Transcript Document
Gross Brain Overview: Part II Basic Neuroscience James H. Baños, Ph.D. Overview Organization Morphology Developmental/Evolutionary Cytoarchitectural 3-D Orientation to Internal Structures How do we organize and characterize different parts of the brain? How do we organize and characterize different parts of the brain? Morphology Developmental/Evolutionary Origins Cytoarchitecture Function Morphology: External Features Frog Rat What’s changing? Cat Monkey Human Sulci - The “valleys” on the surface of the brain Gyri - The “Hills” The term “gyrus” is sometimes used broadly and doesn’t always refer to a single well-defined ridge on the surface of the brain. The distinctions between large gyri are sometimes better seen in coronal sections. Hemispheres Longitudinal Fissure Lobes Central (Rolandic) Sulcus Lateral (Sylvian) fissure Parieto-occipital fissure Lobes Frontal Parietal Temporal Occipital Cingulate Gyrus “Limbic Lobe” Brain Stem Thalamus Hypothalamus Midbrain Pons Medulla Cerebellum: Superior Aspect Ant 2 Hemispheres Vermis Cerebellum: Posterior Aspect Anterior Lobe Primary Fissure Posterior Lobe Hemisphere Vermis Hemisphere Cerebellum: Mid-Saggital Anterior Vermis Posterior Vermis Developmental and Evolutionary Origins: The “Cephalons” Developmental Origins Three Vessicle Stage Areas of the Brain can be characterized by the embryonic origins of the tissue. Nervous system begins as a tube that differentiates into three vessicles: Prosencephalon Mesencephalon Rhombencephalon Developmental Origins Five Vessicle Stage Prosencephalon differentiates: Rhombencehphalon differentiates Telencephalon -- beginnings of hemispheres Diencephalon Metencephalon Meyelencephalon We use this terminology to describe the parts of the brain that develop from these vessicles Developmental Origins Prosencephalon (forebrain) Telencephalon (endbrain) Cerebral Cortex Basal Ganglia Limbic System Hippocampus Diencephalon (interbrain) Thalamus Hypothalamus Mesencephalon Mesencephalon Midbrain Rhombencephalon (hindbrain) Metencephalon Cerebellum Pons Myelencephalon Medulla Organization Telencephalon Cortex Basal Ganglia Limbic System Hippocampus Organization Diencephalon Thalamus Hypothalamus Organization Mesencephalon Midbrain Organization Metencephalon Cerebellum Pons Organization Myelencephalon Medulla Cytoarchitectural Organization Brodmann’s Areas QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Internal Structure Major Internal Structures Ventricular System Amygdala (helpful landmark) Thalamus/Hypothalamus/brain stem Basal Ganglia Hippocampal formation Caudate Nucleus Putamen Globus Pallidus Hippocampus Fimbria Fornix Major white matter landmarks Corpus callosum Internal capsule Evolution and Development Frog Rat Cat Monkey Human Evolution and Development Frog Rat Cat Monkey Human ? Evolution and Development Ventricles Basal Ganglia QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Hippocampus QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Evolution and Development Why not the thalamus? The Ventricular System Ventricles Lateral Ventricles Third Ventricle Fourth Ventricle Ventricles Ventricles are connected (communicate) Intraventricular Foramina (of Monroe) Cerebral Aqueduct (of Sylvius) Third Ventricle to Fourth Long, thin channel Foramen of Magendie Lateral Ventricles to Third Ventricle Wide, oval hole Median aperture -- Fourth ventricle to subarachnoid space Foramina of Luschka Lateral apertures -- Fourth ventricle to subarachnoid space Ventricles Foramen of Monroe Aqueduct of Sylvius Foramina of Luschka Foramen of Magendie Ventricles QuickTime™ and a Microsof t V ideo 1 decompressor are needed to see this picture. Ventricles QuickTime™ and a Microsof t V ideo 1 decompressor are needed to see this picture. Ventricles QuickTime™ and a Microsof t V ideo 1 decompressor are needed to see this picture. Ventricles Choroid Plexus and CSF Choroid Plexus Spongy tissue located in the ventricles Rich capillary bed Pia Mater Choroid endothelial cells Produces CSF About .35 ml per minute Total volume 70-120 ml Choroid Plexus CSF Flow Lateral ventricles Foramina of Monroe 3rd ventricle Aqueduct of Sylvius 4th Ventricle Foramen of Magendie/foramina of Lushka Subarachnoid Space Arachnoid granulations (absorption) Superior sagittal sinus CSF Flow CSF Absorption CSF flows to the dorsal surface of the brain, where arachnoid granulations form a one-way valve and let the excess CSF enter the veinous drainage of the superior sagittal sinus CSF Absorption Arachnoid Granulations Ventricular System plus Amygdala Ventricular System plus Thalamus Ventricular System plus Thalamus Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Ventricles, Brainstem, and Thalamus Ventricles, Brainstem, and Thalamus Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Basal Ganglia -- Caudate Nucleus Basal Ganglia Caudate Nucleus Putamen Globus Pallidus Sometimes Amygdala Basal Ganglia -- Caudate Nucleus Basal Ganglia -- Caudate Nucleus Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Basal Ganglia -- Caudate Nucleus Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Basal Ganglia -- Putamen & Globus Pallidus Basal Ganglia -- Putamen & Globus Pallidus Quic kT ime™ and a Mic rosoft Vi deo 1 dec ompres sor are needed to see thi s pic ture. Basal Ganglia Basal Ganglia Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Basal Ganglia Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Internal Capsule Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Hippocampus Hippocampal formation Fimbria Fornix Anterior Commissure Amygdala Hippocampus Hippocampus Quic kT ime™ and a Mi crosoft Vi deo 1 decompress or are needed to s ee this pi cture. Coming up… Spinal cord Basic Spinal Pathways