Overview of the CNS Flashcards
What is present in the neural tube early in development?
3 visible swellings or vesicles
How are the 5 swellings present later in development created?
The first and third vesicles each subdivide
What are the three primary vesicles?
Prosencephalon, mesencephalon, rhombencephalon
What are the five secondary vesicles?
Telencephalon = gives cerebral hemispheres Diencephalon = gives thalamus and hypothalamus Mesencephalon = gives midbrain Metencephalon = gives pons and cerebellum Myelencephalon = gives medulla oblongata
What secondary vesicles come from the division of the prosencephalon?
Telencephalon and diencephalon
What secondary vesicles come from the division of the rhombencephalon?
Metencephalon and myelencephalon
What structures comprise the brainstem?
Midbrain, pons and medulla oblongata
What is the role of neurons?
Communicators = receive info chiefly via synapses, integrate info then transmit electrical impulses to another neuron/effector cell
What is the structure of most neurons?
Multipolar with many dendrites and one axon
Are glial cells or neurons more common in the CNS?
Glial cells are more numerous
What are the types of glial cells found in the CNS?
Astrocytes, oligodendrocytes, microglia and ependymal cells
What are some features of astrocytes?
Many numerous processes
Often star shaped
Roles in support, maintaining the BBB and environmental homeostasis
What is the function of oligodendrocytes?
Produce myelin in the CNS
What is the appearance of oligodendrocytes?
Numerous branches that extend to produce internodes of myelin around different axons
Round nucleus that stains moderately
What are microglia?
Cells of similar lineage to macrophages = carry out immune monitoring and antigen presentation
What is the appearance of microglia in the resting state?
Elongated nucleus and a number of short spiny cell processes
What is the appearance of microglia in the active state?
Become rounder and take on an appearance similar to a macrophage
What are ependymal cells?
Ciliated cuboidal or columnar epithelium that line the ventricles
How can you differentiate fissures from sulci?
Fissures are deeper
What is white matter?
Medullary centre = axons and their cell processes
What is contained within grey matter?
Huge number of neurons, cell processes, synapses and support cells
What are the lobes of the cerebral hemispheres?
Frontal, parietal, occipital, temporal and insular
What are the relations of the frontal lobe?
Anterior to central sulcus and superior to the lateral sulcus
What are the relations of the parietal lobe?
Posterior to the central sulcus
Superior to the lateral sulcus
Anterior to a line from the parieto-occipital sulcus to the pre-occipital notch
What are the relations of the occipital lobe?
Posterior to line from the parieto-occipital sulcus to the pre-occipital notch
What are the relations of the temporal lobe?
Inferior to the lateral sulcus
Posterior to line from the parieto-occipital sulcus to the pre-occipital notch
Where does the temporal lobe extend medially?
From temporal pole to a line between the pre-occipital notch and the anterior end of the calcarine sulcus
What are some features of the insular lobe?
Normally hidden
Plays important role in patient’s experience of pain
What are the meninges, from superficial to deep?
Dura mater, arachnoid mater and pia mater
Where is the enteric nervous system found?
In the digestive system from the oesophagus to the rectum
How are the neurons arranged in the enteric nervous system?
Into two plexuses in the wall of the gut
What are the two plexuses of the enteric nervous system?
Myenteric plexus = located between outer layers of smooth muscle
Submucosal plexus = located in submucosa
What artery gives the majority of the blood supply to the brain?
Internal carotid artery
How does blood drain from the brain?
Drains via system of dural venous sinuses
Where do the dural venous sinuses drain into?
The internal jugular vein via the jugular foramen
What is located in the calcarine sulcus?
Primary visual cortex
What is the corpus callosum?
White matter structure connecting the left and right cerebral hemispheres
