Exam 3 Ch 12 Flashcards
1
Q
Skeletal muscle—
A
Skeletal muscle—
voluntary, striated muscle
usually attached to bones
2
Q
Striations—
A
Striations—alternating
light and dark transverse
bands
3
Q
What do striations result from
A
- Results from arrangement of
internal contractile proteins
4
Q
How long are muscle fibers (myofiber)
A
30 cm
5
Q
- Site where a motor neuron
stimulates a muscle fiber
A
Neuromuscular junction
6
Q
Area of the muscle fiber
where a motor neuron
stimulates it using the
neurotransmitter,
acetylcholine
A
Motor end plate
7
Q
- Single motor neuron (with its collateral
branches) and all the muscle fibers it
innervates; all the muscle fibers in a motor
unit contract at once.
A
Motor unit
8
Q
Varied contraction strength due to?
A
different
numbers of motor units being activated
9
Q
What gives a fine degree of control?
A
Small motor units
10
Q
what gives more strength than control
A
large motor units
11
Q
Sarcolemma
A
cell membrane of a muscle cell
12
Q
Sarcoplasm?
A
13
Q
Bundles of
myofilaments
A
Myofibrils – Bundles of
myofilaments
14
Q
Storage protein in
muscle for oxygen
A
Myoglobin – Storage protein in
muscle for oxygen
15
Q
Storage of glucose
A
Glycogen – Storage of glucose
16
Q
What does the sarcoplsmic reticulum do
A
stores intracellular calcium. Specialized endoplasmic reticulum.
17
Q
Sarcoplasm
A
muscle cell
18
Q
dilated end sacs of sarcoplasmic reticulum
A
terminal cisternae. They go transversely
19
Q
Thick filaments
A
myofilaments
20
Q
What are myofilaments composed of
A
myosin.
a) Each protein has two
globular heads with actin-
binding sites and ATP-
binding sites.
* ATPase
b) Located at the ends of
hinge region that extend
from the myosin tail portion
21
Q
Comprised of thin filaments
A
actin
22
Q
Actin
A
Globular: pearls off the necklace
Filimentous (F) Actin: on a string
23
Q
Covers active site for actin
A
Tropomyosin
24
Q
Binds calcium and moves tropomyosin
A
Troponin complex
25
Three units of troponin complex and what they do
Troponin I inhibits binding to myosin
Troponin T binds to tropomyosin
Troponin C binds to calcium
26
anchors thick filaments. Stores potential energy in a sarcomere.
Titin (connectin)
27
z line to z line
one unit of functional muscle
28
M line to z line on both sides
Titin (connectin) anchors these thigns
29
Dystrophin
Actin to linking proteins connected to the endomysium.
- Links actin in outermost
myofilaments to membrane
proteins that link to
endomysium
- Transfers forces of muscle
contraction to connective tissue
ultimately leading to tendon
- Genetic defects in dystrophin
produce disabling disease
muscular dystrophy. No connection to tendon to move bone.
30
band that stretches over the M line. Appears lighter.
H band.
31
stretches over the entire myosin thick filament.
A band
32
Steps in an excitation
action potential reaches end of axon, calcium influx in the synaptic knob, 3. Exocytosis of synaptic vesicles containing acetylcholine.
4. Acetylcholine travels across the synaptic cleft and binds to nicotinic receptors on the
muscle fiber.
5. Ligand-gated ion channels open and Na+ flows in K+ flows out.
-90 mV to +75 mV
6. Action potential starts and spreads down the sarcolemma
33
Excitation contracting coupling
1. Action potential travels down the transverse tubule.
2. Voltage-gated calcium channels in transverse tubules change shape,
couple to SR calcium channels, and cause them to open.
3. Calcium binds to troponin C on the thin filaments.
4. Tropomyosin moves to expose active sites on actin.
34
what does the action potential go through
T tubules
35
Contraction
mysin binds to ATP in its natural state, hydrolysis of ATP to ADP cocks the myosin head back, myosin head releases Phosphate group causing power stroke, myosin binds a new molecule of ATP to release actin.
36
the hydrolysis of ATP makes myosin enter what
high energy confirmation
37
ATP binding causes myosin to release what
actin
38
Relaxation
action potential stops and acetylcholine is released, once released from receptor, it's degraded by acetylcholinesterase, action potential in sarcolemma stops, calcium is actively pumped back into the sarcoplasmic reticulum, tropomyosin moves back to block and active sites on actin, myosin no longer bind to actin and the sarcomere slides back to its resting state
39
Botox (Botulism toxin) prevents the release of acetylcholine. What affect does this have?
No ACh release= no ACh binding receptors on muscle = no depolarization. Singlar in neuron but no propagation to muscle
40
After death, the sarcoplasmic reticulum degrades and leaks
calcium into the sarcoplasm
lots of calcium that can bind to troponin C = contraction (rigor mortis)
41
Barbiturates prevent calcium from entering the synaptic knob
No calcium, no exocytosis of ACh, no contraction
42
what's a myogram
a chart of the
timing and strength of a
muscle’s contraction
43
THreshold and twitch
minimum voltage necessary to generate an action potential in a muscle fiber to contract
a quick cycle of contraction and relaxation when stimulus is at threshold or higher
44
explain summation
the second contraction piggy backing off of the first one and ending up higher
45
Full contraction, full relaxation?
Twitch
46
staircase
effect, stimulus
comes after
relaxation, cold
muscle
Treppe. Over time the action potentials get larger, more force
47
stimulus
before relaxation
ends. Force increases as it goes
incomplete tetanus
48
little to no time to relax
complete tetanus. gets to maximum contraction until fatigue
49
Muscle produces internal
tension, but external
resistance causes it to stay the
Isometric muscle contraction
50
Muscle changes in length with no change in tension
Isotonic muscle contraction
51
muscle shortens as it maintains tension
concentric contraction
52
muscle lengthens as it maintains tension
Eccentric contractions
53
- Yields little ATP and lactate, which needs to be disposed of by the
liver
Anaerobic fermentation
54
- Produces far more ATP
- Does not generate lactate
- Requires a continual supply of oxygen
Aerobic respiration.
55
As exercise intensity increases, what energy supply increases and what decreases?
Muscle glycogen increases and plasma free fatty acids decrease
56
what takes glucose into a cell
GLUT 4 transporter
57
Path of glucose
Glucose to pyruvate to aerobic respiration (or fermentation) or acetyl CoA to the citric acid cycle to produce NADH and FADH to go into the ETC to produce ATP
58
what is the biproduct of aerobic respiration?
Carbon dioxide and water
59
Ferm produces what and glycolysis produces what?
Ferm: NAD+
Glycolysis: NADH
60
biproduct of Ferm
Lactate
61
Waste products are typically XXX in nature
nitrogenous. NH3 then is converted to Urea
62
When fats are the metabolites, what are they converted to
glycerol- glyceraldehyde-3-P
Fatty acids- acetyl CoA
63
0-10 seconds of running
aerobic respiration.
64
10-20 seconds of running
phosphagen system
65
20-EPOC seconds
glycogen-lactate system (anaerobic ferm)
66
EPOC onward
aerobic respiration
67
Point of phosphagen system
short, intense exercise. Maintaining until anaerobic system kicks in
68
What are part of phosphagen system
myokines (ADP-ATP)
creatine kinase (creatine phosphate-ATP
69
How many ATP for each glucose in anaerobic fermentation
2
70
How long does anaerobic ferm work for
Produces enough ATP for 30 to 40 seconds
of maximum activity
71
amount of ATP per glucose in aerobic respiration?
30
72
Explain fatigue in high-intensity exercise
-Potassium accumulation in the T tubules reduces excitability
- Excess ADP and Pi slow cross-bridge movements, inhibit
calcium release and decrease force production in myofibrils
- (Possibly a drop in pH, but lactic acid does not seem to
accumulate in the muscle cell
73
Explain fatigue in low-intensity exercise
- Fuel depletion as glycogen and glucose levels decline
- Electrolyte loss through sweat can decrease muscle
excitability
- Central fatigue when less motor signals are issued from brain
74
is this a symptom of low or high intensity exercise: Central fatigue when less motor signals are issued from brain
low
75
is this a symptom of low or high intensity exercise: Excess ADP and Pi slow cross-bridge movements, inhibit
calcium release and decrease force production in myofibrils
high
76
What is EPOC (Excess Post-exercise Oxygen
Consumption) needed for
replenish ATP
Replace oxygen reserves on myoglobin
for liver for disposing lactic acid
many cells that have elevated metabolic
rates after exercise
77
how much oxygen in EPOC being used
6 times the basal consumption (normal). can last an hour
78
Why does cardiac muscle contract as a single unit
gap junctions
79
where does the calcium come from in cardiac muscle
ECF
80
- Actin and myosin filaments
are scattered
- Connected to dense bodies
nonstriated, smooth muscle
81
where is calcium in smooth muscle and what stores it
ECF, calmodulin
82
swelling
alone a nerve
fiber’s length in smooth muscle
varicosity
83
Each myocyte is
associated with a
varicosity
multiunit
84
- Visceral muscle
- Electrical synapses
between cells
single-unit
85
