Part 1A Notes PDF

PART 1A Key Terms CNS central nervous system brain spinal cord PNS peripheral nervous system nerves connecting the rest ofthe bodytothe CNS Autonomic controls selfregulatedaction ofinternal organs glands Sympathetic Parasympathetic arousing...

PART 1A Key Terms CNS central nervous system brain spinal cord PNS peripheral nervous system nerves connecting the rest ofthe bodytothe CNS Autonomic controls selfregulatedaction ofinternal organs glands Sympathetic Parasympathetic arousing calming ex fightorflight ex normal body state Spinal cord slender structure that weighs about 35g extends halfway down your vertebrae canal Brain Weight size 316s Largest brain elephant's brain is physically larger but less proportionate tothe body Neurons 100billion neurons no pain 75 water 4 6 min w Neuroglia neuronglia ratio is lessthan 1 oxygen 60 w matter 401 g matte Synapses 1k 10k perneuron cerebrum85 60 fat Histology brain cells are 2 groups neurons neuroglia Neurons perform all ofthe communication processing within the brain Sensory neurons entering the brain fromthe peripheral nervous system deliver info about the condition of the body its surroundings Most of the neurons in the brain's grey matter are interneurons which are responsible for integrating processing info delivered to the brainby sensory neurons Interneurons send signals to motor neurons which carr signals to muscles glands Axon collateral major axon branches Myelin sheath fat around axons speed Axon send outinfo Dendrite relieveinfo Synapse where neurons get in contact to exchange info  Neuroglia gliacells act asthehelper cells ofthe brain they support protect the neurons Different types Astrocytes protect neurons by filtering out of the blood nutrients preventin chemicals pathogens from leaving the capillaries of the brain Oligodendrocytes wrapthe axons to produce myelininsulation allowingforfaster transmission They accelerate the communication speed withinthe brain Microglia similarto white blood cells attack destroy pathogens trying to ing.gg the Epyndymal cells line the capillaries of the choroid plexuses filter blood plasma to produce cerebrospinal fluid protecting spine brain Sulcus dip in the folds of the brain Gyrus bumps GreyMatter mostly unmyelinated neurons most are interneurons Nerve connections processing transmits gather signals Where action potential is generated White Matter made of myelinated neurons that connect regions of grey matter to eachother restofthe body Acts as the info highway of the brain to speed the connections between distant parts of the brain body Made of dendrites axons Where action potential is carried centralsulcus latersians Concepts How do neuroscientists study the brain Network Neuroscience Encompasses the study of very differentnetworks encountered across many spatial temporal scales Starting fromthe smallest elements it seeks to bridge info encoded in the relationships between genes biomolecules to the info shared between neu Understanding of neuron processing to structure functions of brain system Immunohistochemistry uses antibodies against specific proteins to show where in a tissue the targeted proteins are located w diff colors Lecture specific staining to see specificthings in the neurons Physiological Techniques Opto 3 Chemogenetic Techniques Optogenetic techniques use light activated ion channels from algae or bacteria prokaryotes to alter the activity of eukaryotic cells Most used ion channel ChR2 opened by bluelight Ex Mice feeding aggressive behavior vids Chemogenetics is conceptually similar to optogenetics but uses modified neurotransmitter receptors rather than opsinsto modulate neural activity drugsrather than light to activate receptors calledDREADDs Section Summary A major goal of neuroscience research is to discover general principles of brain organization The search for these principles combines anatomical physiological evolutionary perspectives What are the basic components of the nervous system The nervous system is hierarchically organized into molecules cells cell group major brain divisions CNS PNS CNS spinalcord brafore brain midbrain hindbrain The nervous system contains neurons glial cells The neurons have distinctive dendrites axons synapses Despite these specializations only 1 2 of human genes are brain specific What kinds of circuits do neurons form parallel connections Topographic projections neighboring neurons in one brain regionoften conn to neighboring neurons in another region Divergence allows info computed by on neuron to be transmitted to several oth neurons which can then use the info differently Convergence allowsinfo fromdifferent neurons to be integrated 2 neurons Negative feedback loops giving info to one neuron the info Forward connection is excitatory converges into 1 neuron backward is inhibatory Regulates excitatory activity within the forward pathway keeping it within lim Positivefeedback loops Both forward backward connections are both excitatory Amplifies activity becomes dangerously high Can be useful allow some neurons to maintain their activity in theface of inhibition by other neurons  Section Summary Neural circuits tend tobe replete with diverging converging reciprocal connections Although neural circuits may look as i everything is connected to everything else this is rarely the case What is the Brain's Functional Architecture Why this example Used a child bo they needed a naive brain to illustrate how learning works They used the flametouching behavior bc they needed 2 reflexes that a child mi exhibit Reachingforthe flame then withdrawingfromthepain Read in textbook  Section Summary it'sdifficulttothink abtbrainorg w out resortingto analogies all are flawed Meyenert James 1800s envisioned the brain as containingshort subcortical longtranscortical reflex are Thelatterwerethought to exhibit plasticity modulat activity in the subcortical circuits Modern views of brainorg include notjust long shortreflexarcs but numerous looping pathways a well as central pattern generators circuits that control an animal'sbehavioral state How can scientists reverse engineer the brain Howdo brains evolve The more distantly related twospecies are the more dissimilartheir nervous systems are likely to be Nonetheless many aspects of nervous system org are broadly conserved especially at the higher levels of organization The brain of a human is 3x a chimpanzee's 1 an elephant is 3x a human's  Example Qs how is this b shouldn't it be a vertical creatures not 4 legged it wouldneed makingdifficult July9sthead Swipeup I 3 Neurons must carry out a lot of functions that are common to all cells More importantly whatmakes neurons special 3 often different from one another is the combo of genes that they express the timing of which gen are expressed in development