Chapter 6: The Muscular System Flashcards
(97 cards)
1
Q
What are the 3 types of muscles?
A
Skeletal Muscle
Cardiac Muscle
Smooth Muscle
2
Q
What is the location of skeletal muscle?
A
Attached to bone or skin (for some facial muscles)
3
Q
What is the location of cardiac muscle?
A
walls of the heart
4
Q
What is the location of smooth muscle?
A
mostly in walls of visceral organs (other than the heart)
5
Q
What do skeletal muscle cells look like ?
A
Single, very long, cylindrical, multinucleate cells with very obvious striations
6
Q
What do cardiac muscle cells look like ?
A
branching chains of cells, uninucleate, striations, intercalated discs
7
Q
What do smooth muscle cells look like ?
A
single, fusiform, uninucleate, no striations
8
Q
What are the connective tissue components of skeletal muscle?
A
Endomysium, perimysium, and epimysium
9
Q
What are the connective tissue components of cardiac muscle?
A
endomysium
10
Q
What are the connective tissue components of smooth muscle?
A
endomysium
11
Q
Endomysium
A
encloses a single muscle fiber
12
Q
perimysium
A
wraps around a fascicle (bundle) of muscles fibers
13
Q
Epimysium
A
covers the entire skeletal muscle
14
Q
fascia
A
on the outside of the epimysium
15
Q
What is the direct attachment from muscle to bone?
A
epimysium
16
Q
What are 2 indirect attachments from muscle to bones?
A
tendon and aponeurosis
17
Q
Name the descending order of size muscle structures.
A
Muscle Muscle fascicle Muscle fiber (AKA muscle cell) Myofibril myofilaments = actin & myosin
18
Q
Tendon
A
cord-like structures
mostly collagen fibers
often cross a joint due to toughness and small size
19
Q
aponeuroses
A
sheet-like structures
attach muscles indirectly to bones, cartilages, or connective tissue coverings
20
Q
skeletal muscle attachement sites
A
bones
cartilages
connective tissue coverings
21
Q
skeletal muscle functions (4)
A
produce movement, maintain posture, stabilize joints, generate heat
22
Q
sacrolemma
A
specialized plasma membrane
23
Q
myofibrils
A
long organelles inside muscle cell
24
Q
sacroplasmic reticulum
A
specialized smooth endoplasmic reticulum
25
What are the bands of myofibrils?
I band - light band, contains only thin filaments
| A band = dark band, contains the entire length of the thick filaments
26
sacromere
contractile unit of a muscle fiber
| contains myofilaments
27
Myofilaments
thick filaments = myosin filaments
| thin filaments = actin filaments
28
thick filaments
myosin filaments
composed of the protein myosin, has ATPase enzymes, myosin filaments have heads (extensions, or cross bridges), myosin and actin overlap somewhat
29
Thin filaments
actin filaments
| Composed of the protein actin, anchored to the Z disc
30
What kind of filaments are in the A band.
It has myosin, and lacks actin filaments
31
sacroplasmic reticulum
stores and releases calcium
| surrounds the myofibril
32
excitability
aka responsiveness or irritability
| ability to receive and respond to a stimulus
33
contractility
ability to shorten when an adequate stimulus is received
34
extensibility
ability of muscles cells to be stretched
35
elasticity
ability to recoil and resume resting length after stretching
36
motor unit
one motor neuron and all the skeletal muscle cells stimulated by that neuron
37
neuromuscular junction
association site of axon terminal of the motor neuron and muscle
38
synaptic cleft
gap between nerve and muscle
nerve and muscle do not make contact
area between nerve and muscle is filled with interstitial fluid
39
Describe the nerve stimulus and action potential
The stimulus goes to the synaptic cleft and the action potential reaches the axon terminal of the motor neuron. The Calcium channels open and calcium ions enter the axon terminal.
40
Describe the transmission of nerve impulse to muscle
calcium ion entry causes some synaptic vesicles to release their contents (acetylcholine, a neurotransmitter) by exocytosis. ACh attaches to receptors on the sarcolemma of the muscle cell. The sarcolemma becomes permeable to Na+. Na+ rushes into the cell generating an action potential and potassium leaves the cell. Once started, muscle contraction cannot be stopped.
41
neurotransmitter
chemical released by nerve upon arrival of nerve impulse in the axon terminal.
42
What's the neurotransmitter for skeletal muscle?
acetylcholine (ACh)
43
Describe the Sliding Filament Theory of Muscle Contraction
Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the thin filament. Myosin heads then bind to the next site of the thin filament. Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere. This continued action causes a sliding of the myosin along the actin. THe result is that the muscle is shortened (contracted)
44
graded responses
different degrees of skeletal muscle shortening
| Changes based on the frequency of muscle stimulation and the number of muscle cells being stimulated at one time.
45
Twitch
single, brief contraction
| Not a normal muscle function
46
Summing of contractions
one contraction immediately followed by another.
The muscle does not completely return to a resting state due to more frequent stimulations
The effects are added.
47
Unfused (incomplete) tetanus
Some relaxation occurs between contractions but nerve stimuli arrive at an even faster rate than during summing of contractions. Unless the mucles contraction is smooth and sustained, it is said to be unfused tennis,.
48
Fused (complete) tetanus
No evidence of relaxation before the following. Frequency of stimulations does not allow for relaxation between contractions.
The result is a smooth and sustained muscle contraction.
49
What is the first source of energy for muscle contraction?
ATP. It is stored in the muslces.
| only provides 4-6 seconds worth of energy stored by muscles.
50
What is the second source of energy for muscle contraction?
Direct phosphorylation of ADP by creatine phosphate (CP). Muscle cells store CP. CP supplies are exhausted in less than 15 seconds. About 1 ATP is created per CP molecule.
CP transfers a phosphate group to ADP to regenerate ATP.
51
Aerobic respiration
Glucose is broken down to carbon dioxide and water, releasing energy (about 32 ATP).
A series of metabolic pathways occur in the mitochondria.
This is a slower reaction that requires continuous oxygen.
Carbon dioxide and water are produced.
52
Anaerobic glycolysis and lactic acid formation
reaction that breaks down glucose without oxygen.
GLucose is broken down to pyretic acid to produce about 2 ATP.
Pyruvic acid is converted to lactic acid.
This is fast, but inefficient.
Lactiv acid produces muscle fatigue.
53
oxygen deficit
A common cause of muscle fatigue. Must be "repaid" to cure muscle fatigue. Oxygen is required to rid of accumated lactic acid.
54
Isotonic contractions
The muscle shortens and movement occurs . Myofilaments are able to slide past each other during contractions.
55
Isometric contractions
Tension in the muscles increases. The muscle is unable to shorten or produce movement.
56
Muscle Tone
some fibers are contracted even in a relaxed muscles. Different fibers contract at different times to provide muscle tone and to be constantly ready.
57
Five Golden Rules of Skeletal Muscle Activity
1. With a few exceptions, all skeletal m muscles cross at least one joint.
2. Typically, the bulk of a skeletal muscle lies proximal to the joint crossed.
3. All skeletal muscles have at least tow attachments; the origin and the insertion.
4. Skeletal muscles can only pull; they never push
5. During contraction, a skeletal muscle insertion moves toward the origin.
58
The origin is attachment to a __________ bone
movable
59
The insertion is the attachment to an __________ immovable bone.
immovable
60
Inversion
turn sole of foot medially
61
Eversion
turn sole of foot laterally
62
Frontalis
raises eyebrows
63
orbicularis oculi
closes eyes, squints, blinks, winks
64
buccinator
flattens the cheek, chews
65
zygomaticus
raises corners of the mouth
66
messeter
closes the jaw and elevates the mandible
67
Temporalis
synergist of the masseter, closes jaw
68
platysma
pulls the corners of the mouth inferiorly
69
sternocleidomastoid
flexes the neck, rotates the head
70
pectoralis major
adducts and flexes the humerus
71
intercostal muscles:
External intercostals
Internal intercostals
external: raise rib cage during inhalation
Internal: depress the rib cage to move air out of the lungs when you exhale forcibly
72
rectus abdominis
flexes the vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing)
73
external oblique
flex vertebral column, rotate trunk and bed it laterally
74
internal oblique
flex vertebral column, rotate trunk and bend it laterally
75
transversus abdominis
compresses abdominal contents
76
Trapezius
elevates, depresses, adducts, and stabilizes the scapula
77
latissimus dorsi
extends and adducts the humerus
78
erector spinae
beck extension
79
quadratus lumborum
flexes the spine laterally
80
deltoid
arm abduction
81
Erector Spinae
| I LOVE SPINES (3)
Iliocostalis
Logissimus
Spinalis
82
biceps brachii
supinates forearm, flexes elbow
83
brachialis
elbow flextion
84
brachiradialis
weak muscle; elbow flexion
85
Triceps brachii
elbow extension (antagonist to biceps brachii)
86
gluteus maximus
hip extension
87
gluteus medius
hip abduction, steadies pelvis when walking
88
iliopsoas
hip flexion, keeps the upper body from falling backward when standing erect
89
adductor muscles
adduct the thighs
90
Hamstring group (3) = thigh extension and knee flexion
biceps femoris
semimembranosus
semitendinosus
91
sartorius
flexes the thigh
92
quadriceps group (2) = extends the knee
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rectus femoris
vastus muscles (3)
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93
Tibialis anterior
dorsiflextion, floot inversion
94
extensor digitorum longus
toe extension and dorsiflextion of the foot
95
fibularis muscles
plantar flexion, foot eversion
96
soleus
plantar flexion
97
gastrocnemius
plantar flexion
