Neuroscience How does our brain organize and communicate with itself How does our brain allow us to remember the lyrics to dozens of our favorite songs How do we remember exactly where we were and what we were doing when we heard about 911 ID: 1044559
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1. Unit 2: NeurobiologyNeurons, Brain, Body Systems
2. NeuroscienceHow does our brain organize and communicate with itself?How does our brain allow us to remember the lyrics to dozens of our favorite songs?How do we remember exactly where we were and what we were doing when we heard about 9/11?
3. Neural CommunicationThe basic building block of our body’s communication is the neuronThe human brain has approximately 100 Billion neurons that communicate with each other and allow us to learn, remember, feel pain and function as human beings.
4. Parts of a Neuron
5. DendritesBushy, root-like parts of a cellReceive messages (Neurotransmitters) from the sending neuron i.e. the receiver
6. Soma (Cell Body) and NucleusContains nucleus and other life sustaining parts of the cellIn is resting state is -70 charged
7. AxonThe extension of a neuron“The sender”When the threshold is met an electrical charge travels down the axon
8. Myelin SheathFatty covering of the axon – “the insulator”Speeds up the neural impulsesDeterioration of the myelin sheath causes Multiple Sclerosis
9. Terminal Branches/ButtonsBranched end of the axon containing the neurotransmitters (the chemical messenger)When the neuron fires, the terminal buttons release the NT into the synapse
10. Synapse (Synaptic Gap/Cleft)Space between the terminal branches of one neuron and the dendrite of anotherThe gap is less than one billionth of an inch wide
11. NeurotransmitterThe chemical messenger contained in terminal branches that enable neurons to communicateFit into receptor sites on dendrites like a key to a lock
12. How Neurons Fire – the processNeural communication is an electrochemical process. Electricity travels within the cell (down the axon) and the chemical (the neurotransmitter crosses the synapse to travel between cells). Electricity does not jump between neurons. 1.) In its resting state – the neuron is just hanging out and is at a -70 charge2.) If enough + ions cross the cell membrane to change the charge to +50, the neuron has met its threshold and goes into action potential3.) electricity travels down the axon4.) terminal buttons release the NT5.) the NT crosses the synapse and binds to the dendrites of the receiving neuron6.) the leftover NT is taken back up by the terminal buttons – known as reuptake
13. Firing Neurons cont . . .Once a neuron fires it is in a refractory state and cannot fire again until it pumps the + ions back out of the cell body and returns to a -70 resting state (i.e. it must re-load)Firing is an “all or none" principle – if you meet the threshold, you fire completely. If you don’t, you don’t.Neural firing takes place in Fractions of a second
14. Neurotransmitters – the chemical messengerDozens of NT in your body – imbalances can cause problems1.) Dopamine – controls movement, alertness, emotion – too much = schizophrenia, too little = Parkinson's2.) Serotonin – affects mood, hunger, sleep, arousal – too little = depression3.) Acetylcholine (Ach) – affects motor movement, learning, and memory – too little = Alzheimer's4.) Endorphins – body’s natural pain killers
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18. The Nervous System / /Central Nervous System / \ / \Brain Spinal Chord \ \Peripheral Nervous System / \ / \Autonomic Somatic / \ / \ SympatheticParasympathetic
19. Afferent/Efferent Neurons Afferent = Sensory Neurons – run from body to brainEfferent = Motor Neurons – run from brain to bodyEx: I put my left hand on a warm stove. Afferent neurons in my left hand carry the message to the sensory cortex in my right brain. Efferent neurons from the motor cortex in my right brain, sends a message to move my left hand.
20. Peripheral Nervous SystemLinks the central nervous system with all other nerves in the body
21. Somatic Nervous SystemControls voluntary muscle movement
22. Autonomic Nervous SystemControls autonomic functions of our body (heart, lungs, organs, etc)Usually operates on its ownAutonomic isAutomatic!
23. Autonomic is divided into…..Sympathetic NS: Excitatory - arouses us for defensive actionAlert system of the bodyAccelerates heart rate, blood pressure, breathing; slows digestionMakes you alert and ready for actionParasympathetic NSCalming systemReturns body to normal after stress passesLowers breathing, heart rate, constricts pupils
24. Reflexes – exception to the rule….Message doesn’t go all the way back to the brainSensory neurons carry the info to the spine and the spine makes a motor command without the message getting all the way to the brain firstEx: knee; intense heat or cold
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26. Brain Imaging…..1.) Accidents and Injuries:If a part is damaged, we can deduce what it controlled. – Phineus Gage
27. Brain Imaging2.) Legions:Removal or destruction of part of the brain (brain tumor).Deduces functions
28. Brain Imaging3.) EEG - Detects brain waves
29. Brain Imaging4.) CAT – Computerized Axial Tomography 3-D x-ray of brain Shows Structure, notfunction
30. Brain Imaging5.) Magnetic Resonance Imaging – MRIUses magnetic fields to measure the density and location of brain material Structure, not function
31. Brain Imaging6.) Positron Emission Topography - PETLets researchers see what areas of the brain are most active during certain tasks – shows functionMeasures how much of a certain chemical are used in different parts of the brain.Uses radioactive glucose
32. Brain Imaging7.) Functional MRICombines the MRI and the PET scanShows structure and function
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34. Cerebral Cortex (CC)It’s what you think of when you picture the brain: the gray, wrinkled surface of the brainIt’s a thin layer of densely packed neurons
35. Cerebral CortexLeft HemisphereGets messages from and controls the right side of the bodyLogicLanguageVerbalAnalyticalRight HemisphereGets messages from and controls the left side of the bodySpatialCreativeEmotionally intuitive
36. The Cerebral CortexThe left and right hemispheres look symmetrical – but they are biologically the “odd couple” serving complementary functionsComplex tasks involve both hemispheresCorpus Callosum - band of fibers Connecting left and right hemispheresSplit Brain Surgery – severe corpus callosum – rare treatment for epilepsy
37. Dateline NBC – Growing Hope – Is Medical Marijuana a Viable Treatment for Epilepsy?http://www.nbc.com/dateline/video/dateline-june-7-2015/2870103?onid=209511#vc209511=1
38. 4 Lobes of the Brain
39. Frontal LobeBehind the eyes/foreheadInvolved in abstract thought, emotional control, rational judgment (Phineus Gage)Contains The Motor Cortex – sends out motor messages via efferent neuronsBroca’s Area (left frontal) – speech center
40. Parietal LobeCrown of the headContains the Sensory cortex – where afferent/sensory neurons carry informationThe more sensitive the body area, the greater surface area assigned on the sensory cortex
41. Occipital and Temporal LobesOccipital – Back of the head Processes visionTemporal – sides of head over ears Processes hearing Wernicke’s Area – left temporal – language comprehension
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43. Other Important Brain Parts…
44. Three subsections of the brain
45. Hindbrain
46. Within the hindbrain…Hindbrain – consists of the top of the spine and base of brain – critical life functionsMedulla: blood pressure, heart rate, breathingPons: just above medulla – critical in facial expressionsCerebellum: located on the bottom, back side of the brain. Literally means “little brain.” Critical for balance and fine motor movements.
47. MidbrainJust above spine. Very small in humans. Reticular Formation:Finger shaped network of neurons – extends throughout hindbrain to midbrain. Controls arousal and ability to focus attention.Coma when malfunctions
48. ForebrainForebrainControls thought and reasonMost studied by psychologistsMuch bigger than the midbrain & hindbrainWhat makes us humans
49. Within the forebrain…..Thalamus: sensory switchboard – relays all incoming sensory info except smellHypothalamus: “pleasure center” – regulates hunger, thirst, and sexual arousal. Also regulates the entire endocrine system via the pituitary gland
50. Within the forebrain….Amygdala: aggression and fear center. (Legion the amygdala in a monkey and he will be passive and docile)Hippocampus: critical in forming episodic memories. Not fully formed until age 3. Smell is routed through the hippocampus.Limbic System: the thalamus, hypothalamus, amygdala, and hippocampus all form the limbic system. Deals with aspects of emotion and memory.
51. Brain PlasticityThe brains ability to re-organize its neural connections after some type of damage, such that one part of the brain can develop the capacity to carry out a function it normally wouldn’t in a healthy brain.Brain plasticity is inversely correlated with the age. The older you are the less plastic your brain is and the more difficult it is to overcome brain injury.
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53. GeneticsEvery human cell has 46 chromosomes in 23 pairs. Genetic material that makes up chromosomes is DNA.
54. GeneticsDominant traits over-ride recessiveGenotype – every gene you are a carrier ofPhenotype – what actually manifests in your physical characteristicsHomozygous – having identical alleles for a single trait (BB, bb)Heterozygous – having two different alleles for a single trait (Bb)
55. Dominant V. Recessive
56. Punnett Square
57. Twins….Identical twins come from one fertilized egg that splits and share DNA.Fraternal twins come two separate eggs fertilized by two separate sperm and are no more genetically similar than normal siblings.
58. Gender and X linked DisordersGender is determined by the 23rd pair of chromosomes. XX = girl, XY = boyFemale eggs always carry X. Male sperm carry X or Y and determine the gender of the baby.X-linked disorders are carried on the X chromosome. Women are often the carriers and the disease manifests in their sons.Muscular Dystrophy, color blindness, hemophilia
59. X Linked Disorders
60. Chromosomal AbnormalitiesTurner’s Syndrome - Only one single X (girls). Cannot reproduce, short stature, webbed necks, abnormal sexual developmentKlinefelters Syndrome – males, extra X (XXY), varied effects – minimal sexual development, extreme introversion, cannot reproduceDown’s – extra chromosome on 21st pair. Causes mental retardation.