Exam 3 Flashcards
1
Q
autonomic nervous system
A
two branches- sympathetic and parasympathetic
involuntary control of organ function
organ contraction, HR/BP, stress response
2
Q
ANS in relation to daily acitivity
A
sympathetic branch- associated with stress and physical activity, mental/emotional stress, exercise
parasympathetic- associated with rest and “slow” background activity, increased digestion, lower overall activity
3
Q
ANS neuron configuration
A
2 neuron series- preganglionic neuron and postganglionic neuron
4
Q
where is the cell body in a preganglionic neuron
A
cell body located within CNS
5
Q
where is the cell body of a postganglionic neuron
A
cell body is located within autonomic ganglia
sympathetic: sympathetic chain ganglia parasympathetic: terminal ganglia, near or on surface of effector
6
Q
2 neuron series sympathetic
A
start in spinal cord
preganglionic neuron goes to postganglionic neuron in sympathetic chain ganglia
postganglionic neuron goes to
effector
7
Q
2 neuron series parasympathetic
A
start in brain stem
preganglionic neuron goes way down to postganglionic neuron at terminal ganglia
postganglionic neuron goes to effector
8
Q
where are NTs released in 2 neuron series
A
at preganglionic to postganglionic and at postganglionic to effector
9
Q
autonomic neurons and their NTs
A
different autonomic neurons secrete different NTs
neuron type based on the type of NT that is released
10
Q
types of NTs released
A
cholinergic neuron
adrenergic neruon
11
Q
cholinergic neuron releases
A
acetylcholine
12
Q
adrenergic neuron releases
A
norepinehprine
13
Q
receptors for specific NTs
A
cholinergic
adrengeric
14
Q
cholinergic receptor
A
binds acetylcholine
15
Q
2 types of cholinergic receptors
A
muscarinic
nicotinic
16
Q
nicotinic receptor
A
on postganglionic neuron
both sympathetic and parasympathetic
17
Q
muscarinic receptor
A
on surface of effector, mainly in parasympathetic
18
Q
adrenergic receptor
A
binds norepinephrine and epinephrine
19
Q
2 types of adrenergic receptors
A
alpha adrenergic receptor
beta adrenergic receptor
20
Q
alpha adrenergic receptor
A
responds more to norepinephrine than epinephrine
21
Q
beta adrenergic receptor
A
respond equally to norepinephrine and epinephrine
22
Q
preganglionic neurons: NTs effects
A
preganglionic NTs secreted affects postganglionic neuron
in both sympathetic and parasympathetic
secretes acetylcholine
23
Q
postganglionic neurons: NTs and effects
A
postganglionic NTs affect effector organs
in parasympathetic- cholinergic neurons- secrete acetylcholine in response to preganglionic stimulation
in sympathetic- adrenergic neurons- secrete norepinephrine in response to preganglionic stimulation
24
Q
sympathetic prgn and pgn pathway
A
Prgn- cholinergic neuron secretes Ach binds to nicotinic receptor on pgn- adrenergic neuron secretes norepinephrine binds to alpha or beta adrenergic receptors on effector
25
parasympathetic prgn and pgn pathway
```
prgn- cholinergic neuron
secretes Ach
binds to nicotinic receptor on
pgn- cholinergic neurons
secretes Ach
binds to muscarinic receptor on
effector
```
26
regulation of ANS responses
many effector organs have input from sym and psym divisions
1 antagonistic effects
2 coordinated response
27
antagonistic effects
sympathetic and parasympathetic produce opposite effects
| one may have a stronger effect than the other
28
coordinated response
1 one division can coordinate activity of multiple different structures
2 both divisions can coordinate activity of different structures for the same purpose
29
eyes sympathetic vs parasympathetic
sympathetic- pupil dilation
| parasympathetic- pupil constriction
30
Bronchi sympathetic vs parasympathetic
sympathetic- bronchodilation
| parasympathetic- bronchoconstriction
31
GI tract sympathetic vs parasympathetic
sympathetic- decrease digestion
| parasympathetic- increase digestion
32
heart sympathetic vs parasympathetic
sympathetic- increase HR, BP, force of contraction
| parasympathetic- decrease HR, BP, force of contraction
33
blood vessels sympathetic vs parasympathetic
sympathetic- mostly vasoconstriction (alpha adrenergic receptors), increase BP, some vasodilation (beta adrenergic receptors)
parasympathetic- vasodilation of some blood vessels, very little effect on systemic BP
34
response to stress
mass activity of sympathetic division- activates adaptations to escape stressor
increase BG, HR, blood flow to muscles, respiratory rate, inhibition of non-essential activities (digestion, reproduction)
fast acting response
35
system (whole body) effects
more noticeable with sympathetic stimulation
some preganglionic sympathetic neurons stimulate adrenal medulla
Ach goes to adrenal medulla, adrenal medulla secretes epinephrine, epinephrine enters circulation and affects functions of other organs
36
pharmacology
receptor agonists
| receptor antagonists
37
receptor agonists
drugs that bind to receptor and mimics effects of endogenous NTs
sympathomimetic drugs
parasympathomimetic drugs
38
receptor antagonists
drugs that bind to receptor and block effect of endogenous NTs
39
innervation of vasculature
nervous stimulation- motor neurons
blood vessels- capillary beds around muscle fibers, supplied and drained by arteries and veins
delivery of oxygen rich blood
40
muscle fibers
composed of many myofibrils
41
myofibrils
composed of actin myofilaments (thin filament) and myosin myofilaments (thick filament), titan
42
sarcolemma
plasma membrane of muslce fiber
43
sarcoplasma
cytoplasm of muscle fiber
44
sarcomere
made up of action and myosin joined end to end
45
what is the smallest contractile structure
sarcomere
46
a band
length of myosin, some overlapping of myosin and actin
47
i band
contain actin and z disk
48
actin structure
F actin- 2 strands in a helix
G actin- has an active site for binding myosin heads
troponin
tropomyosin
49
troponin
3 subunits, 1 binds to g- actin, 1 binds to tropomyosin, 1 has binding site for Ca++
50
tropomyosin
sits within indention of helix
| at rest- blocks active sites of g- actin
51
myosin
2 myosin heavy chains forming a rod
hinge region- allows bending of myosin heads
myosin heads- capable of binding to g-actin
4 myosin light chains- attached to myosin heads, regulatory function
52
myosin heads
| cross bridge formation
binding of myosin head and actin molecule
facilitates contraction of muscle- hinge region, bending and straightening
heads have ATPase that does ATP hydrolysis that releases energy for bending of hinge
53
sliding filament model
actin myofilament sliding over the myosin myofilament shortening of sarcomere this translates to muscle contraction
54
sliding filament model
| relaxation
lengthening of sarcomere
| external forces- contraction of antagonist muscle or gravity
55
neuromuscular junction/ motor end plate
synapse of motor neuron on muscle fiber
Ach secretion by motor neuron
Ach binds to ligand gated ion channels on muscle fiber
Na+ rushes into muscle, depolarization of muscle fiber
56
excitation- contraction coupling
```
conversion of neural signals into physical process of contraction
t-tubles
sarcoplasmic reticulum (SR)
```
57
steps to muscle contraction
neuron action potential- muscle action potential- contraction
58
t-tubules
| transverse tubules
infoldings of sarcolema
59
```
sarcoplasmic reticulum (SR)
what is it
what does it store and release
```
modified smooth ER, stores Ca++, release Ca++ into sarcoplasm in response to muscle AP
60
muscle fiber AP and conduction
AP of muscle fiber occurs at NMJ
AP propagates along sarcolemma and along t-tubules
this causes voltage gated Ca++ channels on SR to open
Ca++ flows out of SR, Ca++ binds to troponin
troponin molecules change conformation/position
this causes tropomyosin to move
active sites on G action exposed
myosin heads bind to G actin (cross bridge formation)
sliding filament and muscle contraction occurs
when complete Ca++ re enters SR, restoration of filaments to original position
61
cross bridge cycling
repeated interaction of myosin head and actin myofilament
cross bridge formation
energy stored in myosin heads facilitate sliding filaments
ATP binds to myosin heads, head is released
ATP hydrolyzed, energy stored for next round
happens many times in a single contraction
62
relaxation requires energy
muscle relaxation, Ach secretion at NMJ stops
stops APs along sarcolemma, stops Ca++ release from SR
movement of Ca++ back into SR, energy dependent process
Ca++ actively pumped back into SR (requires ATP)
restoration of membrane potential- Na+/K+ pump (requires ATP)
63
whole muscle physiology
| motor unit
consists of single motor neuron and all muscle fibers it innervates
64
what does a motor unit respond to stimulation as
single unit
65
what does each muscle fiber have for a motor neuron
action potential
66
muscle twitch
single contraction of muscle in response to stimulus
| AP in one or more of muscle fibers
67
phases of muscle twitch
lag
contraction
relaxation
68
force of contraction
all or none
graded muscle response
how to increase force of contraction- summation or recruitment
69
all or none
| force of contraction
threshold must be reached for contraction to occur
70
graded muscle response-
| force of contraction
different strength of contraction
71
to increase force of contraction
force of contraction
summation
increase force via more APs
72
to increase force of contraction
force of contraction
recruitment
increase number of muscle fibers/motor units that are contracting
73
frequency summation
stimuli applied in quick succession before muscle fully relaxed with each stimulus tension increasing
increased frequency of APs
74
complete tetnus
very rapid, high frequency continuous stimulation with no relaxation, causes sustained contraction of muscle
75
what does increased frequency of APs do
Ca++ accumulating in muscle fibers
| results in increased force of contraction
76
types of muscle contractions
isometric
| isotonic
77
isometric muscle contraction
no noticeable change in length of muscle, no movement of joint
increase in tension/force in muscle during contraction
78
example of isometric contraction
maintenance of posture
79
isotonic muscle contraction
tension produced by muscle is constant, change in length of muscle, movement occurs
80
example of isotonic muscle contraction
moving limbs or fingers
81
types of isotonic muscle contractions
concentric contraction
| eccentric contraction
82
concentric contraction
working muscle shortens, tension in the muscle great enough to overcome the load
83
eccentric contraction
working muscle lengthens, tension being maintained against the load
84
fatigue
diminished ability to generate force
85
what causes fatigue
reduced neural stimulation
depletion of substrates (ATP or glycogen)
accumulation of metabolites (lactic acid, Mg++, ROS) may interfere with Ca++ release from SR
86
muscle fiber types and contraction
slow twitch
| fast twitch
87
slow twitch muscle fibers/ type 1
slower contraction, slower response to nervous stimulation, smaller fiber diameter, extensive vasculature, higher mitochondria and myoglobin concentrations, dark appearance
slow ATPase activity on myosin heads, more resistant to fatigue
88
fast twitch muscle fiber/ type 2
faster response to nervous stimulation, fast ATPase activity on myosin heads, less vasculature, less myoglobin and mitochondria, lighter color, higher glycogen content, more susceptible to fatigue
89
what muscle fiber is for endurance
slow
90
what muscle fiber is for olympic lifting
fast
91
heat production
ATP metabolism
| shivering thermogenesis
92
ATP metabolism
during muscle contraction- release of heat normal body temperature maintenance, increase with more contraction
93
shivering thermogenesis
uncoordinated involuntary contraction of skeletal muscle, initiated by hypothalamus in response to signals from skin and spinal cord, generation of heat in response to cold air temperature
94
blood cycle through heart
```
1 O2 poor blood carried in superior and inferior vena cava
2 enters RA
3 passes through tricuspid valve
4 enters RV
5 passes through pulmonary SL valve
6 carried through pulmonary arteries to lungs
7 O2 rich blood carried through pulmonary veins
8 enters LA
9 passes through bicuspid valve
10 enters LV
11 passes through aortic SL valve
12 carried to body by aorta
```
95
coronary circulatioin
carries oxygen rich blood to the heart itself and drains heart of oxygen poor blood
96
myocardial infraction
"heart attack"
| necrosis of myocardium due to one or more coronary blockages
97
"widow maker"
blockage of left anterior descending artery
98
characteristics of cardiac muscle
cardiac myocytes
99
cardiac myocytes
striated, rich in mitochondria, elongated and branched, excitatory and conductive, conduction of AP
100
cardiac muscle functional unit
```
intercalated disk
desmosomes
gap junctions
cardiac syncytium
"all or none" principle
synctia
```
101
intercalated disks
form close contact with adjacent cells
102
desmosomes
hold contact during contraction
103
gap junctions
free flow of cytoplasm for AP conduction
104
cardiac syncytium
when one cell becomes excited, all cells become excited and heart contracts as one unit
105
two syncytia of cardiac muscle
atrial syncytium
| ventricular syncytium
106
types of cadiac myocytes
contractile
| autorhythmic
107
autorhythmic myocytes
```
autonomic foci
sinoatrial node
atrioventricular node
bundle of his
(left and right bundle branches)
purkinje fibers
```
108
autorhythmic foci
autorhythmic cells that fire at their own intrinsic rates
109
what does SA node do
spontaneously generates APs at regular intervals of 70 BPM
110
spread of excitation follows specific sequence
SA node fires- signal spreads across atria (.04s), atria contracts
signal delay (.11s) at AV node- allows atria to fully empty
signal reaches ventricles (.08s)
purkinje fibers stimulate ventricles to contract
force of ventricular contraction pushes blood through arteries
111
heart block
first degree
second degree
third degree
112
first degree heart block
impulses to ventricles slightly delayed
113
first degree heart block
impulses to ventricles slightly delayed
114
first degree heart block
impulses to ventricles slightly delayed
115
second degree heart block
impulses intermittently blocked
116
third degree heart block
no impulses from atria reach ventricles
| atrial pacemaker- medical device that produces electrical signals
117
action potential in contractile myocytes
long refractory period compared to skeletal muscle
| prevention of tetanus
118
what is the RMP for skeletal and contractile myocytes
-90 mV
119
fast Na+ channels
respond quickly to stimulation
120
L- type channels (long opening/slow)
respond slowly to stimulation
| l- type Ca++ channels
121
AP in contractile myocyte graph
```
phase 0- depolarization,
phase 1- early repolarization
phase 2- plateau
phase 3- regular repolarization
phase 4- RMP
```
122
phase 0
| AP in contractile myocytes
fast Na+ channels open, Na+ rushes in
| at -40 mV l- type Ca++ channels open, small steady influx of Ca++
123
phase 1
early repolarization
AP in contractile myocytes
some K+ open briefly, K+ out
124
phase 2
plateau
AP in contractile myocytes
l- type Ca++ open, Ca++ in, K+ open, K+ efflux
| counter balance with Ca++ and K+ at 0 mV
125
phase 3
regular repolarization
AP in contractile myocytes
Ca++ closed, K+ open, K+ out
126
action potential in autorhythmic myocytes
never at rest, SA node "pacemaker potential", positive drift from -60 mV to -40 mV
allows for "readiness" to fire and spontaneous depolarization
127
three causes of pacemaker potential
1 increased influx of Na+- "funny channels" open in response to hyperpolarization, allows Na+ in, pushes up RMP
2 decrease efflux of K+- K+ channels close during hyperpolarization of AP, limiting K+ leaving cell (pushes up voltage)
3 differential influx of Ca++ ions- some Ca++ channels open before threshold, pushes voltage to threshold, once at threshold, l- type Ca++ channels open, producing AP
128
AP in autorhythmic myocytes
threshold- -40 mV
phase 1- pacemaker potential
phase 2- depolarization
phase 3- repolariztion
129
phase 1
pacemaker potential
AP in autorhythmic myocytes
in hyperpolarized state "funny" Na+ channels open, leads to Na+ coming into cell, closed K+ channels reduced K+ from leaving cell, as threshold approached some Ca++ channels open briefly, Ca++ moves into cell, threshold is reached
130
phase 2
depolarization
AP in autorhythmic myocytes
l- type Ca++ channels open, Ca++ in
131
phase 3
repolarization
AP in autorhythmic myocytes
Ca++ channels close, K+ channels open, K+ efflux
132
electrocardiogram (ECG)
record of electrical activity of heart
| electrical events correlate with physical activity
133
p wave
atrial depolarization
| onset of atrial contraction
134
QRS complex
ventricular depolarization
| onset of ventricles contraction
135
t wave
ventricular repolarization
| precedes ventricles relaxing
136
fibrillation "quiver"
atrial fibrillation
| ventricular fibrillation
137
atrial fibrillation (A-fib)
irregular contraction of atria
compatible with life and full activity, irregular spacing of QRS complex and no p waves
treat with beta blockers (block beta-adrenergic receptors) to drop HR and reestablish SA node rhythm
138
ventricular fibrillation (V-fib)
emergency, results in "cardiac arrest"
ventricular twitches- not proper contractions
loss of consciousness within seconds
fatal unless immediate intervention (CPR and defibrillation)
139
defibrillator
applies strong electrical current that depolarizes most/entire heart at once, gives SA node time to re-establish normal sinus rhythm
140
cardiac cycle
pattern of contraction and relaxation of heart chambers initiated by spontaneous AP from SA node
atria- primer pumps- push blood into ventricles
ventricles- power pumps- force blood into pulmonary system and systemic circulation
diastole- relaxation- blood fills chambers
systole- contraction, blood pushed out of chambers
141
cardiac cycle
| steps
1- passive ventricular filling- blood entering left and right ventricles through gravity
SA node
2 atrial systole- pushes rest of blood into ventricles
AV node to purkinje fibers
ventricular systole (early)- pressure increases in ventricles, causes AV valve to close, semilunar valves closed, no movement of blood
ventricular systole (late)- pressure strong enough to open SL valves, blood ejected into great arteries
ventricular diastole- ventricles relax
142
intrinsic regulation of heart
cardiac output- amount of blood pumped per minute
stroke volume- volume of blood pumped per beat
CO= HR*SV
changes in HR and SV leads to changes in CO
143
starling's law of the heart
stroke volume of LV increases as volume of LV increases due to preload (stretch) of cardiac muscle
greater preload- greater force of contraction
144
scenario
| starling's law of the heart
vigorous exercise increases venous return of blood to heart
more blood filling chambers increases preload
increased preload increases stroke volume
healthy heart muscle is like a spring
145
extrinsic regulation of heart (autonomic ns)
PANS- vagus nerve, synpase a SA node and AV node
Ach binds to muscarinic receptors- inhibitory influences
SANS- project to heart as cardiac nerves, nerves synapse at SA node, AV node, and myocardium, NE binds to adrenergic receptors- excitatory influence,
also epinephrine from adrenal medulla binds to adrenergic receptors- excitatory influence
