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The Nervous System, The Sense of Hearing

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The Tympanic Membrane and the Ossicular System Sound from the tympanic Membrane to the Cochlea Tympanic Membrane, Malleus, Incus, Stapes, Oval Window - the ossicular chain. Malleus is also attached to the tensor tympani muscle. Impedance matching between sound waves in air and sound waves in the cochlear fluid is mediated by the ossicular chain. Sound is not amplified by increasing movement at the stapes, but increasing force of movement  at the stapes. Increasing pressure, increases the vibration of the fluid in the membranous labyrinth - via the oval window.  Impedance matching between air waves and fluid waves.  Contraction of the stapedius and the tensor tympani muscles attenuates sound conduction This is the same mechanism used to diminish the sensitivity to ones own speech Increases the rigidity of the stapes, and therefore the ossicular chain. Sound Transmission Through Bone Conduction The cochlea is embedded in bone, vibration of the ...
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AN UNEXPECTED CHEST XRAY

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AN UNEXPECTED CHEST XRAY Mrs MacLeod was a rather prudent 54 year old women, that presented with a shortness of breath, a chronic cough and recurrent pneumonia. She had an obstructive lung pattern on pulmonary function tests. She come in for an xray of the chest. The chest XRAY was rather different. There was unequal lung volumes, with the right lung volume being larger than the left. There was also decreased left lung vessels noted. There were no pleural effusions and no pneumothorax present either. The right lung was perfectly normal. Upon further investigation she reported to have had a significant childhood viral infection that resulted in distal airspace obstruction, probably secondary to an adenovirus or and RSV viral infection. A case of Sweyer-James syndrome was diagnosed. She was treated with influenza vaccinations, but in this case no lobectomy was performed as the no specific lung segment was identified.
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The Nervous System, the Cerebrum

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Cerebral Cortex Basal Ganglia Limbic System Cingulate Gyrus Thalamus Hippocampus Amygdala Brain function Ability to generate information and output signals in the absence of external input. Three systems that influence output by motor systems: the sensory system monitors internal and external environments and initiates reflex responses a cognitive system voluntary responses a behavioural state system sleep-wake cycles and intrinsic behaviours The Cerebral cortex is organised into functional areas There are three functional specialisations: Sensory areas - sensory inputs Motor areas - direct muscle movement Association areas - integrate sensory and motor input and direct voluntary behavious Cerebral lateralization of function or left-right brain dominance. Neurons display a level of plasticity.  Sensory information is Integrated in the Spinal Cord and Brain Primary Somatic Sensory Cortex touch, temperature, pain, itch, and body position Visual Cortex...
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