Knowt
Note
Studied by 20 people
PSYCH 261, Modules 1.1, 1.2
MODULE 1.1
learning objectives
state mind-brain problem and contrast monism with dualism
give examples of physiological, ontogenetic, evolutionary, and functional explanations of behaviour
discuss ethical issues of research with lab animals
notes:
we have one major question that pertains to psychology that we are investgating here.
it is: in a universe composed of matter and energy, WHY IS THERE SUCH A THING AS CONSCIOUSNESS?
computers can do what humans do lol without being conscious, so… why? why consciousness?
THE MIND-BRAIN PROBLEM (the mind-body problem)
how and why are certain types of brain activity conscious??
THE FIELD OF BIOLOGICAL PSYCHOLOGY
biological psychology
study of physiological, evolutionary, and developmental mechanisms of behaviour and experience
(biopsych, psychbiology, physiological psychology, behaviour neuroscience are other names)
biological psychology —> relate biollogy to psychology. neuroscience —> deals with behaviour, but includes details of anatomy and chemistry.
pov of biological psychology: “we think and act as we do because of brain mechanisms that we evolved because ancient animals built this way survived and reproduced”
biological psych (biopsych) deals with brain activity
VIEWPOINTS OF THE BRAIN
dorsal view
view from the top
ventral view
view from the bottom
microscopic level
neurons
convey messages to other neurons, to muscles and glands
many types, many sizes, shapes and functions
glia
smaller than neurons
JUST AS IMPORTANT!! JUST AS PLENTIFUL IN SOME AREAS
many functions, but dont convey info over large distances
3 MAIN POINTS TO REMEMBER
perception occurs in your brain. when something happens to you (hammer striking your hand), you feel it in your brain, not your hand. if you probe the right part of the brain the right way, you’ll feel the same thing in your hand.
what you perceive is not waht something actually is. the colours you see are bcz of what the light rays make your brain do. light waves are not colours.
question: have to go over thsi again, cause im a little confused of what eactly this means. (p. 6)
currently, we support monism, the idea that the universe consists of only one type of being and mental activity and types of brain activity are inseperable
dualism: is the idea that the mind is one thing, and matter is another
my lecture notes go more into depth on this
the question: does brain activity cause thoughts or do thoughts direct brain activity? is like: does temperature control movement of molecules, or do the movement of molecules control temperature? NEITHER CAUSES THE OTHER. WE’RE JSUT DESCRIBING.
ppl are different! ppl have different complexity in picturing things, vary in how well they recognize faces, sensitivity to tastes, smells and pain, understand voices in a noisy environment, ability to recall persoanl experiences, how much sleep they need per night………….
BIOLOGICAL EXPLANATIONS OF BEHAVIOUR
biological explanatiosn of behaviour fall into 4 categoreis
physiological
relates a behaviour to the activity of the brain and other organs
ex. chemical reactions that let hormones influence brain activity
ex. which routes does brain activity take to control muscle contractions
ex. moths + bats. for moths, if sound louder in one ear than the other, it goes the other side, but if its equal on both sides, it dives bcz connectiosn in moth’s head stimulate either a dive or “helter-skelter flight”, in order for it to survive!! this is at ultrasonic sounds
BIRD SONG EXAMPLE:
particular area of brain grows bcz of testosterone so its bigger in males than females. this brain area enables male to sing.
ontogenetic
describing how something develops
ex. examining behaviour at various ages, and relate it to changes in the nervous system
genetic —> genesis —> development
BIRD SONG EXAMPLE: young male bird learns song by listening to adult males. for song to develop, you need the right genes ANDDD hearing the right song during the right time.
evolutionary
evolutionary explanation of a behaviour/structure
ex. bat wings —> modified arms, porcupine quills —> modified hairs
humans evolved elaborations on abilities other specieis have (ex. monkeys use tools, humans use tools better)
question: is this an anthropocentric viewpoint chat
calling attention to behavioural similarities among related species
BIRD SONG EXAMPLE: some birds have similar calls. this suggests they evolved from the same ancestor.
functional
why did a behaviour evolve the way it did?
a gene tahat is prevalent rhough society prolly was helpful, even if its not helpful now
ex. fight or flight for new situations, really stressful and makes anxiety now, but super helpful then
ex. chamealeons able to camoflauge into surroudnigns to avoid predators
BIRD SONG EXAMPLE: in some species, only male sings and that too only during mating season in his area. so the function of birdsong is to attract mates!!
STOP & CHECK:
how does an evolutionary explanation differ from a functional explanation?
an evolutionary explanation is what evolved FROM WHAT.
ex. humans came from primates, so we have those features EVEN IF THEYRE NOT HELPFUL.
but functionally, we’re focused on what function something we evolved HELPS US. we wonder why this trait was advantageous and favoured by natural selection ex. particularities in sight, vision, touch.
ex. why did we develop lateralization of function?
evolutionary —> why a trait developed over time?
functional —> what purpose does this trait have right now?
historical vs immediate.
CAREER OPPORTUNITES
research or therapy
RESEARCH FIELDS:
research —> PhD
or masters or bachelors for lower level position
some have pure reserach positions in government labs, drug companies…
neuroscientist: studies any aspect of the nervous system
behavioural neuroscientist
how do the brain and other organs influence behaviour?
cognitive neuroscientist
use brain scans to analyze and explore people’s knowledge, thinking and problem solving
neuropsychologist
conducts tests to determine abilities and disabilities of ppl with brain damage or impairment. both psychological + medical training
WHAT I WANNA BE HOPEFULLY!!!!!!!!!!!!!
(ex. assessing cognitive abilities of someone with mutliple sclerosis)
psychophysiologist
measures heart rate, breathing rate, brain waves and other body processes
neurochemist
chemical reactions in the brain
comparative psychologist
compares behaviours of different species and relates behaviours to ancestry and ways of life
evolutionary psychologist
relates behaviours to functions they’ve served, and selective pressures that caused them to evolve
PRACTITIONER FIELDS OF PSYCHOLOGY
PhD, PsyD, or masters. hospitals, clinics, schools, colleges, private practice
clinical psychologist (helps ppl with emotional, cognitive and behavioural problems) (ex. have panic disorder)
counselling psychologist (helps ppl with educational, vocational problems + decisions) (ex. struggling with academic stress
school psychologist (finds needs of schoolchildren, makes plan to meet needs, helps teachers implement them)
MEDICAL FIELDS
MD + 4 years of study and practice in a specialization. hospitals, clinics, med schools, private practice. some may conduct research as well as treating patients.
neurologist
treats ppl with brain damage or disease
neurosurgeon
performs brain surgery
psychiatrist
helps ppl with emotinal distress or troubling behaviour
employs drugs and medical proceduers (ex. SSRIs for depression)
ALLIED MEDICAL FIELD
masters or more
hospitals, clinics, private practice, med schools
physical therapist
exercise and other treatments to help ppl with muscle or nervous system problems that imapir movement
ex. parkinson’s disease, affecting many brain areas and impairing movement. physical therapy helps with the movement, and recoments assistnt devices to make walking easier
occupational therapist
helps ppl improve ability to perform functions of daily life after something that did not slay the day (ex. a stroke)
social woker
personal + family problems. overalpping with activities of a clinical psychologist, but can’t diagnose with disorders.
fields of therapy
clinical, counseling, school, medicine, allied medical practice ( physical therapy)
research
must stay up to date on research
conventions, consult with colleagues, reading research journals
NEUROETHICS
excuuuuuse me, WOLVES HAVE BEEN TRAINED TO OBSERVE A SPLIT SCREEN AND COUNT THE DOTS SHOWN, AND INDICATES WHICH SCREEN HAS MORE DOTS BY TOUCHING IT WITH ITS NOSE
why do we study non-humans for human understanding?
many mechanisms of behaviour are similiar across species, and easier to sutdy in a nonhuman sepcies
ex. using squid nerves to study neural connections cause tehyre so much thicker than human nerves!!!!!
ex. a sea slug aplysia has neuronst hat are almost as same as humans, but they have a bunch of big ones that are aesy to study
we care about animals for their own sake!!
we just wanna know why they do what they do
what we learn about animals sheds lifhgt on human evolution!!
why and how do we resemble chimpanzees? why did primates evolve larger brains than other species? what function may this ability of ours have esp if other animals have a similar ability?
legal or ethical restrictions on testing on humans, so we use animals instead lol
but theres critiques here!! if its unacceptable on humans, why is it fine on other animals??
S&C 2:
describe reasons biological psychologists conduct much of their research on nonhuman animals
they often have simpler or larger versions of the same things, so its easier to test on them. ex squid nerves are larger and easier to work on
what we learn about animals tells us more about our evolution
tricky ethical restrictions on humans, so we resort to animals intead
DEGREES OF OPPOSITION
minimalists
theyre okay with some types of animal research but not others depending on value of resarch, amount of distress to animal, and type of animal
ex. no if its a dog, fine if its an ant
the 3 R’s
reduction of animal numbers (using less animals)
replacement (using computer models for animals when possible)
refinement (modify8ing procedures to reduce pain or discomfort)
journals only accept publications after its been cleared of these ethics, scientists evalued proposed experiments with these,
professional organizations publish guidelines for animal research but it varies country to country bcz of political pressures and permissiveness of the country
abolitionists
find NO ROOM FOR COMPROMISE
say all animals have the same rights as humans, killing an aniimal is murder regardless of intention (ex. doesn’t matter if its for knowledge vs its fur, murder is murder)
bcz animals ca'n’t consent, it’s wrong to use them in any way
moral imperative is that people have no right to use animals at all, even if the research is highly useful and totally painless
THE MORAL ARGUMENT?? between: never konwingly harm an innocent, and a little harm is okay for the greater good.
THE DILEMMA??
permitting research can inflict pain and distress on ppl, BUT!! banning it means a great setback in medical research (and animal to human transplants)
fun fact! abolitionists have vandalized labs, placed bombs, banged on children’s windows, and inserted garden hoses to further their point!!
not okay chat, scientists have stopped, so ig its worked but its not okay, theyre saying “oh 15 human lives save 2 million non human animls lives” so like they do lowkey ahve a point but this is extreme
extreme polarization regarding this issue, lack of nuance bcz of people who are so extreme, neuroscientsits do not take htis decision lightly, its for the greater good, but in some cases, its a difficult decision
S&C
what are the 3 Rs?
reduction (use fewer animals)
replacement (use computer models where you can)
refinement (make it less painful)
how does the “minimalist” positiion differ from the “abolitionist position”
minimalists —> have nuance! differntiate based on 1. distress, 2. type of animal, 3. perceived value of research
abolitionist —> NO NUANCE, NO FLEXIBILITY. ABSOLUTELY NOT. ITS A MORAL STANCE THAT YOU CNAT USE THEM FOR ANYTHING, EVEN IF IT CAUSES THEM NO HARM.
ISSUES IN HUMAN RESEARCH
brain surgery conducted while under local anesthesia, and awake bcz brain does not have pain receptors!!!!
informed consent is tricky
if surgeons asked you to participate in a brain surgery that causes you no harm but no pain, would you say yes just to please surgeon?
sometimes types of treatment that are generally good have bad beahvouiral changes. is it the fault of the individual’s personal phsyiology or the fault of the electrodes?
idt there is fault here lol, its just one of those things
bcz most resarch has been done in north america or europe, most studies have used relatively rich, white ppl and not a good sample of all humans
not an issue neuronally, but bcz of differences in genetics, ppl act differently to certain drugs, which can really hurt some populations that they didnt test on!
stop and check
why is diversity an important issue for some types of research on humans and less for others?
so we all have the same neurons and organs and stuff so it isn’t an issue there, but meds wise, we have an issue, cause different ppl have different genetics (not that race has a biological component, but rather that experiences affect which genes are turned on or off, and when you’re testing on a very specific population, you don’t know how ppl with other gene expressions and phenotypes react to certain drugs, which can be super harmful!!
question: is this a good interpretation of the genetics thing?
END OF MODULE QUIZ
what is meant by monism?
( c) —> the idea that the mind is made of the same substance as the rest of the universe
an ontogenetic explanaiton focuses on which of the following?
(a) —> how a behaviour develops
of the following, which one is an explanation of an evolutionary explanation rather than a functional one?
(b) —> humans have a tiny tailbone bcz our ancient monkey-like ancestors had a tail
this is evoltuionary, cause its just something that’s evolved cause it was helpful then. all the other answers have something about the function that the thing serves, why its useful now
ex. “people evolved an ability to recognize faces because that ability is essential for cooperative social behaviours”
which of the following would be most likely to work in a hospital or clinic?
(d) neuropsychologist (cause we do be working there!!)
what does a “minimalist” favour with regard to animal research?
(d) animal research is permissable but should be held to a minimum (the first R!! reduction!! but also the second one!! replacement!! use computers if you can!! you can do it but just keept i tto aminimum!!)
MODULE 1.2
neurons: receive + transmit information
approx 86 billion neurons in the brain, but its differnet person to person
pioneers of neuroscience
charles sherrington + santiago ramon y cajal
discovered that the brain consists of individual cells
during 1880s, biologists found that the body consists of cells but they weren’t sure if the brain consisted of cells too
they found these long fibres stretching from place to place, and they didn’t know if it was one continuous mesh or individual cells
in the late 1880s, camillo golgi stained nerve cells with silver salts, whcih allowed researchers to examine the structure of a single cell.
with this, golgi was like “omg they all link together!! the brain is a mesh, no seperate cells!”
cajal took golgi’s staining method, but he put it on infant brains where cells were smaller and easier to examine
he found that nerve cells are acc seperate!! theres a very very very small gap between them, but they are individual cells!!
they got the nobel in the same year and they both contradicted each other in acceptance speech!!
THE STRUCTURES OF AN ANIMAL CELL
membrane —> surface of a cell, seperates the inside of the cell from the outside
most chemicals can’t cross membrane, protein chanels permit controlled flow of water, oxygen, sodium, potassium, calcium, chloride… (semi-permeable membrane with protein channels)
nucleus —> contains chromosomes. excpet for red blood cells, all animal cells have this
DNA is not stable in water solution for long, so DNA is carefully scaffolded by other molecules (given support/structure)
ribosomes —> sstructures that syntehsize new protein molecules
some float freely, some are attached to the endoplasmic reticulum
endoplasmic reticulum —> thin tubes that transport newly synthesized proteins to other places
mitochondria —> perform metabolic activities, providing energy for the cell to us
have their own genes, seperate from the nucleus of a cell
they’re inherited!! you inherit your mitochondria from mother instead of growing them
bcz brain activity requires a ton of energy, good mitochondrial functioning is a must
healthy mitochondria means good cognition
what makes mitochondria less active?
bcz of issues with the genes in the mitochondria
toxic chemicals
stress
inflammation (inflammation in the gut directly affects the brain!!)
what happens when mitochondrial function isn’t good?
decreased mental energy
high probability of derpession
checks out cause you lack energy
impairments to mitochondria have been linked to
severity of epilepsy
alzheimers
parkinsons
huntingtons
STOP AND CHECK
why would weakened mitochondria affect the brain more than other organs?
because the brain uses more energy than all the other organs. and the mitochondria is the powerhouse of the celll, its the energy center,
THE STRUCTURE OF NEURONS
neurons have highly variable shape
all neurons include a cell body, and most have dendrites, an axon, and presynaptic terminals
smallest of the neurons dont have axons, and some don’t have solidified dendrites
motor neuron —> soma in the spinal cord, excited through dendrites, conducts impulses through axon to the muscle
sensory neuron —> specialized at one end to respond to particular type of stimulation (ex. touch)
tiny branches lead from the receptors into the axon, and hte cell body is on a stalk off the main trunk
dendrites
brnching fibers that get narower near the ends
size perspective: dendrite is as thick as pinky, dendritic branches are as thin as spaghetti, and cell’s axon goes for over 25 city blocks!!!
synaptic receptors
they line the dendrite’s surface
the purpose is to be wehre the drndrite receives information from other neurons
many contain dendritic spines
which are short outgrowths that increase the surface area available for synpases
cell body
contains nucleus, ribosomes, and mitochondria
its covered with synpases, just like the dendrites
hella hella small (0.005mm to 0.1mm)
axon —> thin fiber
takes an impulse to other neurons, organ or muscle
dendrites are always a few mm long, but dendrites CAN BE MORE THAN A METER LONG!!!
the axons from spinal cord to feet are that long!!
from an axon, we have branches near its end
myelin sheath
insulating material made of glia
nodes of ranvier
the little gaps in between the blocks of myelin sheath
a neuron can have many dendrites BUT ONLY ONE AXON, which has branches
invertebrate axons do not have myelin sheaths. this slows down neural transmission. right? question.
dendrites branch out from the cell body!! from the axon, we ahve branches that come out!! these are two seperate things!!
the end of each branch has a swelling called a presynaptic terminal
at the presynaptic terminal, the axon releases chemicals that cross to another cell
these are the bulbs!! the end bulbs or the boutons, which are the swellings.
terminal branches
branches that are at the end of an axon, that branch off from the axon
they end in synaptic “knobs”, which are the bulbs/boutons/terminal buttons of an axon, that lie close to the dendrites of other neurons, with a smalll gap which is the synaptic cleft, where neurotransmitters go from the presynaptic neuron to the postsynaptic neuron (rgith?? question)
the synapse
the presynaptic terminal, post synaptic terminal, synaptic clef
that entire “junction”
the synaptic cleft
the gap between the presynaptic neuron and the postsynaptic neuron
the synapse
the synapse involves the presynaptic terminal, the postsynaptic terminal and the synaptic cleft it’s that area
the synaptic clef specifically is just the gap between the presynaptic neuron and the postsynaptic neuron
as far as i understand it. question.
pre-synaptic terminal
IS THE SAME THING AS THE END BULB!! WHICH IS THE THING AT THE END OF THE AXONAL BRANCH????// QUESTION!!!!!!!
TERMS FOR NEURONS
afferent
BRINGS INFORMATION TOOOOOOOOO a thing (neuron/muscle…)
every sensory neuron is afferent to the nervous system (from the sensation to the brain)
a —> admit
efferent
TAKES INFORMATION AWAYYYYYY FROM SOMETHING
every motor neuron is efferent from the nervous system (from the brain to the limbs)
e —> exit
intrinsic
same thing as an interneuron!!
it’s just the neuron when a cell’s dendrites and axon are entirely contained within a single structure
STOP AND CHECK
how does the structure of a dendrite differ from that of an axon?
the axon is LONGER!! and its diameter is constant
except for when an electric impulse goes through, and it looks like a wave going through because the heat and volume expands and constricts with motion (if that is right to my understanding?)
axons can go on for a meter (the axons in central nervous system are meter long!!), but dendrites are only a few milimeters long, and they get narrower near the end (until terminal buttons, where we have a bulge)
which animal species would have the longest axons?
the bigger the animal, the longer the axon
giraffes and elephants have axons that go from the spinal cord to the feet!! which is about 2 METERS LONG. INSANE.
of the 3 types of neuron - sensory, motor, intrinsic - which would have the shortest axons?
the interneuron!! it has the shortest axon, because its contained entirely within one part of the brain
their purpose is to connect the sensory and motor neurons, and they stay entirely within VERY SPECIFIC REGIONS OF THE BRAIN
they do not connect different parts of the brain to one another, so they’re quite small
question: is this right?
VARIATIONS AMONG NEURONS
neurons vary enormously in size, shape and function
shape of a neuron determines its connections wtih other cells, and ergo its function!
ex. the purkinje cell in the cerebellum, is ONLY FOUND IN THE CEREBELLUM, and it has a shit ton of dendritic branches!! and this lets it receive input from up to TWO HUNDRED THOUSAND (200,000) other neurons!!!!!
this is different from the bipolar neurons in the retina which are so tiny and only have a couple dendritic branches that only connect with a couple neurons.
GLIA
glia have a ton of functions
glia —> glue in greek
ppl thought they just served like nerve glue, to keep neurons together
but thats not true!! they do a bunch of other things
also glia can be 1:1 to neurons!! the ratio changes depending on what part of the brain theyre in ofc, but they can be 1:1 or more than neurons, and are just as important as neurons
astrocytes
star shaped!! remember ap psych!!
so basically, they wrap around the dendrites of axons that are performing the same function (?)
question: is that what functionally-related means? p. 18
what they do is they surround a connection between neurons, shield the neurons from the chemics floating around, take up the ions and neurotransmitters released by the axons, and release them back (whooshhhhh) with the INTENTION: to closely synchronize the related neurons so messages can be sent in waves!!
this is important because it generates rhythmns that are important in your body, like the rhythmn of breathing
they also dilate blood vessels to bring in more nutrients to the most active brain areas.
hypothesis: tripartite synpase
the tip of an axon releases chemicals that cause the neighbouring astrocyte to release ITS OWN chemicals, which modifies the message to the next neurons
question: modifies how? to do the same thing as the rest of them?
in some brain areas, astrocytes
response to hromones, thereby influencing neurons
control the critical period for modification of the visual cortex early in life
basically they play an active, not a passive role!!
MICROGLIA
act as part of the immune system!!
they remove viruses and undgi from the brain
they remove dead or damaged neruons after brain damage
they prune ineffective synpases, adn adjust effectiveness of others
too much or too little pruning during early development leads to developmental disorders so this is hella important
they also provide negative feedback to stop neruonal activity!! too little microglia leads to SEIZURES (which is overactive neural activity)
oligodendrocytes
IN THE CENTRAL NERVOUS SYSTEM
DO NOT REPAIR THEMSELVES!!!!!!! why? look at notes
alter myelin sheaths, which alters the timing of the responses of axons
bcz of this altering,
schwann cells
IN THE PERIPHERAL NERVOUS SYSTEM
build myelin sheaths that surround and insulate vertebrate axons
supply axons with nutrients
radial glia
guide migration of neurons during embryonic development
STOP AND CHECK
what type of glia synchronizes the activity of related group of axons?
the astrocytes!!
in the tripartite synapse, they take a group of neurons, prevent diffusion of neurotransmitters, and synchronize the synapses in case of bodily rhythmn
which type of glia cell removes dead neurons and prunces ineffective synapses?
microglia, act in part of the immune system are in charge of
THE BLOOD-BRAIN BARRIER
barrier that prevents chemical from crossing the blood over to the brain
wehn immune system finds a virus, they kill it and the cell that holds it. which works for skin or blood cells. BUT!! the brain cannot deplace damaged neruons. you can’t regenerate neurons fast enough. to minimize this risk, the body lines the brain’s blood vessels wtih thighly packed cells to keep out viruses and bacteria
BUT A FEW DO CROSS OVER!! wehn this happens, the microglia (who act as the immune system in the brain) attack the viruses, releasing inflammatory agents to fight the virus without kiling the neuron
is this what happens? question. cross reference with notes
BUT THESE INFLAMMATORY AGENTS CONTROL THE VIRUS, THEY DO NOT ELIMATE IT.
examples
syphilis
spirochete —> spiral bacteria responsible for syphilis
it can penetrate the blood brain barrier and have fatal consequences
chicken pox
when chicken pox virus enters spinal cord cells, virus particles REMAIN THERE FOR A LONG TIME EVEN AFTER THEYRE GONE FROM THE BODY, LEADING TO SHINGLES DECAAAAADES LATER
genital herpes
the virus responsible fro this hides in nervous system
doesn’t do much harm, but periodically emerges to caught new gential infections :(
COVID 19
THIS VIRUS DOES CROSS THE BLOOD-BRAIN BARRIER IN MICE!!!!
we don’t know its effects in humans yet
ppl do experience cognitive deficients when infected wtih this
ex. seizures, brain fog, impariments of vision, taste, and smell
even if the virus doesn’t cross the blood-brain barrier, it can harm the brain by
constricting capillaries
decreasing blood flow to the brain
triggering immune response (overactive immune response makes the immune system attack the neurons, leading to decrease in white matter (think lecture of multiple sclerosis)
question: in this case, why dont they attack dendrites and somas as well? why only
HOW DOES THE BLOOD-BRAIN BARRIER WORK?
so there are endothelial cells that form the WALLS of the capillaries. outside the brain, CELLS ALONG THE CAPILLARIES, are seperated by small gaps.
in the brain, they join SOOO TIHGTLY THAT THEY STOP ANYTHING FROM PASSING.
the membrane is made of fats, so chemicals that are fat-soluble can cross freely through the cell wall
ex. vitamin A, D, antidepressants, marijuana, heroin
how fast a drug crosses the blood-brain barrier determines how fast it affects behaviour
the faster, the more the effect? question.
chemo does not cross blood-brain barrier, which is why brain cancer is so hard to treat
water, sodium ions, potassium ions and chloride ions cross through specific channels
brain uses active transport to transprot the following from the BLOOD TO THE BRAIN
glucose
amino acids
omega-3 fatty acids
and vitamins
also ways to get hromones and ketones in
SUPER IMPROTANT TO HEALTH!!! GETS LESS EFFICENT WTIH AGE, WSP IN ALZHEIMTERS
becuase of this, good chemicals enter slower and harmful chemicals can enter easier/more
question: so i guess bad chemicals can seep in bcz barrier is weakned,and active transport is less efficient so chemicals come in less fast
STOP AND CHECK
identify one major advantage and one disadvantage of having a blood-brain barrier
one advantage, keeps inflammation away from the brain in case of viruses so neurons are safe
one disadvantage: its harder to get non-fat-soluble materials in, making it difficult to treat brain cancer, and making it mandatory for psychoactive substances for the purpose of helping the body to be fat-soluble
which chemicals cross the blood-brain barrier passively?
gases (o2, co2)
vitamins a and d
ALL DRUGS THAT AFFECT THE BRAIN
antidepressants
psychiatric drugs (marijuana and heroin)
how do glucose and amino acids cross the blood-brain barrier?
THROUGH ACTIVE TRANSPORT THROUGH PROTEIN CHANNELS!!!
i think, fact check!!
NOURISHMENT OF VERTEBRATE NEURONS
WE NEED GLUCOSE. WE RELY ALMOST ENTIRELY ON GLUCOSE.
glucose needs oxygen to metabolize. so neurons need oxygen.
liver makes glucose from carbs, amino acids, glycerol, so the glucose supply isnt really the issue
SOME PPL CAN’T USE GLUCOSE
you need thiamine to use glucose, which is vitamin B1.
PROLONGED THIAMINE DEFICIENCY, which is common due to excessive alcohol use, LEADS TO DEATH OF NEURONS.
and this leads to the condition called Korsakoff’s syndrome, which is marked by memory impairments
OTHER CELLS: THE GUT BACTERIA
OMGG BRAIN IN THE GUT
1:1 ish ratio of number of cells in body and number of bacteria in intestines
BACTERIA (INCLUDING GUT BACTERIA) INFLUENCE BRAIN ACTIVITY IN A TON OF WAYS
stimulating vagus nerve, which runs from intestines to brain
release chemicals that cross intestinal lining, and enter blood (vitamins and amino acids BUT ALSO CHEMICALS THAT CAUSE INFLAMMATORY AGENTS TO APPEAR)
question: when you say “chemicals that cause inflammation”, do you mean “chemicals that make microglia release infalmmatory agents” or do other substances release inflammatory substances as well? that this is not referring to?
amt and type of chemicals that the BACTERIA RELEASE affect mood, motivation (leads to drug abuse, change how you view, treat, and consume food, sex, socialization)
so question: the bacteria from the gut release vitamins, amino acids, and inflammatory agents? is that where we’re getting these infalmmatory agents from? do they release in hte brain and affect brain activity?
another question: it says it changes your motivations, does that mean that they can change the way you perceive things? need to pull up an article here and articulate question better.
STRESS INCRESAES TYPE OF BACTERIA THAT CAUSES INFLAMMATION AND MITOCHONDRIAL DAMAGE
question: HOW THE FUCK DOES THE BACTERIA DO THIS?????
those with depression tend to have more ‘bad” bacteria, and less of the bacteria that fights inflammation
so with depression, you can try to attack the inflammatory bacteira but getting rid of too many intestinal bacteria can increase anxiety nad dpression,
which is why antibiotics side effects often include depression adn anxiety
probiotics are diet supplements THAT CONTAIN GOOD BACTERIA “GOOD”, and they may help in treating depression.
END OF MODULE QUIZ
santiago ramon y cajal clearly demonstrated that (a) the nervous system is composed of seperate cells. CHECK.
which part of a neuron has the chromosomes? (b) the cell body (in the nucleus!!) CHECK.
what do the mitochondria do? (a) they provide energy for the cell CHECK.
how do dendrite differ from axons? (d) they are short and tapered CHECK.
axons do have branches!! axonal branches!! tapered is important because axons have consistent diameter (when an action potential isn’t going through it)
what do dendritic spines do? (b) they increase the surface area available for synapses? CHECK.
what does an afferent axon do? (d) it brings information into a structure. CHECK.
which of the following is a function of astrocytes? (c ) the synchronize the activity of a group of neurons CHECK.
they do not conduct impulses over long distances, those are neurons. this is a glia
they do not create new neurons to replace those lost in brain damage (the microglia play a role in this as they maintain neuronal networks and are in charge of injury repair)
oligodendrocytes and schwann cells make the myelin sheaths!! not the astrocytes :))
which of the following is a function of microglia? (a) they remove dead cells and weak synapses CHECK
why are chemotherapy drugs ineffective against brain cancers? (d) chemotherapy drugs do not cross the blood-brain barrier CHECK
which of these chemicals cross the blood-brain barrier by active transport? (b) glucose and amino acids CHECK
oxygen, water, and fat-soluble molecules dont need active transport, they can go through freely, as the membrane is made of endothelial cells which have LIPID BASED OUTER MEMBRANE, so if youre a gas or you’re fat soluble, you’re good!
question: so like carbon monoxide, its a gas. does it attack the brain?
proteins are already in the brain, as carrier proteins for active transport. we have amino acids, which are proteins though, and they are brought in through active transport.
what is the brain’s main source of fuel? (a) glucose CHECK
it’s just glucose dude. it just is. we are glucose beings.
glutamate is a inhibitory neurotransmitter
proteins make up the carrier proteins for active transport
question: does the brain have transport or carrier proteins? are those synonymous with each other?
we don’t use DNA for fuel, DNA has genetic instructions in it
why does the brain need thiamine (vitamin B1)? (a) to metabolize glucose CHECK
not to build the blood-brain barrier, those are endothelial cells
oligodendrocytes and schwann cells build myelin sheaths
synapses need ions as electrical charges to create a chemical change that makes an action potential? really need to go over how an action potential happens. question.
under what condition do the intestinal bacteria produce more inflammatory chemicals? (d) under stressful conditions that might lead to bacteria CHECK
question: what might be the evolutionary basis for stress to trigger inflammation that leads to bacteria? lowkey what are the exact mechanics behind this?