(E1) 1 - Nervous System Development Flashcards
Exam 1
What does the notochord originally detach from?
The Endoderm
What functions as the primary inductor (signaling center) in the embryo?
The notochord
The notochord signals the overlying ectoderm to thicken and form what?
The neural plate - the primordium of the CNS
The notochord mostly degenerates as the vertebral bodies develop but persists as _____
intervertebral discs (specifically the nucleus pulposus)
What gives rise to the CNS and retina?
Neuroectoderm
The neural plate invaginates to form what?
Neural groove and adjacent neural folds
The neural folds fuse to form what?
The neural tube
What does the neural tube give rise to?
The brain vesicles and spinal cord
As the neural folds approach each other they migrate away from the ectoderm to form?
The neural crest
What differentiates into the epidermis?
Surface ectoderm
What are the neural tube and nervous system derived from?
Neuroectoderm
What does the neural crest give rise to?
Most structures of the PNS and ANS including ganglia of the nervous system, ARACHNOID MATER AND PIA MATER
What is neurulation?
Process of the formation of the neural tube.
As the neural folds fuse what do the cranial and caudal ends remain open as
Rostral neuropore and caudal neuropore
When do the rostral and caudal neuropores close?
When a blood supply is established
The cells of the neural tube form what?
Brain and spinal cord
What does the neural canal form?
The ventricular system of the brain and the central canal of the spinal cord
In what zone do the cells of the neural tube arise from?
Ventricular Zone
In what zone do neurons develop and become gray matter of the spinal cord?
Intermediate Zone
In what zone do axons grow into it and become the white matter of the spinal cord?
Marginal Zone
What is a sulcus limitans?
Longitudinal groove indicating separation between differentially clustered cells. (length of the spinal cord)
Describe the Alar Plate.
- dorsal in position
- form dorsal gray columns (dorsal horns of gray matter)
- AFFerent function
Describe the Basal Plate.
- ventral in position
- form ventral and lateral gray columns (ventral and lateral horns of gray matter)
- EFFerent function
T or F: neural crest gives rise to ganglia sensory and autonomic
True
What causes the alar and basal plates to assume a more latero-medial position in the brainstem?
Due to the development of the cerebellum and subsequent flaring of the fourth ventricle
Where and what does the sulcus limitans persist as?
Persists in the brainstem as a landmark between alar and basal plates.
Neurons in ganglia such as DRG and other sensory ganglia are mostly what kind - with few exceptions
Pseudounipolar
Describe the movement of sensory info through neurons in the ganglia
- Initially bipolar and unite to a T shape
Peripheral process =Then acts as a dendrite and conducts an impulse towards the cell body.
Central process = Enters spinal cord and forms dorsal roots
What are the 3 general types of neurons?
- Multipolar (most neurons - multiple dendrites, single axon)
- Pseudounipolar (single bifurcating process, peripheral and central)
- Bipolar (one process from each end)
What is another name for forebrain?
Prosencephalon
What is another name for midbrain?
Mesencephalon
What is another name for hindbrain?
Rhombencephalon
What does the brain initially develop from?
3 primary vesicles
What are the 5 secondary vesicles?
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
What does the forebrain divide into?
Telencephalon and diencephalon
What does the midbrian divide into?
It doesn’t - remains Mesencephalon
What does the hindbrain divide into?
Metencephalon and Myelencephalon
What is a cervical flexure?
bend/turn at spinal cord
What is a midbrain flexure?
bend/turn at midbrain
What are the two exceptions of sensory structures that aren’t neural crest-derived?
Olfactory and Optic
What are ventricles?
Expansion of the neural canal
What does the telencephalon give rise to?
Cerebral hemispheres and lateral ventricles 1-2
What does the diencephalon give rise to?
Thalami and third ventricle
What does the mesencephalon give rise to?
Midbrain and Aqueduct
What does the metencephalon give rise to?
Pons, Cerebellum and upper part of fourth ventricle
What does the myelencephalon give rise to?
Medulla and lower part of fourth ventricle
