Chapter 6 Flashcards
(155 cards)
1
Q
Latin word mus means?
A
little mouse
2
Q
Essential function of muscle
A
contraction or shortening
3
Q
What can be viewed as the “machines” of the body?
A
Muscles
4
Q
3 types of muscle tissue
A
Skeletal
Cardiac
Smooth
5
Q
Why are muscle cells called muscle fibers?
A
Because they are elongated, except for cardiac muscle cells
6
Q
What is being referred to when you see the prefixes myo, mys and sarco?
A
Muscle is being refereed
7
Q
Skeletal muscle fibers are packed into the organs called?
A
Skeletal muscles
8
Q
The largest of the muscle fiber type
A
Skeletal muscle
9
Q
Skeletal muscle is also known as?
A
Striated muscle and Voluntary muscle
10
Q
Why is Skeletal muscle called Striated muscle?
A
because its fibers have obvious
11
Q
Why is Skeletal muscle called Voluntary muscle?
A
because it is the only muscle type subject to conscious control
12
Q
Each muscle fiber is enclosed in a delicate connective tissue sheath called an?
A
Endomysium
13
Q
Several sheathed muscle fibers are then wrapped by a coarser fibrous membrane called?
A
Perimysium
14
Q
Perimysium form a bundle what fibers?
A
Fascicle
15
Q
Many fascicles are bound together by an even tougher “overcoat” of connective tissue called?
A
Epimysium, which covers the entire muscle
16
Q
Epimysia blend either into what?
A
Strong, cordlike tendons or into sheetlike aponeuroses, which attach muscles indirectly to bones, cartilages or connective tissue coverings.
17
Q
The most important function of tendons
A
Providing durability and conserving space
18
Q
What muscle type has no striations and is involuntary?
A
Smooth Muscle
19
Q
Where can you find smooth muscle?
A
Mainly in the walls of hollow visceral organs such as the stomach, urinary bladder, and respiratory passages.
20
Q
We can best describe Smooth muscle using the terms
A
Visceral, Non-striated and Involuntary
21
Q
spindle shaped, single nucleus, and are surrounded by scant endomysium
A
Smooth cells
22
Q
smooth muscles handle what kind of “activities”
A
“house keeping” activities
23
Q
The contraction of smooth muscle is
A
slow and sustained
24
Q
Where is the Cardiac muscle found and what does it form?
A
It is only found in the heart and it forms the bulk of the heart walls
25
How is Cardiac muscle similar to Skeletal and Smooth muscle?
Cardiac muscle is striated like skeletal muscle and involuntary like like smooth muscle
26
We can best describe Cardiac muscle using the terms
Cardiac
Striated
Involuntary
27
Cardiac fibers are cushioned by what?
small amounts of soft connective tissue (endomysium)
28
Cardiac muscles are arranged in
spiral or figure 8 shaped bundles
29
Cardiac muscles fibers are branching cells joined by special junctions called
Intercalated disks
30
The term muscular system applies specifically to what system?
Skeletal System
31
Main function of all muscle systems
Proving movement
32
3 main other functions of skeletal muscle
Maintains posture
Stabilizes joints
Generates heat
33
What are responsible for mobility of the body as a whole?
Skeletal muscles
34
Smooth muscles of blood vessel walls and cardiac muscle of the heart, work together to?
circulate blood and maintain blood pressure
35
What is important in reinforcing and stabilizing joints that have poorly fitting articulating surfaces (the shoulder joints, for ex)
muscle tendons
36
What is generated as a by-product of muscle activity?
Body heat
37
what accounts for atleast 40% of the body mass and is the most responsible for generating heat?
Skeletal muscle
38
Many nuclei can be seen beneath the plasma membrane, which is called
Sacrolemma
39
The nuclei are pushed aside by long ribbon like organelles
Myofibers
40
What give the muscle cell as a whole its striped appearance
Alternating light (I) and dark (A) bands along the length of the perfectly aligned myrofibers
41
The light band has a midline interruption, dark area called
Z disk
42
The dark A band has a lighter central area called the
H zone
43
The M line in the center of the H zone contains what?
tiny protein rods that hold adjacent thick filaments together
44
banding patterns reveal what?
working structure of the myofibrils
45
Myofibirls are actually chains of tiny contractile units called
sacromeres, which are alligned end to end like boxcars in a train along the length of the microfibirls
46
what produces the binding pattern?
arrangement of even smaller structures (myrofilaments) within sarcomeres produces the banding pattern
47
2 types of threadlike proteinmyofilaments
Thick filaments
| Thin filaments
48
Another name for Thick filaments?
myosin filaments
49
Myosin filaments are made up of
mostly bundled molecules of the protein myosin
| also contains ATPase enzymes
50
thing filaments are composed of the contractile protein called
actin
51
Another name for thin filament
actin filament
52
actin filaments are anchored to the
Z disk
53
A specialized smooth endoplasmic reticulum
Sarcoplasmic reticulum (SR)
54
the main role of SR?
store calcium and to release it on demand when the muscle fiber is stimulated to contract
55
Skeletal muscle cells are
multinucleate
56
Special functional properties of muscle cells
Excitability (responsiveness)
| Contractility
57
What does Extensibility mean?
its the ability of muscle cells to be stretched
58
What does Elasticity mean?
Its the ability to recoil and resume their resting length after being stretched
59
What does Contractility mean?
Its the ability to shorten (forcibly) when adequately stimulated.
60
What does Excitability mean?
Its the ability to receive and respond to a stimulus
61
To contract, skeletal muscle cells must be stimulated by
Nerve impulses
62
One neuron and all the skeletal muscle cells it stimulates is called a
motor unit
63
nerve fiber
A long, thread like extension of the neuron
64
motor unit
One neuron and all the skeletal muscle cells it stimulates is called a
65
What contains vesicles filled with a chemical referred to as a neurotransmitter?
Neuromuscular (nerve muscle)
66
The specific neurotransmitter that stimulates skeletal muscle cells is called
acetylcholine or ACh
67
Although the nerve ending and muscle cells' membranes are very close, they never
touch
68
The gap between nerve ending and muscle cells is called
synaptic cells
69
synaptic cleft is filled with
tissue (interstitial) fluid
70
Another name for nerve fiber
axon
71
What 2 structures are closely associated at a neuromuscular junction?
The axon ending of a motor neuron and the sarcolemma of the skeletal muscle cell
72
What happens when a nerve impulse reaches the axon terminals?
Calcium channels open and calcium enters terminal
calcium entry causes some of the synaptic vesicles in the axon terminal to release acetylcholine
Then diffuses across the synatic cleft and attaches to receptors
If enough acetylcholine is released, the sarcolemma at that point becomes temporarily even more permeable to sodium ions.
73
What ions enter the muscle cells during action potential generation?
Sodium ions
74
What causes the filaments to slide?
When muscle fibers are activated by the nervous system, the myosin heads attach to binding sites on the thin filaments and the sliding begins
75
The attachment of the myosin cross bridges to actin requires
Calcium ions
76
In skeletal muscle, the "all of non" law of muscle physiology applies to the
muscle cell, not to the whole muscle
77
The whole muscle reacts to stimuli with
Graded responses or different degree of shortening
78
Graded muscle contractions can be produced 2 ways
- changing the frequency of muscle stimulation
| - changing the number of muscle cells being stimulated at one time
79
muscle twitches
single, brief, jerky contractions
80
What does it mean the muscle is said to be in fused or complete tetanus or in tetanuc contraction?
When the muscle is stimulated so rapidly that no evidence of relaxation is seen and the contractions are completely smooth and sustained
81
What produces stronger muscle contractions and what is its primary role?
Tetanus
| Its primary role is to produce smooth and prolonged muscle contractions.
82
True muscle fatigue
Muscle quits entirely. Commonly happens in marathon runners
83
Types of muscle contractions
- Isotonic
| - Isometric
84
What happens during Isotonic contractions?
The microfilaments are successful in their sliding movements, the muscle shortens and movements occurs.
Ex: bending the knee, rotating the arms and smiling
85
Contractions in which the muscles do not shorten are called
isometric contractions
86
The result of different motor units, when are scattered through the muscle, being stimulated by the nervous system in a systematic way
muscle tone
87
What happens if the nerve supply to a muscle is destroyed?
The muscle is no longer stimulated and it loses tone and becomes paralyzed. Soon after it becomes flaccid (soft and flabby) and begins to atrophy (waste away)
88
The join, the origin, is attached to where?
immovable or less movable bone
89
insertion is attached where? when muscle contacts?
to the movable bone.
| the insertion moves toward the origin
90
Common types of body movements
- Flexion
- Extension
- Rotation
- Abduction
- Adduction
- Circumduction
91
Describe flexion
Movement generally in the sagittal plane, that decreases the angle of the join and brings 2 bones closer together.
Flexion is typical of hinge joints (bending of knee or elbow)
Also common at ball and socket joints (bending forward at the hip)
92
Describe extension
Opposite of flexion.
| Increases the angle or the distance between 2 bones or parts of the body.
93
Describe rotation
movement of the bone around its longitudinal axis
| common movement of ball and socket joints and describes the movement of the atlas around the dens of the axis
94
Describe abduction
moving a limb away from the midline or median place
| applies to the fanning movement of the fingers or toes when they are spread apart
95
Describe adduction
opposite of abduction
| movement of a limb toward the body midline
96
Describe circumduction
combination of flexion, extension, abduction and adduction commonly seen in ball and socket joints.
97
Special movements that only occur at a few joints
- Dorsiflexion and plantar flexion
- Inversion and eversion
- Supination and pronation
- Opposition
98
Dorsiflexion
Lifting the foot so that its superior surface approaches the shin is called dorsiflexion
Extension of the hand at the wrist
99
Plantar flexion
depression on the foot
corresponds to flexion of the hand
100
To invert the foot
turn the sole medially
101
To exert the foot,
turn the sole laterally
102
Supination and Pronation
backward and forward, refer to movements of the radius around the ulna
103
Supination occurs
when the forearm rotates laterally so that the palm faces anteriorly and the radius and ulna are parallel
104
Pronation occurs
when the forearm rotates medially so that the palm faces posteriorly
105
Group of muscles that produce opposite movements
lie on opposite sides of a joint
106
Muscles that has the major responsibility for causing a particular movement is called the
prime mover
107
Muscles that opposes or reverse a movement are
antagonists
108
When a prime mover is active,
its antagonist is stretched and relaxed
109
prime mover of elbow flexion
biceps
110
prime mover of elbow extension
triceps
111
Synergists help prime movers by
producing the same movement or by reducing undesirable movements.
112
Specialized synergists
Fixators
113
Function of fixators
They hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone.
114
What action is being performed by a person who sticks his thumb to hitch a ride?
Abduction
115
In what way are fixators and synergist muscles important?
They anchor or aid the prime mover
116
rectus
straight
117
oblique
the muscle fibers run obliquely (at a slant) to the imaginary line
118
skeletal muscles consist of
fascicles, but fascicle arrangements vary, producing muscles with different structures and functional properties.
119
General term for circular muscles
Sphincters (squeezers)
| Ex: orbicularis muscles surrounding eyes and mouth
120
In a convergent muscle,
the fascicles converge toward a single insertion tendon
| triangular or fan shaped
121
In a parallel arrangement,
the length of the fascicles run parallel to the long axis of the muscle.
straplike
122
A modification of the parallel arrangement is called
fusiform, results in a spindle shaped muscle with an expanded belly.
biceps brachii muscle of the arm
123
In a pennate pattern
short fascicles attach obliquely to a central tendon
124
A muscle fascicle arrangement determines its
range of motion and power
125
contractile unit of muscle
sarcomere
126
a muscle cell
Fiber
127
plasma membrane of the muscle fiber
sarcolemma
128
a long filamentous organelle with a banded appearance found within muscle cells
myofibril
129
actin- or myosin-containing structure
myofilament
130
cord of collagen fibers that attaches a muscle to a bone
tendon
131
From the inside out, name the three types of connective tissue wrappings of a skeletal muscle
endomysium
perimysium
epimysium
132
What overlapping structures cause the "banding" appearance of skeletal muscle fibers?
Myofilaments actin and myosin
133
Which of the following describes actin containing filaments?
They slide towards each other during contraction.
134
What does it mean when the sarcolemma is depolarized?
A reverse of the electrical conditions of the membrane due to an influx of sodium ions
135
What is the role of acetylcholine in muscle contraction?
Acetylcholine attaches to the sarcolemma and makes the membrane more permeable.
136
What chemical triggers the sliding of the muscle filaments?
Calcium
137
Which of the following describes complete tetanus of a muscle?
A smooth continuous contraction without any evidence of relaxation because stimulus is delivered rapidly and continually.
138
What is the slowest pathway for ATP regeneration?
Aerobic respiration
139
Which of the following describes isometric muscle exercise?
Muscle size and strength will increase because the muscle fibers are making more myofilaments.
140
Which of the following correctly describes one of the five golden rules of skeletal muscle activity?
Most skeletal muscles cross at least one joint.
141
When a person shakes the head to indicate "no," what type of movement is being demonstrated?
Rotation
142
What type of movement is indicated when a limb is moved toward the midline of the body?
Adduction
143
Which of the following describes muscle insertion?
It moves toward the origin when a muscle contracts.
144
When the knee is bent, the hamstring group of muscles contract. What is the insertion of this muscle group?
Tibia
145
What is the significant role of synergists and fixators?
They stabilize a bone and prevent excessive unwanted movement.
146
What criterion is used in naming the deltoid muscle?
Muscle shape
147
What is the fascicle arrangement of the orbicularis oris muscle?
Circular
148
What muscle compresses the cheek to hold food between the teeth during chewing?
Buccinator
149
What muscle is responsible for the flexion of the head?
Sternocleidomastoid
150
What muscle is a prime mover of arm abduction and also a favored site for administering intramuscular injections?
Deltoid
151
What is the function of the latissimus dorsi muscle?
Extension and adduction of the humerus
152
Which muscle is responsible for knee flexion?
Biceps femoris
153
What muscle is the prime mover for plantar flexion?
Gastrocnemius
154
Which of the following describes muscle fatigue?
The muscle is unable to contract due to oxygen deficiency.
155
Which of the following describes muscular dystrophy?
Muscle weakness due to atrophy and increased fat and connective tissue deposits
