just flashcards from week one idk
1
Q
what does the anterior cerebral artery supply
A
medial surface of cortex
2
Q
what does the middle cerebral artery supply
A
lateral side of cortex
3
Q
what does the posterior cerebral artery supply
A
occipital lobe, bottom of temporal lobes (ventral cortex)
4
Q
what does the middle cerebral artery become when it enters the circle of willis/CNS
A
corotid artery
5
Q
what did golgi discover
A
golgi stains, silver nitrate stains around 1% of cells (but not the axon), thought that all neurons were connected (reticularis doctrine), golgi stain is yello
6
Q
what is the reticularis doctrine
A
golgi thought that all neurons were connected like a web
7
Q
who was the person who discovered the yellow staining technique
A
camillo golgi
8
Q
who was the person who discovered the purple staining technique
A
franz nissl (nissl stain)
9
Q
who came up with the neuronal doctrine
A
ramon santiago y cajal
10
Q
what did ramon santiago y cajal discover/think
A
neurons are not connected but have spaces between them through which they communicate
11
Q
how many neurons are in the human brain
A
around 86 billion
12
Q
name the three types of neurons
A
sensory, motor, interneurons
13
Q
name four zones of a neuron from dendrites to terminal
A
input zone, integration zone, conduction zone, output zone
14
Q
what is a neurite
A
the branches (axon or dendrites) which come off the cell body of a neuronwhat
15
Q
what makes a neuron unipolar
A
one neurite
cell body—————–dendrites
16
Q
what makes a neuron bipolar
A
two neurites
dendrite——-cellbody——————-sensoryreceptor
17
Q
what makes a neuron pseudopolar
A
one axon that splits into two branches
18
Q
where are pseudopolar neurons found
A
in dorsal root ganglia
19
Q
what makes a neuron multipolar
A
more than two neurites
20
Q
what type of neurons are typically multipolar
A
motor neurons, cortical neurons
21
Q
what type of neurons are typically uni and bipolar
A
sensory neurons
22
Q
what is the advantage/point of multipolar neurons
A
receive multiple inputs
23
Q
what is the advantage/point of uni and bipolar neurons
A
rapid transmission (not really needing to do integration of stimulus)
24
Q
what and where is the axon hillock
A
where the neuron integrates info + makes signaling decision (right before axon on cell body)
25
are chemical synapses or gap junctions/electrical synapses faster
electric/gap junction synapses are faster
26
name all 7 shapes of neurons
pyramidal cell, basket cell, chandelier cell, arachniform cell, spiny stellate cell, bitufted cell, double boquet cell
27
what is the main dendrite of a pyramidal cell called
apical dendrite
28
name the parts of a pyramidal cell
cell body, axon, apical dendrite, basilar dendrite, oblique dendrite
29
what is the name of a dendrite that branches from the apical dendrite of a pyramidal cell
oblique
30
what is the name of a dendrite that branches from the cell body (sort of bunchy) in a pyramidal cell
basilar dendrite
31
how much of the axon can you see in a golgi stain of a neuron
barely any, bc myelin doesnt stain in golgi stains
32
name the 5 types of glial cells
microglia, astrocytes, oligodendrocytes, shwann cells, satellite cells
33
what is the function of microglia cells
activated in response to injury, infection, etc. can cause swelling, too much = bad
34
what is the function of astrocytes
regulates local bloodflow, nourishment to blood vessels, and maintains the BBB
35
how do astrocytes help maintain the BBB
astrocytes wrap all around capilaries forming tight junctions so anything cant enter the brain
36
what do astrocytes have to do with cerebral spinal fluid
CSF can travel through the 'feet' of the astrocytes. metabolic waste is carried away through this cerebral spinal fluid mostly as you sleep (slow wave sleep before REM)
37
what does an oligodendrocyte do
provides myelin to neurons in CNS
38
what do shwann cells do
provides myelin to neurons in PNS
39
what is a main difference between oligodendrocytes and shwann cells (beside CNS/PNS)
oligodendrocytes can myelenate MANY axons while shwann cells can only do a little (like one essentially)
40
what can be a problem with glial cells
continue dividing (unlike neurons) and are susceptible to cause tumor
41
what are ependymal cells
found inside of brain ventricles and produce + secrete CSF
42
where are ependymal cells found
inside of brain ventricles
43
what structure do ependymal cells have that many others do not
cilia to create current in the CSF
44
what are nine words for a group of axons
bundle, peduncle, nerve, commisure, fasiculus, funiculus, tract, lemniscus, corpus callosum
45
definition of membrane potential
the difference in electrical charge across the cell membrain (charge inside cell vs charge outside)
46
depolorization definiton
membran potential moves toward zero (more positive)
47
hyperpolarization definition
membrain potential moves away from zero (more negative)
48
equilibrium potential
when the electrical and chemical gradients for a particular ion 'ballance out' and there is no net movement of ions across the membrain
49
which equation do you use to calculate an ions equilibrium potential
nerst equation
50
which equation do you use to predict which direction/where an ion is going to move
goldman equation
51
what does the sodium potasium pump do (specific)
uses ATP to move 3 sodium ions out and 2 potassium ions in, maintaining the negative intracellular charge
52
what does a positive result in the goldman equation mean
ion wants to move OUT of cell
53
what does a negative result from the goldman equation mean
ion wants to move INTO the cell
54
is depolorization excitatory or inhibitory
excitatory
55
is hyperpolarization excitatory or inhibitory
inhibitory
56
when the mp becomes more positive (closer to zero) this is BLANK which is a INHIBIOTORY/EXCITATORY signal
this is DEPOLARIZATION which is EXCITATORY
57
what the mp becomes more negative, this is BLANK which is an INHIBITORY/EXCITATORY signal
this is HYPERPOLARIZATION which is INHIBITORY
58
where do chemical/ligand gated ion chanels exist on a neuron
soma + dendrites
59
where do voltage gated ion channels exist on a neuron
axon
60
what is the space between myelinated sections of an axon called
nodes of ranvier
61
what is a post-synaptic potential
small, brief changes in membane poential
62
what causes a post-synaptic potential
the opening of CHEMICALLY gated ion channels
63
what is an EPSP
excitatory post-synaptic potential
increase chances of generating an action potential (depolorization)
64
what is an IPSP
inhibitory post-synaptic potential
decreases the chances of generating an action potential (hyperpolarization)
65
what does it mean the post-synaptic potentials are graded
have varying strengths
66
3 types of membrane potentials
resting mp, post-synaptic/graded potentials, action potentials
67
what ion channels open to cause depolarization
sodium channels open and sodium rushes into the cell bringing positive charge, making the mp more positive (depolorized)
68
what ion channels open to cause hyperpolarization
chloride channels open and chloride enters the cell making the membaine potential more negative (hyperpolarization)
ALSO CAN OCCUR WHEN:
potassium chanels are opened and potassium exits the cell making the cell more negative
69
what is summation
if EPSP is followed by addition EPSPs, sodium chanels will remain open or more will open increasing the sodium conductance and the EPSPs summate (are all added up)
70
what is threshold mp
each neuron has a threshold mp at which cell will fire an action potential if the summation of EPSPs causes a cell's mp to reach threshold
71
name the two types of summation
temporal and spacial
72
what is temporal summation
when one presynaptic input stimulates a postsynaptic neuron multiple times in a row
73
what is spacial summation
when multiple presynaptic inputs stimulate one post-synaptic neuron at the same time
74
can EPSPs summate with IPSPs?
yes, will result in either weaker deplarization (compared to EPSP(s) alone) or no depolarization (depends on strength of IPSP)
75
what is propogation
the action potential traveling from the axon hillock down the axon to the presynaptic terminal resulting in the release of neurotransmitters
76
what opens voltage-gated ion channels
when the cell reaches the threshold membane potential
77
name the 5 phases of an action potential
depolarization, overshoot (rising phase), falling phase, undershoot, return to rest
78
what causes the rising phase of an action potential
opening of voltage-gated sodium channels which open immediatly once cell reaches threshold mp. sodium rushes in depolarizing the cell
79
what causes the falling phase of an action potential
caused by the inactivation of sodium channels + the opening of potassium channels.
(abt one milisecond after sodium ion channels open, the sodium channels close and potassium channels open. potassium (+) rushes out of the cell repolarizing the mp + returns mp to rest)
80
what is the voltage trigger for the opening of potassium channels (during action potential)
also the threshold mp but sodium channels open immediatly and potassium channels have a short delay
81
what causes the undershoot of an action potential
caused by potassium channels remaining open just long enough to cause hyperpolarization as potassium moves toward its equilibrium potential
82
what causes the return to rest phase of an action potential
voltage gated ion channels close + sodium/potassium pump reestablishes proper ion concentrations (return to resting mp)
83
what is a refractory period
neurons can only fire so fast, the refractory period is the time during and right after an action potential is fired in which a neuron cannot fire another action potential
84
what are the two types of refractory periods
absolute refractory periods and relitive refractory periods
85
absolute refractory period (def)
during rising + falling phases. during absolute rf a second action potential cannot be fired reguardless of stimulus strength
86
relative refractory period (def)
during the undershoot. neuron CAN still fire but need a larger-than-normal stimulus to make cell reach threshold again
87
what causes the absolute refractory period, why physically can the neuron not fire?
the voltage-gated ion channels are either open (rising phase) or inactivated (falling phase)
88
how does the nervous system know the strength of a stimulus
frequency of action potential firing (weak stimuli cause less frequent action potentials that strong stimuli)
89
what keeps an action potential from going backwards/the wrong way
the refractory period.
as an action potential moves from one node of ranvier to the next, the sodium channels inactivate once the action potential has 'passed' and the inactivated channels on the previous axon segment make it impossible for the membane to depolarize again
90
what effects speed of action potential propogation/movement
myelination and axon diameter
91
how does myelin make the propogation of axon potentials faster
action potential 'jumps/skips' over myelinated segments (from one node of ranvier to the next), making the distance traveled much shorter
92
what is saltatory conduction
conduction of action potential on a myelinated axon (jumping from one node of ranvier to the next)
93
how does axon diameter effect conduction speed
larger the axon diameter, faster the propogation of action potentials
