48 Questions
What appears on the 17th day of CNS development?
Neural plate
What is the neural plate wider at the cranial end?
Where the brain will arise
What occurs during the 18-21 day period of CNS development?
Neurulation
What develops on the 21st day of CNS development?
Neural tube and crests
What is the neural plate a thickening of?
Ectoderm
What closes on the 25th day of CNS development?
Neuroporus anterior
During neurulation, what forms from the neural plate?
Neural tube
What is the purpose of the neural crest cells?
Forming sensory ganglia cells
What are the three primary brain vesicles?
Forebrain, midbrain, and hindbrain
What is the caudal part of the roof plate of the diencephalon?
Pineal body
What is the significance of the cervical flexure?
Flexure between the hindbrain and the spinal cord
What forms the lateral walls of the diencephalon?
Alar plates
What is the derivative of the neural tube?
Neurons of the CNS and glia cells of the CNS
What is the result of the continuous growth of the cerebral hemispheres?
Formation of the frontal, temporal, and occipital lobes
What is the term for the transformation of the neural plate into the neural tube?
Neurulation
What is the derivative of the mesenchyme?
Microglia
What is the function of the hypothalamic sulcus?
Divides the plate into thalamus and hypothalamus
What does the thalamus invaginate into?
The lumen of the diencephalon
What develops from the median portion of the prosencephalon?
The diencephalon
What is the origin of the adenohypophysis?
Ectoderm
What is a defect characterized by the absence of brain tissue?
Anencephaly
What is the critical period for the development of anencephaly?
23rd-26th day of pregnancy
What is the result of a failure of neural tube closure?
Neural tube defect
What is characterized by an ossification defect in the bones of the skull?
Cephalus deffectus
What is the location of the region that will give rise to the brain?
Cranial end of the neural plate
What is the neural plate a thickening of?
Ectoderm
What is the fate of the neural crest cells?
They will give rise to various tissues and structures
What occurs at the 21st day of CNS development?
Neural tube and crest formation
What is the significance of the neural groove?
It is the initial stage of neurulation
What is the term for the process of neural plate transformation into the neural tube?
Neurulation
What is the role of the hypothalamic sulcus?
Divides the diencephalon into thalamus and hypothalamus
Which structure develops from the lower portion of the alar plate?
Hypothalamus
What is the origin of the neurohypophysis?
Neuroectoderm
What is the result of a failure of neural tube closure?
Spina bifida
What is the term for the defective ossification of the bones of the skull?
Cephalus Deffectus
During which period of development does anencephaly occur?
23rd-26th day
What is the result of a neural tube defect characterized by the absence of brain tissue?
Anencephaly
What is the name of the structure that develops from the median portion of the prosencephalon?
Diencephalon
What is the result of the fusion of the neural folds?
Formation of the neural tube
What is the origin of the neurons of the central nervous system?
Neural tube
What is the derivative of the neural crest?
Schwann cells, melanocytes, and c-cells
What is the term for the transformation of the neural plate into the neural tube?
Neurulation
What is the result of the expansion of the brain?
Formation of the primary brain vesicles
What is the origin of the glia cells of the CNS?
Neural tube
What is the result of the growth of the cerebral hemispheres?
Formation of the frontal, temporal, and occipital lobes
What is the derivative of the ventricular zone?
Internal limiting membrane
What is the term for the most rostral of the brain vesicles?
Telencephalon
What is the result of the formation of the lamina terminales?
Formation of the lateral ventricles
Study Notes
Nervous System Development
- Develops from Ectoderm
- Neural plate forms at the caudal end, narrower and gives rise to the spinal cord
- Neural folds rise, and the neural plate "sinks" to form a neural groove
- Folds fuse to complete the neural tube, extending cephalically and caudally
- 2 openings at either end: cranial and caudal neuropores
Neurulation
- Transformation of the neural plate into the neural tube
- Fusion of neural folds at the level of the 4th somite
Neural Crest Cells
- Differentiate into:
- Schwann cells
- Melanocytes
- C-cells (in thyroid gland)
- Medulla of the adrenal gland
- Mesenchyme of the pharyngeal arches
Origin of Nervous System Cells
- Neural crest:
- Pseudounipolar neurons of spinal and cranial sensory ganglia
- Postganglionic neurons of autonomic nervous system
- Glia cells of peripheral nervous system (Schwann cells, satellite cells)
- Neural tube:
- Neurons of CNS
- Glia cells of CNS (astrocytes, oligodendrocytes, ependymal cells)
- Mesenchyme:
- Microglia (bone marrow derived)
Development of the Spinal Cord
- Lower part of the neural tube turns into the spinal cord
- Ventricular zone
- Internal limiting membrane
Expansion of the Brain
- Primary brain vesicles:
- Forebrain
- Midbrain
- Hindbrain
- Two flexures:
- Cervical flexure
- Cranial flexure (between hindbrain and spinal cord)
- Secondary brain vesicles:
- Forebrain: Telencephalon, Diencephalon
- Midbrain: remains just midbrain
- Hindbrain: Metencephalon, Myelencephalon
Development of the Telencephalon
- Most rostral of the brain vesicles
- Consists of:
- Cerebral hemispheres (two lateral outpocketings)
- Lamina terminales (a median portion)
- Lateral ventricles: cavities of the hemispheres
Development of the Cerebral Hemispheres
- Arise at the beginning of the 5th week as bilateral evaginations of the lateral wall of the prosencephalon
- Corpus striatum: basal part of the hemispheres begins to grow and bulges into the lumen
- Formation of the hippocampus
- Hemispheres cover the lateral aspect of the diencephalon, mesencephalon, and cephalic portion of the metencephalon
- Continuous growth of the cerebral hemispheres results in the formation of frontal, temporal, and occipital lobes
Development of the Diencephalon
- Rostral part of the roof plate: choroid plexus of the third ventricle
- Caudal part of the roof plate: pineal body
- Alar plates form the lateral walls of the diencephalon
- Thalamus and hypothalamus develop from the median portion of the prosencephalon
Development of the Cortex
- Divides into diencephalic and telencephalic regions
- Ependymal cells and vascular mesenchyme form the choroid plexus of the third ventricle
Defects
- Neural Tube Defects:
- Spina bifida occulta
- Spina bifida cystica
- Meningocele
- Meningomyelocele
- Myeloschisis (rachischisis)
- Cephalus Deffectus:
- Anencephaly
- Meningocele
- Meningoencephalocele
- Meningohydroencephalocele
- Hydrocephalus (internus and externus)
Nervous System Development
- Develops from Ectoderm
- Neural plate forms at the caudal end, narrower and gives rise to the spinal cord
- Neural folds rise, and the neural plate "sinks" to form a neural groove
- Folds fuse to complete the neural tube, extending cephalically and caudally
- 2 openings at either end: cranial and caudal neuropores
Neurulation
- Transformation of the neural plate into the neural tube
- Fusion of neural folds at the level of the 4th somite
Neural Crest Cells
- Differentiate into:
- Schwann cells
- Melanocytes
- C-cells (in thyroid gland)
- Medulla of the adrenal gland
- Mesenchyme of the pharyngeal arches
Origin of Nervous System Cells
- Neural crest:
- Pseudounipolar neurons of spinal and cranial sensory ganglia
- Postganglionic neurons of autonomic nervous system
- Glia cells of peripheral nervous system (Schwann cells, satellite cells)
- Neural tube:
- Neurons of CNS
- Glia cells of CNS (astrocytes, oligodendrocytes, ependymal cells)
- Mesenchyme:
- Microglia (bone marrow derived)
Development of the Spinal Cord
- Lower part of the neural tube turns into the spinal cord
- Ventricular zone
- Internal limiting membrane
Expansion of the Brain
- Primary brain vesicles:
- Forebrain
- Midbrain
- Hindbrain
- Two flexures:
- Cervical flexure
- Cranial flexure (between hindbrain and spinal cord)
- Secondary brain vesicles:
- Forebrain: Telencephalon, Diencephalon
- Midbrain: remains just midbrain
- Hindbrain: Metencephalon, Myelencephalon
Development of the Telencephalon
- Most rostral of the brain vesicles
- Consists of:
- Cerebral hemispheres (two lateral outpocketings)
- Lamina terminales (a median portion)
- Lateral ventricles: cavities of the hemispheres
Development of the Cerebral Hemispheres
- Arise at the beginning of the 5th week as bilateral evaginations of the lateral wall of the prosencephalon
- Corpus striatum: basal part of the hemispheres begins to grow and bulges into the lumen
- Formation of the hippocampus
- Hemispheres cover the lateral aspect of the diencephalon, mesencephalon, and cephalic portion of the metencephalon
- Continuous growth of the cerebral hemispheres results in the formation of frontal, temporal, and occipital lobes
Development of the Diencephalon
- Rostral part of the roof plate: choroid plexus of the third ventricle
- Caudal part of the roof plate: pineal body
- Alar plates form the lateral walls of the diencephalon
- Thalamus and hypothalamus develop from the median portion of the prosencephalon
Development of the Cortex
- Divides into diencephalic and telencephalic regions
- Ependymal cells and vascular mesenchyme form the choroid plexus of the third ventricle
Defects
- Neural Tube Defects:
- Spina bifida occulta
- Spina bifida cystica
- Meningocele
- Meningomyelocele
- Myeloschisis (rachischisis)
- Cephalus Deffectus:
- Anencephaly
- Meningocele
- Meningoencephalocele
- Meningohydroencephalocele
- Hydrocephalus (internus and externus)
This quiz covers the development of the nervous system from the ectoderm, including the formation of the neural groove and neural tube. Learn about the key stages of neural development.
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