Topic 2 Lectorial - Introduction to the Nervous System PDF

Topic 2 Lectorial - Introduction to the Nervous System (2 activities cases & 3 cases) Activity 1 - Which Glial Cell? Which Glial Cell would be responsible for each of the following? Generating CSF - Maintaining the Blood Brain Barrier - Allowing for faster signal transduction in PNS neurons - P...

Topic 2 Lectorial - Introduction to the Nervous System (2 activities cases & 3 cases) Activity 1 - Which Glial Cell? Which Glial Cell would be responsible for each of the following? Generating CSF - Maintaining the Blood Brain Barrier - Allowing for faster signal transduction in PNS neurons - Phagocytosing bacteria - Regulating the ionic composition of CSF - Generating the myelin sheath for CNS axons - Surround PNS neurons and regulate flow between neuronal soma and IF - Activity 2 - Why is Resting Membrane Potential Negative? Using a diagram, explain to the person next to you what contributes to resting membrane potential being negative What would happen to membrane potential if K+ channels opened? 1 Case 1 - Action Potentials Deloris needs stitches, the doctor puts in a local anesthetic prior to the treatment. Deloris is trying to distract themself from the needle and asks the doctor how the 'local' works. The doctor says it blocks Na+ channels. They then ask you to explain why this provides a local anesthetic effect. What would your response be? Be as thorough as you can with your explanation Case 2 – The dodgy eye Jenny, a 32 year-old sales manager, has a history of sudden blurred vision in her right eye. This has occurred a number of times, but always got better after a few days. Four years ago she experienced a “foot drop” – she was unable to lift her left foot up at the ankle. This was diagnosed as a nerve palsy and improved after treatment by a chiropractor. A few months ago, she developed urinary incontinence and right-sided muscle weakness. Jenny had started to notice a pattern with these attacks – that they often occurred when she was sick with the flu or a cold, and she put them down to the infection. 2  With her most recent attack, Jenny was taken into hospital and a CT scan of the brain (shown here) was performed, which was reported as normal. Jenny was given a course of the anti-inflammatory steroid prednisolone, and had some improvement. She was also sent for an MRI. Jenny’s MRI report read: “Axial diffusion-weighted MRI shows several hyperintense lesions indicating inflammation and numerous white matter plaques.” What is white matter, and how would inflammatory lesions affecting the white matter account for Jenny’s symptoms? 3  What does inflammation indicate? Assuming Jenny’s symptoms have all been caused by the same problem, which neurons (sensory, motor, somatic, autonomic) have been affected by the problem? Blood tests and a CSF test were also carried out. Amongst other things this showed: Serum positive for Epstein-Barr virus (EBV) CSF contained a high level of IgG, and elevated cell count. The cells were identified as activated T-lymphocytes. What does CSF stand for? CSF normally contains very few cells, and the central nervous system normally contains very few immune cells. Why do you think the CNS normally contains few immune cells? 4 After reviewing the MRI and test results, the neurologist informed Jenny that she has multiple sclerosis. Multiple sclerosis involves a loss of integrity of myelin. How would this affect electrical signaling in affected neurons? What effects might that have on nervous system communication between cells? Case 3 - Jason - Your Face is Not Moving Jason has come to the clinic because he is unable to generate appropriate facial expressions. Jason explains this has occurred after he received botox to smooth out wrinkles at the suggestion of his modeling agent. What physiological process happens to generate facial expressions? Botox stops the interaction of neurotransmitter with receptors on post- synaptic cells. How would this allow botox to smooth out wrinkles? So why can't Jason smile? 6