Cortex PDF

Cortex 11 November 2024 09:55   Sulcus vs fissure; Both depressions - sulcus is shallow, fissure is deep   Deep fissure separating hemisphere = longitudinal fissure       Arterial supply      Circle allows for bypassing of potential blockages in the arteries    ...

Cortex 11 November 2024 09:55   Sulcus vs fissure; Both depressions - sulcus is shallow, fissure is deep   Deep fissure separating hemisphere = longitudinal fissure       Arterial supply      Circle allows for bypassing of potential blockages in the arteries            **Stroke** 2 main causes; Ischemic- interruption of blood supply to brain Haemorrhagic- rupture of blood vessel     Cortex consists of grey matter Forms a complete covering of the cerebral hemisphere   Folds - gyri Grooves - sulci   4 lobes Central sulcus separates frontal and parietal lobes   Lateral sulcus separates frontal and temporal lobes  Parieto-occipital sulcus     4 sulcus total; Central Lateral Parieto-occipital calcarine     Precentral and postcentral gyrus separated by central sulcus      **Function of the cerebral cortex**   Precentral gyrus - primary motor area Post central gyrus - primary somesthetic area                **White matters of the cerebral hemisphere**   Commissural fibres; connect 2 regions of the hemispheres Association fibres; connect cortical regions within the same hemisphere Projection fibres; afferent and efferent fibres   Corpus callosum= largest commissural fibre     Corpus callosum; Splenium Body Genu rostrum          Connects temporal lobes       **Association fibres- connect cortical regions within the same hemisphere** Short association fibres- lie beneath cortex and connect adjacent gyri Long association fibres- connect lobes within the same hemisphere             **Layers of cerebral cortex** Layer 1 = 1 most superficial Focus on 3-5   Layer 3- neurons give rise to association and commissural fibres Layer 4- termination site for thalamocortical afferents Layer 5- efferent fibres - pyramidal cells send efferent fibres to extracortical targets - thalamus- brainstem- basal ganglia ect In precentral gyrus - large pyramidal cells called Betz cells which give off fibres to form pyramidal tract        ACA = anterior cerebral artery Medial surface as far back as the parieto-occipital sulcus - supply leg area   MCA = middle cerebral artery Most of lateral surface of cortex   PCA= posterior cerebral artery Inferolateral and medial surface of the temporal lobe Medial and lateral surface of the occipital lobe - supply the visual cortex       Circle of willis  Anterior communicating artery Middle cerebral artery Anterior cerebral artery  Internal carotid artery  Posterior communicating artery Posterior cerebral artery  Basilar artery   Vertebral artery