Chapter 10 part 1 muscular system Flashcards
1
Q
the ability to receive and respond to stimuli
A
Excitability
2
Q
the ability to shorten forcibly
A
Contractility
3
Q
the ability to be stretched or extended
A
Extensibility
4
Q
the ability to recoil and resume the original resting length
A
Elasticity
5
Q
electrical signals can be conducted along the sarcolemma
A
Conductivity
6
Q
Muscle Function:
Skeletal muscles
A
are responsible for all locomotion
maintain posture and body position
stabilize joints
generate heat
7
Q
Cardiac muscle is responsible for
A
coursing the blood through the body
8
Q
Smooth muscle helps maintain
A
blood pressure, and squeezes or propels substances (i.e., food, feces) through organ
9
Q
Skeletal and smooth muscle cells are elongated and are called
A
muscle fibers
10
Q
Muscle contraction depends on two kinds of
A
myofilaments – actin and myosin
11
Q
muscle plasma membrane
A
Sarcolemma
12
Q
cytoplasm of a muscle cell
A
Sarcoplasm
13
Q
myo, mys, and sarco all refer to muscle
A
Prefixes
14
Q
Skeletal Muscle Tissue
Packaged in skeletal muscles that attach to and?
A
and cover the bony skeleton
15
Q
Skeletal Muscle Tissue
Has obvious stripes called?
A
striations
16
Q
Skeletal Muscle Tissue
has what kind of cells
A
Long, cylindrical, multinucleate cells
17
Q
Skeletal Muscle Tissue
Is controlled how
A
voluntary (i.e., by conscious control
18
Q
Skeletal Muscle Tissue
Contracts at what pace
A
rapidly but tires easily
19
Q
Skeletal Muscle Tissue
Is responsible for overall
A
body mobility
20
Q
Skeletal Muscle Tissue
Is extremely adaptable and can exert forces ranging
A
from a fraction of an ounce to over 70 pounds
21
Q
Cardiac Muscle Tissue
located only in the
A
heart
22
Q
Cardiac Muscle Tissue
are shaped
A
Short, wide, branched cells with 1 or 2 nuclei
23
Q
Cardiac Muscle Tissue
what kind of movement
A
Is striated like skeletal muscle but is not voluntary
24
Q
Cardiac Muscle Tissue
Contracts at a
A
fairly steady rate set by the heart’s pacemaker
25
Cardiac Muscle Tissue
| Neural controls allow what kind of responce
heart to respond to changes in bodily needs
26
Smooth Muscle Tissue
| Found in the walls of
hollow visceral organs, such as the stomach, urinary bladder, and respiratory passages
27
Smooth Muscle Tissue
| shape like
Spindle shape, uninucleate
28
Smooth Muscle Tissue
| Forces
food and other substances through internal body channels
29
Smooth Muscle Tissue
| movement
It is not striated and is involuntary
30
skeletal muscle
| The three connective tissue sheaths are:
Endomysium
Perimysium
Epimysium
31
skeletal musclean overcoat of dense regular connective tissue that surrounds the entire
muscle
Epimysium
32
skeletal musclefibrous connective tissue that surrounds groups of muscle fibers called
fascicles
Perimysium
33
skeletal musclefine sheath of connective tissue surrounding each muscle fiber
Endomysium
34
Nerve and Blood Supply to Skeletal Muscle:
| Each muscle is served by one
nerve, an artery, and one or more veins
35
Nerve and Blood Supply to Skeletal Muscle:
| Each skeletal muscle fiber is supplied with a
nerve ending that controls contraction
36
Nerve and Blood Supply to Skeletal Muscle:
| Contracting fibers require
continuous delivery of oxygen and nutrients via arteries
37
Nerve and Blood Supply to Skeletal Muscle:
| Wastes must be removed via
veins
38
Skeletal Muscle Fiber
| Each fiber is shaped like
a long, cylindrical cell with multiple nuclei just beneath the sarcolemma
39
Skeletal Muscle Fiber
(muscle
plasma membrane)
sarcolemma
40
Skeletal Muscle Fiber
| Fibers are shaped
10 to 100 m in diameter, and up to hundreds of centimeters long
41
Skeletal Muscle Fiber
| ? has numerous glycosomes and a unique oxygen-bindingprotein called?
Sarcoplasm
| myoglobin
42
Skeletal Muscle Fiber
| Fibers contain
the usual organelles
myofibrils
sarcoplasmic reticulum (specialized ER)
T tubules (extension of sarcolemma into muscle cell)
43
Skeletal Muscle Fiber
| Myofibrils look like
densely packed, rod-like contractile elements
44
Skeletal Muscle Fiber
myofibrils
They make up most of the
muscle volume
45
Skeletal Muscle Fiber
| The arrangement of myofibrils within a fiber is such that a
perfectly aligned repeating series
| of dark A bands and light I bands is evident
46
The smallest contractile unit of a muscle
Sarcomeres
47
sarcomeres
| The region of a myofibril between
two successive Z discs
48
Sarcomeres are composed of ? that are made up of ?
myofilaments made up of contractile proteins
49
have are of two types – thick and thin
myofilaments
50
extend the entire length of an A band
Myofilaments/Filaments:
| Thick filaments
51
extend across the I band and partway into the A band
Myofilaments/Filaments:
| Thin filaments
52
sheet of proteins (connections) that anchors the thin filaments and connects myofibrils
to one another
Myofilaments/Filaments:
| z disk
53
appear darker due to the presence of the protein myomesin
Myofilaments/Filaments:
| m line
54
are composed of myosin
Thick filaments
55
Each myosin molecule has a
rodlike tail and two globular heads
56
two interwoven, heavy polypeptide chains
Tails
57
two smaller, light polypeptide chains called cross bridges
heads
58
Thin filaments are chiefly composed of
actin
59
Each actin molecule is a
helical polymer of globular subunits called G actin
60
The subunits of the actin molecule contain the active sites to which myosin heads attach
contraction
61
are regulatory proteins bound to actin
Tropomyosin and troponin
62
is an elaborate, smooth endoplasmic reticulum that surrounds each myofibril
Sarcoplasmic Reticulum (SR):
63
```
Sarcoplasmic Reticulum (SR):
Stores and releases
```
calcium
64
Deep extensions of the muscle cell membrane (sarcolemma
T-tubules
65
T-tubules
| Conduct impulses to the deepest regions of the?
muscle
66
Thin filaments slide past the thick ones so that the
actin and myosin filaments overlap to a
| greater degree
67
In the relaxed state, thin and thick filaments overlap
slightly
68
Upon stimulation, myosin heads bind to
actin and sliding begins
69
Each myosin head binds and detaches several times during
during contraction, acting like a ratchet to
| generate tension and propel the thin filaments to the center of the sarcomere
70
during the contraction As this event occurs throughout the sarcomeres the muscle
the muscle shortens
71
In order to contract, a skeletal muscle must
a. Be stimulated by a nerve ending
b. Propagate an electrical current, or action potential, along its sarcolemma
c. Have a rise in intracellular Ca2+ levels, the final trigger for contraction
72
Linking the electrical signal to the contraction is
excitation-contraction coupling
73
Skeletal muscles are stimulated by
motor neurons of the somatic nervous system
74
Axons of these motor neurons travel in
nerves to muscle cells
75
Axons of motor neurons branch
profusely as they enter muscles
76
Each axonal branch forms a
neuromuscular junction with a single muscle fiber
77
The neuromuscular junction is formed from:
Axonal endings
| motor end plate of a muscle,
78
? which have small membranous sacs (synaptic vesicles) that contain the neurotransmitter?
Axonal endings
| acetylcholine (ACh)
79
which is a specific part of the sarcolemma that
| contains ACh receptors and helps form the neuromuscular junction
motor end plate of a muscle
80
Though exceedingly close, axonal ends and muscle fibers are always separated by a space
called the
synaptic cleft
81
When a nerve impulse reaches the end of an axon at the neuromuscular junction what happens
Voltage-regulated calcium channels open and allow Ca2+ to enter the axon
Ca2+ inside the axon terminal causes synaptic vesicles to fuse with the axonal
membrane
82
synaptic vesicles to fuse with the axonal
| membrane, This fusion releases
ACh into the synaptic cleft via exocytosis
83
ACh diffuses across the synaptic cleft
to ACh receptors on the sarcolemma
84
Binding of ACh to its receptors generates an
end plate potential
85
ACh bound to ACh receptors is quickly destroyed by the enzyme
acetylcholinesterase
86
being destroyed by the enzyme, This destruction prevents continued
muscle fiber contraction in the absence of additional
| stimuli
87
All cell membranes are
polarized
88
with the cell membrane There’s a voltage difference across the membrane
Inside is more
negative relative to the outer membrane face.
89
Role of ACh:
| When ACh binds to ACh receptors at the motor end plate
gated ion channels for Na-K open.
90
Role of ACh
| More Na+ diffuses in than
K+ out, temporarily changing the membrane potential
91
Role of ACh
| Interior becomes less
negative
92
Role of ACh
| when the interior does become negative its called
depolarization.
93
depolarization
| Initially, this is a local electrical event called
end plate potential
94
Later, it ignites an action potential that
spreads in all directions across the sarcolemma
95
Action Potential: Electrical Conditions of a Polarized Sarcolemma
The outside (extracellular) face is
while the inside face is
positive
| negative
96
Action Potential: Electrical Conditions of a Polarized Sarcolemma
This difference in charge is the
resting membrane potential
97
Action Potential: Electrical Conditions of a Polarized Sarcolemma
The predominant extracellular ion is
NA+
98
Action Potential: Electrical Conditions of a Polarized Sarcolemma
The predominant intracellular ion is
K+
99
Action Potential: Electrical Conditions of a Polarized
An axonal terminal of a motor neuron releases ACh and causes a patch of the sarcolemma to
become permeable to
Na+ (sodium channels open)
