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Brain & spinal cord
CNS anatomy lec 1
Question | Answer |
---|---|
what are the components of forebrain? | ie. prosencephalon, cerebrum and diencephalon |
what are the components of midbrain? | ie. mesencephalon, midbrain |
what are the components of hindbrain? | ie. rhombencephalon, pons, medulla oblongata, cerebellum |
what re the brain lobes? | frontal, parietal, occipital, temporal |
why is the cerebrum folded into gyri and sulci? | to increase surface area |
what do gray and white matter refer to? | gray matter: cell bodies, white matter: axons |
how are the grey and white matter arranged in the brain? | grey matter on the outside, white matter on the inside |
what re basal nuclei? | cluster of subcortical nuclei deep to cerebral hemispheres |
what is the lateral sulcus of brain? | separates the temporal lobe from the frontal and parietal lobes of the brain |
what does the central sulcus of the brain do? | separates the frontal lobe from the parietal lobes |
what does the parieto-occipital sulcus of the brain do? | separates the parietal lobes from the occipital lobes |
what is the diencephalon? | masses of grey matter located around the third ventricle |
what are the components of diencephalon? | thalamus, hypothalamus, subthalamus, epithalamus |
what re the components of the brainstem? | midbrain, pons, medulla |
where is the cerebellum located? | in the post. cranial fossa, below the occipital lobe. has connections w/ the spinal cord, brainstem, and thalamus |
describe the location of the spinal cord | from the medulla oblongata superiorly to the sup. border of L2 vertebra in adults and L3 vertebra in children |
why is there a difference in spinal cord extension between adults and children? | due to the difference in growth rate between the spinal cord and vertebrae (spinal cord grows faster) |
what is conus medullaris of spinal cord? | end of the spinal cord that marks the end of the central nervous system (CNS), It is located at the level of the first or second lumbar vertebra in adults |
what is the clinical significance of filum terminale? | it provides a guide for surgeons to avoid injuring the spinal cord while performing procedures on the lower part of the vertebral column |
what is the cauda equina? | a bundle of spinal nerve roots that extend from the lower end of the spinal cord, at the level of the conus medullaris, through the lumbar and sacral vertebrae and into the pelvic cavity |
how are the grey and white matter arranged in the spinal cord? | grey matter on the inside surrounded by white matter |
what are important landmarks of the spinal cord? | ventral median fissure, dorsal median fissure, grey commissure, central canal, ventral and dorsal white commissure |
what is the function of the ventral gray horn? | for motor functions |
what is the function of dorsal grey horn? | for sensory function |
where are the lateral grey horns present? | present only in the thoracic, upper lumbar, and sacral segments, responsible for autonomic functions |
what is the function of ventral white columns? | receive motor impulses from the brain |
what is the function of dorsal white column? | send sensory impulses to the brain |
that is the function of lateral white columns? | present in the thoracic region, contra visceral motor neurons |
what re ascending tracts? | send sensory signals to the brain |
what are descending tracts? | receive motor signals coming from the brain |
number the spinal nerves | 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal |
what are the two roots of spinal nerves? | ventral root, dorsal root |
what are the spinal rami? | dorsal ramus, ventral ramus, meningeal branch |
what does the dorsal ramus innervate? | innervates post. trunk |
what does the ventral ramus innervate? | anteroposterior trunk and extremities |
what re plexus? | networks formed by ant. rami of spinal cord (except for the ones of the thoracic region) |
what are the two main cell types of the CNS? | neurons and neuroglial cells |
what is the function of neurons? | generate and propagate electrical and chemical signals |
what is the function of neuroglial cells? | modulate neurons function and signaling (supportive to neurons) |
what are the four types of neuroglial cells? | osteocytes, oligodendrocytes, microglial cells, ependymal cells |
describe astrocytes morphology | many cytoplasmic processes and perivascualr feet |
what are the two types of astrocytes? | fibrous: white matter: long but thin processes protoplasmic: gray matter: short but thick processes |
what are the functions of astrocytes? | framework support, supports BBB, recycling of neurotransmitters |
describe oligodendrocytes morphology | small cell body, conspicuous cytoplasm, long thin processes rich in microtubules |
what is the function of oligodendrocytes? | forms myelin sheaths within CNS |
what is the difference between oligodendrocytes and shwann cells? | oligodendrocytes can cover more than one segment of the axon or of multiple neurons, within CNS shwann cells cover only one segment at a time, outside CNS |
describe microglia morphology | small cells, elongated nuclei, several short branched processes |
what is the function of microglia? | macrophages of the CNS |
describe the ependyma morphology | simple cuboidal to columnar epithelium |
what is the function of ependymal cells? | line the ventricular system (ie. brain cavities) |
what are three types of ependymal cells? | ependomocytes: majority, ciliated, no tight junctions tanycytes: long basal processes, transport chemicals from CSF to piutary portal system choroidal epithelial cells: cover choroid plexus, ciliated |
what is the function of the BBB? | protect the brain from harmful substances and pathogens |
what are the components of BBB? | 1. tight junctions between endothelial cells 2. thick basement membrane 3. processes of astrocytes |
what arteries provide blood supply to the brain? | internal carotid artery and vertebral arteries |