CNS Development 2.0 Flashcards
Where do the “meninges” arise from?
Neural crest cells.
What are the three layers of “meninges”?
- Dura matter
- Aranchoid matter
(Supcharanoid space) - Pia matter
Where do the four ventricles arise from?
First ventricle: Telencephalon
Second ventricle: Telencephalon
(First- and second- ventricle = Lateral ventricles)
Third ventricle: Diencephalon
Fourth ventricle: Mesencephalon & Myelencephalon
What are the cavities of the brain vesicles filled with?
Cerebro Spinal Fluid (CSF)
What needs to happen for brain ventricles to form?
The embryonic CSF (eCSF) needs to be secreted into the ventricular lumen.
How are the lateral-, third- and fourth ventricle located?
Lateral ventricle: Enclosed in the cerebral hemispheres.
Third ventricle: Located at the center of the brain and walls are made up of hypothalamus and thalamus.
Fourth ventricle: Located dorsal and posterior to the medulla and pons and is anterior to the cerebellum.
How are the ventricle connected and how do they communicate with each other?
- The lateral ventricles communicate with the third ventricle via the interventricular foramina
- The Third ventricle communicates with the fourth ventricle via the cerebral aqueduct.
- The fourth ventricle is connected with the central canal of the spinal cord.
Where does the choroid plexus derive from?
From expansions of the roof plate neuroepithelium.
What are the main functions of the choroid plexus?
(Choroid plexus are found within ventricles)
- Production of the CSF
- Comprising the brain-blood barrier
Where does the CSF circulate
- Lateral ventricles
- Third and fourth ventricles
- Cisterns of the brain
- Subarachnoid space
Where does fluid carrying inflammatory waste go?
It returns to the subcharanoid space and drains into the lymphatic vessels and arachnoid granulations (connect CSF with venous circulation).
What is the role of the embryonic cerebral fluid?
- Regulating Neural Proliferation and Determination
- Brain development
- Growth Factors and Proteins
How do we call the defect caused by a slit in the brain tissue allowing CSF to escape?
Schizencephaly.
What is Anencephaly?
Failure of the tube to close
How do we call the defect caused by an obstruction of the foramen magnum?
Hydrocephaly
How do we call the dorsal structure part of the dorsal side of the neural tube?
Alar plate
What are neurons found in the alar plate?
Sensory Neurons
–> Low SHH, high BMP4
What is the ventral structure part of ventral side of the neural tube?
Basal plate
Which neurons are found in the basal plate?
Neurons primary associated with motor funtions
–> High SHH, low BMP4
How to we call neurons that acts as receptors of “sensory input” that bring information to the brain?
Afferent system.
How do we call neurons that act as effectors bringing information from the CNS as “voluntary motor output”
Efferent system
At the end of week 4 neurons in the spinal cord organise into four plates, where?
At the “Mantle layer”. (Outside of the ventricular layer)
Neurons in the spinal cord organise into four layers; how are the two pairs called?
- Dorsal/ Alar columns
- Ventral/Basal columns
The spinal cord has a groove that is laterally enclosed by two plates, how are they called?
Sulcus limitans
The sulcus limitans are connected by two non-neurogenic structures, how are they called?
“Floor plate” at the ventral end and
“Roof plate” at the dorsal end
What do the basal/ ventral columns divide into?
- Intermediolaoteral column Thoracic and lumbar
- Intermedioloateral column Sacral
Which spinal cord nerves is the Intermediolaoteral column Thoracic and lumbar connected to?
“Motor neurons”
Which neurons constitute the central autonomic motoneurons of the sympathetic division?
Motor neurons.
Which neurons constitute the central autonomic motoneurons of the parasympathetic division?
Visceral motor neurons.
Which spinal cord nerves is the intermediolaoteral column Sacral connected to?
Visceral motor neurons.
What is the Alar/ Dorsal column connected to?
Association neurons. Receive synapses from sensory neurons of the dorsal root ganglion.
In what way are the brain and spinal cord organised similarly?
Motor neurons are found ventral,
Sensory neurons are found dorsal.
Three roots arise from the spinal nerve, which are they?
- Dorsal root
- Ventral root
- Visceral root
Where do the axons in the dorsal root come from?
The cell bodies reside in the dorsal root ganglion.
Where do the axons in the ventral root come from?
The cell bodies reside in the ventral columns.
Where do the axons in the visceral root come from?
Too much sorry.
What induces the neuronal crest cells to form pharyngeal arches?
Rhombomers.
How are rhombomers regulated
By How genes.
What are the components of the brain stem?
Pons, Medulla, Midbrain
Where are most of the 12 cranial nerve cells nuclei located?
In the brain stem.
Where does the “Medulla” arise from and what are its main functions?
- It arises from Rhombomers 3-8.
- It is the relay center for the spinal cord and higher regions & Center for heart beat, reflex, respiration and vomiting.
Where does the Pons arise from and what are its main functions?
- Rhombomeres (1-2)
- Relay center for spinal cord and cerebral cortex with cerebellum.
Where does the cerebellum arise from and what are its main functions?
- From alar plates and rhombic limbs
- Coordination, postal control, balance
What are the parts of the mesencephalon (mid-brain)?
The Corpora Quadrigemina/ tectum
1. Superior colliculus
2. Inferior colliculus
What does the superior colliculus do?
- Receives axons from the retina and mediates ocular reflexes
- Contains a two-dimensional map representing half of the visual field
What does the inferior colliculus do?
- It relays inout from the cochlea to cerebrum
- Mediates auditory reflexes
What connects the midbrain tectum/ corpora quadrigemina to the cervical regions of the spinal cord?
Tectospinal tract
What are the important functions of the tectospinal tract?
- Contralateral connection of motor impulses from one side of the brain to opposite of the body
- Mediates reflex movements of the head in response to auditory and visual stimuli
Fetal valproate syndrome in rats
Affects development of superior colliculus
