Exam 4: February 6-10 Flashcards

Question

how does the cilia on the ependymal cells help its function?

Answer 1

cilia allows them to move and create movement in the cerebral spinal fluid things move in interstitial fluid by diffusion but we know diffusion has a problem with distance so if we can give those things that need to move a bit of help by creating some flow movement we can fix the distance/diffusion problem and the cilia generating flow movement does that for us

Answer 2

ependymal cells can be stem cells they’re cells that can generate themselves but also other cells – can serve to make more ependymal cells AND they can generate more neurons!!!

Answer 3

type of glial cell of the CNS and they're our big workers, they're doing the daily interaction in helping our neurons they regulate what's inside the cerebral spinal fluid

Answer 4

there’s more K inside a typical cell so astrocytes make sure that that gradient remains so that we can do electrical messages better so it actually takes away K from the cerebral spinal fluid

Answer 5

takes away neurotransmitters from cerebral spinal fluid because a neurotransmitter is kind of like sending a note to someone but once you get the job done you throw the note away we want to make sure things only happen once and not linger on later so we want to clean up neurotransmitters quickly

Answer 6

they make sure there’s a good level of glucose around our neurons so that our neurons can uptake glucose and do self metabolism pathways and start glycolysis so that they can always make ATP

Answer 7

to get the most ATP, neurons need O2 so you need a blood supply so astrocytes also participate in blood supply component to provide O2 so that neurons can make the most ATP possible capillaries are our smallest blood vessels: we have tons of them in association with our brain – however you don’t want the pathogens in our blood to get across and get to your neurons – it’s okay for pathogens to attack viruses in our body but we don’t want viruses to reach our neurons

Answer 8

it’s difficult to move things from the blood to the cerebral spinal fluid because the astrocytes are doing their job by enhancing the blood brain barrier

Answer 9

they enhance the blood brain barrier by keeping the tight junctions between the endothelial cells and create our capillary walls and keep everything tight so that stuff can’t move from the blood to the interstitial fluid and that way pathogens can’t get out

Answer 10

the trade off is that if we don’t let things out of our blood, hello oxygen, glucose, endocrine system, and your immune system use your blood your white blood cells are moving in your blood so that they can get to spots where there’s some sort of pathogen outside of your blood, they leave your vascular system and go to that point so now our WBC warriors can’t leave the blood and get to our CSF to fight because of the astrocytes

Answer 11

they help with the development and growth of neurons both structurally in giving them locations to grow into and with metabolic support so that they can become the biggest neurons they can be so astrocytes are critical during fetal development so that the brain can develop the way it should

Answer 12

astrocytes have gap junctions that exist between astrocytes which can help with direct communication through those channels they also have gap junctions with our neurons so they can communicate with our neurons they also impact our neurotransmitters and how much of them are around and how long they’re around so when neurons are communicating with other neurons they can impact that communication by how long the neurotransmitter is around

Answer 13

glial cells of the CNS that are in our cerebral spinal fluid and are the immune cells in the cerebral spinal fluid they're phagocytic cells so if they come across something that's not supposed to be there they engulf it and destroy it

Answer 14

they aren’t always doing battle – when they aren’t doing battle they’re in their resting mode in their resting mode they look like mini neurons because they have a cell body with lots of little processes coming off of it – in this resting mode they still serve an important function = in this highly branched form they’re releasing chemicals that insure that the neurons are able to do their job properly and can grow and develop properly = sort of assisting the astrocytes

Answer 15

• When a pathogen is detected in the CSP, the microglial cells change from resting to phagocytic form and they pull in all the projections and become a classic looking round cell which will aid them in having to move because now they’re smaller they also need to be able to effectively endocytose the pathogen and so they need more straight off surface area so they bring in projections now the chemicals that they release are not for the neurons development anymore, they’re chemicals that make a not hospitable environment for pathogens so that the pathogens can’t function and not survive

Answer 16

1) afferent neurons 2) efferent neurons 3) interneurons

Answer 17

bring information to our CNS from receptor which is the first part of our reflex arc a separate cell can be acting as the receptor or the afferent itself could be picking up the signal they don't have dendrites, there's an axon terminal on both sides that does the gathering and carrying out information function located in the PNS except the axon terminal is in the CNS so it can communicate to it

Answer 18

take information from the CNS - it serves as our efferent pathway in our reflex template the dendrites are in the CNS while the axons are in the PNS because you have to connect up to the effectors to get us a response through the reflex template

Answer 19

act as integrator – connect A to E entirely within CNS the CNS is the area where we draw a circle around our interneurons and the interneurons define the CNS

Answer 20

for every 1 afferent neuron, we have 10 efferent neuron for every one afferent neuron there’s 200,000 interneurons

Answer 21

synapse is the space where a neurotransmitter gets released into interstitial fluid to get to the next cell

Answer 22

1) chemical synapses | 2) electrical synapses

Answer 23

like when neurotransmitters release sites – slower than electrical synapses

Answer 24

based on our gap junctions we’re going to be able to keep an electrical activity as an electrical message and move it from cell A to cell B faster than chemical synapses

Answer 25

electrical

Answer 26

chemical synapses are what’s dominantly found the tradeoff is that electrical activity is bidirectional while chemical is unidirectional - when we’re talking about communication we want it to go as fast as possible in one direction when communication turns around and goes back the other way actually makes it slower

Answer 27

the tan one and it’s connecting up to 4 neurons and communication is happening from left to right

Answer 28

any synapse is about two cells; one cell connecting to another – so there’s always one neuron communication with another since it’s chemical synapses and the message only goes in one direction – they’re referred to as pre and post synaptic neurons pre synaptic is releasing neurotransmitters and post synaptic is receiving the neurotransmitters/message defining a neuron as pre and post isn’t a thing because most times it’s both

Answer 29

they move through interstitial fluid so it can diffuse over and reach post synaptic cell – membrane bound receptors receive the message

Answer 30

five different pre-synaptic neurons come together and all talk to one post-synaptic focal neuron more pre talking to fewer post (4:1)

Answer 31

dividing, making more focus neuron communicating with four other neurons – the number of pre is less than the number of post (1:4)

Answer 32

we have a variety of electrical potentials associated with our cells we created potential energy with our gradients – our potential energy is our electrical energy

Answer 33

this is the main type of potential because the rest are based off/rely on membrane potential - it's the potential that makes all the others possible

Answer 34

we can have a separation of ions on either side of the membrane electrical charge separation across PM due to distribution of charged components – the membrane stops the ions from moving relative to their gradient Na/K/ATPase pump made a electrical gradient because more + went out than came back in because 3 Na went out and only 2 K got brought back in so most cells end up being a little bit more negative inside = a little more positive on the outside – more sodium on the outside and more potassium on the inside

Answer 35

potassium on the inside is happy being near negative charge but the sodium on the outside next to the positive charge isn’t happy and wants to move away from it this means we have to pay attention to both chemical (concentration) and electrical gradient and what they’re tell the cell to do

Answer 36

Net G = conc. G + electrical G

Answer 37

concentration gradient tells Na to go into the cell and the electrical gradient is also telling sodium to go into the cell to get closer to the negative charged inside so sodium will go into the cell

Answer 38

concentration gradient tells K to go out of the cell but the electrical gradient tells K to go into the cell towards the negatively charged inside so the gradient directions are opposite of each other if these are vectors, the only way you know which way K goes you need more information: you have to know the sizes of the arrow – you know how to calculate concentration (#/volume)

Answer 39

yes! every cell has a membrane potential so every cell can experience a graded potential

Answer 40

voltage across the membrane

Answer 41

at rest, most cells Vm = -70 mV since cells are usually negative on the inside

Answer 42

due to all charged components like Na, K, Cl, Ca, etc. what’s the distribution of all of these? If you change the distribution for one of those you’re going to change your membrane potential

Answer 43

if permeability stays the same, Vm doesn’t change increased permeability causes ions to move which causes a change in membrane potential (delta Vm) = graded potential** ex. if permeability changes, like opening a channel for Na, then Na will go into the cell and our Vm will change

Answer 44

LOCAL local change in ion flow only! Sodium is moving because it’s diffusing into the cell following its electrochemical gradient the change in graded potential is therefore also dependent on diffusion – we know diffusion has a problem with distance so therefore, so does graded potential! Vm of the entire membrane doesn’t change, just the area around the Vm change – like when you open a window in a hot room, you feel the cold air near the window but the other side of the room doesn’t feel anything

Answer 45

resting potentials

Answer 46

cells are polarized at rest

Answer 47

depolarized means make it less negative and decrease the potential and bring it closer to zero since we started at -70 mV

Answer 48

hyperpolarized means making it more negative and increasing the potential

Answer 49

cells are more likely to do things when they’re depolarized so depolarizing is a stimulatory stimulus cells are less likely to do things when they’re hyperpolarized so hyperpolarized is an inhibitory stimulus

Answer 50

going back to rest

Answer 51

1) size variable: change in number of ions – if more ions move there’s a bigger change 2) decrease with distance: these are local events – graded potentials are related to diffusion

Answer 52

a change in electrical distribution opens a voltage gated channel – change in potential can open voltage gated channel

Answer 53

graded potentials can cause an action potential

Answer 54

action potentials only happen in special cells in your body called excitable cells such as neurons, muscle cells, etc they are quick, large delta s in Vm last 1 to 2 milliseconds we're changing our Vm so it really is a Vm, it's just a special case of GP so everything from GP still applies to AP

Answer 55

they are very stereotyped one of the traits of grated potentials is that they can be different sized, they can be depolarizations or hyperpolzarization however when we look at AP, they always look the exact same = same time → as a result it’s an all or none event = we either meet the conditions and it stays as a normal GP and we see no AP

Answer 56

shooting a gun is an all or none event = squeeze the trigger the bullet comes out – squeeze the trigger three times harder, the bullet doesn’t come out any faster – once you reach the threshold you get the AP to happen pregnancy

Answer 57

action potential

Answer 58

1) voltage gated Na channels 2) voltage gated K channels the same Vm opens both channels!

Answer 59

it doesn’t close the Na channel, it just blocks the channel so you don’t see Na move with its gradient like Bronson opening her garage door opener but there’s a car in the way so she can’t get into her garage because there’s a car in the driveway don’t need anything to bind to them to get this to happen, you just need the right membrane potential to cause a change in voltage voltage that causes the channel to open also causes the inactivator to swing over and block the entrance

Answer 60

Na channels are incredibly quick to open inactivator is slower to swing over so Na will flow in until the inactivator gets the chance to move over – same amount of Na will go through every time because the rate of the inactivator is the same each time

Answer 61

open, closed, inactivated

Answer 62

slower to respond than Na like an automatic door that doesn’t open by the time you get there and you have to jerk back – it’s the same signal as the Na channel telling it to open, it just takes longer to open

Answer 63

the same Vm opens both Na and K channels! so therefore channels have to be near each other first see Na channel go from closed to open --> then the inactivator moves over some period of time later and the K channel open kind of at the same time but K channel technically opens up after the inactivator gets to it’s position

Answer 64

this is at rest Na channel is closed and K channel is closed this is redundant because duh the same Vm activates both of them --> we know there are gradients for both Na and K so if we open the channels we know they’ll both want to move

Answer 65

depolarization gets us up to the TP - we have to get Vm up to this spot

Answer 66

1) Na channels open → Na will go into the cell due to chemical concentration gradient reasons and electrical reasons since inside of the cell is negative 2) with positive Na going in, the cell becomes less negative and we further the depolarization → the huge peak in the graph is due to the influx of Na positive feedback

Answer 67

positive feedback some stimulus causes us to vary from steady state and we continue to move away

Answer 68

inactivator swinging over will stop the depolarization which causes us to hit a peak in the graph → Na is inactive K channel opens → by concentration K wants to go out of the cell AND by charge K wants to go out of the cell since at the peak of the graph we’re at +30 mV and the inside of the cell is actually positive now we’ll have less positive charges on the inside when K goes out of the cell and we are now repolarizing the cell to make it polar again which is the downhill part of the graph we will cross the threshold again on the way down which is also the trigger to close the channels so Na closes (there’s a slight period where they’re closed and inactivated but it’s super small)

Answer 69

just like how K opens slow, they also close slow so they’ll stay open a little longer even after we cross the TP so what ends up happening is too much K ends up leaving the cell and it becomes hyper polarized (super negative like -80 mV) eventually K will close and we'll end up back at the resting potential of -70 mV

Answer 70

this is the Vm where we see the immediate opening of our Na channels – also the same Vm that opens K channels but there’s just a lag

Answer 71

initial stimulus is some grated potential that happened once we hit the threshold, it’s the influx of Na into the cell that takes over the driving force of what’s changing our Vm

Answer 72

when a graded potential occurs but it doesn't depolarize enough to reach he TP and thus it is sub-threshold potential and an action potential will not occur because it is all or none the initial stimulus doesn’t get us to the threshold the subthreshold potential stays as a grated potential, it’s not an AP the size of the grated potential doesn’t matter, as long as you hit the threshold it doesn’t matter if it was exact or 700 times bigger

Answer 73

the amplitude won’t change as long as we reach threshold which is why they’re stereotyped it's independent of original grated potential that caused the threshold potential and triggered it no change in size since they’ll all look exactly the same→ unlike grated potentials which can vary in size

Answer 74

local anesthetics that block Na channels litocaine that kill pain in the mouth block Na channels that are voltage gated so no action potential

Exam 4: February 6-10 Flashcards

(101 cards)