Nervous System Workshop 2 BIOS1158, 2024 PDF

BIOS1158 Structure, Function, and Disease B Semester 2 – 2024 Nervous System II Basic Organization & Function Workshop Developed by Dr Jin Huang email: [email protected] Nervous System 2: Basic Organisation and Function Workshop Jigsa...

BIOS1158 Structure, Function, and Disease B Semester 2 – 2024 Nervous System II Basic Organization & Function Workshop Developed by Dr Jin Huang email: [email protected] Nervous System 2: Basic Organisation and Function Workshop Jigsaw red Understand the function of the major components of the central nervous system (CNS) 1. Pathways / tracts are often named according to their anatomical locations and/or where they come from or go to. Which of the following tracts are ascending and which are descending? a) Spinothalamic tract b) Spinocerebellar tract c) Corticospinal tract d) Corticobulbar tract e) Vestibulospinal tract 2. Identify the location of the ascending (sensory) and descending (motor) pathways / tracts in the cross- sections of the spinal cord below. Nervous System 2: Basic Organisation and Function Workshop Jigsaw red 3. Would tracts known as dorsal column pathways carry sensory or motor information? 4. Let's start thinking about processing sensory information. a) Name four sensory functions that both spinal and cranial nerves carry. This sensory information can be used to test whether the sensory pathways have been damaged. b) Name two examples of functions that only cranial nerves carry. 5. Information relating to all the functions you have named is destined for the cerebral cortex, so there must be ascending tracts that terminate in the cerebral cortex. Locate the following: a) Somatosensory area b) Auditory area c) Visual area 6. The cerebellum and basal nuclei influence muscle activity via descending motor pathways. Some important examples of these pathways originate in the motor cortex. a) Identify the motor cortex on a model of the brain and on the image above. b) Describe the functions influenced by the following descending tracts: (i) Corticospinal (ii) Corticobulbar Nervous System 2: Basic Organisation and Function Workshop Resources When the name of a pathway starts with spino-, it is an ascending (sensory) pathway. When the name of a pathway ends with -spinal, it is a descending (motor) pathway. Dorsal column tract / pathway is a large ascending tract carrying sensory information from the periphery to the brainstem. The types of sensation carried are general body sensations which are fine touch, pressure, and proprioception. Spinothalamic tract / pathway carries pain, temperature and coarse touch. It is important to note that general body sensations differ to special senses. Special senses carried by the cranial nerves are vision (CN II), hearing (CN VIII, cochlear branch), balance (CN VIII, vestibular branch), smell (CN I) and taste (CN VII, IX, and X). Examples of motor pathways are corticospinal tract (cortex  spinal cord: voluntary movements of the body and limbs) and corticobulbar tract (cortex  brainstem: muscle movements of the face and neck). (in postcentral gyrus) (in precentral gyrus) https://www.britannica.com/science/primary-motor-area © University of Sydney, 2023 Prepared by Dr Jin Huang. Last update: 01/07/2021 Page 4 of 15 Nervous System 2: Basic Organisation and Function Workshop Jigsaw yellow BLOOD SUPPLY Preparation Review the material covered in the Blood Supply lecture, paying particular attention to the following: Distribution of blood to the cerebral cortex. Arterial blood supply to the brainstem. Location of venous sinuses and pattern of venous blood flow from the brain. Required Reading: Chapters 5, 6, 7 of Crossman, A. R., Neary, D. Neuroanatomy. [Elsevier Health Sciences]. 1. Understanding the basic anatomy of the Circle of Willis and cerebral arteries. 1.1. Identify the Circle of Willis (yellow) and its branches. Note, middle cerebral artery (MCA) is not part of the circle. https://teachmeanatomy.info/neuroanatomy/vessels/arterial-supply/ Nervous System 2: Basic Organisation and Function Workshop Jigsaw yellow 1.2. Identify the vertebral and internal carotid arteries. The four arteries come indirectly from the aortic arch. Each common carotid artery bifurcates forming the and carotid arteries, the internal enters the cranium through the carotid canal to supply the CNS. The arteries ascend by passing through the foramina of C1- C6 vertebrae and enter the cranium through the. 1.3. Branches of the vertebral artery are the posterior inferior cerebellar, anterior and posterior spinal arteries. The two vertebral arteries fuse to form the artery, which then branches into the cerebral arteries. Branches of the internal carotid artery are the and cerebral arteries. internal carotid artery https://geekymedics.com/arterial-supply-of-the-brain/ Nervous System 2: Basic Organisation and Function Workshop Resources * * * * * https://neupsykey.com/circulation-of-the-brain/ Nervous System 2: Basic Organisation and Function Workshop Resources The vertebral arteries ascend by passing through the transverse foramina of C1-C6 vertebrae and enter the cranium through the foramen magnum. Inside the skull, the two vertebral arteries join to form the basilar artery at the base of the pons. * https://aneskey.com/sonoanatomy-relevant-for-ultrasound-guided-injections-of-the-cervical-spine/ https://www.kenhub.com/en/library/anatomy/circle-of-willis https://www.scienceabc.com/humans/circle-of-willis-anatomy-diagram-and-functions.html Nervous System 2: Basic Organisation and Function Workshop Resources 1.4. Using the brain models, identify the anterior, middle, posterior cerebral arteries (ACA, MCA, PCA) and complete the following: Cortical region Source/s of Effects of unilateral damage for area with* (in your /related area arterial blood own time) motor* somatosensory* speech / Broca’s limbic auditory* visual* corpus callosum Colour in the regions of the brain supplied by: ACA; MCA; PCA. https://www.memorangapp.com/flashcards/155064/Neurology%3A+Anatomy+and+Physiology/ Nervous System 2: Basic Organisation and Function Workshop Resources the pattern of blood supply to the brainstem. 2. Understanding 2.1. Complete the following: Brainstem Sources of arterial blood. Just list a couple. You are not expected to region know them all, just need to understand the pattern of blood supply is wedge-like or segment-like. midbrain pons medulla 2.2. List three consequences of vascular damage to the medulla. Nervous System 2: Basic Organisation and Function Workshop Resources https://www.researchgate.net/figure/Illustration-depicting-the-vascular-territories-of-the-MCA-red-ACA-yellow-and- PCA_fig5_316589286 Medulla connects the rest of the brain with the spinal cord. Any vascular damage to the medulla could have serious consequences. Some are listed below: Damage to cranial nerves V-XII functions. Damage to major pathways passing through medulla lead to sensory and motor loss: o Sensory: spinothalamic, dorsal column-medial lemniscal tracts o Motor: corticospinal tract (pyramids) Damage to reticular nuclei can be fatal: control of cardiovascular functions, respiratory functions and other autonomic reflexes. Loss of communication to the cerebellum (damage to ICP). Nervous System 2: Basic Organisation and Function Workshop Jigsaw blue 3. Understanding the return of venous blood of the brain through venous sinuses. 3.1. Examine the head and neck model. Identify the structures with *: superior and inferior sagittal; straight; confluence of; transverse; sigmoid sinuses. Identify internal jugular vein. * * * * * * * https://www.kenhub.com/en/library/anatomy/veins-of-the-brain Nervous System 2: Basic Organisation and Function Workshop Jigsaw blue 3.2. Complete the following flow chart: Superior sinus Confluence of sinuses Inferior sinus Heart https://www.mikaelastiver.com/neuroanatomy/ Nervous System 2: Basic Organisation and Function Workshop Jigsaw blue 3.3. A subdural hematoma / haemorrhage occurs when a blood vessel near the surface of the brain bursts. A collection of blood then accumulates below the inner layer of the dura but external to the brain and arachnoid. It is the most common type of traumatic intracranial mass lesion. On CT (computerised tomography) scans, the appearance of subdural hematomas varies with clot age and organisation. An acute subdural hematoma appears as a hyperdense colour -. Visible changes are: o The midline has been shifted to the (see ). o Ventricles have been. o Basal nuclei have been. o Insular cortex is not visible on the. o Brain tissue has been while the skull remains the size. What are some consequences of these changes? Common symptoms are a severely depressed conscious state or a temporary loss of , and pupillary abnormalities. Other symptoms include severe headache, sensory deficits, weakness on one side of the , , changes in vison or. L R http://www.med-ed.virginia.edu/courses/rad/headct/trauma4.html  Nervous System 2: Basic Organisation and Function Workshop Resources A subdural hematoma is a collection of blood between the dura mater and the arachnoid. It occurs when a blood vessel near the surface of the brain bursts. Subdural hematomas are usually characterised by their size and location and the amount of time elapsed since the inciting event age (i.e., whether they are acute, subacute, or chronic). Acute subdural haemorrhages usually present in the setting of head trauma. Most patients present with a severely depressed conscious state or a temporary loss of consciousness, and pupillary abnormalities. Other symptoms include severe headache, sensory deficits, weakness on one side of the body, seizures, changes in vison or speech. On a CT scan, an acute subdural hematoma appears as a hyperdense (the colour is white), crescent-shaped mass between the inner table of the skull and the surface of the cerebral hemisphere. Visible changes are: The midline has been shifted to the right. Ventricles have been displaced. Basal nuclei have been distorted. Insular cortex is not visible on the left. Brain tissue has been compressed while the skull remains the same size. https://www.topneurodocs.com/subdural-hematoma/