BIOL 152 1st Edition Lecture 18 Outline of Last Lecture I. Animal nervous systemsII. Types of nerve cellsIII. Neuron organizationa. WATCH PODCASTIV. Glial cells a. Characteristics & functionb. Myelin sheathV. Salutatory propagation in vertebrates a. Refer to fig 35.11VI. Resting membrane potentiala. Depolarization in action potentialb. Repolarization in action potentialVII. Action potential propagationVIII. NeurotoxinsIX. SynapsesOutline of Current Lecture I. Nerves and nervous systemsa. CNS vs. peripheralb. Autonomici. Sympatheticii. ParasympatheticII. Reflexes: not all signals go to brainIII. Sensory receptor typesIV. Sensory system examplesV. Evolution of the eye and visionCurrent LectureCentral nervous system: brain and spinal cordPeripheral nervous system: everything elseAutonomic nervous systemsThese 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.- Parasympathetic- Sympathetico These are automatically doneo Cannot be controlledo CounterbalancingFast reflexes PASS the brain- Knee jerk reflex is a small signal, sending signals to the brain takes a longer time to process the signalChapter 36Most ancient sense: chemoreception (smell and taste)Huge variety of sensory receptorsSensory transduction= converting sense signal to neuronal signal - Chemoreceptors- Mechanoreceptors- Thermoreceptors- Nociceptors- Photoreceptors- ElectroreceptorsChemoreceptors: affected by a molecule from the environment that connects to a protein that signals the ion channel to openMechanoreceptors: sensory protein changed based on pressure, ion gates opened (sound receptors)Thermoreceptors: detect temperature stimuliNociceptors: detect pain stimuli Photoreceptors: detect light stimuli (photons), ion channel closes-hyperpolarizedElectroreceptors: detect electrical stimuliSensory organs to the brainNerve impulses from sensory organs convey information to the brain. These impulses:- Convey the strength of the signal- Carry the information about even weak signals- Convey location of signal’s source- Filter unimportant signals Adaptation- continuous stimuli reduces the firing rate over timeChemoreceptors: smell/ taste (gustation)= typically needs higher concentration than olfaction Mechanoreceptors- Statolith moves and depresses hair cell sterocilia, producing gravity detection- Vestibular system- Hair cells function by releasing neurotransmitters- Pitch= frequency- Hair cell activation (36.9)Vision- No absorption, no vision- Color is what is reflected, not what is absorbed- Photoreceptors act as light photon countersRhodopsin (36.11)- Molecule involved in sightCompound eye- insects, contains facets (ommatadia)Single-lens eye- single lens focuses light on a retina and allows for a high degree of
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