2. Embryology Of The Brain And Spinal Cord Flashcards
What is the embryological germ layer derivative of the nervous system?
Ectoderm
Which structure chemically directs embryological development?
Notochord
What occurs on day 18 of development?
A medial band of ectoderm thickens to form the NEURAL PLATE (aka neuroectoderm)
What occurs on day 19/20 of development?
Neural groove forms, lateral to this are the neural folds
What occurs on day 21/22 of development?
Neural folds fuse to close the neural tube. Cranial and caudal ends remain open (neuropores)
What happens to the neural tube on day 24 and 26?
Day 24 - cranial neuropore closes
Day 26 - caudal neuropore closes
What is the clinical diagnosis when the caudal neuropore remains open?
Spina bifida
What is the name and fate of the ectodermal cells lateral to the neural tube?
Neural crest cells Differentiate into various cells of the peripheral nervous system: Melanocytes (pigment) Craniofacial cartilage and bone Smooth muscle Peripheral and enteric neurons Glia (Schwann cells)
What is the fate of the notochord?
Central part of vertebral discs
What is the name and fate of the mesodermal bulges lateral to the neural tube?
Somites Important for organising the segmental nature of vertebrate embryos Develop into: Vertebrae Vertebral skeletal muscle Associated nerves
What are the primary vesicles of the brain?
Prosencephelon (forebrain)
Mesencephelon (midbrain)
Rhombencephalon (Hindbrain)
What are the secondary vesicles of the PROSENCEPHALON?
Telencephalon
Diencephalon
Optic growths
What is the secondary vesicle of the MESENCEPHALON?
Mesencephalon
What are the secondary vesicles of the RHOMBENCEPHALON?
Myelencephalon
Metencephalon
When do the primary vesicles develop?
In the 4th week
When do the secondary vesicles develop?
In the 5th week
What is developed from the optic growths?
Optic nerves and retina of the eyes
What is developed from the telencephalon?
Cerebral cortex Basal Ganglia Cerebral white matter Internal capsule Olfactory bulbs Corpus callosum Limbic system structures a Association fibres
What is developed from the DIENCEPHALON?
Thalamus Hypothalamus Subthalamus Epithalamus Third ventricle
What is developed from the MESECEPHALON?
Midbrain (tectum, colliculi, tegmentum and cerebral aqueduct)
What signifies the beginning and end of the process of neurulation?
Beginning - formation of the neural plate (18)
End - Closure of the neural pores (24/26)
What is developed from the METENCEPHALON?
Cerebellum
Pons
What is developed from the MYELENCEPHALON?
Medulla oblongata
Medullary pyramids
What are the 2 types of information in the nervous system?
Sensory (afferent)
Motor (efferent)
