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103 Cards in this Set
- Front
- Back
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Neuron
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-100 billion in brain
-cells in the nervous system that communicate with one another to perform information processing tasks -information reception and transmission |
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Cell Body
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-Soma
- coordinates the information processing task adn keeps the cell alive -protein synthesis, energy production, metabolism |
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nucleus
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- houses chromosomes
-contains DNA |
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What are the special extensions on a nueron and what are their functions?
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-Dendrites and Axons
-Reception and transmission of information in and out of the cell |
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Dendrites
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-Receive information from other neurons and relay it to the cell body
-Tree |
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Axons
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-transmits information to to other nuerons, muscles, or glands
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Neuron left to right
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Dendrites
Cell Body Nucleus Axon Axon Hillcock Myelin Sheath Nodes of Raniver Terminal Branches Axon Terminals |
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Axon Hillock
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- Located: the end of the soma
- Function: controls the firing of the neuron (If the total strength of the signal exceeds the threshold limit of the axon hillock, the structure will fire a signal down the axon) |
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Myelin Sheath
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-Location: nsulating envelope surrounding the core of a nerve fiber or axon
- Function: facilitates the transmission of nerve impulses -made of glial cells |
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Glial Cells
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- support cells found in the nervous system
-Digest parts of dead neurons -physical/ nutritional support/ aids in transmission of info |
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Demyelinating Diseases
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-slows down transmisson
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Synapse
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-Jucntion or region btw the axon of one neuron and teh dendrites or cell body of another
-100-500 trillion synapses |
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Where do neurons transmit information?
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- Neurons do not touch eachother
-An electrochemical wave called an action potential travels along the axon of a neuron. When the wave reaches a synapse, it provokes release of a puff of neurotransmitter molecules, which bind to chemical receptor molecules located in the membrane of another neuron, on the opposite side of the synapse. |
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Parts Working in the Synapse
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-Sending Neuron (vesicles)
-Synaptic Gap (neurotransmitters) -Recieving Neuron (receptor site) |
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Three Major Types of Neurons
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1. Sensory Neurons
2. Motor Neurons 3. Interneurons |
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Sensory Neurons
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Function- receive information from external world and convery this information to the brain via spinal chrord
-Secialized endings for sense perception - External world => sensory neuron => spinal chrord => brain |
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Motor Neurons
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-carry signals from the spinal cord to the muscles to produce movement
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Interneurons
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-connect sensory neurons, motor neurons, and other interneurons
-most of the nervous system is composed of this type of cell -work in small circuts to perform simple task such as locating the location of a signal |
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Two ways in which neurons are specialized
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-Function (motor, sensory, inter)
-Location |
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Purkinje Cells
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-interneurons that carry mostly motor information from the cerebellum to the rest of the brain and spinal cord
-dense dendrites |
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Pyramidal Cells
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-found in cerebral cortex
-carry all kinds of information from the cortex |
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Bipolar Cells
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-Single axon and dendrite
-sensory neuron in retina |
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Mirror Neurons
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- frontal and temporal cortex
-particularly active when observing other people in action |
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2 Stages of Communication btw Neurons
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conduction and transmission
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Conduction and Transmission aslo referred to as...
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Electrochemical Action
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what occurs in the 1st stage of Electrochemical Action?
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1. First the a signal is received and may initiate electrical conduction down the axon
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what occurs in the 2nd stage of Electrochemical Action?
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2. Second, the signal travels chemically across the synapse to the next neuron
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Resting Potential
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– the difference in electrical charge between the inside and outside of a neuron’s cell membrane
-difference in concentrations of ions in/out the neurons cell body |
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Ions
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-small electrically charged molecules
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Describe ions influencing resting potential...
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-At rest there is a higher concentration of potassium (K+) on the inside of the cell and sodium (Na+) outside of the cell
-The flow of ions across the cell membrane is controlled by opening and closing channels that are specific to each ion |
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The resting potential of a neuron is approximately....
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-70 millivolts
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Action Potential
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– an electrical signal that is conducted along the length of a neuron’s axon to the synapse
-all or none -does not change despite intensity above threshold |
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When does action potential occur?
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- electric shock reaches threshold
-change in axons membranes channels -K+ channels shut down - other channels open (Na+) -pushes the action potential to its maximum value of +40 millivolts |
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Refractory Peridod
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-the time following an action potential during which a new action potential cannot be initiated
-chemical pump in cell membrance moves Na+ outside the axon and moves K+ inside the axon |
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Nodes of Ranvier
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which causes action potential to “jump” (Saltatory Conduction) and speeds conduction
-gaps/ between the myelin sheaths/ the axonal membrane is uninsulated/ capable of generating electrical activity |
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Inside the Synapse
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-Presynaptic Neuron
-AP stimulated release of nuerotrnsmitters from vesicles into the synaspe -Bind to receptor sites on postsynaptic nueron |
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Synaptic Transmission
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electrochemical action that underlies every process of our mind and body
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Receptors
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– parts of the cell membrane that receive neurotransmitters and initiate a new electrical signal
-lock and key |
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Enzymatic degradation
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– enzymes can destroy the neurotransmitter while still in the synapse
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Reuptake
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– neurotransmitters are taken back into the presynaptic neuron through transporters
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Autoreceptors
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detect if there is too much neurotransmitter being released and signal the presynaptic neuron to stop the release
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Acetylcholine
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-a neurotransmitter involved in a number of functions, including motor control
-ex of deficiency is Alzheimer's |
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Dopamine
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– a neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal
- high levels linked to schizo low levels parkinsons |
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Glutamate
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- a major excitatory neurotransmitter involved in information transmission throughout the brain
-oversupply can overstimulate teh brain migranes |
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GABA
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– the primary inhibitory neurotransmitter in the brain
E. Norepinephrine – a neurotransmitter that influences mood and arousal, particularly states of vigilance or danger awareness -undersupply seizures |
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Serotonin
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– a neurotransmitter involved in the regulation of sleep and wakefulness, eating, and aggressive behavior
-undersupply depression |
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Endorphins
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chemicals that act within the pain pathways and emotion centers of the brain
-lack can lower pain threshold |
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Norepinephrine
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-helps control moods
-undersupply can cause depression |
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Agonists
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-drugs that increase the action of a neurotransmitter
-LSD is an agonist for serotonin |
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Antagonists
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-drugs that block the function of a neurotransmitter
-Propanolol blocks the beta receptors for norepinephrine in the heart, which helps with stage fright |
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Two Major Divisions of th Nervous System
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1. Central Nervous System
2. Preipheral Nervous System |
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Nervous System
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An interacting network of nuerons that conveys electrochemical information throughout the body
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Central Nervous System
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-brain and spinal cord
-recieves info/ sends commands/ process and coordinates info |
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Peripheral Nervous System
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-connects the central nervous system to the body’s organs and muscles
-divides into Autonomic and Somatic |
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Somatic Nervous System
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-a set of nerves that conveys information into and out of the central nervous system
-control voluntary movements |
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Autonomic Nervous System
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– a set of nerves that carries involuntary and automatic commands that control blood vessels, body organs, and glands
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Sympathetic Nervous System
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– a set of nerves that prepares the body for action in a threatening situation
-Arousal |
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Parasympathetic Nervous System
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– helps the body return to a normal resting state
-Calming |
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Spinal Reflexes
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– simple pathways in the nervous system that rapidly generate muscle contractions
-ex removing hand from hot stove |
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Spinal Chord
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-takes care of simple tasks
-allows the brain to handle more complex tasks -4 sections Cervical, Thoracic, Lumbar, Sacral |
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The Nervous System Flow
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Central
Peripheral (Autonomic/Somatic) Autonomic (Sympathetic/Parasympathetic) |
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3 regions of the Brain
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Hindbrin, Midbrain, Forebrain
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HIndbrain
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– lower area of the brain that coordinates information coming into and out of the spinal cord
-Basic Functions (eg,..breathing,alertness) -Pons/ Medulla/ Reicular Formation/ Cerebellum |
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Medulla
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Location: connects to sinal chord, left of cerebellum, touches
Function: coordinates heart rate, respiration and circulation |
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Reticular Formation
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– a cluster of neurons in the medulla that regulates sleep, wakefulness, and levels of arousal
-cut off = coma |
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Cerebellum
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– a large structure of the hindbrain that controls fine motor skills, coordination, and balance
-Little Brain -Grace |
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Pons
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– a structure that relays information from the cerebellum to the rest of the brain
-Bridge - relay station for cerebellum |
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The Midbrain
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Location: Above hind brain, below forebrain
Function: coordinates orientation and movement in the environment, and contributes to arousal Tectum/tegmentum |
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Tectum
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orients orgaism in enviroment
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Tegmentum
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Involved in movement and arousal
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The Forebrain
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– highest level of the brain, controlling complex cognitive, emotional, sensory, and motor functions
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Cerebral Cortex
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-the outermost layer of the brain, visible to the naked eye, and divided into two hemispheres
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Subcortical Structures
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– areas of the forebrain housed under the cerebral cortex near the very center of the brain
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Thalamus
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Description: appears rounded egg shaped/ lined by hippocampus/ touching hypothalumus
Function: relays and filters information from the senses and transmits the information to the cerebral cortex -actively filter sensory information -connets to optical and auditory nerve -closes pathways during sleep |
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sulci
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fissures
sulk |
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gyri
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the "bumps" on the brain's surface.
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Hypothalamus
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Description: below thalamus (hypo = below)
Function: regulates body temperature, hunger, thrist and sexual behavior -blood sugar levels. body temp, metabolism -releases hormones for sex - four F's fighting, fleeing, feeding, f.. .. .. mating |
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Pituitary Gland
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Location: Below hypothalamus, rounded oval like
Function: the “master gland” of the body’s hormone-producing system, which releases hormones that direct the functions of many other glands in the body -recieves sig from hypo and send out to other glands |
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Limbic System
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Hypothalamus
Amygdala Hippocampus .... which are involved in motivation, emotion, learning, and memory. |
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Hippocampus
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structure critical for creating new memories and integrating them into a network of knowledge so that they can be stored indefinitely in other parts of the brain.
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Amygdala
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Location: at the tip of each horn of the hippocampus,
Function:plays a central role in many emotional processes, particularly the formation of emotional memories -encoding events as fearful -activates hippocampus to remeber details of significant emotional events |
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Basal Ganglia
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Located: near Thalamus and Hippocampus
Function: a set of subcortical structures {including the striatum ..(posture)} that directs intentional movements |
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The Cerebral Cortex
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-Divided into two hemispheres housing 4 lobes each with each lobe having specific association areas
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Contrallateral
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Hemisphere function for opposite side of body
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Commissures
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– bundles of axons that make possible communication between parallel areas of the cortex in each half, the largest being the corpus callosum
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Occipital Lobe
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– a region in the back of the brain that processes visual information
-Vision |
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Parietal Lobe
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– located in front of the occipital lobe and carries out functions such as touch
-Touch |
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Temporal Lobe
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– located laterally and below parietal cortex, is responsible for hearing and language
-Sound |
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Frontal Lobe
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– behind the forehead, has specialized areas for movement, abstract thinking, planning, memory, and judgment
-Complex thinking |
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Motor Cortex
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-frontal lobe parallels somatoensory cortex
-each part maps for a particular contrallateral movement of the body |
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Somatosensory Cortex
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-on parietal lobe
-represents skin areas on contralteral parts of the body -Homounculus man |
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Association Areas
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– areas of cortex that are composed of neurons that help provide sense and meaning to information registered in parts of the primary cortex
-"Associated areas, then, help stitch together the threads of informatin in various parts in a meaningful understanding of whats being registered in the brain -nuerons here can be shaped by learning and experience -more flexible; less specialized |
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How can the brain adapt to changes in the enviroment and individual?
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Functions that were assigned to certain areas of the brain may be capable of being reassigned to other areas
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Nervous System Timeline
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1. Nervous system is the first major bodily system to take form in an embryo
a. After the third week of fertilization the nervous system goes from a sphere with a ridge, to a groove, to a neural tube b. Fifth week the forebrain and hindbrain differentiate c. Seventh week and later, forebrain expands into cerebral hemispheres |
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Ontogeny
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– how the brain develops within an individual
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Phylogeny
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– how the brain developed within a particular species
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How did the nervous system become so complex?
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Primates’ brains, particularly humans, have evolved more rapidly than other mammals, partially because of gene mutations (changes in a gene’s DNA) that resulted in adaptation
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Nature or Nurture?
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The interaction between nature and nurture determines what humans do
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Gene
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unit of hereditary transmission, built from DNA (deoxyribonucleic acid)
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Chromosomes
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– strands of DNA wound around each other in a double-helix configuration
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Degree of Relatedness
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– the probability of sharing genes
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Monozygotic Twins vs Dizygotic Twins
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share 100% of genes because they came from one fertilized egg vs share 50% of genes because they came from 2 fertilized eggs, just like other siblings
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Heritability
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– a measure of the variability of behavioral traits among individuals that can be accounted for by genetic factors
-Heritability is not fate; circumstances can change the likelihood of behaviors or pathologies |
