WEEK ONE: ACTION POTENTIAL Flashcards
(101 cards)
1
Q
Membrane
A
surrounds the cell
2
Q
nucleus
A
structure that contains the cells genetic material in the form of DNA
3
Q
mitochondrion
A
structure that performs metabolic activities
4
Q
ribosomes
A
protein synthesis
5
Q
motor neurons
A
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
6
Q
sensory neuron
A
neurons that carry incoming information from the sensory receptors to the brain and spinal cord
7
Q
dendrites
A
branchlike parts of a neuron that are specialized to receive information
8
Q
dendritic spines healthy vs intellectual disability
A
healthy: consistent branches,
intellectual disability: not many, inconsistent sizes
9
Q
dendritic spines
A
short outgrowth that increase the surface area available for synapses
10
Q
axon
A
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
11
Q
cell body
A
contains nucleus
12
Q
myelin sheath
A
insulating membrane surrounding the axon in some neurons
increase speed
13
Q
presynaptic terminal
A
end bulb or bouton point where an axon releases chemcials
14
Q
afferent axon
A
brings info into a structure
15
Q
efferent axon
A
carries information away from a structure
16
Q
glia
A
cells found throughout the nervous system that provide various types of support for neurons
17
Q
astrocytes
A
star shaped glia that synchronize the activity of the axons
play a role in nutrition, can withdraw nutrients form blood vessels to neurons
18
Q
Shcwann cells
A
mylenate axons in PNS
19
Q
microglia
A
cleaners
act as phagocytes, eating damaged cells and bacteria, act as the brains immune system
20
Q
oligodendrocytes
A
form myelin sheath in CNS
mylonite more than one neuron at a time
21
Q
radial glia
A
guide the migration of neurons and their axons and dendrites during embryonic development
22
Q
blood brain barrier
A
blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out
23
Q
BBB advantage
disadvantage:
A
ADV: keeps out viruses
DIS: keeps out nutrients
24
Q
what chemicals cross BBB passively
A
small uncharged molecules (ie, oxygen)
25
what chemicals cross BBB by active transport
large molecules such as glucose, AA
26
purkinjie cells
found in the cerebellum
27
kenyon cells
from a honeybee
28
bipolar cells
found in retina of the eye
29
Santiago Ramón y Cajal was responsible for which of these discoveries?
The nervous system is composed of separate cells.
30
Which part of a neuron has its own genes, separate from those of the nucleus?
The mitochondria
31
What is most distinctive about neurons, compared to other cells?
Their shape
32
Which do dendritic spines do?
They increase the surface area available for synapses.
33
What does an efferent axon do?
It carries output from a structure.
34
Which of the following is a function of astrocytes?
Astrocytes synchronize activity for a group
of neurons.
35
Which of the following is a function of microglia?
Microglia remove dead cells and weak synapses.
36
Which of these can easily cross the blood–brain barrier?
A. Fat-soluble molecules
37
Which chemicals cross the blood–brain barrier by active transport?
Glucose and amino acids
38
What is the brain’s main source of fuel?
glucose
39
For the brain to use its main source of fuel, what does it also need?
Thiamine
40
MS
the glial cells in the central nervous system (CNS), particularly oligodendrocytes, are damaged, and the body's immune system attacks the CNS.
41
brain matter
grey matter is on the outer layer (the cortex), and white matter is located deeper, inside the brain
42
spine: matter
Grey matter is in the center, forming a butterfly or "H" shape, while white matter surrounds it
43
Blood brain barrier
border
protection of CNS against viruses and dangerous chemicals
regulation of brain metabolism
44
polarization
difference in electrical charge between the inside and outside of the cell
45
selective permeability
some substances cross a membrane more easily than other substances do
46
sodium-potassium pump
a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell
47
concentration gradient
A difference in the concentration of a substance across a distance.
48
depolarize
reduce its polarization toward zero
49
threshold
the level of stimulation required to trigger a neural impulse
50
action potential
messages sent by axons
51
hyperpolarization
The movement of the membrane potential of a cell away from rest potential in a more negative direction
52
all-or-none law
principle that the action potential in a neuron does not vary in strength; the neuron either fires at full strength or it does not fire at all
53
propagation of the action potential
transmission of an action potential down an axon
54
voltage gated channels
open and close in response to changes in membrane potential
55
refractory period
a period of inactivity after a neuron has fired
56
absolute refractory period
the membrane cannot produce an action potential, regardless of the stimulation
57
relative refractory period
a stronger than usual stimulus is necessary to initiate an action potential
58
local neurons
neurons without an axon
59
graded potential
a membrane potential that varies in magnitude in proportion to the intensity of the stimulus
60
sodium potassium pump
3 sodium out
2 potassium into the cell
*active transport
61
binary signal
fire or don't fire
62
electrical conduction
electrical message is passed on along the axon
does not travel down the axon, but it regenerates, so it doesn't not weaken
63
temporal summation
repeated stimulation at the same location
64
spatial summation
synaptic input from several locations can have a-cumulative effect and trigger a nerve impulse
65
inhibitory post synaptic potential (PPSP)
hyper-polarization
65
excitatory post synaptic potential (EPSP)
depolarization
66
otto loewis experiment (1921)
stimulating the vagus nerve inhibited heart rate, and stimulating the accelerator nerve released increased heart rate
realized he was collecting and transferring chemicals, not loose electricity
67
synapses
neurons communicate by transmitting chemicals at junctions called synapses
68
excitation nt
glutamate
69
inhibitory nt
GABA
70
NT SYNTHESIS TABLE
top are precursors can get from food (milk, nuts etc)
and in cascade brain can convert NT into other NT
71
Modified AA cascade
1. acetly coenzme a + chline =
ACETYLCHOLINE
72
catechoalamines
1. phenylalaine (from diet)
2. tyrosine
3. dopa
4. DOPAMINE
5. NOREPI
6. EPI
73
Indoleamines
1. tryptophan
2. 5-hyrdoxy
3. SERATONIN
74
contrasts
75
ionotropic effects
controlled by Nt,
LIGAND-GATED
76
METATROPIC
nt initating a sequence of metabolic rxns ) G protein activating a second messager
77
metabotropi are ___ than ionotropic synapes
slower and longer
*sequence of events and last longer
78
binding to NT receptors
LSD binds to seratonin receptors
79
stimulutating release
MDMA releases dopamine/seratonin
80
blocking reuptake
ampetamine/cocain block reuptake of dopamine and seratonin and norepi
81
negative feedback
cannabinoids excite negative feedback receptors on the presynaptic neuron
82
4 drug effects
1. binding to NT receptors
2. stimulating release
3. blocking reuptake
4. negative feedback
83
When the membrane is at rest, are the sodium ions more
concentrated inside the cell or outside? Where are the
potassium ions more concentrated?
sodium are more concentrated outside of the cell
and potassium is more concentrated inside the cell
84
When the membrane is at rest, are the sodium ions more
concentrated inside the cell or outside? Where are the
potassium ions more concentrated?
the membrane is at rest, the concentration gradient tends
to drive potassium ions out of the cell, and the electrical
gradient draws them into the cell. The sodium–potassium
pump also draws them into the cell.
85
What is the difference between a hyperpolarization and a
depolarization?
depol = closer to zero
hyper = more negative
86
What happens if the depolarization does or does not reach
the threshold?
no AP occur
87
Does the all-or-none law apply to dendrites? Why or why
not?
The all-or-none law does not apply t
dendrites, becaouse they do not have action potentials.
88
As the membrane reaches the peak of the action potential,
what brings the membrane down to the original resting
potential?
After the peak of the action
potential, potassium ions exit the cell, driving the mem-
brane back to the resting potential. Important note: The
sodium–potassium pump is NOT responsible for return-
ing the membrane to its resting potential. The sodium–
potassium pump is too slow for this purpose.
89
When the neuron’s membrane is at rest, where are the sodium ions and potassium ions most concentrated?
Sodium is mostly outside and potassium is mostly inside.
90
2. When the membrane is at rest, what are the forces acting on sodium ions?
A. Both the concentration gradient and the electrical
gradient tend to move sodium ions into the cell.
91
When the membrane is at rest, what are the forces acting on potassium ions?
. The concentration gradient tends to move potassium
ions out of the cell, and the electrical gradient tends to
move them into the cell.
92
4. Which direction does the sodium–potassium pump move ions?
It moves sodium ions out of the cell and potassium
ions into the cell.
93
Under what conditions does an axon produce an action potential?
B. Whenever the membrane’s potential reaches the
threshold
94
If a membrane is depolarized to twice its threshold, what happens?
The neuron produces the same action potential it
would at the threshold.
95
To which part or parts of a neuron does the all-or-none law apply?
A. Axons
96
During the rising portion of the action potential, which ions are moving across the membrane and in which direction?
Sodium ions move in.
97
After the action potential reaches its peak, the potential across the membrane falls toward its resting level. What accounts
for this recovery?
C. Potassium ions move out because their channels are
open and the concentration gradient pushes them out.
98
What does the myelin sheath of an axon accomplish?
It enables action potentials to travel more rapidly.
99
11. What causes the refractory period of an axon?
The sodium channels are closed.
100
