Session 1 Flashcards
Appreciate the role of neuroglia
90% cell type in brain
Formed of astrocytes, oligodendrocytes, microglia, epemdymal cells
Describe the external appearance of the brain
Cerebral hemispheres –> cortex (frontal, parietal, temporal, occipital lobes)
Thalamic masses
Cavities - ventricles
Cerebellum
Brainstem - midbrain, pons, medulla
Grooves = sulci, major sulci = fissure, ridges/elevations = gyri
Describe the external appearance of the spinal cord
Swellings for cervical and lumbar plexus
Ends at conus medullaris
Describe the dura and compartments of the cranial cavity
Dura mater:
Falx cerebri - sagittally in midline, separates R+L hemispheres
Tentorium cerebelli - roof over posterior cranial fossa, divides into supra/infratentorial
Define the term neural crest and list some neural crest derivatives
Neural crest - cells of the lateral border of neuroectoderm tube –> mesoderm –> epithelial to mesenchymal transition
Derivatives - cranial nerves, dorsal root ganglion, para/sympathetic ganglia, connective tissue, odontoblasts, dermis, C cells, heart, melanocytes, adrenal medulla
Describe the timeline of and formation of the neural tube
Day 18 - induction of neural plate
Day 19 - elevation of lateral edges to form neural grove
Day 21-23 - neural folds approach and fuse in midline to form neural tube
Day 25 - anterior neuropore closes, shortly followed by (day 28) posterior neuropore
Explain some neural tube defects, how they result and their diagnosis
Result from failure of neural tube to close:
Cranially - encephaly
Causally - spina bifida –> hydrocephaly
Failure of neural fold elevation –> rachischisis (complete spina bifida)
Diagnosis - elevated maternal a-fetoprotein, USS
*hydrocephaly readily treatable by use of a shunt
Describe the ventricular system of the brain
Interconnected reservoirs filled by CSF
Lateral ventricle –> third ventricle –> cerebral aqueduct –> fourth ventricle
Describe the divisions of the nervous system during neural fold formation
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
Describe the divisions of the nervous system at 5 weeks development
Telencephalon --> cerebral hemispheres Diencephalon --> thalamus Mesencephalon --> midbrain Metencephalon --> pons, cerebellum Myelencephalon --> medulla oblongata
Describe the development of the spinal cord and its implication in performing a lumbar puncture
In the third month the spinal cord and vertebral column are the same length
After, the vertebral column grows faster, leading to the cauda equina (bundle of spinal nerves)
In a LP procedure, the needle should be inserted at L3/L4 or L4/L5 as it is suitably below the spinal cord (terminates at L1)
In neonates, the spinal cord terminates at L1-L3 so the LP should be performed lower than in adults
Understand how grey and white matter are arranged in the spinal cord, cerebral cortex and sub-cortical aspects of the brain
Grey matter - inside, composed of cell bodies, synapses, dendrites, axon terminals, function of the senses and motor control, no myelin sheath White matter - outside, composed of axons (nerve fibres), co,poses thalamus, hypothalamus, found between brainstem and cerebellum, allows communication, controls autonomic functions (temperature, blood pressure, heart rate), myelinated Dorsal root (back) is where sensory fibres enter Ventral root (front) is where motor fibres leave
Understand the meaning of the terms ‘nucleus’, ‘ganglion’ and ‘tract’ as used in neuroanatomy
Nucleus - a cluster of densely packed cell bodies of neurons in the CNS
Ganglion - a cluster of cell bodies of neurons in the PNS
Tracts - a bundle of axons that connects one part of the nervous system to the other
Appreciate the central and peripheral decisions of the nervous system
CNS –> brain/spinal cord
PNS –> somatic –> sensory/motor
PNS –> autonomic –> sympathetic/parasympathetic
Describe important features on the external appearance of the brain
Central sulcus - pre central gyrus (motor), post central gyrus (sensory)
Lateral sulcus - division of frontal/temporal lobes
