Exam 5: February 13 - February 17 Flashcards
what are the parts of the central nervous system?
brain and spinal cord
what are the parts of the brain?
cerebellum, diencephalon, and cerebrum
what does the cerebellum look like?
like coral or a ball of yarn
what are the functions of the cerebellum?
1) balance and coordination of muscle activities
2) muscle tone
how does the cerebellum help with balance and coordination of muscle activities?
so complex activities instead of having to individually work, the cerebellum kind of sorta does a feedforward type process and is proactive about the idea that if I have to stand up the same sort of muscles need to work
knows which muscles need to be involved and gets them involved
how does the cerebellum help with muscle tone?
if there’s damage to the cerebellum, muscles don’t get engaged as much as they would so muscle tone gets lost
what is the diencephalon?
it’s a two part brain component that is one area but has two distinct parts that each have their own functions as well
what are the two parts of the diencephalon?
thalamus and hypothalamus
what does the thalamus do?
part of the diencephalon that controls your movements
major relay station for motor control to get messages off to the muscles
also a major relay station for crude level sensation
how does the thalamus help with crude level sensation?
your thalamus is a major relay station for crude level sensation
visual goes through your thalamus so it registers big things about your visual like is there something moving in my field of vision? Is there something moving that could attack me or is there something I could eat?
Another crude sensation it picks up on is sound so really loud sound or high pitched sound
where is the hypothalamus located?
it’s located below the thalamus
“hypo”
what is the function of the hypothalamus? how does it accomplish it?
part of the diencephalon that maintains homeostatic regulation
helps get the appropriate things activated to get us back to steady state
it does this by being the link between the nervous system, registering those change, realizing we’ve moved away from steady state and realizing we need to activate the endocrine system to get us back to steady state
what is the cerebrum? what are the components of the cerebrum?
cerebral cortex
it’s 80% of your brain by weight and volume
what is the cerebral cortex? what does it look like?
often times it will get equated to be the cerebrum but this isn’t exactly true – it’s an outer shell (cortex)
it’s highly convoluted, it’s not a smooth surface, it’s ridged like how you imagine the brain, it’s coral looking – convoluted shape gives us more surface area which gives us more function since it’s the outer layer – high function within space
what are the parts of the cerebral cortex?
1) matters
2) corpus callosum
3) ventricles
4) basil nuclei
what are the types of matter in the cerebral cortex?
grey and white matter
if you crack open your skull your brain looks grey on the outside and the white is deeper inside
axons are insulated with myelin to increase speed of communication – white parts of steak are lipids so there are probably going to be more cell bodies that don’t have a lot of oligodendricites – there’s going to be more myelin on the inside
what is the corpus callosum?
when you look at your cerebral cortex it’s actually two groupings brought together which is your left and right hemisphere – your corpus callosum is a massive bundle of axon that helps your two
it’s white matter and it’s in the middle of your brain
what are ventricles?
4 fluid filled chambers
when you get a headache it’s because n has changed. Since V is constant, P must increase to accommodate for the decrease in n which is what gives you a headache. drinking water helps because you can restore the number of molecules of water in the ventricles and decrease the temperature
what are the functions of the cerebral cortex?
1) perception
2) voluntary movement
3) language and learning
how does the cerebral cortex help with voluntary movement?
the ability to control where your skeletal muscles are in space
when you have a stroke it damages the cells of the cerebral cortex which is why a lot of people lose the ability to move
how does the cerebral cortex help with language?
another function is language so again after a stroke people can’t understand things or lose the ability to talk
how does the cerebral cortex help with learning and memory?
the cc is what makes you you!
if you damage this area you take away features that define you and differentiate you from the person next to you
so when people say they’re brain-dead they aren’t actually, it’s because their cc is no longer functioning
what are the components of the forebrain?
cerebrum + diencephalon
aka thalamus + hypothalamus + cerebrum
how is the spinal cord protected?
vertebrae and processes
the spinal cord needs protection because we don’t want to damage it and lose our ability to gather and send information
what do vertebrae do?
they are the main bone and are on the ventral side relative to the spinal cord aka they’re on the belly side
so they’re actually protecting us more on the inside more than the outside – this is because the biggest threat to our spine is internal movement
what are processes?
processes are what protect the spinal cord on the outside by surrounding the spinal cord and they are on the dorsal side
what is the composition of the spinal cord?
grey and white matter just like the cerebral cortex
what is in the grey matter of the spinal cord?
interneurons, part of efferent and afferent neurons within the CNS, glial cells are also within this area
what is the white matter of the spinal cord? what is it made up of?
white because of myelination
made up of axons
axons associated with afferent neurons are always dorsal to the axons associated with our efferent neurons which are on the ventral side
where are the afferent and efferent neurons in the spinal cord located?
axons associated with afferent neurons are always dorsal to the axons associated with our efferent neurons which are on the dorsal side
DAVE = dorsal afferent ventral efferent
why is position of ventral vs. dorsal axons in the spinal cord important?
It’s important because of protection. If one was going to get cut and damaged would you rather give up incoming or outgoing information? You’re more likely to see damage on the dorsal side so we protect our efferent pathway more so that we can react
what is the most used neurotransmitter in the body?
acetylcholide (ACh)
what destroys acetylcholine?
gets rapidly destroyed by ACh-esterase
this is to remind you that astrocytes clean up neurotransmitters because you don’t want the neurotransmitter to keep doing the task after it’s already done it
what does acetylcholine do?
cognition, behavior, how we interact and do things, control of glands and organs
what are the key neurotransmitters in the body?
1) acetylcholine
2) biogenic amines
3) amino acids
4) neuropeptides
what are examples of biogenic amines?
dopamine, norepinephrine, epinephrine, serotonin, histamine
what are biogenic amines?
they are a type of key neurotransmitters that control consciousness, mood and endocrine regulation
have a similar chemical structure which is why they’re grouped together
control a lot of our consciousness which is why antihistamine warning is drowsiness aka reducing consciousness
what are amino acids?
key type of neurotransmitter
some AA act as excitatory pre-synaptic potential creates so they depolarize
other ones act as inhibitory pre-synaptic potentials so they hyper polarize the potential and make it harder to reach the threshold component
what are neuropeptides?
peptides just mean a small chain of AA that’s not quite a protein yet
this category tells us that they got named neuropeptides because they don’t just act as neurotransmitters, they also sometimes as paracrine and endocrines so they can be released and removed in different ways aka they don’t have to stay as a neurotransmitter all the time
what are the components of the peripheral nervous system?
efferent (action) and afferent (sensory)
what are the components of the efferent PNS?
autonomic and somatic nervous system
our brain can use one of both of those systems if it decides we need to take action
what is the similarity between autonomic and somatic nervous systems?
both send signals from the CNS to effectors
they’re outgoing messages
what are the differences between the autonomic and somatic components of the efferent PNS?
1) # of neurons it takes to reach our effector
2) what gets innervated
3) actions
what is the difference between autonomic and somatic in the # of neurons it takes to reach our effector?
our autonomic requires 2 neurons to get to our effector while somatic only takes a single neuron to get to our effector = spinal cord
what is the difference in what gets innervated between the autonomic and somatic nervous systems?
what effectors can be controlled by our autonomic vs. somatic?
somatic only controls one category of things, your skeletal muscles
however to control basically everything else like to control your breathing, heart rate, smooth muscles, cardiac muscles, glands, digestive system is all autonomic
what is the difference between autonomic and somatic in the actions that they can perform?
how we can do things with our effectors
somatic can only excite our skeletal muscles – we can basically only get it to squeeze and we can’t force it to not squeeze, we just stop sending it signals to squeeze to get it to relax
autonomic can excite and inhibit: we can increase heart rate and decrease heart rate so we can impact in both directions
what does the autonomic components of the efferent PNS do?
regulates automatic/visceral responses
this system controls how things are going on in the background, you don’t have to think about these things like digestion or increasing your heart rate if you’re exercising
what are the components of the autonomic nervous system?
sympathic and parasympathetic
what analogy can be used to describe the autonomic nervous system?
the sympathetic nervous system is the gas in the car to speed you up while the parasympathetic nervous system is the breaks to slow you down
some effectors need to be slowed down and sped up so they’re effected by both systems
how many neurons does it take the autonomic nervous system to get to the effector?
2
because the two neurons are in series you end up seeing clustering of the second cell body outside, in our CNS
they’re called ganglia
what are ganglia?
a cluster of neurons in our autonomic nervous system
because the autonomic nervous system requires two neurons to reach the effector, you end up with a clustering of the second cell body outside in our CNS
what types of ganglia are there? what do they do?
pre-ganglionic and post-ganglionic neurons
pre-ganglionic releases neurotransmitters to post-ganglionic neurons
post-ganglionic neurons release its neurotransmitters to the effectors
what is your sympathy nervous system?
fight or flight response (efferent pathway)
it’s job is to make sure you’re alive 10 minutes from now
something has been registered as life threatening and we need to do something right now by either fighting it or get out of the way and dodge it
what is your parasympathetic nervous system?
rest or group (efferent pathway)
you don’t want to waste energy so instead take a chill pill instead of continuously gunning the engine and wasting gas
what are the possible locations of the ganglia?
ganglia for the sympathetic nervous system are closer to our spine
parasympathetic ganglia are closer to our effector
if they were near each other then NTs would intermix
what pre-ganglionic neurotransmitters does the efferent pathway use? (sympathetic and parasympathetic)
both use acetylcholine
what post-ganglionic neurotransmitters does the efferent pathway use? (sympathetic and parasympathetic)
parasympathetic still uses acetylcholine
sympathetic uses epinephrine and norepinephrine for its neurotransmitter
you can’t just use Ach everywhere because you need to differentiate the responses!
what is the adrenal medulla?
part of our sympathetic nervous system
it’s the inner part of the adrenal gland like the inner part of an orange
what does the adrenal medulla do?
it’s a special case of the sympathetic nervous system that doesn’t release signal to an effector but instead puts them directly in the plasma which no longer makes them neurotransmitters they’re now endocrines!
what is the relationship between epinephrine and adrenaline?
they’re the same thing!
what problem do action potentials have? why?
a distance problem because they rely on diffusion
do action potentials move?
action potentials do not move
we triggers the next one, it is not all only one action potential it is multiple
one action potential like dominos can trigger another action potential to occur- each domino looks like every other one- the last one falls the exact same way the first one does)
no decrease with signal in distance
how do action potentials cover a large distance?
AP cover a large distance by triggering a series of action potentials to cover that distance, it’s not one action potential going that distance
there’s no movement of individual action potentials - it’s like doing the wave in the stadium
how do action potentials solve their problem?
We convert the original graded potential into an action potential that can trigger multiple action potentials allowing the signal to travel large distances
a single graded potential or a single action potential decreases with distance but because we’re triggering a new one next to the old one, we keep them all the same size
the first AP looks exactly like the last one
in what direction do action potentials move?
unidirectional!
it will take less time to go in the same direction rather than changing direction like weeble wobbles
the AP that is triggering the domino on the left is creating the same result in the opposite direction. So how do we make sure the one before doesn’t pop back up and fall over in the other direction?
An action potential creates a hyperpolarization that seemed bad at the time but it’s actually is a good thing when this hyperpolarization happens because now the next one at rest is easier to get to threshold potential, now the one that just had an action potential and is hyperpolarized
the one that’s hyper polarized from the current AP has closed Na channels and needs to get back to rest then up to the threshold so we need a much bigger depolarization to get a hyperpolarization to get to the threshold
the Na ions moving backwars couldn’t trigger an action potential even if they wanted to because the Na channel open but is still inactivated from the AP
what do you need for an AP to happen?
without sodium influx there’s no AP!
so if you hit a current AP with another graded potential because we get to our hyper polarization, nothing will happen because the Na channel is still inactivated
what makes myelin?
Schwann cells in the PNS
oligodendrocytes in the CNS
what will myelin do in relationship to action potentials?
myelin is insulation so is it going to allow movement of Na and K in and out cell? No!
myelin aids graded potentials and completely blocks action potentials
what problem do action potentials have?
it takes 1-2 milliseconds for a single AP to happen but then there are tons of APs in one neuron
it still takes time to cover the 1 m distance and for all the influx and outflux to happen so yes we can cover distance but it takes 1-2 milliseconds per AP so it’ll take longer to cover a larger distance
how do you solve the problem with APs?
eh you can’t really but what happens is that if we could make the AP system go faster we could make the system better
so what myelin does is it allows us to have a faster conduction velocity so we can cover a set distance faster if myelin is there
neurons that need speed are myelinated but ones that don’t necessarily need speed aren’t
how does myelin help us with speed?
it takes out some of our action potentials
if we can cover that distance with a graded potential and avoided the number of AP that would be in that area it would go faster because a graded potential that is protected by myelin moves faster than the number of AP it would take to cover that distance
to what extend does myelin aid graded potentials? what limitation is there on the size of the myelin?
it aids them by increasing the conduction velocity but it doesn’t make graded potentials perfect…
there’s still a little bit of a decrease in the signal
we can’t have a myelin too big though because we have an AP on one side of the myelin that makes a graded potential but then on the other side of the myelin the graded potential still needs to be big enough to be a partial potential to trigger the AP on the other side of the myelin
AP –> myelin –> graded potential –> no myelin –> AP
what is conduction velocity?
how fast we can get from one end to the other of our axon
what is jumping conduction? what’s another name for it?
saltatory conduction
because of the myelin, it looks like there’s an AP then it disappears where there’s myelin, then it pops up again
Bronson would rather it be called burrowing conduction
where are AP found?
the nodes of ranveir! aka the un-myelinated sections of the neuron
AP only happen at the nodes!
where are graded potentials found?
everywhere! AP are graded potentials
but when it comes to the myelinated parts, the graded potential moves underneath the myelin that creates a threshold potential so that the AP can occur at the next node
like whack a mole
do graded potentials decrease?
yes they decrease with distance but not as much as it would without myelin
what are excitable cells?
cells that can experience an action potential aka have Na/K channels and an inactivator
what are the two outcomes a graded potential can cause in a cell?
there are two types of input that affect the likelihood of an action potential occurring
it can either depolarize or hyper polarize the cell
what two inputs can a pre-synaptic neuron give to a postsynaptic neuron?
EPSP = excitatory pre-synaptic potential = depolarizing = more likely to have an AP = stimulatory
IPSP = inhibitory pre-synaptic potential = hyper polarizing = less likely to have an AP because we now have to have a bigger graded potential to get back up to a threshold potential
what are the types of summation?
temporal summation and spatial summation
what is temporal summation?
summing over time
a SINGLE presynapatic neuron is sending multiple signals
they’re smaller signals but you send multiple in quick succession so that they build on each other and they eventually reach threshold potential to trigger an action potential
star trek
is temporal summation convergence?
NO
this is one pre-synaptic to one post-synaptic whereas convergence is multiple pre to multiple post
you’re summing over the same pre-synaptic close in time hitting that same postsynaptic cell
what is spatial summation?
different presynaptic in different areas at the same time
they use their small impacts all at the same time to reach the threshold potential
each one of these signals is not very big on their own but putting them all together at the same time gives you a much bigger response
it’s spatial because we’re summing over space, not time
is spatial summation convergence?
yes!
multiple pre-synaptic to one post-synaptic
can you combine spatial and temporal summation?
yes! they aren’t isolated
we can combine them and do some summation over time and some over space
as we increase the number of synapses/raise the level of convergence, increase the potential ways that we can combine these to reach threshold potential- you can combine different numbers of temporal and spatial - the number of these possible summations increases astronomically
what increases the combinations of summations possible?
increasing the number of synapses or increasing the level of convergence
what is the most common type of synapse?
chemical synapses
what is synapse strength?
how likely/what is going to successfully impact cell A to cause the message to be passed on to cell B
what presynaptic factors increase synapse strength?
1) Ca availability in the interstitial fluid around the axon terminal
2) neurotransmitter availability
3) receptor availability
4) Vm
how does Ca availability at the pre-synaptic in the interstitial fluid around the axon terminal increase synapse strength?
Ca is needed for exocytosis/release of neurotransmitters
we steal Ca from our bones to make sure our nervous system has enough!
it’s key for development and communication
how does neurotransmitter availability at the pre-synaptic neuron increase synapse strength? where do NT get made?
need to have the NT available to release a message
neurotransmitter gets made in the cell body and then it got transported within our axon to the axon terminal waiting to get exocytosed
how does receptor availability at the pre-synaptic neuron increase synapse strength?
this is because our pre-synaptic neurons were most likely a post-synaptic for another cell
how does membrane potential, Vm at the pre-synaptic neuron increase synapse strength?
hyperpolarization vs. depolarization (impacts Ca^+2 entry)
what’s the membrane potential going on in this particular cell? If we hyperpolarize the axon of neuron A, it’s not likely that our AP are actually going to reach the end of the axon because we might not be able to reach the threshold potential so boom we’re done
what post-synaptic factors influence synapse strength?
1) receptor availability
2) Vm
3) Other presynaptic inputs
how does receptor availability at the post-synaptic neuron increase synapse strength?
receptor availability to bind neurotransmitters released by presynaptic
how does membrane potential at the post-synaptic neuron increase synapse strength?
Vm impacts reaching threshold potential
we know that we have other pre-synaptic signals that we can sum with this post-synaptic signals and they can either hyperpolarize or depolarize
how do other presynaptic inputs at the post-synaptic neuron increase synapse strength?
other presynaptic inputs = combos of summations
are we having convergence on this post-synaptic, and if so what are the summations that are happening?
are we having this particular pre-synaptic hitting it multiple times then it’s temporal summation or if we have A and D hitting it at the same time that’s called spatial summation
synapses are gaps between two neurons where they communicate by releasing neurotransmitters. Increasing the level of convergence would be increasing the number of presynaptic neurons compared to the number of postsynaptic neurons. Summations are the sum of all of the signals acting on a postsynaptic neuron. So if you increase the number of presynaptic neurons acting on a postsynaptic neuron (convergence) , they will collectively release more signals causing an increase in summations which can be temporal (multiple signals from one neuron at one time) or spatial (multiple signals from multiple neurons at one time) or a combination of both.
what is the oldest part of our brain historically?
brain stem
the end of the spinal cord
it’s what keeps us alive and is needed for basic life
referred to as the out pocketing at the end of the spinal cord in animals without a developed brain
what are the functions of the brain stem?
1) respiration
2) circulation
3) digestion
how does the brainstem regulate digestion?
tied to respiration
choking/ swallowing- we need to make sure that what we eat to digest goes down esophagus instead of into lungs into the trachea
shove a snickers bar into someone’s mouth during CPR
first thing you do during CPR is clear the airway
what are the parts of the brain stem?
1) medulla
2) pons
3) midbrain
what is the order of the parts of the brain stem?
the medulla is the lowest part closest to the spinal cord
pons are in the middle
midbrain is at the top closest to the rest of our brain
why can’t an AP move backwards?
sodium channels become inactivated and by the time they reset the ions are too far away down the neuron
also there’s a greater outflow of K and the cell is very hyperpolarized
what is the length of the neurons in the sympathetic system?
short then long
what is the length of the neurons in the parasympathetic system?
long them short
why are the neurons of the sympathetic and parasympathetic neurons different lengths?
they’re different lengths so that diffusion doesn’t happen between the systems and there isn’t any cross talk or confusion
it’s okay that the second neurons line up because there are different neurotransmittesr are released at the end
S: –< ————–<
P: ————–< –
what does the adrenal medulla act as?
post-ganglionic cell
what are the 4 parts of the cerebrum?
cerebral cortex, ventricles, basil nuclei, and corpus collasum
what do biogenic amines effect?
brain stem and hypothalamus
what systems does the hypothalamus link?
it links the endocrine and nervous system?
how many hemispheres are in the cerebrum?
two hemispheres
what type of matter is in the cerebrum?
grey and white
the grey matter is on the outside and it includes the nuclei of the neurons
the white parts are white because of the myelin
how much of the brain by weight is the cerebrum?
80%
what connects the two hemispheres of the cerebrum?
corpus callosum
what is the cortex responsible for?
perception, memory, language and learning, and voluntary movement
what makes up the forebrain?
cerebrum and diencephalon
what protects the spinal cord and where are they located?
processes on the dorsal side
vertebrae on the ventral side
what are characteristics of the grey matter of the spinal cord?
it’s made up of interneurons
it includes glial cells
it has both efferent and afferent components
what component of the efferent neurons in the grey matter of the spinal cord?
their cell body is in the grey matter
what component of the afferent neurons in the grey matter of the spinal cord?
axon terminals are in the grey matter
which neurotransmitters are most related to consciousness, mood and endocrine regulation?
dopamine and histamien
which neurotransmitter is more related to cognition, behavior, and gland/organ control
acetylcholine
where is acetylcholinesterase found and what does it do?
it’s typically found in between neurons in order to destroy acetylcholine
what are neuropeptides made out of?
two or more amino acids
T/F: neuropeptides can also act as endocrines and paracrine
True
what does the somatic nervous system innervate?
skeletal muscles
what kind of response does the somatic and autonomic nervous system induce?
somatic system is considered excitatory
autonomic nervous system is excitatory and inhibitory
what are the two components of the autonomic nervous system?
sympathetic and parasympathetic
what are the second cluster of cell bodies in the autonomic nervous system called?
ganglia
where are the ganglia of the sympathetic neuron located?
ganglia of the sympathetic neuron is located closer to the spine and receives acetylcholine as the NT
what kind of synapse does not use acetylcholine?
postganglionic of the sympathetic
what is the adrenal medulla composed of?
postganglionic neurons which release epinephrine to the plasma
the effects of the epinephrine released by the adrenal medulla are long lasting
