Topic 2 (Exam 2) Flashcards
(119 cards)
1
Q
long and straight, multi=nucleated is what type of muscle tissue?
A
skeletal muscle
2
Q
cardiac muscle has what?
A
branches, striations, intercalated discs
3
Q
describe smooth muscle tissue in general
A
looks like messed up snake skin
4
Q
what is skeletal muscle activated by?
A
lower motor neurons (somatic efferents)
5
Q
what is smooth muscle responsible for?
A
movement of material in and out of our body
6
Q
Cardiac and smooth muscle is driven by what nervous system?
A
visceral efferents.
7
Q
skeletal tissue is innervated by _________ nervous system
A
somatic
8
Q
fasicles
A
bundles of muscle fibers
9
Q
muscle fiber
A
muscle cell
10
Q
myofibrils
A
overlapping thick and thin filaments
11
Q
sarcolemma
A
muscle cell plasma membrane
12
Q
sarcoplasm
A
muscle cell cytoplsam
13
Q
sarcoplasmic reticulum
A
muscle ER
14
Q
motor unit
A
a motor neuron and all muscle fibers it innervates
15
Q
what are the two muscle contractile proteins
A
actin (thin)
myosin (thick)
16
Q
actin is ___filament
A
thin
17
Q
myosin is ____filament
A
thick
18
Q
muscle regulatory proteins are
A
troponin; tropomyosin (on actin)
19
Q
sarco and myo refer to ___
A
muscle
20
Q
what is the arrangement of a muscle?
1-2-3-4-5
A
muscle body, fasicle, muscle fiber, myofibril, actin/myosin
21
Q
myofibrils are composed of fundamental units called ____
A
sarcomeres
22
Q
thin to thick filament exist in what ratio?
A
2 thin filamnet to every 1 thick
“not everyone can have a phat Az”
23
Q
What does the Sarcoplasmic Reticulum do?
A
wraps around each myofibril
overlays thick and thin filaments
stores Ca2+
works with T-tubules
24
Q
what are t-tubules?
A
“transverse tubules”
hole in sarcolemma
allows APs from neuromuscular junction to reach interior of cell quickly
25
What does the Myosin (thick) head do?
binds actin
binds ATP
has ATPase activity
26
ATPase
hydrolyzes atp for energy
27
myosin head is also called a
crossbrigde
or two nutsacks
28
contractile protein contains
g-actin
29
regulatory protiens need
tropomyosin and troponin
30
Troponin (CAT)
binds Ca 2+
binds actin
binds tropomyosin
31
tropomyosin (total bitch)
blocks actin binding sites
stops contraction
stiffens and supports actin
32
t/f each actin has a myosin binding site
true
33
During contraction, ______ filaments slide over _____ filaments toward the center of the sarcomere. What happens to the length of the sarcomere?
thin slides over thick
length shortens
34
In sliding filament theory, I band_____
shrinks/disappears
35
In sliding filament theory, H band_____
in thick
shrinks
36
H-zone
only thick filaments (no overlap)
37
I band (light band)
only thin filaments (no overlap with myosin)
38
A-band
thick and thin filaments, spans the entire length of myosin, has some actin overlap
39
z-lines
anchor the thin filaments. Sarcomere boundary
Thick filaments don't change length. Actin slides over the myosin
40
Neuromuscular junction
looks like a big monster that connects to muscle fibers to release ca2+
41
t/f each muscle fiber recives info from multiple nuerons
false
42
What is the dummed down version of the 7 steps of excitation-contraction sequences
1)RELEASE THE KRACKENNN
ACh released, binds to nicotinic on motor end plate
2) LIGHT THE FIRES
ACh opens cation channels, gives AP down muscle fiber
3) TELL THE BASE
AP falls into T-Tubule, activates DHP receptors
4) CALL THE TROOPS
DHP receptors attach to Ca, SR gates open and Ca is
released
5) BREAK THE OARS
Ca binds to troponin, pulls of tropomyosin off the actin
binding site allowing cross bride cycling to occur
6) ROW MEN
myosin executes power stroke
7) FORWARD, UNTO DAWN
actin filaments slide toward the center of the sarcomere
43
Explain the various parts of the Myosin head
binds actin
binds ATP
has ATPase activity
44
ATPase
hydrolyzes ATP for energy
45
myosin head is also called a _______
crossbridge
46
Regulatory proteins of Muscle contractile proteins
CAT
binds Ca2+
binds Actin
bind Tropomyosin
47
What does Tropomyosin do in muscle contractile proteins
blocks actin binding sites
stops contraction
stiffens and supports actin
48
t/f each g-actin has a myosin binding site
true
49
contractile protein is _________
G-actin
50
regulatory protein of muscle contractile proteins is ___ and ____
tropomyosin and troponin
51
Explain the Sliding Filament Theory of Contraction
THIN slides over THICK
length of sarcomere shortens
H and I bands disapeers/shrinks
52
H-zone;
only thick filaments (no overlap with actin)
53
I band
only thin filaments (no overlap with myosin)
54
A Band
thick and thin filaments, spans the entire length of myosin, has some actin overlap
55
Z-lines
anchor the thin filaments. Sarcomere boundary
thick filaments don't change length
56
The neuromuscular junction has a _______ receptor which is classified under the _____ receptor cateogroy
nicotinic receptor
cholergenic
57
each motor neuron innervates ______muscle fiber(s)
several
58
each muscle fiber receives innervation from ______motor neuron(s)
one
59
What is Excitation-Contraction Coupling
events that link AP to muscle contraction
we must fire the somatic motor neuron first
60
Excitation Contraction Sequence:
1) ___ is released from axon terminal of ____neuron
ACh; motor
61
Ca2+ binds to _____ and pulls the ____ of the _____ on the ______
calcium binds to troponin and pulls the tropomyosin off the binding site on the actin
62
how is Ca pumped into the SR
using Ca2+ ATPase
63
a single contraction-relaxation cycle is called a
twitch
64
_______break down ACh in the synapse into acetate and choline
Cholinesterases
65
when AP generation stops, it causes ___ ____ _____ on the SR to close
ryanodine ca channels
66
pumping Ca into the SR requires _____
ATP
67
DHP receptor acts as a ____ ____ that, when activated, induces a conformational change in the ___ ____ to cause Ca release from the SR
voltage sensor
ryanodine receptor
68
Rigor MOrtis
postmortem stiffening of body muscle due to chemical changes in myofibrils
69
Why does rigor mortis stiffen muscles?
no oxygen to generate ATP to release myosin heads
no ATP to fuel calcium ATPase, calcium increases in cytoplasm and myosin is glued onto actin binding sites
70
Explain why Sarin Gas is deadly
too much ACh, keeps generating APs=continued contraction
which means no heart beat, no breathing no nothing
71
Curare is a ________ _______ ________; why is it deadly?
nicotinic receptor antagonist
ACh can't bind to Nicotinic receptor, can't contract, can't move
blow dart herb tribe thing
72
Why does Botox work?
ACh is blocked from release in the motor neuron on the muscle
fixes migranes, excessive sweating, surgeries,
73
Where do muscles get ATP?
Creatine Phosphate
Anaerobic-Glucose
Aerobic-cellular respiration
74
Creatine Phosphate
quick energy=creatine phosphate
limited so we quickly switch to metabolism
75
Anaerobic respiration
glycogen-glucose
first few seconds of exercise
not enough O2?=glucose breakdown=lactic acid buildup
ineffienct, fast but not sustainable
useful for high-intensity exercise
76
Aerobic Respiration
after glycogen is depleted
after about 30 minutes
yeild high ATP, but sluggish
useful for low intensity
does not cause lactic acid
77
tension
force exerted on an object by contracting muscle
78
load
force exerted on muscle by an object
79
isotonic contraction
sliding of thin filaments
contraction where muscle shortens while load remains constant
ex picking up a heavy object
80
Isometric Contraction
contraction when muscle develops but does not change length
ex standing
81
T/F the electrochemical and mechanical events in isometric and isotonic contraction are different.
false
the electrochemical and mechanical events in isometric and isotonic contraction are the same, the RESULT IS DIFFERENT
82
What are some factors that affect whole muscle tension/force and active cross bridge generation
tension (or force) generated in individual muscle fibers and number of muscle fibers contracted
1) Tension from each fiber
2) AP frequency
3) fiber length
4) fiber diameter
83
force of contraction (increases/decreases) with fiber diameter
increases
84
force of contraction (increases/decreases) with frequency of AP
increases
there's a latent period after AP before muscle tension developes
85
why does increasing frequency of APs cause an increase in tension?
Ca2+ release from the SR greater than Ca2+ reuptake into SR.
IF can't remove Ca2+ the muscle fiber cannot completly relax.
86
tetanus
summate twitches until you reach the maximum tension for that muscle
unfused and fused
87
fused tension
no ability to relax
88
unfused tension
some ability to relax
89
force of contraction (increases/decreases) with fiber length
increase
90
more cross bridges =
more force
91
fine motor control ex
fingertips
92
gross motor control
hamstring
93
all muscle fibers fire at the same time to generate force
false
94
three broad groups of muscle fibers are based on speed of contraction and resistance to fatigue
1) slow twitch oxidative fibers
2) fast twitch oxidative
3) fast twitch glycolytic
95
Speed of Contraction:
depends on isoform of MYOSIN ATPase,
fast myosin ATPase hydrolyzes ATP quickly
genetically determined
96
Resistance to Fatigue
depends on which metabolic pathway is used
oxidative or glycolytic
97
myoglobin
a red protein containng heme, which carries and stores oxygen in muscle cells
slow twitch oxidative
98
Oxidative FIbers
red muscle
slow twitch
small diameter
many mitochondria and capillaries
myoglobin
marathon runner
99
Glycolytic Fibers
white muscle
fast-twitch
glycolytic enzymes in the cytosol
large diameter
few mitochondira and capillaries
weightlifting
100
slow twitch oxidative fibers (Type I)
smallest motor units; most commonly used; posture
101
Fast Twitch Oxidative Fibers (Type IIa)
intermediate motor units (walking)
trainable
have some glycolytic enzymes, less myoglobin
102
Fast Twitch glycolytic fibers (Type IIb)
largest motor units
least used (jumping)
103
Why would you want to change types of active motor units?
so that muscle activity could be altered
104
a marathon runner would have a lot of ______ _____ ______ _____ muscle fiber
fast oxidative Type IIa
105
Arnold Shwaznegger has a lot of ____ ____ ____ muscle fiber
fast glycolytic Type IIb
106
T/F as more force is needed more motor units are recruited starting with the smallest (Type I/ Slow oxidative)
True
107
muscle hypertrophy
increase in muscle size
Fast Glycolytic Type IIb
108
Most trainable muscle is
Type IIa
109
Key characteristics of smooth muscle
lacks straitions, no sarcomeres
internal organs
not under somatic control
allows contraction in many different directions
110
In Smooth muscle.....
ATPase of the myosin is much _______(slower/faster) and the contraction phase of the twitch is much ______(slower/faster)
ATPase=slower
twitch=longer
111
In Smooth muscle.....
There are ___- _______ _______ in the myosin head (specificically in the myosin light chains)
small regulatory protein chains
112
In Smooth muscle.....
T/F they have more SR
false,
they have less SR
113
Two types of smooth muscle
multi-unit
single-unit
114
Multi-Unit
smooth muscle
iris, eye, testicular tract
WHERE FINE CONTROL IS NEEDED
115
Single Unit (visercal)
GI tract, uterus, bladder
COUPLED BY GAP JUNCTIONS (so all tissue behaves like a single unit)
116
What does multi-unit smooth muscle look like?
woven tapestry with autonomic neuron varicosity woven between cells
117
What does a single-unit smooth muscle look like?
a beaded curtain with a string of autonomic neuron varicosity laced over the top.
118
How is smooth muscle different from skeletal muscle
smooth:
lacks striatations
no T-tubule system
no troponin (uses Calmodulin as Ca2+ binding protein)
inner and outer Ca2+
autonomic nervous system
less SR
119
MLCK
myosin light chain kinase
phosphorylates myosin light chains, allowing myosin and actin to interact (very similar to troponin in skeletal muscle)
