Exam 3 Flashcards
(238 cards)
1
Q
what are the different ions that are involved in membrane potential?
A
K+
Na+
Cl-
Ca2+
2
Q
what are the two different aspects of membrane potential?
A
concentration gradient
membrane permeability
3
Q
what is a concentration gradient?
A
ions inside versus outside
4
Q
what is membrane permeability?
A
K+ is the most permeable
5
Q
what is influx?
A
ions into the cell
6
Q
what is efflux?
A
ions out of the cell
7
Q
what are the different ion channels?
A
mechanical
chemical
voltage-gated
8
Q
what is a mechanical ion channel?
A
respond to pressure/stretch
9
Q
what is a chemical ion channel?
A
respond to ligands
ex: neurotransmitter
10
Q
what is a voltage-gated channel?
A
respond to changes in membrane potential
11
Q
what is repolarization?
A
return to the resting membrane potential
neuron = -70mV
-usually the 2nd half of action potential
-K+ enters cell
-K+ channel is slow to open
-Na+ channels close
12
Q
why are membrane potentials always fluctuating?
A
due to the influx of Na+ and Cl- and the efflux of K+
only a few ions are needed to cause a change
13
Q
what is resting potential?
A
-70mV
14
Q
what is polarization?
A
flow of electrical charge carried by an ion is called the ion current
15
Q
what does the flow create?
A
polarization
16
Q
what does polarization create?
A
an electrical signal
17
Q
what are the two types of signals?
A
graded potential
action potential
18
Q
what are some characteristics of graded potential?
A
variable-strength signal
travel short distance
19
Q
what is action potential?
A
very brief
large depolarization
travel far
20
Q
what do you need to create action potential?
A
graded potential
21
Q
what is graded potential?
A
change in membrane potential whose size is proportional to the stimulus
22
Q
where does graded potential occur?
A
dentrites
cell body
23
Q
what might graded potential do?
A
trigger or inhibit action potential
24
Q
what is hyperpolarization?
A
becoming more negative than resting potential
- last part of action potential
- final K+ channel closes
25
what is depolarization?
decreasing the membrane potential difference
generally = more positive mV
-usually at the start of an action potential
-Na+ channels are open
26
what are the four steps of graded potential?
1. ion channels open
2. membrane potential changes
3. resistance/current causes current flow to decrease over distance
4. may reach trigger zone if strong enough and cause action potential
27
what two things does the strength of potential depend on?
1. strength of initial stimulus
| 2. distance from stimulating point
28
where is the trigger zone?
at the axon hillocks
29
there are a lot of __________ at the trigger zone
Na+ channels
30
what needs to happen for action potential to occur?
graded potential reaches zone and is above the threshold voltage
31
what is another name for trigger point?
threshold potential
32
where does threshold potential happen?
near -55 mV
33
what are the two different types of graded potential additive effects?
spatial summation
| temporal summation
34
what is spatial summation?
graded potentials produce at the same time from different neuron
35
what is temporal summation?
graded potentials produced in the same neuron and close together in time
36
what happens when action potential begins?
it proceeds through the entire length to the axon
| all-or-none
37
what is excitability?
ability of a neuron to respond rapidly to a stimulus and fire an action potential
38
what are the four phases of action potential?
resting
rising
falling
hyperpolarization
39
what is conduction?
movement of action potential through axon at high speed
40
how does axon diameter influence conduction speed?
larger is faster than smaller
41
how does myelination influence conduction speed?
presence of myelin allows salutatory conduction which increase action potential transfer speed
42
what is a synapse?
anatomical connection between neurons and their targets
| -information transmission
43
what are the three regions of a synapse?
1. axon terminal on presynaptic cell
2. synaptic cleft
3. membrane on post synaptic cell
44
what are the different kinds of cells that a synapse can be?
neurons
| non-neuronal cell
45
what are the two different types of synapse?
electrical
| chemical
46
what is a electrical synapse?
electrical signal passes directly from cytoplasm of one cell to another
47
what does an electrical synapse use to pass the electrical signal?
gap junction
48
where does electrical synapse occur?
in neurons of CNS
| -also cardiac and smooth muscle
49
what is a chemical synapse?
electrical signal of presynaptic cell converted to chemical signal and sent across synapse
50
what does an chemical synapse use to pass the electrical signal?
neurohormones
| neurotransmitters
51
what are the majority of synapses?
chemical
52
where does action potential arrive?
axon terminal
53
what happens after action potential reaches the axon terminal?
voltage gated Ca2+ channel opens
54
what does Ca2+ trigger?
exocytosis of vesicles
55
what happens after exocytosis of vesicles is triggered?
NT enter the synaptic cleft
56
what do the NT do after they enter the synaptic cleft?
bind to receptor on post synaptic cell
57
what happens after NT bind to receptor on post synaptic cell?
there is a cell response
58
what are the different types of chemicals used for NT?
```
amines
purines
gases
peptides
lipids
AA
```
59
what are the different types of chemical signals?
paracrine
| autocrine
60
in the CNS how many different kinds of NT are there?
many different kinds
61
in the PNS what are the different kinds of NT are there?
ACh
norepinephrine
epinephrine
62
what are the amino acid NT that excite?
glutamate
| aspartate
63
what are the amino acid NT that inhibit?
glycine
| GABA
64
what are the amine NT?
```
serotonin
histamine
dopamine
norepinephrine
epinephrine
```
65
what are the peptide NT?
```
substance P
vasopressin
somatostatin
leu-enkephalin#
met-enkephalin#
beta-endorphin#
```
66
what are the purines NT?
adenosine
ATP
AMP
67
what are the gases NT?
NO
| CO
68
what are the different methods that can be used to clear NT from that synapse?
removal from ECF
inactivation by enzymes
diffusion
69
what are some example of removing NT from the ECF of a synapse?
1. bring back to the presynaptic cell
- norepinephrine
2. adjacent neurons/glial cells
- astrocytes
70
what are some example of inactivating NT by enzymes in a synapse?
ACh
| AChE
71
what are two different ways to integrate neural info transfer?
divergence
| convergence
72
what is divergence?
one presynaptic neuron + many postsynaptic neurons
73
what is convergence?
many presynaptic neurons + one postsynaptic neuron
74
what are the division of the nervous system?
central
| peripheral
75
what are the two components of the CNS?
brain
| spinal cord
76
what are the types of the neurons in the PNS?
afferent
| efferent
77
what does an afferent neuron do?
detect stimuli
| -sensory
78
what does an efferent neuron do?
trigger responses
| -motor
79
what is the CNS surrounded by?
meninges
80
what are meninges?
layers of protective membranes that are specific to the CNS
81
what is the structure of PNS?
composed of spinal and cranial nerves that carry action potentials toward (afferent) or away from (efferent) the CNS
82
what is a nerve?
bundles of axons with CT
83
what is a ganglion?
mass of PNS cell bodies
84
what is a preganglionic?
occurring before a ganglion
85
what is a postganglionic?
occurring after a ganglion
86
what does a ganglion form into?
knots
| swelling
87
what does a ganglion create?
satellite cells form supportive capsule around the cell bodies
88
what is a plexus?
groups of ganglia
89
what are the two different types of ganglia?
dorsal root
| autonomic
90
what is the general layout of the PNS and the spinal cord?
afferent enters through dorsal root ganglion
| efferent exits through ventral root
91
what is a root?
end of nerve
92
what is a dorsal root ganglia?
swellings on root
| -cell bodies of sensory neurons
93
what is a ventral root?
carries info from CNS to muscle/glands
94
what is gray matter?
unmyelinated nerve cell bodies, dendrites, axon terminals
95
what does gray matter contain?
contains dorsal, lateral, and ventral horns
96
what is white matter?
myelinated axons
| -bundles of axons known as tracts
97
what is an ascending tract?
carry sensory info to brain
| -dorsal, external lateral
98
what is a descending tract?
```
carry efferent (motor) signals from brain to spinal cord
-ventral, interior lateral
```
99
what are the subdivision of the PNS?
somatic
| visceral
100
what is somatic?
we are consciously aware of these and may have the ability to consciously control
-includes special senses
101
what is visceral?
responsible for involuntary sensation and control
| -associated with the ANS
102
what does the brain determine for somatic and visceral?
modality
location of stimulus
intensity of stimulus
103
what do all receptors use?
transduction
104
what do all receptors require?
stimuli to reach a threshold
105
what is transduction?
changes to an electrical signal
106
what happens when you get used to a stimuli?
threshold changes
107
where does the afferent somatic tract originate?
skin
certain viscera
-receptor activation triggers AP in sensory neuron
108
what are the four somatosensory modalities?
touch
temperature
nociception
propriocecption
109
what is touch?
most common receptor: corpuscles
110
what is temperature?
cold and warm receptors
111
what is nociception?
pain and itch
respond to noxious stimuli
cause tissue damage
112
what is proprioception?
awareness of body position in space
113
what are the special senses of the afferent tract?
olfactory
taste bud
retina
inner ear
114
what are special senses?
```
smell
taste
vision
hearing
equilibrium
```
115
what is a chemoreceptor?
oxygen
pH
various organic molecules such as glucose
116
what is a mechanoreceptor?
```
pressure
cell stretch
vibration
acceleration
sound
```
117
what is a photoreceptor?
photons of light
118
what is a thermoreceptor?
varying degrees of heat
119
what is responsible for voluntary motor control?
skeletal muscle
120
what are some examples of involuntary motor control?
cardiac muscle
smooth muscle
exocrine muscle
121
what is the efferent visceral also called?
autonomic nervous system
122
what are the two different parts of the autonomic system?
sympathetic
| parasympathetic
123
what is parasympathetic?
rest and digest
routine
day to day
124
what is sympathetic?
fight or flight
| stressful, threatening situation
125
what is antagonistic control?
one action opposes the other
126
what are some examples of tonic control?
sweat glands
| blood vessels
127
what are neurons connected by?
synapses
128
what is the origin of the sympathetic nervous system?
thoracolumbar region of the spinal column
129
what is the thoracolumbar region?
- begins with 1st thoracic vertebra
| - ends with 3rd/4th lubar vertebra
130
where do ganglia lie for the sympathetic nervous system?
close to the spinal cord
131
pre for sympathetic nervous system
short
132
post for sympathetic nervous system
long
133
what is the purpose of the parasympathetic nervous system?
to regulate normal body function during periods of reduced stress
134
what are some example of associated responses for the parasympathetic nervous system?
increased exocrine gland secretions
GI smooth muscle contractions
decreased heart rate
increased gut & pancreas enzyme secretion
135
what is the origin of the parasympathetic nervous system?
craniosacral region
136
what does the craniosacral region include?
```
- cranial nerves:
III - oculomotor
VII - facial
IX - glossopharyngeal
X - vagus 75%
- nerves of the sacrum are included as well
```
137
where do ganglia lie for the parasympathetic nervous system?
close to the target tissue
138
pre for parasympathetic nervous system
long
139
post for parasympathetic nervous system
short
140
what is DEF?
synapse between postganglion and target
141
what does the axon end have?
varicosities
142
what are varicosities filled with?
NT
143
what are sympathetic preganglionic autonomic neurotransmitters?
acetylcholine
144
what are parasympathetic preganglionic autonomic neurotransmitters?
acetylcholine
145
what are sympathetic postganglionic autonomic neurotransmitters?
norepinephrine
| epinephrine
146
what are parasympathetic postganglionic autonomic neurotransmitters?
acetylcholine
147
what are the two different pathways for PNS & SNS?
cholinergic
| adrenergic
148
what is cholinergic?
uses ACh
muscarinic - parasympathetic
nicotinic - preganglion only
149
what is adrenergic?
norephinphrine or epinephrine
150
what is alpha adrenergic?
the most common - norephinphrine
151
how many different kinds of beta adrenergic are there?
three
B1
B2
B3
152
what is beta 1 adrenergic?
heart
kidney
epinephrine = norepinephrine
153
what is beta 2 adrenergic?
blood vessels
smooth muscle of organs
epinephrine
154
what is beta 3 adrenergic?
adipose tissue
| norepinephrine
155
what is the adrenal medulla also known as?
modified ganglion
156
what are chromaffin cells?
modified postganglion neuron
157
what does the chromaffin cell do?
secretes epinephrine
158
what is muscle?
excitable, contractile tissue
159
what does muscle respond to?
electrical stimuli
160
what does electrical stimuli begin?
muscle contraction
161
what does it mean to be contractile?
shortens in response to an electrical stimulus
162
what are the three different types of muscle?
skeletal
smooth
cardiac
163
what % of the body is skeletal muscle?
40%
164
what % of the body is smooth and cardiac muscle?
10%
165
what are the characteristics of skeletal muscle?
highly organized
| fast contractions
166
for skeletal muscle where does the source of Ca2+ come from?
intracellular
167
what are the different fiber types for skeletal muscle?
Type 1
Type 2A
Type 2B
168
what is type 1 skeletal muscle fiber?
```
slow twitch (ST)
highly oxidative
```
169
what does it mean to be oxidative?
high endurance
| low power
170
what is type 2A skeletal muscle fiber?
```
fast twitch (FOG)
oxidative-glycolytic
```
171
what does it mean to beoxidative-glycolytic?
moderate endurance
| moderate power
172
what is type 2B skeletal muscle fiber?
```
fast twitch (FG)
glycolytic
```
173
what does it mean to be glycolytic?
low endurance
| high power
174
what are the different colors of the skeletal muscle fibers?
type 1: lots of myoglobin - very dark red
type 2A: light red
type 2B: pale pink
175
what is a different name for muscle cell?
muscle fiber
176
what is an example of type 1 skeletal muscle fiber?
posture
| low power endurance
177
what is an example of type 2A skeletal muscle fiber?
jogging
| movement
178
what is an example of type 2B skeletal muscle fiber?
jumping
179
what are the characteristics of smooth muscle?
unorganized contractile protein structure
slow contractions
hormonal influence
180
for what organs and tubes does smooth muscle form walls for?
blood vessels
GI tract
repro tract
specialized organs
181
for smooth muscle where does the source of Ca2+ come from?
extracellular
182
what does smooth muscle also have?
gap junctions
183
what doe gap junctions allow for?
for skeletal muscle where does the source of Ca2+ come from?
184
what are the characteristics of cardiac muscle?
```
similar to skeletal & smooth muscle
organized
intermediate contractions
epinephrine influence
exclusive to the heart
```
185
what are the shared features between cardiac and smooth muscle?
extracellular Ca2+ needed
| cells connected by gap junctions
186
where are gap junctions found?
intercalated discs
187
what are some similarities with all the types of muscle?
1. muscle contractions always begin through some form of excitation-contraction coupling
2. Ca2+ plays a role in ALL muscle contraction
3. actin & myosin are the primary contractile proteins
188
what is fascicle?
bundle of adjacent muscle fibers
189
what is myofibril?
intracellular bundles of contractile and elastic proteins
190
what is sarcolemma?
cell membrane
191
what is sarcoplasmic reticulum?
modified ER
| releases Ca2+
192
what are T-tubules?
allow action potential to move rapidly into fiber & release Ca2+ from sarcoplasmic reticulum
193
what is epimysium?
connective tissue wrapped around skeletal muscle
194
what is perimysium?
connective tissue around fascicle
195
what is endomysium?
cell membrane/sarcolemma
196
what are myofibrils?
contractile structures
197
what are contractile proteins?
actin
| myosin
198
what are giant accessory proteins?
titin
| nebulin
199
what are regulatory proteins
tropomyosin
| troponin
200
what is actin?
smaller protein
| forms thin filaments
201
what are the two subtypes of actin?
g-actin
| f-actin
202
what is g-actin?
globular
203
what is f-actin?
filament
204
what is myosin?
very large protein
| forms think filament
205
what is tropomyosin?
wrapped around actin filament
| blocks binding sites for myosin on the actin filaments
206
what does troponin connect to?
connects tropomyosin to actin filaments
| binds to start tropomyosin movement
207
what is troponin responsible for?
moving tropomyosin during excitation-contraction coupling
208
what is titin?
largest protein (25,000 AA)
stabilizes position of contractile filament
elastic
209
what is nebulin?
inelastic
lies along actin
attaches to z-dish
210
what does nebulin allow for?
allow proper alignment of filaments within sarcomere
211
what is an origin?
end of muscle that attaches to more stationary bone
| proximal
212
what is an insertion?
muscle attached to more mobile, distal bone
213
what is a tendon?
bone to muscle attachment
214
what is a flexor?
muscle that brings bones closer together
215
what is an extensor?
muscle that moves bones away from each other
216
what are flexor-extensor pairs known as?
antagonistic muscle groups
| ex: biceps brachii & triceps brachii
217
where does the z-line move?
toward m-line
218
where does actin move?
toward m-line
219
what happens to i-band?
gets smaller
220
what happens to h-zone
gets smaller
221
what are contractions?
creation of tension in a muscles
222
what does the active process of contractions require?
ATP
223
what is relaxation?
release of tension created by contractions
224
what is muscle tension?
force created by a contracting muscle
225
what is a load?
weight/force that opposes contractions
226
what are the three major steps in muscle contractions?
1. events at neuromuscular junctions
2. excitation - contraction coupling
3. contraction - relaxation: sliding filament theory
227
what is the sliding filament theory?
a band does not change length with contraction
- myosin shortening does not occur
- instead, actin & myosin slide past each other
228
why can muscles create force without movement?
actin and myosin slide past each other
229
what are some characteristics of somatic motor division?
always excitatory
cell bodies in ventral horn
no ganglion
branching of axon terminals (clusters)
230
what are neuromuscular junction?
synapse of neuron on muscle fiber
231
what is the autonomic system?
lateral
232
what is the motor end plate?
ligand-gated Na+ channel
233
what does a somatic motor neuron release?
ACh at neuromuscular junction
234
what does the net entry of Na+ through ACh receptor channel initiate?
muscle AP
235
what does muscle AP lead to?
excitation - contraction coupling
236
what is excitation - contraction coupling?
muscle APs initiates Ca2+ signals that activates muscle contractions
237
what is AP conduction?
similar to AP in axon but slower
238
how is the release of Ca2+ from SR initiated?
AP moves down T-tubules
