Chapter 9&10 - Muscle Flashcards
(155 cards)
1
Q
What is coupling?
A
Sequence of events by which an action potential along the sarcolemma leads to sliding of protein myofilaments
2
Q
Follow depolarization to the cisternae
A
First there is excitation with electricity…. By depolarization
Then this is coupled to sliding filaments of muscle contraction
2
Q
Follow depolarization to the cisternae
A
Neuron depolarization: Na+ enters neuron cytoplasm in small steps to end of neuron,synaptic vesicles lyse at membrane of neuron, NT[ach] released into synaptic cleft of synapse
Synaptic cleft neurotransmitter transmission : Ach diffuses high to low, neuron to muscle
Skeletal muscle cell depolarization: NT/Ach binds @ motor end plate & starts local ion changes, opening Na+ channels-> muscle cell inside becomes slightly less negative=local graded potential
Depolarization/action potential sweeps down sarcolemma into T-tubule into cell [1-2 millisec]
Soooo cisterns release Ca++ which exits into cytoplasm
3
Q
What is the sliding filament theory?
A
Thin filaments slide past thicker myosin so that actin & myosin overlap to a greater degree-> shortening of muscle
Heads of myosin attach to actin, and de attach->ratcheting motion;requires Ca++ [Ca++ rearranges troponin/tropomyosin with actin, freeing it to slide]
4
Q
What is contraction?
A
Ca++ binds to troponin which then changes shape
Myosin binding sites on actin exposed
actin is “let go” & it slides into myosin
actin binds to myosin heads in cross bridges; using ATP to de-attach=ratcheting motion
muscle shortens=contraction
5
Q
Explain the Cross Bridge Cycle, specific detail of myosin changes
A
- Cross bridge attachment (energized myosin attaches to actin)
- Working stroke (ADP and Pi are released, myosin head binds & pivots, pulling on actin)
- Cross bridge detachment (after new ATP binds to head, actin is let go)
- “Cocking” of myosin head (hydrolysis of ATP to ADP and Pi by ATPase gives energy and myosin head returns to high energy position, “cocked”)
Contraction (SLIDING) continues as long as there is Ca++ and ATP
6
Q
How much do muscles shorten during contraction?
A
Muscles shorten 30 to 35%
7
Q
What are the major events of relaxation?
A
Acetylcholinesterase (ACHase) on sarcolemma decomposes Ach
Muscle no longer stimulated
Ca++ moves from cytoplasm into sarcoplasmic reticulum
cross bridges break
actin slides back out of myosin
8
Q
2 major facts about RELAXATION
A
Muscle lengthens
Troponin & tropomyosin hold actin
9
Q
Relaxation & Contraction
A
Relaxation: when Ca++ is low in the cell cytoplasm [high in cisterns], muscle is relaxed & tropomyosin blocks actin
Contraction: when Ca++ rises in the cell cytoplasm, it binds to troponin, it changes shape, tropomyosin moves, and actin is freed to slide
10
Q
Where does muscle get ATP for cross bridging in contraction?
A
- stored ATP in muscle cell
- stored creatine changed to creatine phosphate in muscle cell
These last a few seconds and cell must make ATP from glucose
11
Q
What is Direct phosphorylation?
A
Coupled reaction of creatine phosphate (CP) and ADP, No O2 use, 15 seconds of energy
12
Q
What is Anaerobic pathway?
A
Glycolysis and lactic acid formation, No O2 use, 30-40 seconds of energy
13
Q
What is Aerobic pathway?
A
Aerobic cellular respiration, O2 REQUIRED, hours of energy!!!!!!!!!!!!!
14
Q
In 6 seconds of short duration….
A
ATP stored in muscles is used first
15
Q
In 10 seconds of short duration….
A
ATP is formed from creatine phosphate and ADP
16
Q
in 30-40 seconds short duration…
A
Glycogen stored in muscles is broken down to glucose, which is oxidized to generate ATP (anaerobic)
17
Q
Hours pf Prolonged duration exercise…
A
ATP is generated by breakdown of several nutrient energy fuels by aerobic pathway
18
Q
How does muscle get glucose?
A
Liver and muscle change glycogen to glucose & delivers it to muscle through blood
19
Q
How does glucose diffuse into muscle cell?
A
From BLOOOOOd
20
Q
What in cytoplasm changes glucose to pyruvic acid (3C)?
A
enzymes
21
Q
Glycolysis in muscle cell yield how many ATP?
A
2
22
Q
what in glycolysis in muscle cell diffuses into mitochondria?
A
pyruvic acid
23
Q
in krebs cycle/aerobic respiration in muscle cell….what changes to acetyl co-A?
A
pyruvic acid
24
in krebs cycle/aerobic respiration in muscle cell....what enters krebs cycle?
co-A
25
in krebs cycle/aerobic respiration in muscle cell....what diffuses into cell?
O2
26
in krebs cycle/aerobic respiration in muscle cell....what enters mitochondria & Krebs cycle couple with oxidative phosphorylations?
O2
27
in krebs cycle/aerobic respiration in muscle cell....what are the products? (4) --->?
```
heat
CO2 gas
36 ATP
H+
------------------->>>>>>> H2O
```
28
How is O2 supplied for Krebs cycle?
1 Hemoglobin, blood protein in red blood cell releases oxygen to muscle cell
2 myoglobin a protein in muscle cell stores O2 from blood in muscle cell temporarily and releases O2 to cytoplasm when blood vessel clamped in contracting muscle
29
What happens when O2 to cell runs out? EPOC
no more krebs cycle
EPOC = oxygen debt = excess post exercise oxygen consumption
when no O2, pyruvic acid decreases
pyruvic acid cannot diffuse out of cell to blood so pyruvic changes to lactic acid to diffuse out of cell to blood
blood carries lactic acid to liver
30
EPOC/ oxygen debt in liver
Liver runs glycolysis backwards: changes lactic acid back to pyruvic acid & adds ATP to change it back to glucose
Therefore liver uses its ATP
31
EPOC/oxygen debt in liver ..... body in oxygen debt until...
1 liver replaces its ATP
2 muscle replaces its creatine phosphate & original ATP
3 Mb O2 reserves replenished
4 glycogen replenished
32
Contraction of a whole skeletal muscle, muscle tension
force exerted by contracting muscle on an object
33
contraction of a whole skeletal muscle, load
force exerted on the muscle by the weight of the object
34
contraction of a whole skeletal muscle,motor unit
a motor neuron and all the branches to muscle fibers it supplies
35
contraction of a whole skeletal muscle, explain muscle and motor units
muscles exerting fine control have SMALL motor units, large motor units to large muscles with less precise control, like hip
36
Force of muscle contraction affected by.....
1 number and size of contracting muscle cells
2 frequency of stimulation
3 degree of muscle stretch
THE GREATER THE LOAD THE SLOWER THE CONTRACTION
37
muscle twitch
response of motor unit to single action potential
38
threshold stimulus
minimum strength stimulus needed for contraction, anything less than threshold gives no contraction
39
all-or-none response
if muscle gets threshold stimulus, contracts completely
if muscle gets greater than threshold, still contracts exactly same as threshold
no PARTIAL CONTRACTION OF ISOLATED MUSCLE
40
MYOGRAM
graph of single contraction of isolated muscle lasting fraction of second
41
phases of twitch
```
latent/lag = period between threshold stimulus until contraction begins
contraction= beginning to max contraction
relaxation= max contract to NO contract
REFRACTORY = period after stimulation & contraction in which muscle will not respond. can stimulate w threshold stimulus and no response
```
42
tetany
sustained contraction; no relaxation period in skeletal
43
fatigue
inability to contract muscle, increased LACTIC ACID; low ph, high K+ usually not lack of ATP
44
cramp
prolonged spasms, LACK OF ATP, low ca++, drink h2O
45
tone
relaxed muscles always slightly contracted
46
rigor mortis :0
rigor of death
muscles stiffen 3-4 hrs after death
peak rigidity TWELVE HOURS
Ca++ rises in muscle cells
NO ATP FOR DETACHMENT OF ACTIN FROM MYOSIN
rigidity decreases over 48-60 hours by bacterial degradation
47
prime mover
muscle in a group responsible for most movement
48
synergist
muscle in a group that assists prime mover
49
antagonist
muscle in group that opposes prime mover
50
origin
point of attachment of one end of muscle that is relatively immobile
51
insertion
point of attachment of one end of muscle that moves
52
insertion moves toward origin during what?
contraction
53
origin-insertion nomenclature
stern0cleidomastoid , origin = first - sternum
| insertion = last = mastoid process
54
points of origin in biceps
2 heads of origin (attachment)
55
size in pectoralis major is what?
large
56
_____ maximus and minimus?
big and little what? i like big ... butts
57
deltoid is what shape? trapezius is what shape?
triangle; trapezoid
58
the extensor digitorum does what action?
EXTENDS idiot
59
flexor digitorum probably...
flexes?
60
name the 2 types of contraction
isotonic
| isometric
61
isotonic =
muscle shortens with contraction
62
isometric =
muscle stays the same length with contraction
63
velocity of contraction (3)
slow OXIDATIVE fibers
fast OXIDATIVE fibers
fast GLYCOLYTIC fibers
64
immobilization of muscles lead to what?
cell wasting or atrophy
65
resistance exercise cause what to happen to skeletal muscle?
hypertrophy or cell enlargement
66
regular aerobic exercise leads to what 2 things?
increased ENDURANCE, increased STRENGTH
67
Central nervous system
brain and spinal cord
68
peripheral nervous system
nerves that connect central nervous system to rest of body, afferent sensory and efferent motor (2) somatic and ANS
69
automatic nervous system
one efferent part of PNS, divided into sympathetic and parasympathetic, that maintains unconscious homeostasis
involuntary
70
2 types of nerve tissue
neuron
| neuroglial cells
71
neuron
basic functional unit
excitable; reacts to change
transmits messages
72
neuroglial cells
accessory cells
variety of support function
no impulse transmission
73
central nervous cells
```
neuron
neuroglial (half mass of brain small cells)
astrocyte (star)
oligodendrocyte
microglia
ependymal cell
```
74
astrocyte (star)
support to neuron
exchange with blood capillaries for neuron
help form the blood brain barrier
synapse formation
75
oligodendrocyte
makes myelin sheath (CNS ONLY)
76
microglia
phagocyte
| assist injured neurons
77
ependymal cell
lines ventricles of brain
| help circulate cerebrospinal fluid
78
PNS cells
neuron
| neuroglial - satellite cell, schwann cell
79
schwann cell
makes myelin sheath (PNS ONLY)
| used in regeneration of axons
80
anatomical types of neurons
multipolar
bipolar
unipolar
81
multipolar neurons
```
many cytoplasmic extensions from cell body - 3 or more
most common (99%)
major type in cns
function = motor or association
```
82
bipolar neurons
```
2 extensions from cell body
function = special sensory (eye, olfactory)
```
83
unipolar neurons
```
one extension from cell body
function = sensory (GANGLIA)
```
84
functional types of neurons
1 sensory
2 association = interneuron
3 motor
85
sensory neurons
sensory receptors send messages through PNS to CNS (afferent)
most unipolar
sensory from organs = visceral afferent
86
association neurons or interneuron
in CNS
transmits messages from 1 part of CNS to another part of CNS
multipolar
87
motor neuron
from CNS to PNS (EFFERENT)
multipolar
carry messages to effector = muscle & gland
88
2 main parts of motor neuron
somatic nervous to skeletal muscles
| autonomic nervous to smooth, cardiac muscles, and glands
89
neuron characteristics
amitotic
extreme longevity
high metabolic rate (ONLY SURVIVE FEW MINUTES WITHOUT OXYGEN)
90
neuron structure (PNS OR CNS)
```
cell body with neuroplasm and organelles
no centrioles... used in mitosis
golgi well developed
endoplasmic reticulium = NISSL BODIES
nucleus: no reproduction after maturity
PIGMENT INCLUSIONS - held in vacuole sac, lipofuchsin pigment is a sign of aging
```
91
cell body has cytoplasmic extensions...
dendrite, axon
92
clusters of cell bodies
in cns= nuclei
| in pns= ganglia
93
bundles of cell processes
in cns= tracts
| in pns= nerves
94
detail dendrites
short, highly branched
enormous surface area for receiving signals from other neurons
receptor for message= graded potential; conducts into cell body
95
detail of axon
long and singular
1 per cell
arises from axon hillock (trigger zone) near cell body
generates and conducts messages away from cell body
ex motor axons controlling great toe 3-4 feet long~@!@@@@@@!!!!!!!!
96
more detail of axon
fine branching @ end is PRE SYNAPTIC terminal with synaptic knobs containing neurotransmitter NT that can diffuse into ECF when released
has ALL the organelles of cell body and dendrite EXCEPT NISSL BODIES AND GOLGI, for protein packaging... so quickly deteriorates if cut
97
use of what in axon aids movement of molecules in long axon in either direction?
use of microtubules, communication in cell
98
certain viruses like polio can use this to invade cell body?
use the axon's same retrograde movement
99
presynaptic terminal @ tip of axon
contain vesicles with neurotransmitter (NT)
| releases NT to diffuse across synapse to next dendrite on 2nd neuron = synaptic transmission
100
synaptic transmission
dendrite neuron #1 -> cell body neuron #1-> axon neuron #1->
nt diffuses ->
dendrite neuron #2->cell body #2-> axon #2
101
role of myelin in PNS
white lipid-protein membrane of schwann cell wrapped around axon called myelin sheath (DENDRITES NEVER WRAPPED)
EXTERNAL TO MYELIN SHEATH is neurilemmal sheath = rest of schwann cell, cytoplasm, nucleus, membrane
102
neurilemmal sheath in PNS
increases impulse conduction
| allows regeneration
103
myelin and impulse conduction
as increased myelin, increase speed of transmission
myelin is in patches on axon, each patch a SWANN CELL
- naked axon in between is a node of rangier
104
saltatory conduction
transmission can jump from node to node
105
white matter in PNS
regions of brain and cord with dense myelination
106
grey matter in PNS
cell bodies and unmyelinated fibers
107
myelin & regeneration in PNS
if axon is severed, all except sheath distal to cut is DECOMPOSED
proximal axon sprouts cytoplasm & seeks tube of sheath for path to muscle
if sprout enters sheath, then axon can re-grow
sheath shows path to growing axon until finds muscle or gland
108
regeneration in CNS
no neurilemmal sheaths in CNS
no axon regeneration
adult neuron does not divide
cut through cell body, in PNS OR CNS BRINGS CELL DEATH!!!!!!!!!!!!!!!
limited growth with fetal tissue implants
109
neurophysiology: resting membrane potential
AT REST ( NO MESSAGE TRANSMITTED) membrane is charged so outside positive with respect to inside
110
how can ions move to create this imbalance in resting membrane potential?
respond (open/close) to pressure/voltage/chemicals
each channel selective for ions to pass
so can permit unequal distribution or ions in ECF vs cytoplasm
111
RMP
NA + higher outside
K+ higher INSIDE
cytoplasm= 150 mm k+ and 15 mm na+
ECF= 150 mm Na+ and 5 mm k+
112
if add all charges in ECF nD COMPARE to all charges in cytoplasm, greater positive charge outside than inside where?
AT MEMBRANE
113
at the membrane for RMP...
cytoplasm is neutral, elf is neutral ECF not elf
114
potential across membrane is what #
~-70mV
115
hyper polarizing agents
chemicals that affect RMP and make it more negative > -70mv
more difficult to fire message (action potential) on that nerve
patient has more difficulty responding
116
hyper polarizing agents affect what?
they affect RMP and make it more positive (+) than -70 e.g. -60, -50
nerve message fired more easily
eg. caffein (in chocolate, colas, pepper, tea, coffee, mountain dew
117
generating action potential
RMP- voltage gates closed for Na and k
depolarization- increase in membrane na permeability and na moves from ECF into cytoplasm in small steps & once reaches threshold becomes self generating
repolarization
118
2 types of signals produced by change in membrane potential
graded potentials
| action potential
119
graded potentials
incoming signals operating over short distances, short lived; can initiate action potential
120
action potential
long distance messages=rapid series of depolarizations and depolarizations; don't decrease in strength with distance ----- often graded potential change to AP at hillock
121
depolarization
the membrane potential moves toward 0 mv the inside becoming less negative and more positive
122
hyperpolarization
the membrane potential increases, the inside becoming more negative
123
the key players
voltage gated Na+ channels and k+ channels
124
repolarization
k+ exits membrane in a linear pattern directly behind Na+ movement restoring original resting potential
na+ blocked
occurs in small steps
Na+/ka+ pump restores ion distributions of original RMP
125
the events 1-4
resting state
depolarization
depolarization
hyperpolarization
126
the events 1-4 explained
no ions move through voltage-gated channels
then na+ flows into the cell
then k+ flows out of the cell
then k+ continues to leave the cell
127
threshold response
depolarization when AP becomes self generating ---- graded potentials add at hillock
128
all or none response
AP happens completely with threshold stimulus or not at all
129
refractory period
period of open Na+ channels in which neuron cannot respond to another stimulus
130
synapse
junction that mediates information transfer
ex axodendritic - btwn axon/dendrite
presynaptic neuron= neuron conduction impulses toward synapse
131
postsynaptic neuron=
neuron transmitting electrical signal away from synapse
132
electrical synapse=
less common, protein channels between neurons, like gap junctions, synchronous activity
133
chemical synapses
depolarization releases Ca++ that opens vesicles in axon terminal that releases NT-> diffuses across synapse to receptor on next dendrite
134
in chemical synapses after few milliseconds NT
terminated by enzymes or reuptake by astrocytes or cell or diffusion away
135
the rate limiting step of message is much slower in what?
much slower in synapse, 150 m/sec is .3-5.0 m/sec
136
excitatory post synaptic potential EPSP
neurotransmitters that hypo polarize & excite next neuron with graded responses - may trigger hillock - AP
137
inhibitory post synaptic potential IPSP
inhibitory neurotransmitter that hyper polarizes next neuron-> less likely to fire
138
esps can add together to increase what?
threshold depolarization
139
temporal
rapid accumulations in time of presynaptic impulses
140
spatial
many neurons add together to stimulate the post synaptic neuron
141
neurotransmitters
chemicals released from end of axon that carry message of depolarization through synapse to next neuron
have specific receptors on post neuron
ex: ACH- degraded by a chase to choline and reused to make ash
all skeletal muscles
CNS
monamines/biogenic amino acids (eli,norepi,serotonin,dopamine)
some amino acids -- glycine, GABA, aspartic acid
142
monamines/biogenic amino acids -- eli, norepi, serotonin, dopamine
broad distribution in brain
inhibited by monamine oxidase
diet can affect monamine production
143
some peptides
neurotransmitters - strings of amino acids
can enhance- substance P transmits pain
can inhibit message: endorphins and enkephalins inhibit pain
144
neurotransmitters: some can excited or inhibit
ash excites skeletal muscle and inhibits cardiac muscle
145
neuromodulators
chemicals in the synapse that can alter the message of the transmitter
NO nitric oxide
146
convergence of a message
action potentials of several neurons converge at synapse
many neurons converge to fewer neurons
used to go from sensory ons into cps
147
divergence
action potential of one neuron synapses into several neurons
| CNs --> motor effectors (can take same message to may parts)
148
neuronal pools=
functioning group of millions of neurons in CNS
if presynaptic neuron branches @ synapse, it will excite some post neurons in discharge zone and facilitate or help other neurons reach a threshold facilitated zone
149
patterns of neural processing- SERIAL
predictable patter of stimulation of one after another after another like spinal reflexes or serial killers
150
reflex arc
automatic unconscious response to change inside or outside body
151
reflex arc
maintains homeostasis
4 or 5 parts
sensory neuron -> interneuron in CNS-> motor ->
effector (muscle or gland)
152
reflex arc simplest
knee-jerk (2 neuron); unipolar in & multipolar out (no interneuron
153
parallel processing
input segregated into many different pathways simultaneously
154
nerve fiber classification
nerve fibers classified according to diameter, degree of myelination, speed of conduction
