neuroscience - exam 3 Flashcards
1
Q
neurons
A
cells that send & receive electrical or chemical signals (nerve cells)
2
Q
nervous systems
A
circuits of neurons that integrate internal & external
3
Q
How do neurons and nervous systems differ in association with species complexity
A
more complex organisms have more complex nervous systems & more neurons
4
Q
least complex organisms nervous system
A
neurons spread out
nerve net
5
Q
nerves
A
neurons bundled
6
Q
cephalization
A
neurons cluster in the head = brain
7
Q
bilateral symmetry
A
both sides the same
8
Q
central nervous system
A
brain & spinal cord
9
Q
peripheral nervous
A
nerve cells outside the CNS
10
Q
dendrites
A
receives signals
11
Q
cell body
A
contains cell machinery
12
Q
axon hillock
A
integrates signals
“decider”
13
Q
axon
A
carries signals to synaptic terminals
14
Q
synaptic terminals
A
send signals to other cells
15
Q
astrocytes
A
blood-brain barrier
prevents toxins from entering the brain
nourish/support neurons
role in mental disorders
16
Q
microglia
A
immune cells
protect brain against pathogens
clean up debris
17
Q
oligodendrocytes
A
glial cells in CNS
wrap around axons
18
Q
schwann cells
A
glial cells in PNS
wrap around axons
19
Q
myelin sheath
A
encases neurons & insulates
increases signal speed
20
Q
what disease is associated w/ myelin degeneration
A
multiple sclerosis
21
Q
what type of signals travel down neurons
A
electrical signals
22
Q
what type of signals travel between neurons
A
chemical signals
23
Q
sensory neurons
A
PNS –> CNS
24
Q
interneurons
A
“talk” to other neurons
can be CNS or PNS
25
motor neurons
CNS --> PNS
26
cone snail sensory, inter, & motor
sensory input of PNS - cone snail's siphon senses a fish
integration - sensory input sent to CNS
motor output (PNS) - proboscis sends thing out to inject fish w/ poison
27
which type of neuron is affected by Lou Gehrig’s disease?
motor neuron
28
membrane potential
voltage across a plasma membrane
29
voltage
electrical charge difference
30
resting potential
membrane potential of a neuron that is not transmitting signals
-70mV
31
what forms the resting potential
differences in ions across the plasma membrane
32
distribution of ions in membrane
Na+ = sodium - more outside cell
K+ = potassium - more inside cell
A- = anions (negatively charged ions)
33
polarization of cell
more positive ions outside of cell
INSIDE of cell is relatively MORE NEGATIVE than the outside
34
selective permeability
channels only let certain things through
35
are ion channels mostly open or closed in a
neuron at rest
closed
keeps Na+ on 1 side & K+ on the other side
36
sodium potassium pump
moves Na+ ions out of the cell & K+ into the cell in a 3:2 ratio
active transport
37
why are sodium potassium pumps important
for making sure the inside stays more negative
38
concentration gradient w/ Na+ & K+
concentration gradient pressures Na+ to enter the cell
pressures K+ to exit the cell
passive transport
39
voltage-gated ion channels
electrical signals from other neurons cause ion channels to open
change in membrane potential (voltage) causes ion channel to open
40
hyperpolarization
inside becomes MORE negative
channel opens, K+ leaves, cell becomes more negative
41
depolarization
inside becomes more positive
Na+ channel opens, Na+ enters, neuron becomes less negative
42
graded potentials
depolarization & hyperpolarization under the threshold
the stronger the stimulus, the larger the change in membrane potential
43
what happens when a depolarization crosses the “threshold potential"
action potential
not a graded response
44
action potential
brief all-or-none depolarization of a neuron's plasma membrane
type of signal that carries info along axons
45
size & shape of action potentials
size & shape of each one is the same
a stronger stimulus generates more action potentials
46
stages of action potential
1. resting state
2. depolarization
3. rising phase
4. falling phase
5. undershoot
1. restoration of resting potential
47
1. resting state of action potential
Na+ & K+ channels are closed
48
2. depolarization of action potential
Na+ channels open
Na+ diffuses into the cell
49
3. rising phase
MANY Na+ channels open
Na+ rushes into the cell
positive feedback
50
4. falling phase
K+ channels open
K+ rushes out of the cell
51
5. undershoot
K+ slowly closing
Na+ inactivated
52
refractory period
brief period when a neuron cannot generate an action potential
53
1. restoration of resting potential
K+ channels close
54
sodium potassium pump
moving Na+ inside neuron
moving K+ outside neuron
helps restore resting membrane potential
55
tetrodotoxin
blocks Na+ channels
used by puffer fish for defense
56
alpha & beta toxins
shifts opening & closing of Na+ channels
used by scorpions to capture prey
57
apamin
blocks K+ channels
used by honey bees for defense
58
how do action potentials move down the axon
the depolarization of one region of the axon stimulated depolarization of the next region
59
why doesn't the action potential move backwards
Na+ channels become inactivated
60
what determines conduction speed of an axon
axon diameter
myelin sheath
61
How can axons send rapid signals in humans even though axons are small
a myelinated axon is faster than a giant axon 40x its size
>2000 myelinated axons can be packed into the space occupied by just 1 giant axon
62
nodes of ranvier
gaps in myelin sheath where action potentials are generated
concentrated w/ sodium ion channels
63
saltatory conduction
action potentials are "jumping" down the length of the axon
64
synapse
site of communication between the synaptic terminal & another cell
65
presynaptic cell
neuron 1
sending signal
66
postsynaptic cell
neuron 2
receiving signal
67
chemical synapses
a chemical acts as a signal between cells
68
electrical synapses
electrical current flows from cell to cell
69
vesicle
a packet of neurotransmitters
70
neurotransmitter
a chemical messenger between neurons
71
synaptic cleft
gap between pre & post synaptic neurons
72
chemical synapse @ synaptic terminal
1. action potential depolarizes presynaptic membrane
2. voltage-gated Ca2+ channels open
Ca2+ enters the neuron
3. Ca2+ causes vesicle to fuse to membrane & release neurotransmitter --> exocytosis
73
EPSP
excitatory postsynaptic potentials
depolarization
74
IPSP
inhibitory postsynaptic potentials
hyperpolarization
75
ionotropic receptors
neurotransmitters bind to receptors that are part of ion channels
open ion channel
change membrane potential
rapid, short lasting
76
If one input to a postsynaptic neuron is usually too weak to initiate an action potential,
then how are action potentials elicited
synaptic integration / summation
epsp & ipsp are added together
77
where does synaptic integration take place
axon hillock
78
metabotropic receptors
neurotransmitters bind to a receptor that is not part of an ion channel
activates a signal transduction pathway
slower, longer lasting
can open an ion channel or activate another molecule
