Neuroanatomy Flashcards
What are the components of the midbrain?
Mesencephalon
- tectum
- tegmentum
What are the components of the hindbrain?
Metencephalon & myelencephalon
Metencephalon:
- pons
- cerebellum
Myelencephalon:
- medulla
What is the difference in composition of grey and white matter?
Grey matter = layers of cell bodies (but no nuclei)
White matter = axons
What is the main difference in imaging between a CT head scan and an MRI head scan?
CT head = ischaemic tissue looks the same as normal tissue
MRI head = distinguishes infarcted tissue from normal tissue
What are the main cells comprising the CNS?
Neuroglia (90%)
Neurones (10%)
What does it mean to say neuronal networks have emergent properties?
Neuronal networks (neural circuits - connections of neurones) have complex manners not seen in the individual members of the network, inc. consciousness, sensory awareness, thought processes, sensory attention, etc.
Why is there a difference between neural & vertebral levels?
Somites do not travel all the way down the vertebral column, therefore not every vertebral level is next to the corresponding neural level
Contrast the anatomy & disease states of the CNS & PNS.
CNS PNS
Covered in meninges Covered in endoneurium,
perineurium, & epineurium
Myelin = oligodendrocytes Myelin = Schwann cells
Adaptable Dependent on CNS
DISEASES \++intracranial pressure nerve compression syndromes multiple sclerosis demyelinating polyneuropathies e.g. Guillain-Barré no capacity to regenerate capacity to regenerate after injury glia ---> malignant tumours all tumours are benign neurones ---> benign tumours
Describe the anatomy of the spinal cord.
Continuation of the medulla
Enlargement at cervical level (brachial plexus) and lumbar level (lumbo-sacral plexus)
Central cavity throughout length (central canal)
Ends in conus medullaris
What are the different regions of the cranial base?
ANTERIOR = alveolar arches of maxilla —> posterior edge of hard palate
MIDDLE = posterior edge of hard palate —> anterior edge of foramen magnum
POSTERIOR = behind middle area
What is responsible for the internal appearance of the roof of the calvaria?
- imprints of blood vessels
- foramina for emissary veins
- granular pits (where CSF moves from ventricles into venous system)
What are the different components of the telencephalon?
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
What are sulci? What are gyri? What are the major sulci, gyri, & projections of the brain?
SULCI = grooves or depressions in the brain (major sulci = fissures)
- LONGITUDINAL FISSURE = divides left & right hemispheres
- parietal-occipital sulcus
- calcarine sulcus
GYRI = ridges or elevations in the brain
- precentral gyrus (motor)
- postcentral gyrus (sensory)
- superior temporal gyrus
- cingulate gyrus
- parahippocampal gyrus
Projections:
FALX CEREBRI & TENTORIUM CEREBELLI = downward projection of meningeal dura mater, divides left & right hemispheres and supra-tentorial & infra-tentorial compartments, secures brain, resists displacement of brain during acceleration/deceleration
TENTORIAL INCISURE = allows passage of midbrain through tentorium cerebelli
Septum pellucidum
Fornix
Corpus callosum
What are the components of the forebrain?
Telencephalon & diencephalon
Telencephalon:
- cerebral cortex
- basal ganglia
- hippocampus
- amygdala
Diencephalon:
- thalamus
- hypothalamus
What are the different territories of the grey matter of the spinal cord?
Dorsal horn = sensory neurones
Ventral horn = somatic motor neurones
Lateral horn = autonomic motor neurones (bulge caused by autonomic cell bodies)
- only present at T1-L2 (sympathetic) or S2-S4 (parasympathetic)
- more grey matter present at these levels due to brachial & sacral plexuses
- autonomic ganglia are prevertebral and paravertebral
Central part & central canal = interneurones (only within spinal cord)
What is the trigeminal cave?
Cell bodies of trigeminal nerve in dorsal root ganglion
Contrast the effects of the dorsal root or ventral root entrapment.
Dorsal root entrapment —> pain (no reduced motor function)
note: can treat by removing dorsal root (dorsal root rhizotomy)
Ventral root entrapment —> reduced motor function (no pain)
What is the spinal cord?
Assembly of neuronal cell bodies and axons of nerves collected as bundles or fibre tracts housed in the vertebral column
What are the functions of neuronal cell bodies?
Neural level of spinal cord:
- local reflexes
- sensory functions of local neuronal segment (dermatome)
- supplying muscles of local neuronal segment (myotome)
Relaying sensory information to the brain via neurones with long axons, collected as fibre bundles which travel together
Define fibre tracts/fasciculi.
Collection of axons with similar origins and destinations which ascend to the cerebral cortex.
What are the functions of the axonal fibres of the spinal cord?
- carry sensory information from the surface of the body and muscles to the brain (ascending tracts)
- carry motor information from the brain to cell bodies of spinal motoneurones (descending tracts)