chapter 3 Flashcards
Neuroscience
The study of how nerves and cells send and receive info from the brain, body and spinal cord
everything psychlogical is biological
cerebral cortex
The top of the brain - wrinkly region
whats below is the subcortex
humans have a highly develop cerebral cortex
It is eolutinarly young and gives cognitive skills and ability to experience complex emotions
The cerebral cortex surround inner evolutianrly old parts - the older parts sned and receive connections from all organs, regultaing mental and bodily functions needed for survival
neurons
the cells that makeup the brain
contain genes which infleunce how our brains are similar and diff
brain is product of both genes and envirnment
genes give the brain the abiilty to adapt to envirnment and learn from epxiernces
Nervous system
A network of neurons that run throughout your brain and body
Nerves - collection of neruons - carry signals toa nd from the brain, relating perceptions, thoughts and feelings into actions
Neurons
Motor neurons: Send meesages to the whole body, enabling you to interct with the envirnment
Sensory neurons: these neerves send status report back to brain - cary info from within the body and the outside world to the brain
Interneurons: connecting other neruons - interpret, store and retrieve info abt the world allowing you to make informed decisons before you act - most brain resoruces are devoted to processing sensory data it receives and using the data to plan and execute future actions
Spinal cord
bundle of nerves that connects the body to the brain - encased in bone known as spine
central nervous sytem
CNS exchanges info between teh brain and body - made of the brain and spinal cord
Periphral nervous system
composed of sensory and motor nerves that travel in the whole body
Somatic nervous sytem
PNS seperated into this system whcih allows you to feel external sensations
voluntary comands - controls the conscious body movements
includes skeltal muscles
Autonomic nervous system
PNS also dived into this whch allows you to feel internal sensations
involunayr commands - maintains operations inside the body like heartbeat
includes organs, blood vessles and glands
sympathetic and parasympatheic
autonomic nervous sytems splits into this
sympatheic nervous system acts on blood vessels, organs and glands in a way that prepares the body for action in life thretain situations
parasympatheic acts on blood vessels, organs and glands in a way that returns the body to a resting state by both counteracting adn complementing the actions of sympethic system
endocrine system
network of glands that release hormones
coordinates hormone release with CNS and PNS allwing signal exchange from your brain to your body and back again
reaches crooks and crannies of body even though slower than nervous system
adrenal glands
on kidneys
role in flight or fight
activated by sympatheic branch of autonmic system duirng stress
release adrenaline and cortisol which boost energy and icnrease heart rate, blood pressure and blood sugar
hypothalamus
interestion of CNS and encodrine system happens here
plays imprtant role in governing many survival related behaviours lke eating, drinking and having sex
these all give pleasure which links psycholgical needs and wants to behaviours body needs
pituitary galnd
under hypothalmus
master endocrine gland - oval shaped cluster
sends messages to regulate other endocrine glands, modulate hunger, sexual arousal and via the pineal gland, sleep
communicates with male and female sex glands to produce sex hormones
releases oxytocin
major structures of brain
forebrain: occipital, temporal, parietal, frontal and insular - in the subcortex is the hippocampus, amygdala, basal ganglia, thalamus and hypothalmus
midbrain: tegmentum, ventral tegmental area, substantia nigra
hindbrain: pons, medulla oblogata, reticular formtaion and cerebellum
cerebral cortex
largest and outermost portion of brain
supports complex mental activty
majority is neocortex - develops through late adolescence and adulthood - supports most complex functions like language, thought problem solving and imagination
neocortex is folded to accomdate large number of neursons
lobes:
- occiptal lobe: devoted to vision, primary visual cortex is for sight
- temproal lobe: contains primary auditory cortex, responsble for hearing and understanding language, helps reocgnize objects and ppl, damage can cause you to not know what an objetc is or the meaning of a word
- parietal lobe:contains primary somatosnsry cortex which supports a map of the bodys skin surface and the sense of touch - helps you pay attenion, locate objects
- frontal lobe:essential for moevemt and planning, conatins primary motor cortex and map of bodys muscles whcih worsk withe spinal cord to control movement - the rest is prefrontal cortex which is for thoyght, planning, decison making and self conrol
- insular lobe: hidden under tempral, frontal and parietal, perceive the inside of our bodies, includes primary taste cortex, allows us to precive states of interal organs
each lobe has a primary sensory area which is cortical region to receive signals from associated sensory nerves - without them you would have no sensory expernces
primary motor cortex - repsonsible for volunary movements and conencts with motor neurons that make body move
most of the coretx surroudning primary somatosensry and motor cortex is association cortex which intergeates ifno comining in from the sneses with existing knowledge to produce meaningful expeirnce of world and how to navigate
Subcortical structures
parts beneath the cerebral cortex
limbic system: bridges the higher brains trcyres that are related to compelx mental fucntions with odler brain regions that regulate the body and its moevemnst
Constsists of hippocampus, amygdala, basal ganglia, thalamus and hypothalamus
defined as emotional brain but also plays role in smell, leaning, memory and motivation
Hippocampus: crucial fro aspects of memory and ability to navigate the envrinment - creates memories of events time and place, supprting mental tiem travel into past - can related to emotions as it remembrers emotionally prominent events
amygdala: dedicated to emotion - plays role in how you register emotional signifacne of events - emotional behaviour- usually enhances emotionally signfianct memories
basal ganglia: group of interconnected sttcutures that are evolutinarly older subcortical motor system that is necesary for planning and executing movement - bridges motor regions of cebral cortex with ncueli that communcite with spinal cord,s ending signals to msucles to act
thalamus: located between basal ganglia - serves as subcorical hub fro signals it reecives from all sensory systems except smell - two way connection betwee thalamus and rbain regions that receive its info - relays sensory info from and to cerebal cortex
hypothalmus: interface between brain and body, integrating internal bodily signals with their associated feeelings and behaviours - composed of specilzied nuceli that regulate specifc functions like hunger or reward seeking
brainstem and cerebellum
brainstem ensures that brain gets oxygen it needs - regulates vital functions
sensory nerves connect with brain from brainstem - brainstme consisst of midbrain, pons, medulla oblognata, and reticular formation
brainstem collects sensory signals from body and sendds signals down - plays role in emotion related chnages in the body
midbrain: includes tegmentum which reflexively moves the head and eyes towards sudden sights and sounds - ventral tegmental area is compnent of motiavtion and reward system - substatntia nigra regulates movement itself
pons and medulla oblongata are located in hindbrain part of brainstem - generates certain autmtc movements -pons controls breathing and relays senstaions like hearing and taste to cortex and subcortex - medula oblogata involved in controlling autonomic fnctions like hear rate
- these contain the reticular formation - plays cnetral role in arousal and attention - helps with mainting cognitive abilities
cerebellum contributes to coordination, precison, baalnce and timing
Where is self
- distributed all over
- in the frontal lobe, thoughts, planning, decison making and self control are all tehre
- frntal lobe needs inputs form other regions that conatin emmories and knowledge and personal traits
- fonrtal lob reps conscience and will - keeps behaviour in check
prefrontal cortexx supports executive functions - congintve processes that allow you to plan, focus attention and organisze multiple takss to complete - includes inhibtory control
Gage was proof that prontal cortex and self are connected
Two hemispheres
parallel structures of the brain dont necisarly divide the same job in half
left hemisphere improtant for language - damage to left frontal (brocas) impairs ability to speak but not to comperehend speech
damage to uppler left temproal lobe (Wernickes) results in impaired ability to comprehend speech not the ability to speak
hemispheric lateralization/specialization in left side for language
two halves of brain work via bridge of fibers clled corpus callosum - allows both sides to share info and support the contralateral communciation between brain and body
allows interhemispheric transfer
left hemisphere focus on details and right focuses on seeing big picture
split brain procedure
severing corpus callosum
Neuron parts
regardless of type, neurons have same basic parts
- Have cluster of dendrites which receive chemical messages from other neurons
- cell body or soma collects neural impuslses, contains the cell ncuelus and rpvides life sustainng functions for the cell
- axon whcih transports electrcal impulses to other neurons via terminal branches which convert these impulses into chemical messages
some neurons have long axons to transmit messages a long way
myelin sheath is fatty tissue that covers axon and ensures signal gets there fast and with less resistance - gives brain white matter light appearnce and critcal for human brain dvelpemnt - demylentaion is chatacetric of neurodiegnative diseases - provides proetcion and speed of conducted eletrcial signals
myelin, not part of neuron, is made up of glial cells or glia - insulate and noruish neurons - vacuum up neruosnal debris and sevre as cellular glue between nuerons gving brain jelly like consistency - contrbute to info processing in dveelopment - essentail in brain dveelopment, providng scaffol along which axons grow and gudie them to correct location - glia aid in fomration of neural netwroks
Action potential - neurons firing
when stimulated with sufficnet energy and called into action, neurosn fire an eletrical impulse called an action potential down the axon- this impulse creates volatge needed for action - that is teh capacty to communicate with other neurons
action potential is wave of change in elcrical potential that rushes down the axon
the electricty in neurons is created by chem
nuerons are bathed in extracellular fluid composed of pos an neg charges particles or ions of sodium, chloride, potasisum and calcium
The memrbane that seperates intracellular and extracellular fluids is sleetive
Pos charged ions reside outside so extracellular fluid is relatevly pos to the neg intracellular envirnment
These chem conc differences result in neg voltage
As long as resting potential is strongly neg polzarised, a neuron cannot fire an action potential
when other neurosn sufficently stimulate neurons dendrites, ion channels open allowing pos sodium ions to enter, they set off a chain rxn as they spread down axon causing more channels to open
this results in depolarization moving neg resting potental to zerp
when neuron passes voltage threshold of -50 milivolts, voltages controlled ion channels opne rapidly allowing more pos ions in and then voltage surges and becomes pos
action potetals are bases for neural signaling
when ion flood is completem the flood reverses causing memrban repolarization in which membrane returns to resting potential
there is a refractory period in which neuron cannot fire action potential again
some signals from neurons are excitatory messages, mvoing the volatge of neuron closerto threshold
some are inhibitory messages moving it further away from. threshold
if the excitatory pos messages outweight the inhibory neg messages to research threshold then action potental is fired
How neurons communicate
a gap called synapse spans the axon terminals of the sending neuron with the dendrites or cell body of receving neuron
Process of neurotransmission allows eltrcical messages to bridge the synaptic gap by converting the eeltrcial implse into a chemcial one allowing neurons to trasnmit their signals
eletrcal to chem trasnlation is critcial for communication between enurons - from sending presynaptic neuron temrinals to receving postsynpatic tagret neuron dendrites
the terminal braanches release chem messengers called neurotransmitters across the synpatic gap toarad the target receving neuron
surface of target neuron has rceeptors that bind with specific neurotransmitters - once they bind, ion channels open up thereby inducing changes in ion flow on the taregt neuron cll membrane creating eeltrical signal
receptors response to neurotransmitter is either excitory or inhibitory
inactivation of neurotransmitters in synapse is imprtant - if not removed that target neuron would be bombared by stimulationfrom the neurotransmitter causing an imbalance
neurtransmitters in synpase removed by diffusion, degradation, and reuptake into the presynaptic terminal bracnehs
neuortransmittr classes: aa, monoamines and acetylcholine
aa like glutamate or GABA are brain abusdant neurtransmitters - important exciattroy receptors - involved in ability to form long term memories
GABA for inhibory - inolved in regulation of muscle tone
monoamines like norepinephrine are imprtant for fliht or fight - dopamine and serotoin also are monoamines
acetylcholine: behave as both inhibory and excitatry - supprots heart and skeltal muscle and cognitive function
