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Cerebrum
- 3. 2 MIN NEUROSCIENCE: THE MENINGES https://www.youtube.com/watch?v=CIkgQcmv0Xs
- 4. MENINGES OVERVIEW ⸠The meninges refer to the membranous coverings of the brain and spinal cord ⸠There are three layers of meninges, known as the dura mater, arachnoid mater and pia mater ⸠These coverings have two major functions: ⸠Provide a supportive framework for the cerebral and cranial vasculature ⸠Acting with cerebrospinal ďŹuid to protect the CNS from mechanical damage ⸠The meninges are often involved cerebral pathology, as a common site of infection (meningitis), and intracranial bleeds
- 6. MENINGES DURA MATER ⸠the outermost layer of the meninges ⸠lying directly underneath the bones of the skull and vertebral column ⸠thick, tough and inextensible ⸠Within the cranial cavity, the dura contains two connective tissue sheets: ⸠Periosteal layer ⸠lines the inner surface of the bones of the cranium ⸠Meningeal layer ⸠deep to the periosteal layer inside the cranial cavity ⸠the only layer present in the vertebral column
- 7. MENINGES DURA MATER ⸠Between these two layers, the dural venous sinuses are located ⸠They are responsible for the venous vasculature of the cranium, draining into the internal jugular veins ⸠In some areas within the skull, the meningeal layer of the dura mater folds inwards as dural reďŹections ⸠They partition the brain, and divide the cranial cavity into several compartments ⸠For example, the tentorium cerebelli divides the cranial cavity into supratentorial and infratentorial compartments ⸠The dura mater receives its own vasculature; primarily from the middle meningeal artery and vein ⸠It is innervated by the trigeminal nerve (V1, V2 and V3)
- 10. MENINGES ARACHNOID MATER ⸠The arachnoid mater is the middle layer of the meninges, lying directly underneath the dura mater ⸠It consists of layers of connective tissue, is avascular, and does not receive any innervation ⸠Underneath the arachnoid is a space known as the sub-arachnoid space ⸠It contains cerebrospinal ďŹuid, which acts to cushion the brain ⸠Small projections of arachnoid mater into the dura (known as arachnoid granulations) allow CSF to re-enter the circulation via the dural venous sinuses
- 12. MENINGES PIA MATER ⸠The pia mater is located underneath the sub-arachnoid space ⸠It is very thin, and tightly adhered to the surface of the brain and spinal cord ⸠It is the only covering to follow the contours of the brain (the gyri and ďŹssures) ⸠Like the dura mater, it is highly vascularised, with blood vessels perforating through the membrane to supply the underlying neural tissue
- 15. MENINGES REVIEW QUESTIONS ⸠Which of the following cranial nerves provides sensory innervation to the dura mater? ⸠Abducens nerve ⸠Accessory nerve ⸠Olfactory nerve ⸠Trigeminal nerve
- 16. MENINGES REVIEW QUESTIONS ⣠The dura mater is primary innervated by branches of the trigeminal nerve
- 17. MENINGES REVIEW QUESTIONS ⸠Where does blood accumulate in an extradural haematoma? ⸠Between the dura mater and arachnoid mater ⸠Between the periosteal and meningeal layers of the dura mater ⸠Between the arachnoid mater and pia mater ⸠Between the skull and periosteal layer of the dura mater
- 18. MENINGES REVIEW QUESTIONS ⸠In an extradural hematoma, arterial blood collects between the skull and the periosteal layer of the dura mater
- 19. MENINGES REVIEW QUESTIONS ⸠What is contained within the sub-arachnoid space? ⸠Skull periosteum ⸠Dural venous sinuses ⸠Cerebrospinal ďŹuid ⸠Emissary veins
- 20. MENINGES REVIEW QUESTIONS ⸠The sub-arachnoid space contains cerebrospinal ďŹuid that acts to cushion the brain
- 21. VENTRICLES
- 23. DEEP BRAIN STRUCTURES VENTRICLES: OVERVIEW ⸠The ventricular system is a set of communicating cavities within the brain ⸠These structures are responsible for the production, transport and removal of cerebrospinal ďŹuid, which bathes the central nervous system
- 24. DEEP BRAIN STRUCTURES VENTRICLES: FUNCTIONS OF CEREBROSPINAL FLUID ⸠Cerebrospinal ďŹuid is an ultraďŹltrate of plasma that surrounds the brain and spinal cord ⸠It serves three main functions: ⸠Protection â acts as a cushion for the brain, limiting neural damage in cranial injuries ⸠Buoyancy â by being immersed in CSF, the net weight of the brain is reduced to approximately 25 grams and prevents excessive pressure on the base of the brain ⸠Chemical stability â the CSF creates an environment to allow for proper functioning of the brain, e.g. maintaining low extracellular K+ for synaptic transmission
- 26. DEEP BRAIN STRUCTURES VENTRICLES ⸠The ventricles are structures that produce cerebrospinal ďŹuid, and transport it around the cranial cavity ⸠They are lined by ependymal cells, which form a structure called the choroid plexus ⸠It is within the choroid plexus that CSF is produced ⸠Embryologically, the ventricular system is derived from the lumen of the neural tube
- 27. DEEP BRAIN STRUCTURES VENTRICLES ⸠In total, there are four ventricles; right and left lateral ventricles, third ventricle and fourth ventricle
- 28. DEEP BRAIN STRUCTURES VENTRICLES Lateral Ventricles ⸠The left and right lateral ventricles are located within their respective hemispheres of the cerebrum ⸠They have âhornsâ which project into the frontal, occipital and temporal lobes ⸠The volume of the lateral ventricles increases with age
- 29. DEEP BRAIN STRUCTURES VENTRICLES Third Ventricle ⸠The lateral ventricles are connected to the third ventricle by the foramen of Monro ⸠The third ventricle is situated in between the right and the left thalamus ⸠The anterior surface of the ventricle contains two protrusions: ⸠Supra-optic recess â located above the optic chiasm ⸠Infundibular recess â located above the optic stalk
- 30. DEEP BRAIN STRUCTURES VENTRICLES Fourth Ventricle ⸠The fourth ventricle is the last in the system â it receives CSF from the third ventricle via the cerebral aqueduct ⸠It lies within the brainstem, at the junction between the pons and medulla oblongata ⸠From the 4th ventricle, the ďŹuid drains into two places: ⸠Central spinal canal ⸠bathes the spinal cord ⸠Subarachnoid cisterns ⸠bathes the brain, between arachnoid mater and pia mater ⸠location where the CSF is reabsorbed back into the circulation
- 32. DEEP BRAIN STRUCTURES VENTRICLES: PRODUCTION AND REABSORPTION OF CSF ⸠Cerebrospinal ďŹuid is produced by the choroid plexus, located in the lining of the ventricles ⸠It consists of capillaries and loose connective tissue, surrounded by cuboidal epithelial cells ⸠Plasma is ďŹltered from the blood by the epithelial cells to produce CSF ⸠In this way, the exact chemical composition of the ďŹuid can be controlled ⸠Drainage of the CSF occurs in the subarachnoid cisterns (or space) ⸠Small projections of arachnoid mater (called arachnoid granulations), protrude into the dura mater ⸠They allow the ďŹuid to drain into the dural venous sinuses
- 34. DEEP BRAIN STRUCTURES CLINICAL RELEVANCE: HYDROCEPHALUS ⸠Hydrocephalus is deďŹned as an abnormal collection of CSF within the ventricles of the brain ⸠It is a serious condition, with chronic hydrocephalus causing raised intracranial pressure, and consequently cerebral atrophy
- 35. DEEP BRAIN STRUCTURES CLINICAL RELEVANCE: HYDROCEPHALUS ⸠Based on the underlying cause, there are two clinical classiďŹcations: ⸠Communicating (Non-obstructive) Hydrocephalus â Abnormal collection of CSF in the absence of any ďŹow obstruction in the ventricles ⸠Common causes usually involve the functional impairment of the arachnoid granulations, such as ďŹbrosis of the subarachnoid space following a haemorrhage ⸠Non-communicating (Obstructive) Hydrocephalus â Abnormal collection of CSF, with ďŹow obstructed within the ventricular system ⸠The most common site of obstruction is the cerebral aqueduct, connecting the third and fourth ventricles
- 36. DEEP BRAIN STRUCTURES CLINICAL RELEVANCE: HYDROCEPHALUS ⸠There is also a third classiďŹcation, hydrocephalus ex vacuo â this refers to ventricular expansion, secondary to brain atrophy ⸠This is often seen in patients with neurodegenerative conditions, such as Alzheimerâs disease ⸠Treatment of hydrocephalus primarily involves reversing the cause ⸠Whilst treating the cause, a shunt can be inserted, which drains the ďŹuid into the right atrium or the peritoneum
- 38. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠Which structure of the ventricular system synthesises cerebrospinal ďŹuid (CSF)? ⸠Cerebral aqueduct ⸠Arachnoid granulations ⸠Choroid plexus ⸠Subarachnoid cisterns
- 39. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠Cerebrospinal ďŹuid is produced by the choroid plexus - which is located within the lining of the ventricles
- 40. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠A patient is seen in ED with recurrent headaches. Further investigations reveal raised intracranial pressure and obstruction of the cerebral aqueduct. What type of hydrocephalus is most likely? ⸠Communicating hydrocephalus ⸠Hydrocephalus ex vacuo ⸠Obstructive hydrocephalus ⸠Restrictive hydrocephalus
- 41. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠Non-communicating (obstructive) hydrocephalus refers to an abnormal collection of CSF due to restricted ďŹow through the ventricular system
- 42. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠Which type of epithelial cells are present in the choroid plexus of the ventricular system? ⸠Cuboidal ⸠Columnar ⸠Transverse ⸠Squamous
- 43. DEEP BRAIN STRUCTURES REVIEW QUESTIONS: VENTRICLES ⸠The choroid plexus consists of capillaries and loose connective tissue surrounded by cuboidal epithelial cells
- 44. 2 MIN NEUROSCIENCE: LOBES AND LANDMARKS https://www.youtube.com/watch?v=LQ4DlE1Xyd4&list=PLNZqyJnsvdMr5DGiq0XhTnspQqaFh8vEu&index=1
- 45. CEREBRUM OVERVIEW ⸠The cerebrum is the largest part of the brain, located superiorly and anteriorly in relation to the brainstem ⸠It consists of two cerebral hemispheres (left and right), separated by the falx cerebri of the dura mater ⸠Embryologically, the cerebrum is derived from the prosencephalon
- 46. CEREBRUM ANATOMICAL POSITION AND STRUCTURE ⸠The cerebrum is located within the bony cranium ⸠It extends from the frontal bone anteriorly to the occipital bone posteriorly ⸠Within the skull, the cerebrum ďŹlls the anterior and middle cranial fossae, and is located above the tentorium cerebelli inferoposteriorly
- 47. CEREBRUM ANATOMICAL POSITION AND STRUCTURE: INTERNAL STRUCTURE ⸠The cerebrum is comprised of two different types of tissue â grey matter and white matter: ⸠Grey matter forms the surface of each cerebral hemisphere (known as the cerebral cortex), and is associated with processing and cognition ⸠White matter forms the bulk of the deeper parts of the brain and it consists of glial cells and myelinated axons that connect the various grey matter areas
- 48. CEREBRUM ANATOMICAL POSITION AND STRUCTURE: EXTERNAL STRUCTURE ⸠Externally, the cerebrum has a highly convoluted appearance, consisting of sulci (grooves or depressions) and gyri (ridges or elevations) ⸠It is divided into two anatomically symmetrical hemispheres by the longitudinal ďŹssure â a major sulcus that runs in the median sagittal plane ⸠The falx cerebri (a fold of dura mater) descends vertically to ďŹll this ďŹssure ⸠The two cerebral hemispheres are connected by a white matter structure, called the corpus callosum
- 49. CEREBRUM ANATOMICAL POSITION AND STRUCTURE: EXTERNAL STRUCTURE ⸠The main sulci are: ⸠Central sulcus â groove separating the frontal and parietal lobes ⸠Lateral sulcus â groove separating the frontal and parietal lobes from the temporal lobe ⸠Lunate sulcus â groove located in the occipital cortex
- 50. CEREBRUM ANATOMICAL POSITION AND STRUCTURE: EXTERNAL STRUCTURE ⸠The main gyri are: ⸠Precentral gyrus â ridge directly anterior to central sulcus, location of primary motor cortex ⸠Postcentral gyrus â ridge directly posterior to central sulcus, location of primary somatosensory cortex ⸠Superior temporal gyrus â ridge located inferior to lateral sulcus, responsible for the reception and processing of sound
- 52. CEREBRUM LOBES OF THE CEREBRUM ⸠The cerebral cortex is classiďŹed into four lobes, according to the name of the corresponding cranial bone that approximately overlies each part ⸠Each lobe contains various cortical association areas â  where information from different modalities are collated for processing ⸠Together, these areas function to give us a meaningful perceptual interpretation and experience of our surrounding environment
- 53. CEREBRUM LOBES OF THE CEREBRUM: FRONTAL LOBE ⸠The frontal lobe is located beneath the frontal bone of the calvaria and is the most anterior region of the cerebrum ⸠It is separated from the parietal lobe posteriorly by the central sulcus and from the temporal lobe inferoposteriorly by the lateral sulcus ⸠The association areas of the frontal lobe are responsible for: higher intellect, personality, mood, social conduct and language (dominant hemisphere side only)
- 54. CEREBRUM LOBES OF THE CEREBRUM: PARIETAL LOBE ⸠The parietal lobe is found below the parietal bone of the calvaria, between the frontal lobe anteriorly and the occipital lobe posteriorly, from which it is separated by the central sulcus and parieto-occipital sulcus, respectively ⸠It sits superiorly in relation to the temporal lobe, being separated by the lateral sulcus ⸠Its cortical association areas contribute to the control of: language and calculation on the dominant hemisphere side, and visuospatial functions (e.g. 2-point discrimination) on the non-dominant hemisphere side
- 55. CEREBRUM LOBES OF THE CEREBRUM: TEMPORAL LOBE ⸠The temporal lobe sits beneath the temporal bone of the calvaria, inferior to the frontal and parietal lobes, from which it is separated by the lateral sulcus ⸠The cortical association areas of the temporal lobe are accountable for memory and language â this includes hearing as it is the location of the primary auditory cortex
- 56. CEREBRUM LOBES OF THE CEREBRUM: OCCIPITAL LOBE ⸠The occipital lobe is the most posterior part of the cerebrum situated below the occipital bone of the calvaria ⸠Its inferior aspect rests upon the tentorium cerebelli, which segregates the cerebrum from the cerebellum ⸠The parieto-occipital sulcus separates the occipital lobe from the parietal and temporal lobes anteriorly ⸠The primary visual cortex (V1) is located within the occipital lobe and hence its cortical association area is responsible for vision
- 58. 2 MIN NEUROSCIENCE: BLOOD SUPPLY OF THE BRAIN https://www.youtube.com/watch?v=uMMMqkVZAhk
- 59. CEREBRUM VASCULATURE: ARTERIAL SYSTEM ⸠The blood supply to the cerebrum can be simply classiďŹed into 3 distinct paired arterial branches: ⸠Anterior Cerebral Arteries â branches of internal carotid arteries, supplying the anteromedial aspect of the cerebrum ⸠Middle Cerebral Arteries â continuation of internal carotid arteries, supplying most of the lateral portions of the cerebrum ⸠Posterior Cerebral Arteries â branches of the basilar arteries, supplying both the medial and lateral sides of the cerebrum posteriorly
- 60. CEREBRUM VASCULATURE: VENOUS SYSTEM ⸠Venous drainage of the cerebrum is via a network of small cerebral veins ⸠These vessels empty into the dural venous sinuses â endothelial lined spaces between the outer and inner layers of dura mater
- 66. QUICK REFERNCE SUMMARY OF TRACTS ⸠Projection tracts ⸠From brain to spinal cord and vice vera ⸠Forms internal capsule ⸠Commissural tracts ⸠Cross to opposite hemisphere ⸠Corpus callosum ⸠Anterior and posterior commissures ⸠Association tracts ⸠Connect lobes and gyri within a hemisphere
- 68. QUICK REFERENCE SPEECH CENTRES ⸠Language interpretation in the brain includes reading, writing, speaking and understanding words ⸠Wernickeâs area ⸠permits recognition of spoken and written language and creates a plan for speech ⸠Brocaâs area ⸠generates motor signals for larynx, tongue, cheeks and lips and transmits these to the primary motor cortex for action
- 73. CEREBRUM REVIEW QUESTIONS ⸠From which structure is the cerebrum embryonically derived? ⸠Mesencephalon ⸠Myelencephalon ⸠Diencephalon ⸠Prosencephalon
- 74. CEREBRUM REVIEW QUESTIONS ⸠Prosencephalon ⸠The cerebrum is derived from the prosencephalon
- 75. CEREBRUM REVIEW QUESTIONS ⸠Which lobe of the cerebrum is responsible for personality? ⸠Frontal lobe ⸠Parietal lobe ⸠Occipital lobe ⸠Temoral lobe
- 76. CEREBRUM REVIEW QUESTIONS ⸠Frontal lobe ⸠The frontal lobe is responsible for personality, higher intellect, mood, social conduct and language
- 77. CEREBRUM REVIEW QUESTIONS ⸠Which arteries supply the most lateral portions of the cerebrum? ⸠Anterior cerebral arteries ⸠Middle cerebral arteries ⸠Posterior cerebral arteries ⸠Basilar artery
- 78. CEREBRUM REVIEW QUESTIONS ⸠Middle cerebral arteries ⸠The middle cerebral arteries supply the most lateral portions of the cerebrum
- 79. References ⸠These slide reďŹect a summary of the contents of TeachMeAnatomy.info and are to be used for educational purposes only in compliance with the terms of use policy. SpeciďŹc portions referenced in this summary are as follows: ⸠https://teachmeanatomy.info/neuroanatomy/ structures/cerebrum/ Additional sources are referenced on the slide containing that speciďŹc content.