Topography of the brain Flashcards
Where does the neuroectoderm receive signals from?
Notochord
Where does the nervous system develop from?
Ectoderm - Neural plate
How does the neural tube develop?
`Lateral neural plate margins fold inwards
When does the neural plate fold?
Embryonic day 20
What do the neural crest cells differentiate into?
Neurons and glia of the sensory and autonomic nervous systems
Cells of the adrenal gland
Epidermis
Skeletal/connective tissue of the head
What does the mantle layer form?
Brain parenchyma
What does the ependymal layer do?
Lines the ventricles
What does the lumen become?
Ventricles and central canal
What is anencephaly?
Failure of anterior neuropore to close
Fatal
Occurs in 1 in 1000 pregnancies
What is spinal bifida?
Failure of posterior neural tube to close
Leads to open vertebral canal
What is the difference between spina bifida occulta and spina bifida cystica?
Occulta - hidden, vertebral arch defect only
Cystica - meningocele- meninges projects out
Morbidity is 25% of cases
How are the main brain regions formed?
Expansion of the cranial end
What does the prosencephalon form?
Fore brain
Telencephalon - cerebral hemispheres
Optic vesicles- eyes
Diencephalon - thalamus/hypothalamus
What does the mesencephalon form?
Midbrain
What does the rhombencephalon form?
Hindbrain
Metencephalon - pons/cerebellum
Myelencephalon - medulla
When does the further development of secondary vesicles of the brain occur?
Embryonic day 36
What is found in grey matter?
Mainly neuronal cell bodies
What is found in white matter?
Mainly myelinated axons
What is the CNS made up of?
Grey and white matter
Describe the telencephalon
Comprises the cerebral hemispheres/cerebral cortex, components of the limbic system and the basal ganglia
What are cerebral hemispheres divided into?
4 lobes
- frontal
- temporal
- parietal
- occipital
Describe the cerebral cortex
Outer layer of cerebral hemispheres
Folded to form gyri and sulci
What is the precentral gyrus?
Motor
What is the postcentral gyrus?
Sensory
What is the lateral sulcus?
Divides temporal from parietal lobe
What is the central sulcus?
Divides frontal lobe and parietal lobe
What is found in precentral gyrus?
Premotor cortex
What is found in the frontal lobe?
Motor speech area of Broca
What is found in the occipital lobe?
Visual cortex
What is found in the central sulcus?
Somatosensory cortex
What is the corpus callosum?
White matter tract linking cerebral hemispheres
What is the corpus callosum split into?
Genu
Body
Splenium