PHIS 206 1st Edition Lecture 6 Outline of Last Lecture I Electrical Properties of Membrane cont d II Neurons III Myelinated and Nonmyelinated IV Neurotransmitters Outline of Current Lecture I Cellular Neurophysiology cont d A Neurons B Convergence C 4 Major Processes of CNS II Central Nervous System overview III Peripheral Nervous System IV Central Nervous System V Brain Protection VI Anatomy Current Lecture I 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 Convergence These 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 Divergence II Central Nervous System overview 2 components brain and spinal chord III Peripheral Nervous System Every neuron apart from the CNS Afferent nerve impulses to the brain Efferent nerve impulses away from the brain A Somatic part that control the muscle s activity B Autonomic controls efference that goes to other organs internally Parasympathetic v Sympathetic IV Central Nervous System Has lots of physical protection Ex 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 selective o Sometimes referred to as the blood brain barrier o Keeps toxic foreign things away from the brain o 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 barrier VI 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 axons o 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 speech
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