Unit 3 Part 2 Flashcards
(108 cards)
1
Q
What makes up 40 percent of an individual’s body weight?
A
Muscle
2
Q
Muscle, tissue or organ contraction is usually a response to a
A
Stimulus
3
Q
Muscle size depends upon___
A
Use
4
Q
How many muscles are there in the human body
A
656
5
Q
How many antagonistic pairs of muscles
A
327
6
Q
2 unpaired muscles
A
– Orbicularis oris
– Diaphragm
7
Q
Usual number of contractions around eyes
A
100,000x/day
8
Q
how long can individual muscle cells be
A
12 inches (30cm) long
9
Q
number & diameter of muscle fibers begins to decrease at what age
A
40
10
Q
___ muscle mass may be lost at what age
A
50%; 80
11
Q
release a neurotransmitter that causes a chemical reaction and the muscles contract.
A
motor neurons
12
Q
____ happens when the brain sends electronic signals to the _____ on the muscles,
A
Movement; motor neurons
13
Q
stabilizes joints and help maintain body positions, such as standing or sitting.
A
Skeletal muscle contractions
14
Q
__ continuously contracts when you are awake.
A
Postural muscles
15
Q
what contraction of neck muscles hold your head
upright
A
sustained contractions
16
Q
muscles in our _____ keep us upright by maintaining constant tension.
A
torso
17
Q
accomplished by sustained contractions of sphincters
A
Storage
18
Q
ringlike bands of smooth muscle, which prevent outflow of the contents of a hollow organ.
A
sphincters
19
Q
closes off the outlets of stomach or urinary bladder that causes storage
A
smooth muscle sphincters
20
Q
pumps blood through the blood vessels of the body.
A
Cardiac muscle contractions
21
Q
Adjust blood vessel diameter
Move food and substances
Push gametes (sperm and oocytes)
Propel urine
A
Smooth muscle contractions
22
Q
promote the flow of lymph and aid the return of blood in veins to the heart.
A
Skeletal muscle contractions
23
Q
% of body heat is
produced by muscle
A
85
24
Q
Body movement
produce ___ that helps regulate body temperature
A
heat
25
carried by the blood to the surface of the skin and turn into sweat (sweat evaporation)
Excess heat
26
-Multinucleated
-Striated
-Voluntary control
-thick
-long
-unbranched
-cylindrical
skeletal muscle
27
-Striated and uni-nucleated
-Branching cells
-Intercalated discs separate cells
- Rhythmicity
-Only found in wall of heart
- Self-exciting tissue
- Large transverse tubules
cardiac muscle
28
-Uninucleated
-No striations
-Involuntary control
-small
-spindle shaped
smooth muscle
29
Contraction of muscles is due to
the movement of
microfilaments
30
prefixes of muscle
myo, mys, sacro
31
shape of muscle cells/muscle fiber
elongated
32
The ability to receive and respond to a stimulus
ELECTRICAL EXCITABILITY
33
skeletal muscle stimulus
neurotransmitter (chemical signal) release by a neuron (nerve cell).
34
smooth muscle stimulus
neurotransmitter, hormone, stretch, change in pH, change in Pco2 or change in Po2
35
cardiac muscle stimulus
neurotransmitter, hormone, or stretch.
36
types of stimulus
-autorhythmic electrical signals
-chemical stimuli
37
___ is the generation of an electrical impulse or ____ that travels along the plasma membrane of the muscle cell.
RESPONSE; MUSCLE ACTION POTENTIALS
38
– ability to shorten forcibly
–defining property
CONTRACTILITY
39
–ability to be stretched within limits, without
being damaged
– Smooth muscle is subject to the greatest amount of
stretching (stomach filled with food); Cardiac muscle
stretched when heart is filled with blood
EXTENSIBILITY
40
ability to recoil and resume original length
after being stretched.
ELASTICITY
41
– More than a local effect
– Electrical charge spreads along the muscle fiber
CONDUCTIVITY
42
Each skeletal muscle is a separate organ
composed of hundreds to thousands of cells
called
fibers
43
surround muscle fibers and whole muscles
Connective tissues
44
penetrate into muscles
Blood vessels and nerves
45
-sheet or broad band of fibrous connective tissue
-deep in the skin and surrounds muscles and other organs of the body.
Fascia
46
separates muscle from skin
Superficial fascia
47
-dense irregular connective tissue
-lines the body wall and limbs and holds muscles together.
Deep fascia
48
around single muscle fiber
Endomysium
49
around a fascicle (bundle) of fibers
Perimysium
50
covers the entire skeletal muscle
Epimysium
51
on the outside of the epimysium
Fascia
52
Endomysium, perimysium, and epimysium come together:
AT?
TO?
example?
– at ends of muscles
– to form connective tissue attachment to bone matrix
– i.e., tendon or aponeurosis
53
Skeletal muscles are _________ muscles, controlled by ____ of the central nervous system
voluntary; nerves
54
Neurons that stimulate skeletal muscle are
somatic motor neurons
55
Form a neuromuscular junction (= myoneural junction)
somatic motor neurons
56
Sites of muscle attachment
– Bones
– Cartilages
– Connective tissue coverings
57
-bring in oxygen and nutrients (glucose, fatty acids) and remove heat and waste
-plentiful in the muscle tissue
Capillaries
58
Skeletal Muscle Organization
(Largest to Smallest)
Skeletal Muscle
Muscle Fascicles
Muscle Fibers
Myofibrils
Sarcomere
Myofilaments
59
-The cell membrane of a muscle cell
- Surrounds the sarcoplasm
-A change in transmembrane potential begins contractions
-All regions of the cell must contract simultaneously
Sarcolemma
60
– Tiny invaginations of the sarcolemma
– Penetrate the sarcolemma
– Bring extracellular materials into close proximity of the deeper parts of the muscle fiber
– Open to the outside of the fiber, filled with interstitial fluid
– Muscle action potentials travel along
– Closely associated with SR
Transverse tubules (T-tubules)
61
- Contains various organelles specifically designed to meet the needs of the contractile skeletal muscle fiber
-multi-nucleated - located in the periphery of the muscle cell
Sarcoplasm
62
- High demand for energy (ATP)
- Lots of glycogen granules
- Myoglobin
- Myofibrils
Sarcoplasm
63
provide glucose for energy needs
glycogen granules
64
Protein with a high affinity for oxygen; Transfers oxygen from the blood to the mitochondria of the muscle cell
Myoglobin
65
create the biggest part of the cytoplasm, oriented longitudinally with long axis of muscle fiber
Myofibrils
66
– Saclike membranous network of tubules
– Surrounds each myofibril
– Contains terminal cisternae
Sarcoplasmic reticulum (SR)
67
Dilated end sacs
terminal cisternae
68
- Located where the SR ends
-Store high concentrations of calcium
-Concentrate Ca2+ (via ion pumps)
- Release Ca2+ into sarcomeres to begin muscle
contraction
terminal cisternae
69
– Release of Calcium
– Activate skeletal muscle contraction
– Transmit nerve impulses
– store high concentrations of calcium
SR and T-tubules Function
70
Each T-tubule will be flanked by a terminal cisterna. This forms ______ consisting of 2 terminal cisternae and one T-tubule branch.
triad
71
* rod-like structures that extend the length of the cell.
* long bundles of protein structures called myofilaments (thick and thin).
* Sarcomere are the basic unit
* built from three kinds of proteins
Myofibrils
72
3 Muscle Proteins
Contractile
Regulatory
Structural
73
Contractile muscle proteins
Myosin
Actin
74
Regulatory muscle proteins
Troponin
Tropomyosin
75
Structural muscle proteins
Titin
Nebulin
Alpha-actin
Myomesin
Dystrophin
76
Workhorses – generate force during contraction
Contractile Proteins
77
-forms backbone of thin filament; contains sites where myosin heads bind during muscle contraction
22%
Actin
78
-form shaft of thick filaments; binds to binding site on
actin during muscle contraction.
-Functions as motor protein
-44%
Myosin
79
the basic component of each actin myofilament
G-actin (globular actin)
80
two strands of G-action molecules are twisted together with two regulatory proteins:
–tropomyosin
–troponin
81
– Rod-shaped protein that occupies the groove between the twisted strand of actin molecules
– Blocks the myosin binding sites on the G-actin
molecules when muscle is relaxed
-5%
Tropomyosin
82
-A complex of three globular proteins.
* One is attached to the actin molecule
* One is attached to tropomyosin (holds in position)
* One contains a binding site for calcium\
- 5%
Troponin
83
Thin Myofilaments in a RELAXED muscle
* ___ is blocked from binding to actin
* Strands of _____ cover the myosin binding sites
* _____ binding to ____ moves tropomyosin away from myosin-binding sites
* Allows muscle contraction to begin as myosin binds to ___
Myosin
tropomyosin
Calcium ion; troponin
actin
84
Thick myofilaments are made the protein __
myosin
85
* Composed of a rod-like tail and two globular heads
* Interact with actin during contraction.
* Form CROSS-BRIDGES
* Contain binding sites for both actin and ATP
Myosin
86
-each myosin can interact with___actin filaments
-each actin can interact with __ myosin filaments.
6
3
87
* Align the thick and thin filaments properly
* Provide elasticity and extensibility
* Link the myofibrils to the sarcolemma
Structural Proteins
88
(9%)
-extends from Z disc to M line and attaches to myosin.
Titin
89
-forms the M line; helps stabilize position of thick filaments
Myomesin
90
(3%)
-attaches into Z disc and lies alongside thin filaments; internal support and attachment for actin
Nebulin
91
-links thin filaments to integral membrane proteins of sarcolemma.
Dystrophin
92
- bind to actin molecules of the thin filament and to titin
a-actinin
93
- Repeating individual units in each myofibril
– Smallest contractile unit of the muscle fiber
– Arrangement of Myofilaments
Sarcomere
94
-borders of the sarcomere
– Perpendicular to long axis of the muscle fiber
– Anchor thin myofilaments (actin)
Z-lines
95
Anchors the filaments and interacts with cytoskeletal framework
Z disc
96
– Perpendicular to long axis of the muscle fiber
– Anchor thick myofilaments (myosin)
M-lines
97
* Anisotropic
* Area where actin and myosin overlap
* Equal to the length of the thick myofilaments (myosin)
* Contains the H-Zone
A-Bands
98
dark under the microscope
Anisotropic
99
– Lighter area within the A-Band that contains only myosin
– The M-Line is located with the H-zone
H-Zone
100
- Isotropic
- Light area composed of actin only
- Contains the Z line, which is the boarder of the sarcomere
I-Bands
101
Thin filaments slide past the thick filaments, and the
sarcomere and muscle fiber shortens
Walk Along Theory or the Ratchet Theory.
102
Thin filaments move towards the center of
the sarcomere from both ends
Sliding Filament Theory
103
Sarcomere Partially Contracted
I Band – shorter
H Band - shorter
A Band – same length
Z line - closer
104
Sarcomere Completely Contracted
I Band – almost disappeared
H Band – almost disappeared
A Band – same length
Z line - closer
105
accomplished by the thin filaments from opposite sides of each sarcomere sliding closer together or
overlapping the thick filaments further.
Contraction
106
becomes smaller as the thin filaments approach each
other.
H-zone
107
becomes smaller as the thin filaments further overlap the thick filaments.
I band
108
width of the _____ remains unchanged as it depends on the thick filaments and the thick filaments do not change length.
A band
