M555 Medical Neuroscience Lab 1: Gross Anatomy of Brain, Crainal Nerves and Cerebral Blood Vessels

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1 M555 Medical Neuroscience Lab 1: Gross Anatomy of Brain, Crainal Nerves and Cerebral Blood Vessels Anatomical Directions Terms like,, and posterior provide a means of locating structures relative to the overall orientation of the nervous system. Complications with those terms mayarise for two reasons: i) humans stand upright ii) the CNS curves or flexes as it grows from the embryonic neural tube, and the forebrain structures (telencephalon and diencephalon) are oriented somewhat differently than the brain stem (midbrain,, medulla, ) and spinal cord. This drawing shows the application of these terms to the human central nervous system. Forebrain Orientation superior diencephalon telencephalon posterior midbrain inferior medulla Brain Stem and Spinal Cord Orientation superior spinal cord posterior inferior Axis of CNS

2 gross neuroanatomical structures and spaces forebrain telencephalon frontal lobe parietal lobe temporal lobe occipital lobe limbic lobe lateral sulcus central sulcus in the frontal lobe precentral gyrus in the temporal lobe superior temporal gyrus transverse gyri parahippocampal gyrus uncus in the parietal lobe postcentral gyrus angular gyrus supramarginal gyrus between the parietal and occipital lobes parieto-occipital sulcus in the occipital lobe calcarine gyrus in the limbic lobe cingulate gyrus corpus callosum genu, body, splenium commissure lamina terminalis spaces containing cerebrospinal fluid lateral ventricles interventricular foramina (cerebral) aqueduct third ventricle fourth ventricle central canal (in spinal cord) forebrain diencephalon pineal medial surface of the thalamus medial surface of the hypothalamus mammillary bodies brain stem mesencephalon tectum superior and inferior colliculi (corpora quadregemina) substantia nigra cerebral peduncles pontine nuclei middle cerebellar peduncle medulla obex location of column nuclei upper parts of columns olives and inferior olivary nuclei pyramids lateral hemispheres tonsils vermis meninges dura mater arachnoid and pia mater (leptomeniges) arachnoid granulations (arachnoid villi) cranial nerves II XII olfactory bulbs and olfactory tracts optic nerves, optic chiasm and optic tracts arteries internal carotid As, middle and posterior cerebral As communicating arteries superior cerebellar A, AICA and PICA basilar artery vestibular arteries regions of cerebral cortex supplied by, middle and posterior cerebral arteries see next page...

3 Blood Supply to the Cerebral Cortex Three major arteries - the Anterior, Middle and Posterior Cerebral Arteries - supply the forebrain. Below are three views of the cerebral hemispheres. On the drawings, identify the regions supplied by these three major arteries. Lateral Surface of Right Cerebral Hemisphere Medial Surface of Left Cerebral Hemisphere lateral Inferior Surface of Right Cerebral Hemisphere

4 Cerebrovascular System Two systems of arterial blood flow supply the CNS. - the Internal Carotid System - the Vertebrobasilar System Internal Carotid System Find the remaining part of the Internal Carotid Arteries at the base of the brain. Anterior Cerebral Artery Anterior Communicating Artery Middle Cerebral Artery Posterior Cerebral Artery Posterior Communicating Artery Vertebrobasilar System Look for the Vertebral Arteries on the brain stem. Several smaller arteries branch from the vertebral arteries. Anterior and Posterior Spinal Arteries and the Posterior Inferior Cerebellar Arteries. Blood from the vertebral arteries enters the basilar artery. Basilar Artery is found on the surface of the, part of the brain stem. From the basilar artery, blood distributes to several smaller arteries: Superior Cerebellar Artery. Anterior Inferior Cerebellar Artery (AICA). Posterior Communicating Artery (PICA) cerebral A communicating A middle cerebral A internal carotid A posterior communicating A circle of Willis posterior cerebral A superior cerebellar A inferior cerebellar A posterior inferior cerebellar A vertebral A Circle of Willis A network of arteries in the vicinity of the optic chiasm forms an interconnecting network of vessels. Blood enters the Circle of Willis from both the Internal Carotid and Vertebrobasilar Systems.

5 MRIs Horizontal Views medulla (top row) pyramids (approx location) olive (approx location) inferior cerebellar peduncle (approx location) fourth ventricle vermis cerebellar hemispheres pontine nuclei (approx location) vertebral artieries and basilar artery Sagittal Views prime panel: bottom row, left-hand column corpus callosum splenium, body and genu cingulate gyrus and cingulate sulcus parieto-occipital sulcus calcarine sulcus lamina terminalis thalamus and hypothalamus mammillary body brain stem medulla, and midbrain tectum: superior and inferior colliculi pontine nuclei (location) cerebellar tonsil lateral ventricle, third ventricle, cerebral aqeduct and fourth ventricle cervical spinal cord Coronal Views lateral ventricles and third ventricle temporal lobe (and uncus) cingulate gyrus corpus callosum - vermis and hemispheres