Bio 235 Midterm 2 Exam Questions and Answers All Correct

Bio 235 Midterm 2 Exam Questions and Answers All Correct What are the two motor pathways that control movement? - ANSWER Pyramidal Tract Extrapyramidal tracts Describe the pyramidal tract - ANSWER Corticospinal Pathway Controls learned motor actions Describe extrapyramidal tracts - ANSWER Upper MNs in the brain Axons descend to modulate lower MNs in the spinal cord Adjustments in muscle tone, balance, voluntary movements How does the CNS develop in utero? - ANSWER As an embryonic neural tube Neural folds fuse along the dorsal midline to form a hollow tube Describe Anencephaly - ANSWER Failure to fuse at the rostral end of the neural tube Brain and skull do not develop Infant does not survive Describe spina bifida - ANSWER Failure of vertebral arches to fuse over the caudal end of the spine and cord What are the 4 types of spina bifida? List in order of severity - ANSWER Occult Spina Bifida Meningocoele Meningomyelocoele Myelochisis Describe Occult Spina Bifida - ANSWER Protrusion of meninges under skin (acystic) Asymptomatic, no treatment required Describe Meningocoele - ANSWER Cyst containing meninges only Surgical repair generally required Describe Meningomyelocoele - ANSWER Most common Meninges plus cord bulge under protruding cyst Neurological deficits below the cyst Surgical repair can cause further damage but is generally necessary to prevent complications like meningitis Describe Myelochisis - ANSWER Most severe Spinal cord fused to overlying ectoderm No good way to separate or treat List 5 common causes of CNS injury - ANSWER Trauma Tumours Hemorrhage Infection/Abscess Chronic inflammation Potential responses to CNS injury - ANSWER Axon degeneration Neuronal death Astrogliosis - astrocytes respond to damage signals and trigger cell division, creating a physical barrier to axon regrowth List 3 common causes of PNS injury - ANSWER Crush Severance Tumours Potential responses to PNS injury - ANSWER Wallerian degeneration - Distal axon degenerates and disappears Demyelination by inflammatory response Axon regeneration may occur - up to 1mm/day - depends on Schwann cell survival to secrete growth factors Neuroma formation - benign tumour