Module 2 - h.o. ver. Flashcards
(113 cards)
1
Q
divisions of the nervous system
A
central n.s. and peripheral n.s.
2
Q
the CNS consists of
A
the brain and the spinal cord
3
Q
the PNS consists of
A
the nerves outside the skull and spinal cord and the sensory organs
4
Q
types of neurons
A
sensory, motor, and interneurons
5
Q
neuron that detects changes in the internal or external environment
A
sensory
6
Q
neuron that controls muscular contractions to create movement
A
motor
7
Q
neuron that lies in between sensory and motor neurons within the CNS
A
interneurons
8
Q
basic structure of a neuron
A
soma, dendrites, axon, and terminal buttons (+ axoplasmic transport)
9
Q
the junction between the terminal buttons of one neuron and the somatic or dendritic membrane of the receiving cell
A
synapse
10
Q
often covered by the myelin sheath; carries the action potential
A
axon
11
Q
site of neurotransmitter release
A
terminal buttons
12
Q
types of axoplasmic transport
A
anterograde and retrograde
13
Q
transport wherein movement goes from the soma to the terminal buttons; accomplished by the protein kinesin; remarkably fast, up to 500mm/day
A
anterograde axoplasmic transport
14
Q
transport wherein movement is from the terminal buttons to the soma; uses the protein dynein; about half as fast as anterograde transport
A
retrograde axoplasmic transport
15
Q
internal structure of a neuron
A
membrane, cytoskeleton, cytoplasm, nucleus, golgi apparatus, mitochondria
16
Q
boundary of the cell; contains proteins
A
membrane
17
Q
gives the neuron its shape; composed of microtubules
A
cytoskeleton
18
Q
jellylike fluid containing organelles
A
cytoplasm
19
Q
produces ribosomes, which synthesize protein
A
nucleolus
20
Q
contain genes; consist of long strands of DNA; when active, genes produce mRNA
A
chromosomes
21
Q
leaves nucleus and attaches to ribosomes; codes for proteins, including enzymes
A
mRNA
22
Q
forms of endoplasmic reticulum
A
rough and smooth
23
Q
endoplasmic reticulum that contains ribosomes and produces proteins destined for secretion
A
rough
24
Q
endoplasmic reticulum that channels for molecules involved in various cellular processes; produces lipid molecules
A
smooth
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a special kind of smooth endoplasmic reticulum
Golgi apparatus
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assembles and packages product in a membrane; produces lysosomes
Golgi apparatus
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process by which cell secretes packaged substances; occurs in the Golgi apparatus
exocytosis
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sacs contains enzymes that break down waste products
lysosomes
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extract energy from nutrients; synthesize adenosine triphosphate (ATP)
mitochondria
30
supporting cells in the CNS
glia cells
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supports cells in the PNS
Schwann cells
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types of Glia cells
astrocytes, oligodendrocytes, microglia
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Glia cell that controls chemical environment around neurons; processes (arms) wrap around neurons and blood vessels; help nourish neurons; act as "glue"; surround and isolate synapses to limit dispersion of neurotransmitters; remove debris via phagocytosis
astrocytes
34
Glia cells that produce the myelin sheath in the CNS; node of Ranvier (space on axon between tubes of myelin)
oligodendrocytes
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Glia cells that act as phagocytes; protect the brain from invading organisms (immune system function)
microglia
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produce myelin in the PNS; help after injury
Schwann cells
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true or false. 1 segment of myelin=1 Schwann cell
true
38
how do Schwann cells help with injury?
- digestion of dead and dying axons
| - form tubes for axon regrowth
39
true or false. glial cells in the CNS provides the same support Schwann cells do in the PNs for axon regrowth
false
40
true or false. chemical composition of myelin in PNS differs from that of the CNS and is not affected by multiple sclerosis
true
41
a selectively permeable barrier that
- controls composition of substances inside and outside of neurons
- active transport ferries many molecules into the CNS
- is more permeable in some areas (e.g. area postrema)
the blood-brain barrier
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withdrawal reflex; inhibition of withdrawal reflex
neural communication overview
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small electrical recording device
microelectrode
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the difference in charge (+, -) across the membrane
membrane potential
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membrane resting potential
70 mV
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hyperpolarized membrane potential
the inside is more negative than outside
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depolarized membrane potential
the inside is more positive than the outside
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the main electrical event of an axon; characterized by rapid depolarization followed by hyperpolarization
action potential
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the action potential is triggered by -
the threshold of excitation
50
research model to understand the action potential
squid's giant axon
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how large is the squid's axon?
0.5mm in diameter
52
the membrane potential is a balance between which two forces?
diffusion and elecrotstatic pressure
53
force wherein molecules distribute evenly throughout a medium over time
diffusion
54
true or false. without barriers, molecules flow from areas of high concentration to areas of low concentration (diffusion)
true
55
the force of attraction/repulsion between charges
electrostatic pressure
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molecules that split into two parts with opposing charges
electrolytes
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kinds of ions
cations (+) and anions (-)
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ions in the extracellular and intercellular fluid
organic anions, potassium ions, chloride ions, and sodium ions
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ions inside the cell; unable to pass through the membrane
organic anions
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ions concentrated inside the membrane; diffusion pushes it out while electrostatic pressure pushes it in; little net movement
potassium ions
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ions concentrated outside; diffusion pushes it in while electrostatic pressure pushes it out; little net movement
chloride ions
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ions concentrated outside the membrane; diffusion pushes it in while electrostatic pressure pushes it out
sodium ions
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helps keep concentration of Na+ (sodium ions) low inside the neuron; uses high levels of energy
sodium-potassium pump
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the sodium-potassium pump exchanges - in for - out
two K+ (potassium); three Na+ (sodium)
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the sodium-potassium membrane is relatively impermeable to -
Na+ (sodium ions)
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form pores through the membrane that permit ions to enter or leave the cell; changes permeability of membrane
ion channels
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explain the sequence of events of an action potential
1. at threshold of excitation, voltage-dependent ion channels open and Na+ enters cell (membrane potential moves from -70mV to +40mV)
2. voltage dependent K+ channels begin to open and K+ leaves the cell
3. Na+ channels close and become refractory at the peak of the action potential
4. K+ continues to leave the cell until the membrane potential nears normal
5. Na+ channels reset
6. membrane overshoots resting potential, but returns to normal as K+ diffuses
68
the action potential either occurs or does not
all-or-none law
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once the action potential is initiated, it is transmitted to -
the end of the axon
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rate of firing reveals strength of information
rate law
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action potential moves passively under the myelin, experiencing decremental conduction
saltatory conduction
72
in saltatory conduction, the action potential is regenerated where?
at each node of Ranvier
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advantages of saltatory conduction
- neurons expend less energy (ATP) to maintain ion balance
| - faster conduction
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the transfer of information from one neuron to another across another synapse; relies on neurotransmitters; many found on dendrites or dendritic spine, can occur on some and other axons
synaptic transmission
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how does the synaptic transmission rely on neurotransmitters?
1. produce postsynaptic potentials
| 2. attach to receptor at binding site with complementary shape
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a chemical that attaches to a binding site
ligand
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- are natural ligands
neurotransmitters
78
terminal buttons preceding the synpase
presynaptic membrane
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the membrane of the neuron receiving a signal
postsynaptic membrane
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the synaptic cleft contains - and is - wide
extracellular fluid; 20nm
81
located in terminal buttons, near the release zone; hold neurotransmitters; transport proteins and fills vesicles with neurotransmitters
synaptic vesicles
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small synaptic vesicles are produced by - in the - or from -
Golgi apparatus; soma; recycled material in terminal buttons
83
true or false. large synaptic vesicles are produced only in the soma
true
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the location of neurotransmitter release in synaptic vesicles
release zone
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synaptic vesicles fused with the membrane
omega figures
86
steps from action potential to release
1. Vesicles “dock” against membrane via proteins on vesicle binding with proteins on presynaptic membrane
2. Action potential results in opening of voltage-dependent Ca++ channels
3. Ca++ enters the cells
4. Binds with docking proteins on presynaptic membrane and causes them to separate (thereby forming the fusion pore)
5. Neurotransmitter released to synaptic cleft
87
three pools of synaptic vesicles
release-ready, recycling, and reserve
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pool of synaptic vesicles that are docked against the inside of the presynaptic membrane; < 1% of vesicles; open even with low rate of firing
ready-release pool
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pool that make up 10-15% of vesicles
recycling pool
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pool that makes up 85-90% of vesicles; only open with high rate of axon firing
reserve pool
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after neurotransmitter release, pore closes, vesicle undocks and moves to be refilled with neurotransmitter
"kiss and run"
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process of bulk endocytosis
"merge and recycle"
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postsynaptic receptor receives neurotransmitter, opening neurotransmitter-dependent ion channels
activation of receptors
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two classes of postsynaptic receptors
ionotropic and metabotropic
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postsynaptic receptors wherein binding of the neurotransmitter opens channels; direct method
ionotropic receptors
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postsynaptic receptors wherein activation of G protein produces second messenger; indirect method (requiring metabolic energy); close to a G protein
metabotropic receptors
97
true or false. potential takes and lasts longer in ionotropic receptors compared to metabotropic receptors
false
98
kinds of postsynaptic potentials
excitatory (EPSP) and inhibitory (IPSP)
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postsynaptic potential that is depolarizing
excitatory
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postsynaptic potential that is hyperpolarizing
inhibitory
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termination of postsynaptic potentials occur through
reuptake and enzymatic deactivation
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wherein enzymes destroy neurotransmitters in the synapse (e.g. acetylcholine (ACh) by acetylcholinesterase (AchE)
enzymatic degradation
103
disease characterized by muscular weaknesses; immune system attacks its own Ach receptors; can be treated by drug that blocks AChE, increasing ACh
myasthenia gravis
104
receptors that respond to neurotransmitters that they themselves released; metabotropic receptors with generally inhibitory effects; help regulate the amount of neurotransmitter released and available for use
autoreceptors
105
other types of synapses
axoaxonic, dendrodendritic, gap junction
106
synapse that alters the amount of neurotransmitters released; presynaptic inhibition and facilitation
axoaxonic
107
synapse with regulatory functions
dendrodendritic
108
synapse that is electrical rather than chemical; ions flow between cells; more common in invertebrates
gap junction
109
released by neurons in larger amounts and diffused for longer distances than neurotransmitters
neuromodulators
110
secreted by endocrine glands; distributed via bloodstream; target cells contain specialized receptors for this
hormones
111
types of hormones
peptide and steroid
112
hormones that activate metabotropic receptors
peptide
113
hormones that bind to a receptor, which alter protein production; small, fat soluble molecules
steroid
