PHIS 206 1st EditionLecture 6Outline of Last Lecture I. Electrical Properties of Membrane (cont’d)II. NeuronsIII. Myelinated and NonmyelinatedIV. NeurotransmittersOutline of Current Lecture I. Cellular Neurophysiology (cont’d)A. NeuronsB. ConvergenceC. 4 Major Processes of CNSII. Central Nervous System (overview)III. Peripheral Nervous SystemIV. Central Nervous SystemV. Brain ProtectionVI. AnatomyCurrent LectureI. Cellular Neurophysiology (cont’d)A. Neurons -Common for neurons to be postsynaptic-Convergence: several neurons are postsynaptic to 1 neuron-Divergence: 1 neuron is postsynaptic to many neurons B. ConvergenceThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Excitatory neurons: decreases (-) input of membrane potential-Inhibitory neurons: increases (-) input of membrane potential-Summation: neurons sum up all of the information-When the excitatory > inhibitory, then change is called Excitatory Postsynaptic Potential (EPSP).-When the inhibitory > excitatory, then change is called Inhibitory Postsynaptic Potential (IPSP).-You can sensitize neurons to make them reach threshold and fire action potentials (EPSP).C. 4 Major Processes of CNS-EPSP, IPSP, Convergence, DivergenceII. Central Nervous System (overview)-2 components: brain and spinal chordIII. Peripheral Nervous System-Every neuron apart from the CNS-Afferent: nerve impulses to the brain-Efferent: nerve impulses away from the brainA. Somatic: part that control the muscle’s activityB. Autonomic: controls/efference that goes to other organs internally-Parasympathetic v. SympatheticIV. Central Nervous System-Has lots of physical protectionEx.) spine/spinal cord and brain/skull-Brain: between it and the skull is called meninges Dura mater: outer furry layer “tough mother” Arachnoid mater: extremely vascular and looks like a spider web; involved in generating the cerebral spinal fluid that goes to the brain Pia mater: follows all convolutions; attached closer to brain V. Brain Protection-Cerebrospinal fluid: fluid b/w the meninges same density as brain buoyancy density: brain stays in place; the fluid does not rise or fall Brain does not bump against the skull b/c it is suspended in fluid CSF cushions the brain CSF requires less energy than plasma, which helps ease the formation of action potentials Brain capillaries have different permeability than the rest of the body (body allows larger molecules to go through easily compared to the brain) Brain capillaries are more selectiveo Sometimes referred to as the blood-brain barriero Keeps toxic/foreign things away from the braino Adversely, some good things (antibiotics) cannot get to the brain b/c of the blood-brain barrier Brain is not exposed to plasma, but parts of the brain are responsible for controlling the composition of plasma How so?o Parts of the brain responsible (HYPOTHALAMUS) is outside the blood-brain barrierVI. Anatomy-Cerebral cortex: sensory perception, decision making, personality (higher functions) 6 layers (named Layers 1 (outermost) to 6 (innermost) with similar functions-Cerebral hemispheres: 2 recognizable parts 1.) medulla: primarily axonso with “naked eye” see white matter - Lobes of cerebral cortex Frontal: front of the head o motor homunculus (controls muscles) Temporal: temples of the head Parietal: middle of the top of the head; involved with processing sensory information on the body surface (body position, temperature, blood pressure)o sensory homunculus: (If the body surface is stimulated and mapped out active body parts, then in front of parietal lobes, see body surface. Sizes are not anatomically correct.) Sensory/Motor Homunculus are subject to change (in size) Occipital: back of head- Broca’s Area: part of frontal lobe that allows you to generate speech-Wernicke’s Area: allows you to comprehend
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