Meninges and Ventricle.pptx

Meninges and Ventricle s UM1010 NEUROENDOCRINE BLOCK  about MR IZUCHUKWU OBAZIE FHEA (he/his/him) BSc., M.Sc. Human Anatomy, PGCAP. Teaching fellow, Anatomy School of Medicine University of Central Lancashire...

Meninges and Ventricle s UM1010 NEUROENDOCRINE BLOCK  about MR IZUCHUKWU OBAZIE FHEA (he/his/him) BSc., M.Sc. Human Anatomy, PGCAP. Teaching fellow, Anatomy School of Medicine University of Central Lancashire, Preston Email: [email protected] Learning Outcomes Understand Understand Meninges structure Describe Describe the cerebral Dural venous sinuses Describe Describe the ventricular system anatomy Explain cerebrospinal fluid ( CSF) formation, absorption and Explain circulation Recognize the clinical implications of meningeal and ventricular Recognize anatomy Structure Part 1 Meninges Part 2 Ventricles and Cerebrospinal Fluid Meninges Greek “meninx” meaning membrane Part 1 Yes or No? Is the central nervous system the sole vital component for sustaining NO life, or do the structures surrounding the brain and spinal cord also contribute significantly to this crucial function? (Yes/No) Is the cranium/skull and vertebral column sufficient in protecting and maintaining the structure of the NO brain and spinal cord? (Yes/No)  These layers, arranged from outermost to innermost, are known as the dura mater, Meninges arachnoid mater, and pia mater. Three layers of membranes, collectively serving to safeguard the central nervous system, provide support to blood vessels, and encase a cavity filled with cerebrospinal fluid (CSF).  Tentorium cerebelli Dura Mater (Latin. “hard mother”) The meningeal dura mater has 3 major tough fibrous connective tissue arranged in reflections two layers – periosteal and meningeal Falx cerebri layer. Meningeal layer of the dura mater of the brain in continuous with that of the Tentorium cerebelli spinal cord. Falx cerebelli Arachnoid mater (Greek Arachne, “spider”) a soft, translucent membrane that, like the dura mater, loosely envelops the brain separated from the dura by a narrow subdural space, through which pass veins enroute to the dural venous sinuses Joined with weblike trabeculae to the underlying pia mater. Pia Mater thin translucent membrane that is closely adherent to the surface of the brain. Spaces between the meningeal layers and bony skull Epidural space – between the dura mater and the bony skull Subdural space – between the dura mater and the arachnoid mater Subarachnoid space – between the arachnoid and the pia mater. Contains cerebrospinal fluid and cerebral blood vessels.  endothelial-lined venous channels, devoid of valves, located between the periosteal and Cerebral Dural meningeal layers of dura mater. Venous Sinuses Dural venous sinuses serve as low pressure channels for venous blood flow back to the systemic circulation. Meningitis Inflammation of the meninges from infection with viruses, bacteria, fungi and protozoa. Usually due to an infection of the cerebrospinal fluid in the subarachnoid space. opisthotonos End of part 1 Please proceed to Part 2 Ventricles and cerebrospina l fluid (CSF) Part II  The brain contains 4 ventricles A ventricle is an internal cavity of the brain, within the brain, which is filled with CSF  The brain contains 4 ventricles A ventricle is an internal cavity of the brain, within the brain, which is filled with CSF Lateral ventricles Two curved shaped cavities located in the cerebrum. They are separated by the septum pellucidum and do not communicate directly Third Ventricle Narrow slit-like cavity between the walls of the thalamus Communicates; Anteriorly with lateral FUN FACT: ventricles through interventricular Aqueduct of Sylviusforamina is named (of Monro)for the ancient way of Posteriorly with fourth moving water made ventricle famous bythrough the cerebral Romans byaqueduct 17th (of Sylvius) century Dutch physician Franciscus Sylvius  A wide flattened space located just Fourth Ventricle anterior to the cerebellum and A rhomboid or diamond shaped posterior to the upper, or superior, half cavity within the rhombencephalon of the medulla oblongata and the pons Central canal opens superiorly into the 4th ventricle and runs the whole length of the spinal cord CSF leaves the ventricular system through the lateral foramen of Luschka and the midline foramen of Magendie Ventricles and CSF CSF is formed within the ventricles, fills them, and emerges from apertures in the fourth ventricle to fill the subarachnoid space. CSF is responsible for suspension of the brain through its partial flotation. It regulates the composition of the fluid bathing the neurons and glial cells of the CNS It provides a route through which certain chemical messengers can be distributed throughout the nervous system. Absorption of the CSF into the Dural venous sinuses CSF percolates (drains) around the brain and spinal cord in the subarachnoid space It is ultimately reabsorbed by the arachnoid granulations into the dural venous sinus and thus back. into the blood stream Subarachnoid Cisterns The subarachnoid space widens in a few area to form larger CSF collections called cisterns. The most clinically relevant include: Perimesencephalic cisterns Ambient cistern Quadrigeminal cistern Interpeduncular cistern Prepontine cistern (pontine cistern) Cisterna Magna Lumbar cistern Hydrocephalus “water in the head” Caused by excess CSF in the intracranial cavity. Excess CSF production Obstruction of flow at any point in the ventricles or subarachnoid space Decrease in reabsorption via the arachnoid granulations Learning Outcomes Review Explain cerebrospinal fluid (CSF) Explain formation, absorption and circulation Understan Understand Meninges structure d Recognize the clinical implications Recognize of meningeal and ventricular anatomy Describe the cerebral Dural Describe venous sinuses Describe the ventricular system Describe anatomy This Photo by Unknown Author is licensed under CC BY-SA Questions? Please send me an email to [email protected] Thank You Izuchukwu Obazie FHEA [email protected]