerebral Peduncles
Crus Cerebri
In the mesencephalon, the neural canal narrows and forms what structure that connects the 3rd ventricle to the 4th ventricle?
Cerebral Aqueduct
T/F: The substantia nigra comes from the mesencephalon and we are still not sure if its origin is from the basal or alar plates
True
The Diencephalon is a bunch of gray matter that starts as 3 swellings in the lateral walls of what ventricle?
A. Right Lateral Ventricle
B. Left Lateral Ventricle
C. 3rd Ventricle
D. 4th Ventricle
3rd Ventricle
The Epithalmus is seperated from the Thalamus by what structure?
The Thalamus is seperated from the Hypothalamus by what structure?
Epithalamic Sulcus
Hypothalamic Sulcus
Which of the following portions of the Diencephalon forms on either side of the 3rd ventricle?
A. Epithalamus
B. THalamus
C. Hypothalamus
D. Subthalamus
Thalamus
Which of the following portions of the Diencephalon comes from the neuroblasts in the intermediate zone where endocrine and homeostatic nuclei develop?
A. Epithalamus
B. THalamus
C. Hypothalamus
D. Subthalamus
Hypothalamus
What structure grows on the ventral or anterior surface of the hypothalamus?
A. Inferior and Superior Colliculi
B. Lans Terminalis
C. Mammilary bodies
D. Optic Chiasm
Mammilary bodies
Which of the following portions of the Diencephalon develops from the roof and dorsal portion of the lateral wall?
A. Epithalamus
B. THalamus
C. Hypothalamus
D. Subthalamus
Epithalamus
In the caudal portion of the roof of the diencephalon there is a median diverticulum that is home to what melatonin producing, cone shaped gland?
Pineal Gland
The pituitary gland is formed by the fusion of the hypophyseal diverticulum (Rathke’s Pouch) and the neurohypophyseal diverticulum. Describe the growth of these two structures.
Which of these structures is responsible for forming the anterior pituitary gland and posterior pituitary gland?
Hypophyseal Diverticulum (Rathke’s pouch): is the upward growth of the stuodenum (oral cavity) and it develops the anterior pituitary
Neurohypophyseal Diverticulum is the downward groth of the diencephalon and forms the posterior pituitary gland
Is the anterior pituitary or posterior pituitary neurally derived?
Posterior Pituitary is actually neurally derived, and comes off the neurohypophyseal diverticulum
The Telencephalic or Cerebral Vesicles of the Telencephalon form what structure?
Cerebral Hemispheres
As the rostral neuropore closes the optic vesicles occur within the telencephalon and are the primordia of what 2 things?
Retina
Optic nerves
What structure allows the 3rd Ventricle to communicate with the cerebral hemispheres?
A. Interventricular Foramina
B. Cerebral Aqueduct
C. Median apeture
D. Lateral Apeture
Interventricular Foramina
The Balloon shape of the cerebral hemisphere is due to the cortex rapidly proliferating and the deeper portions moving at a slower pace. During the growth, the hemispheres expand and combine in the midline. Left over mesenchyme trapped between these growths forms what strucuter?
Falx Cerebri
T/F: The median wall of cerebral hemisphere (Telencephalon) becomes very thin and is continuous with the roof of the 3rd ventricle, also the location of the choroid plexus
True
What is Holoprosencephaly?
What defects is it often closely associated with?
Holoprosencephaly is when the Telencephalon nerver divides into left and right hemispheres, leaving us with only one lobe
Defects of the face like cyclopia, single nostrils, facial clefts,, pre-maxillary agenesis, etc.
Cerebral commissures are white matter tracts that connect portions of the brain. The Cerebral commissures can be found along the Lamina Terminalis. Which of the following two cerebral commissures form first?
A. Anterior commissure and Anterior portion of Corpus Callosum
B. Anterior Commissure and Hippocampal commissure
C. Corpus Callosum and Hippocampal commissure
D. Septum Pellucidum and Corpus Callosum
Anterior Commissure and Hippocampal commissure
Which of the following cerebral commisures interconnects the olfactory bulb with the hemispheres?
A. Anterior Commissure
B. Hippocampal Commissures
C. Corpus Callosum
D. Septum Pellucidum
Anterior Commissure
Which of the following cerebral commisures seperates the right and left lateral ventricles?
A. Anterior Commissure
B. Hippocampal Commissures
C. Corpus Callosum
D. Septum Pellucidum
Septum Pellucidum
All of the following statements are true of agenesis of the corpus callosum EXCEPT?
A. Condition may be asymptomatic
B. Mental deficiencies and seizures are common
C. Associated with more than 50 human congenital syndromes
D. All are correct
All are correct
Initially during fetal development the cerebral cortex is smooth but growth causes the development of the sulci and gyri. Postnatal growth of the brain occurs through growth of what two process?
Increasing size of neurons
Myelination of axons
Which of the following layers has the oldest neurons when Layer 1 is the most superior and Layer 6 is the deepest?
A. Layer 1
B. Layer 3
C. Layer 4
D. Layer 5
Layer 5
neurons born later on are found more superficially on the brain
Lissencephaly means smooth brain, and it results from the abnormal migration of younger neurons to the surface. Initally the child will appear normal, but later seizures, mental deficiency and spastic quadriplegia develop. The following terms are used to describe what the brain looks like. Define these terms
Pachygyria:
Agyria:
Neuronal Heterotopia:
Pachygyria: broad, thick gyri
Agyria: lack of gyri
Neuronal Heterotopia: abberant patterning of cells compared to a normal brain
Microcephaly is a neurodevelopmental disorder where the calvaria and brain are small, while the face is normal sized. There are many causes that can lead to the development of microcephaly, but in general what is the development attributed to?
Maternal Toxicity from exposure to toxins, infectious agents, alcohol abuse
