Neuroanatomy Lecture Notes (CM100) - September 24, 2024 PDF

ANATOMY: Neuroanatomy CM100: Integrated Basic Sciences Dr. Mary Lou Cabacang | September 24, 2024 TOPICS CEREBRUM AND CEREBELLUM A. Learning Objectives...

ANATOMY: Neuroanatomy CM100: Integrated Basic Sciences Dr. Mary Lou Cabacang | September 24, 2024 TOPICS CEREBRUM AND CEREBELLUM A. Learning Objectives CEREBRUM B. Topics a. Basic Organization of the Nervous System b. Cerebrum and Cerebellum i. Cerebrum ii. Cerebellum c. Brainstem and Cranial Nerves i. Subdivisions 1. Anterior View Largest part the brain 2. Posterior View Located in the anterior and middle cranial fossae d. Basal Ganglia, Thalamus, and Limbic Occupies the whole concavity of the vault of System skull i. Basal Ganglia ii. Thalamus A. Lateral View iii. Limbic System Dura C. Miscellaneous Information (From Professor or - outermost covering of the skull video source) - Part of the meningeal covering D. Review Questions (At least 10-15 items) - Toughest layer E. References - Fibrous and thick F. Appendix Middle meningeal artery- if severed, it could lose consciousness BASIC ORGANIZATION OF THE NERVOUS SYSTEM A. Central Nervous System Brain ○ Forebrain Cerebrum Diencephalon (between brain) ○ Midbrain ○ Hindbrain Medulla oblongata When you remove the dura… Pons Cerebellum Sagittal sinus- intersection of the left and right Spinal Cord dura ○ Cervical segments Interhemispheric fissure- separates left and right ○ Thoracic segments cerebrum ○ Lumbar segments ○ Fissure- deep groove or depression ○ Sacral segments ○ Coccygeal segments MAIN SULCI B. Peripheral Nervous System Cranial nerves and their ganglia ○ 12 pairs that exit the skull through the foramina Spinal nerves and their ganglia ○ 31 pairs that exit the vertebral column through the intervertebral foramina Cervical - 8 Thoracic - 12 Lumbar - 5 Sacral - 5 Coccygeal - 1 Most important fissures! REMEMBER ME 1. Central sulcus of Rolando- 2. Lateral fissure of Sylvius/ Slyvian fissure- 3. Parieto-occipital fissure- more seen medially PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 1  Neuroanatomy – Week 7 LOBES Anterior ascending ramus and anterior horizontal ramus- demarcates Broca’s area in the inferior frontal gyrus Anterior to rolandic fissure is the precentral gyrus- motor cortex Anterior to precentral gyrus- premotor area Area of Expression- inferior frontal gyrus Aphasia- pt is not able to express what he/she wants to say B. PARIETAL LOBE Frontal lobe Parietal lobe Temporal lobe- below the frontal and parietal lobes because of the sylvian fissure Occipital lobe- parietooccipital fissure A. FRONTAL LOBE Found behind posterior to central sulcus and superior to sylvian fissure 2 important sulcus 1. Post central sulcus- demarcate post central gyrus or somatosensory cortex 2. Intraparietal sulcus- divides parietal lobe to superior and inferior parietal lobule ➔ Superior parietal lobule- important in demarcating space. For us to demarcate frontal lobe, we need central sulcus ➔ Lesions: neglect of the contralateral side of the and sylvian fissure space (If right is affected, neglect in the left) Ramus- branching of 2 sulci Inferior parietal lobule- imp Supramarginal gyrus- caps the end of sylvian 1. Anterior ascending ramus fissure 2. Anterior horizontal ramus Angular gyrus- cap the end of superior temporal sulcus Gyrus- convolutions or “kulubot” INFERIOR Parietal lobe main fx: understanding 3 major gyrus of Frontal lobe language or comprehension ➔ Lesion to inferior parietal lobe: Wernicke’s aphasia C. TEMPORAL LOBE 1. Superior frontal gyrus 2. Middle frontal gyrus 3. Inferior frontal gyrus Pars opercularis Pars triangularis Premotor area “Behind your ear” Precentral gyrus Remember! 3 important gyri Pars triangularis and pars opercularis are part of 1. Superior temporal gyrus broca's area 2. Middle temporal gyrus Broca’s area- area for language expression, to 3. Inferior temporal gyrus be able to speak and communicate thoughts and emotions Main Function: for hearing PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 2  Neuroanatomy – Week 7 B. Medial View C. Inferior View D. OCCIPITAL LOBE Remember! Main function:vision Anterior- olfactory bulb and olfactory nerve Olfactory nerve Parietooccipital sulcus- demarcate parietal lobe from the - cranial nerve I occipital lobe - NOT SEEN IN BRAIN STEM Important sulci!!! Remember me Structures found in inferior view 1. Parieto occipital sulcus Gyrus rectus and orbital gyrus!! 2. Calcarine sulcus Collateral sulcus- delineate parahippocampal gyrus Cunus and lingual gyrus- think about occipital lobe! ➔ Uncus- “rounded tip of parahippocampal gyrus ➔ Uncal herniation- occurs due to rising ICP Anterior to parieto-occipital sulcus is the precuneus gyrus 3 important gyri 1. Parahippocampal gyrus Structures found in Medial view 2. Occipitotemporal gyrus 3. Inferior temporal gyrus D. Ventricles Found in medial surface Purpose: for circulation of CSF which serves as cushion of our brain CEREBELLUM Located behind the brain stem when viewed anteriorly E. Sagittal View Corpus callosum Sagittal View of the Cerebellum - white matter tract located in between 2 Cerebellum hugs brainstem (left side of figure) cerebral hemispheres Fourth ventricle is located in between the - Connects 2 hemispheres so that cerebellum and brainstem information from one hemisphere can be transferred to another Callosal sulcus- demarcates corpus callosum from cingular gyrus Thalamus Hypothalamus Hypothalamic sulcus - separates thalamus to hypothalamus Paracentral lobe - responsible for holding urination Fornix ○ white matter fiber located beneath corpus callosum Anterior commisure Septum pellucidum ○ like a membrane that separates the two ventricles- F. Superior View Superior View of the Cerebellum Superior vermis located in the midline PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 3  Neuroanatomy – Week 7 Two lateral cerebellar hemispheres located laterally Divided into two lobes via the primary fissure ○ Anterior lobe (red in figure) ○ Posterior lobe (in green in figure) Horizontal fissure separates superior and inferior vermis I. Functional Subdivisions Vermis Found in the middle Influences the movements of the long axis of the body Components of the Superior Vermis (from Anterior Axial movement (such as in the trunk) to Posterior) Intermediate Zone (Paravermis) Central lobule Lateral to vermis Culmen Control the muscles of the distal parts of the Declive limbs Folium Lateral Zone Found in lateral hemispheres G. Inferior View Planning of sequential movements of the entire body Inferior View of the Cerebellum Anterior and posterior lobes are present Flocculonodular lobe present in between the anterior and posterior lobes ○ Consists of the flocculus extending laterally and the nodule medially Bilateral tonsils now can be viewed lateral to inferior vermis Lingula is present on superior vermis, but can only be seen in the inferior view BRAINSTEM AND CRANIAL NERVES BRAINSTEM Located at the posterior cranial fossa of the skull Stalk like structure that connects the Tonsillar Herniation narrow spinal cord with the expanded Can be caused by large lesions in cerebrum that forebrain push down on tonsils Functions: Herniated tonsils can press on medulla, leading ○ serves as a conduit for the to death ascending tracts and descending tracts connecting the spinal cord H. Cerebellar Nuclei to the different parts of the higher Four Cerebellar Nuclei of the Cerebellum (from centers in the forebrain Medial to Lateral) Fastigial ○ it contains important reflex Globose centers associated with the Emboliform control of respiration and the Dentate (looks like teeth) cardiovascular system and with the control of consciousness Preceptor’s note: Use DEGF to remember the cerebellar nuclei from lateral to medial. Think of the ○ it contains the important nuclei of alphabet but switch G and F. CNS 111 through XII PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 4  Neuroanatomy – Week 7 Anterior view of Brainstem Diverges from the optic chiasm and into the occipital lobe of the brain. Anterior surface of the Midbrain Posterior view of the Brainstem Interpeduncular fossa - Deep depression, bounded by crus cerebri. posterior perforated substance - Small blood vessels perforate the fossa floor Oculomotor nerve emerges from crus cerebri groove, passing forward in cavernous sinus lateral wall. Lateral surface of the Midbrain MIDBRAIN Superior brachium - passes from the superior colliculus to the lateral geniculate body and the optic tract. Inferior brachium - connects the about 0.8 in (2 cm) in length and connects the inferior colliculus to the medial geniculate body. pons and cerebellum with the forebrain traversed by the cerebral aqueduct Midbrain Posterior surface of the Midbrain ○ Oculomotor Nerve & Trochlear Nerve (CN III & CN IV) Four rounded eminences (corpora ○ Cerebral Peduncles (also known as quadrigemina) on the posterior surface. Crus Cerebri) Superior colliculi: Centers for visual reflexes. Part of motor pathway Inferior colliculi: Lower auditory centers. Lesion in Midbrain may lead Trochlear nerves emerge below inferior to paralysis of other parts of colliculi, winding around midbrain lateral aspect the body. to enter cavernous sinus. ○ Optic chiasm Part of visual pathways Diverges the optic nerves for pathways of division. ○ Optic Tract PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 5  Neuroanatomy – Week 7 PONS Posterior Surface of the Pons Start of 4th ventricles - Hidden by cerebellum, forms upper half of fourth ventricle floor. Associated with a hollow part appearance. Triangular shape, limited by superior cerebellar peduncles. Divided into symmetrical halves by median sulcus. Medial eminence, bounded by sulcus limitans, forms facial colliculus. Superior sulcus limitans floor - substantia ferruginea - is bluish-gray due to pigmented nerve cells. Area vestibuli produced by underlying anterior to the cerebellum and connects the vestibular nuclei, located laterally. medulla oblongata to the midbrain about 1 inch (2.5 cm) long Pons (Boob-like appearance in the brainstem) ○ Trigeminal Nerve (CV). Lateral part of the anterior brainstem; emerges on each side Responsible for facial sensation Thick and thin motor route. ○ Abducens nerve (CVI) More medial to CVII and CVIII. MEDULLA OBLONGATA ○ Facial nerve & Vestibulocochlear nerve (CVII, & CVIII) Medial to lateral Near each other ○ Basis Pointis Part of motor pathway from Crus cerebri and unto the medulla. ○ Pontine Sulcus - Groove for basilar artery which supplies the pons located ○ Lesions in basis pontis = paralysis of other half connects the pons superiorly with the spinal cord Anterior surface of the Pons inferiorly the junction of the medulla spinal cord is at the origin of the anterior and posterior roots of the first cervical spine; approximately to the level of the foramen magnum. conical in shape Anterior Surface of Medulla Middle cerebellar peduncle - anterior surface is convex from side to side and shows many transverse fibers that converge on each side Basilar groove - shallow groove in the midline that lodges the basilar artery ○ CN - IX, X, XI, & XII - all located laterally to the medulla ○ Glossopharyngeal Nerve (CIX) PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 6  Neuroanatomy – Week 7 ○ Vagus Nerve (CX) ○ Spinal Accessory Nerve (CNXI) ○ Hypoglossal Nerve(CXII) located medially at the Anterior lateral sulcus ○ Pyramids Continuation of Crus Cerebri and Basis Pontis swelling on each side of the median fissure compose of bundles of nerve fibers called corticospinal fibers from the precentral gyrus ○ Olives BASAL GANGLIA, THALAMUS & Cerebellar pathway LIMBIC SYSTEM oval elevations produced by the BASAL GANGLIA underlying inferior olivary nuclei. A. Basal Ganglia ○ Anterior Median Sulcus - continuous inferiorly with the anterior median fissure of the spinal Basal Nuclei/ Ganglia cord - A collection of masses of gray matter situated within Pyramidal decussation each cerebral hemisphere Criss crossing of fibers - Includes: corpus striatum, amygdaloid nucleus, and Responsible for the crossing of claustrum motor nerve fibers at the level of Basal Nuclei/ Ganglia System the spinal cord. - A collection of subcortical nuclei of the telencephalon, “One side of the brain is subthalamus, and midbrain that modulate motor and affected, the other half will cognitive functions of motor cortex manifest the symptom.” ○ Anterior Lateral Sulcus Divides Pyramids from Olives the groove between the pyramid and the olive emerge the rootlets of the hypoglossal nerve Posterior Surface of the Medulla B. Corpus Striatum Striped body Lateral to the thalamus Divided by the internal capsule into: - Caudate Nucleus (Tail) - Lenticular (Lentiform) Nucleus Obex - End of 4th ventricles; posterior surface of B1. Caudate Nucleus the superior half of the medulla oblongata forms C-shaped mass of gray matter the lower part of the floor of the fourth ventricle Largest nucleus Posterior median sulcus - continuous with the Lies dorsolateral to the thalamus posterior aspect of the spinal cord Parts: Gracile tubercle - an elongated swelling that is - Head produced by the underlying gracile nucleus. - Body Cuneate tubercle - Lateral to the gracile - Tail tubercle is a similar swelling, and is produced Closely related to the parts of the lateral ventricle by the underlying cuneate nucleus. - Lateral wall of anterior horn - Floor of the body of lateral ventricle - Roof of the inferior horn B2. Lentiform Nucleus Collectively is a wedge-shaped mass of gray matter Related laterally to the external capsule Putamen + Globus Pallidus PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 7  Neuroanatomy – Week 7 LENTIFORM NUCLEUS: putamen + globus pallidus Divided by sheets of myelinated fibers into: CLAUSTRUM → Putamen (shell) Larger, darker lateral portion THALAMUS With numerous packed neurons Large, ovoid mass of gray matter lying above the → Globus Pallidus midbrain (more medial) Inner, lighter area → Flanks on the third ventricle Relay station for sensory, motor pathways to and from Neo /Dorsal Striatum the cerebrum (except olfactory) → Putamen + Caudate Nucleus Acetylcholine (Ach) is the neurotransmitter of interneurons Although it may look like a single structure, you actually have two, side-by-side thalami, one in each side NEOSTRIATUM: caudate nucleus + putamen of your brain. → Separated by internal medullary lamina which Globus Pallidus divides the thalamus into different groups: → Medial to putamen, lateral to internal capsule anterior group → Pale, sparsely large cells transversed by many medial group myelinated lateral group fibers ventral group → Divided into: pulvinar (posterior part) Globus pallidus externa (GPe) Globus pallidus interna (GPi) C. Amygdaloid Nucleus In the temporal lobe near uncus Part of the limbic system Can influence the body's response to environmental changes → It can affect blood pressure, heart rate, and respiratory rate when one feels scared D. Claustrum Thin sheet of gray matter Separated from the lateral surface of the lentiform nucleus by the external capsule Unknown function PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 8  Neuroanatomy – Week 7 1. WHICH STATEMENT IS TRUE REGARDING THE SPINAL NERVES? A. 12 CERVICAL NERVE PAIRS B. 5 LUMBAR NERVE PAIRS C. 8 THORACIC NERVE PAIRS D. 2 COCCYGEAL NERVE PAIRS 2. WHICH OF THE PERIPHERAL NERVOUS SYSTEMS CONTAINS BOTH MOTOR AND SENSORY FIBERS? A. ANTERIOR RAMUS B. POSTERIOR RAMUS C. SPINAL CORD D. SPINAL NERVE 3. A MAJOR PERIPHERAL NERVE PLEXUS, EXCEPT? A. CERVICAL B. BRACHIAL LIMBIC SYSTEM C. THORACIC “Limbic” D. LUMBAR Means border Border structures around the base of the 4. SALLY, A 14 YEAR OLD FEMALE, HAS A BRAIN INJURY. SHE cerebrum KNOWS WHAT SHE WANTS TO SAY BUT SHE IS HAVING DIFFICULTY IN VERBALIZING IT, WHICH PART OF THE BRAIN IS AFFECTED? A. ANGULAR GYRUS B. BROCA’S AREA C. WERNICKE’S AREA D. BASAL GANGLIA 5. WHICH LOBE OF THE BRAIN PROCESSES VISUAL INFORMATION? A. TEMPORAL B. PARIETAL C. OCCIPITAL D. FRONTAL Limbic system entire neuronal circuitry that controls emotional ANSWERS: REFER TO APPENDIX SECTION behavior and motivational drives Limbic System REFERENCE Limbic Cortex Subcortical structures BOOK: RAD, A., SMITH, M. (2018). TITLE OF WORK: CAPITAL Orbitofrontal area Hypothalamus LETTER ALSO FOR SUBTITLE. PUBLISHER. Subcallosal gyrus Parolfactory Area SAMPLE: JOHNSON, P. L. (2017). PSYCHOLOGICAL Cingulate gyrus Septum PRINCIPLES OF EFFECTIVE THERAPY. HARPERCOLLINS. Parahippocampal Anterior Thalamic gyrus Nucleus JOURNAL ARTICLE: AUTHOR, A. A., & AUTHOR, B. B. (YEAR OF Uncus Portions of the PUBLICATION). TITLE OF ARTICLE. TITLE OF PERIODICAL, Basal Ganglia VOLUME(ISSUE), PAGES. HTTPS://DOI.ORG/XX.XXX/YYYY Hippocampus SAMPLE: WILLIAMS, R. T., & JONES, M. K. (2018). Amygdala THE EFFECTS OF MINDFULNESS ON ANXIETY. JOURNAL OF MENTAL HEALTH STUDIES, 10(2), 113-124. HTTPS://DOI.ORG/10.1016/J.MHS.2018.01.015 Preceptor’s note: take note of the important parts: cingulate gyrus, Fornix fiber, amygdala, mamillary WEBSITE: AUTHOR, A. A. (YEAR, MONTH, DATE OF body, anterior thalamus and anterio-medial thalamus, PUBLICATION). TITLE OF WEB DOCUMENT. SITE NAME. URL parahippocampal SAMPLE: AMERICAN PSYCHOLOGICAL ASSOCIATION. (2020, JUNE 1). UNDERSTANDING THE PSYCHOLOGY OF LEARNING. APA. Hippocampus HTTPS://WWW.APA.ORG/LEARNING mainly for formation of memory still part of the limbic system due to its proximity to amygdala APPENDIX MISCELLANEOUS INFORMATION ANSWERS TO QUESTIONS REVIEW QUESTIONS PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 9  Neuroanatomy – Week 7 Item Answer Explanation 1 B. 5 Lumbar Cervical - 8 Nerve Pairs Thoracic - 12 Lumbar - 5 Sacral - 5 Coccygeal - 1 2 D. Spinal Each spinal nerve is connected to Nerves the spinal cord by two roots:the anterior root and the posterior root (Fig.1-6B). The anterior root consists of bundles of nerve fibers carry- ing nerve impulses away from the central nervous system. Such nerve fibers are called efferent fibers. Those efferent fibers that go to skeletal muscles and cause them to contract are called motor fibers. Their cells of origin lie in the ante- rior gray horn of the spinal cord. The posterior root consists of bundles of nerve fibers, called afferent fibers, that carry nervous impulses to the central nervous system.Because these fibers are concerned with conveying information about sensations of touch,pain, temperature, and vibration, they are called sensory fibers. (Retrieved from Snell’s Clinical Neuroanatomy 7th edition) 3 C. Thoracic The major nerve plexuses are the cervical plexus, brachial plexus, lumbar plexus, and sacral plexus. Some references would include the coccygeal plexus. (12.6C: Plexuses, 2018). There is no major redistribution of nerves in the thoracic region. 12.6C: Plexuses. (2018, July 20). Medicine LibreTexts. 4 B. Broca’s Broca’s area - area for language area expression, to be able to speak and communicate thoughts and emotions 5 C. Occipital Occipital lobe - The primary visual area (Brodmann area 17) is situated in the walls of the posterior part of the calcarine sulcus and occasionally extends around the occipital pole onto the lat- eral surface of the hemisphere. Retrieved from Snell’s Clinical Neuroanatomy, 7th edition. PREPARED BY I. ARCILLA, L. BALDO, K. BEDIA, J. BONIFACIO, F. BRUIZUELA, K. CANDELA, J. CLEOFE, L. CRUZ, S. CURIMAO, M. ESPIRITU, G. GODISAN, D. GONZALES, K. GONZALES, AND T. GRECIA. (YL1-A4) 10