U2- Nervous Tissue Flashcards
1
Q
nervous system function
A
maintains homeo.
w/ electrical + chem. signals
2
Q
stages
A
1- detects change (sensor)
2- CNS decodes message
3- CNS ignites muscl. + gland cells
3
Q
peripheral nervous system (PNS) parts
A
to or away from CNS
inc. sensory and motor
then visceral and somatic
4
Q
nerve
A
bundle of nerve fibers wrapped in CT
fun- carry signals btw organs
5
Q
gangilia
A
swelling of nerve
6
Q
sensory branch of PNS
A
carries sig to CNS
7
Q
motor branch of PNS
A
sign to CNS that ignite muscle and gland cells
8
Q
visceral motor branch of PNS- parts
A
“autonomic”
sympathetic and parasympathetic
9
Q
visceral motor branch PNS- sympathetic
A
arouses body for action
10
Q
visceral motor branch PNS- parasympathetic
A
calming affect
stim. digestion
11
Q
visceral motor branch PNS- function
A
sign to glands
cardiac + smooth muscl.
adipose tissue
12
Q
somatic motor branch PNS
A
sign to skeletal musc.
13
Q
somatic sensory branch PNS
A
sig from skin, musc. and bones
14
Q
visceral sensory branch PNS
A
sign from heart, lungs, stomach, bladder…
15
Q
neuron charac.
A
excitability
conductivity
secretion
16
Q
neuron excitability
A
respond to environ. changes (stimuli)
17
Q
neuron conductivity
A
respond to stimuli w/ electrical sig.
18
Q
classes of neurons
A
sensory
interneurons
motor
19
Q
sensory neurons
A
“afferent”
toward
detect stim. + transfer to CNS
exterorecptors + proprioreceptors
20
Q
interneurons
A
makes decisions
only in CNS
21
Q
motor neurons
A
“efferent”
away
send sig. from CNS to musc. + gland cells
22
Q
dendrites
A
receive sig. from o/ neurons
23
Q
node of ranvier
A
space on axon btw internodes
24
Q
internode
A
thick protein structures
25
soma
control center of neuron
26
neurofibrils
actin filament
| organize rough ER
27
penkaryon
cytoplasm of soma
| produces neurotrans.
28
axon
conduction of nerve sig. away from soma
| long tail
29
axon terminal
forms synapse w/ next neuron
| where neurotransm. released
30
axonal transport
anteograde
| retrograde
31
anteograde
performed by kinesins
| soma to axon
32
reterograde
performed by dyneins
| axon to soma
33
neurogilia
"microgilia"
| protect neurons and provide framework
34
types of cells in CNS
ependymal
microgllia
astrocytes
oliogodendrocytes
35
types of cells in PNS
schwann + satellite cells
36
ependymal cells
line brain and spine
| produce cerebral spinal fluid (CSF)
37
microglia
destroy foreign bodies (not very effective)
| immune cells of brain
38
astrocytes
supportive structure
stim. neurons
regulate comp of ICF
maintain blood-brain barrier
39
oligodendrocytes
myleination of axons
40
schwann cells
regen of damaged nerve fibers
| form sheath around PNS axons
41
satellite cells
surround soma in ganglia
| electrical insulator
42
myelin sheath for PNS and CNS
CNS- oliogodendrocytes
| PNS- Schwann
43
multipolar neuron
form all motor systems
| very long
44
bipolar neuron
long axons
45
unipolar neuron
horizontal
cell body off to one side
found in afferent- sensory neurons
46
anaxonic neuron
no axon
alters act. of o/ neurons
found in brain
act as junction box
47
schwann cells
wrap around axon like toothpaste tube
cytoplasm forced to one end
if unmyleinated
folds only once around axon
48
oligodendrocytes
cannot migrate
| have centrifugal myleination (away) and centripetal myleination (towards center)
49
factors of nerve conduction speed
diameter of fiber
| presence of myelination
50
nerve regeneration (only PNS)
1- fiber cut + degenerated by macrophages
2- soma swells
nucleus moves off center
axon makes new terminals
3- near cut, schwann cell make re-gen tube
4- tube guides terminals to target cell
synapse reestablished
5- soma shrinks
reinnervated musc. fibers grow
5-
51
electrical potential
diff in conc. of charged part. btw points
| form potential energy
52
potential energy
can produce a current (flow of charged par.)
53
polarized
if has poten. voltage
54
resting mem. pot. (RMP)
charge diff. across plasma mem.
through ele. currents
ion flow through ion gated channels
55
RMP factors
diffusion of ions down conc. gradient
selective permeability of mem. for ions
attraction of cations and anions
56
mvmnt of Na and K across mem.
3 Na out- mre conc. in ECF
| 2 K in- most permeable to mem.
57
sensors
rxn in PNS
| change RPM
58
effectors
sensors send signal to effectors in CNS
59
current flow diagram
```
resting
graded
action pot.
neurotransmitter
(disturbes resting mem. again)
```
60
local potential location
dendrites and soma
61
local pot. charact.
graded
decremental
reversible
62
graded
vary in volt. based on stim. (Ex. hyper, or re/depolarization)
higher stim- channel open for more time
63
decremental explanation
as Na charge reaches surr. K it quickly gets repolarized (more negative)
64
reversible
mem. returns to resting
| excitatory or inhibitory
65
excitatory reversibility + postsynaptic pot.
depolarize by ACh
| neuron more likely to reach action potential
66
inhibitory reversibility + postsynaptic pot.
hyperpolarize (extra neg.)
| neuron less likely make action pot.
67
ways to open and close gated channels
chemically
mechanically
voltage
68
local pot. channels charac.
graded
| mech. and chemically controlled
69
action potential location
axon
70
action pot. charac.
```
all or none rule
if depolar. to threshold- fires max voltage
NOT GRADED
nondecremental
not reversible
action pot. cannot be stopped
```
71
action pot. channel charac.
gated
vol. gated
need density of vol. to work
can be caused by excitatory local pot. if reaches trigger zone
how action pot. move in one direction (transfer)
72
action pot. steps
1- depolar. of mem by current (local pot.)
2- threshold met
3- neuron produces action pot.
Na enters cells + depolar.
mem. vol. inc
4- Na flow stops
polarity flipped from RMP
ICF mre + and ECF mre -
5- K ions repelled by positive charge and exit cell
repolar. mem. to -
6- mre K channels open than Na
causes mre neg. repolarization (hyperpolar.)
73
simplified action pot. steps
```
1- RMP
2- Local pot.
3- Threshold
4- depolar (Na in)
5- Na channels close and K channels open @ top
6- repolar (K out)
7- RMP passed negatively (hyperpolar.)
8- Na K pump compensates and returns mem. to RMP
```
74
refractory period
resistance against restimulating an action pot. after neuron fires
75
absolute period
as long as Na gates open
| no amnt of stim will trigger neuron
76
relative period
from Na gates closure to hyperpol.
strong stim. wil trigger neuron
has to overcome output of K+ ions w/ Na (hard to do)
77
signal conduction- unmyleinated
uninterrupted chain rxn of current
"continuous conduction"
channels along entire length
78
signal conduction- myelinated
faster
"salatory conduction"
current not continuous
only gated channels at node of ranviers
79
continuation of signal in myelinated neuron
Na enters node of ranv. + repelled by o/ Na
moves dwn axon like repelling magnets
dec. strength w/ distance
80
roll of synapses
if delay signal speed
| used bc are processing componet
81
temporal summation
stim from only one synapse
stim regen before 1st current fades
build up overtime
triggers action pot. w/ threshold vol.
82
spatial summation
stims from many synapses
| meet at hillock
83
presynaptic facilitation
one neuron enhances effects of o/ neurons
84
presynaptic inhibition
one neuron suppresses effects of o/ neurons
85
synpatic plasticity
synapses can be added and taken away in responce to experience
allows signals to travel easier
86
maintenance of RMP
Na K pump
| ion gated channels
87
why is RMP negative if K and Na are +
k mre permeable to mem.
| mem. favors K at -90 v Na at +50
88
Na ion mvmt across mem
```
originally- moves into cell along conc. gradient
lessens negative - charge of ICF
since not opposite anymore
Na channels close
equilibrium = +50
```
89
K ion mvmnt across mem
K more permeable
moves along conc. gradient to less conc. which is outside of the cell
cell becomes more neg.
since not opposite charges anymore
K channels close
equilibrium = -90
90
RMP voltage amount
-70
