Muscular System Flashcards
(125 cards)
1
Q
Refers to the study of the Muscular System
A
Myology
2
Q
What are the three different types of muscle tissue/muscles
A
Skeletal, cardiac, and smooth
3
Q
It permits the movement of the body, maintains postures and circulates blood throughout the body body
A
Muscular System
4
Q
What are the five properties of the muscles
A
Excitability
Contractility
Extensibility
Elasticity
Tonicity
5
Q
The capacity of muscles to receive and respond to stimulus.
A
Excitability
6
Q
The capacity of the muscles to shorten and tighten.
A
Contractility
7
Q
The capacity of the muscles to stretch/extend upon the application of force.
A
Extensibility
8
Q
The ability of the muscle to regain the original shape and size after being stretched.
A
Elasticity
9
Q
What are the functions of muscles
A
- Movement
- Heat production
- Posture
- Alters diameters of tubes and vessels in the body
- Protect vital organs
10
Q
Two major types of muscles according to the type of action
A
Voluntary and involuntary
11
Q
One of the four primary tissue types of the body
A
Muscle
12
Q
Multinucleated structures that compose the skeletal muscles.
A
Skeletal muscles fibers
13
Q
What are the 2 characteristics of skeletal muscles
A
Voluntary and striated
14
Q
These muscle cells are also called cardiocytes/heart muscle
A
Cardiac Muscles
15
Q
They have one to two nuclei and are physically and electrically connected to each other, so that the entire heart to contract as one unit, called a syncytium.
A
Cardiac muscles
16
Q
Where are cardiac muscle fibers found?
A
Walls of the heart
17
Q
What are the typical dimensions of a cardiac muscle fiber?
A
Length: 50–100 µm; Diameter: 10–20 µm.
18
Q
What are the two main characteristics of cardiac muscles?
A
Striated and involuntary
19
Q
small, spindle-shaped, and mononucleated, with fewer actin and myosin filaments than skeletal muscles.
A
Smooth muscle fibers
20
Q
the ability of the muscle to stretch without developing lasting high tension.
A
Plasticity
21
Q
What are the dimensions of smooth muscle fibers?
A
Length: 30–200 µm; Width: 5–10 µm.
22
Q
Where are smooth muscles primarily located?
A
In the walls of the small intestines, blood vessels, vagina, and stomach.
23
Q
What are the two main characteristics of smooth muscles?
A
Non-striated and involuntary
24
Q
What are the three layers of connective tissue in skeletal muscles called?
A
Mysia, which enclose and provide structure to the muscle while compartmentalizing muscle fibers.
25
a sheath of dense fibrous connective tissue beneath the skin or around muscle fibers, holding muscle fibers together
Fascia
26
What are the three connective tissue components covering skeletal muscle?
Epimysium – Connective tissue/fascia surrounding the entire muscle.
Perimysium – Connective tissue extending inward from the epimysium, surrounding muscle fascicles (bundles of fibers).
Endomysium – Connective tissue surrounding individual muscle fibers.
27
Skeletal muscle attachments
Tendon
Aponeuroses
Tendon sheaths
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a cord of dense fibrous connective tissue that attaches a muscle to the periosteum of a bone.
Tendon
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Tendons that take the form of broad, flat sheets, attaching to the coverings of a bone, another muscle, or the skin.
Aponeuroses
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tubes of fibrous connective tissue that enclose certain tendons, especially those at the wrist and ankle, allowing tendons to slide back and forth more easily.
Tendon sheaths
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Attachments of Both Ends of Skeletal Muscles
Original and insertion
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less movable, generally proximal point of attachment, where the muscle tendon attaches to the stationary bone.
Original
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more movable, generally distal point of attachment, where the muscle tendon attaches to the movable bone.
Insertion
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the central, fleshy part of the muscle between the origin and insertion.
Belly/ gaster
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Skeletal muscle shapes
Longitudinal
Pennate
Circular
Convergent
Fusiform
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The fasciculi run parallel to the long axis of the muscle, terminating at flat tendons. These muscles are typically quadrilateral in shape.
Example: Stylohyoid muscle, sartorius muscle.
longitudinal/parallel
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The fasciculi are short, obliquely oriented, and directed toward a tendon that runs nearly the entire length of the muscle, resembling feather plumes.
Pennate
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The fasciculi are arranged on only one side of the tendon.
Example: Extensor digitorium.
unipennate
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fascicles are arranged on both sides of a centrally positioned tendon.
bipennate
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It has a complex arrangement involving the convergence of several tendons.
Example: Deltoid muscle.
multipennate
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It has a broad origin of fasciculi converging to a narrow insertion, forming a triangular shape.
Example: Pectoralis major.
convergent
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The fasciculi are arranged in a circular pattern, enclosing an orifice.
Example: Orbicularis oculi muscle.
circular
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The fasciculi run nearly parallel to the longitudinal axis, tapering toward tendons at both ends, with the belly being wider than the tendons.
Example: Biceps brachii.
fusiform
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Elongated, cylindrical cells that lie parallel to one another, with a diameter of 10 to 100 μm and lengths of 30 μm or more.
Muscle fibers
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The plasma membrane of a muscle fiber, a thin membrane that surrounds the muscle cells.
Sarcolemma
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The cytoplasm of a muscle fiber, containing enzymes, the sarcoplasmic reticulum, and myofibrils.
Sarcoplasm
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- a network of membrane enclosed tubules comparable to smooth endoplasmic reticulum
Sarcoplasmic reticulum
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- it is where protein and lipids are manufactured, it also transports products within the muscle fiber
Sarcoplasmic reticulum
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Dilated sacs of the sarcoplasmic reticulum that form ring-like channels around myofibrils.
Terminal cisternae
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Extensions of the sarcolemma that open to the outside of the muscle fiber and interface with the sarcoplasmic reticulum.
Transverse tubules
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consists of transvers tubule and the segments of sarcoplasmic reticulum (terminal cisterns) on either side.
Triad
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Cylindrical structures 1 to 2 μm in diameter, made of thin and thick myofilaments.
Myofibrils
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What are thin myofilaments made of?
Composed of actin, tropomyosin, and troponin (which binds with actin, calcium, and tropomyosin).
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Diameter of thin myofilament
6 nm um
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What are thick myofilaments composed of?
Mainly composed of myosin, shaped like a golf club with two bulbous heads
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contains actin-binding sites and ATP-binding sites.
Cross-bridges
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Structural and functional units of muscles, fundamental unit of muscle contraction.
Sarcomeres
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light colored, less dense area, composed of thin myofilaments only
I band
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represents the length of thick myofilaments
A band
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narrow zones of dense material that separates sarcomeres from one another
Z line/ Z disk
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What are the three regions of the A-band?
H-Region
- narrow region in the center of A-Band, contains thick myofilaments only
M-Line
- located in the center of the H-zone
- series of fine threads that appear to
connect the middle parts of adjacent thick myofilaments
Zone of Overlap
- where thick myofilaments at either end of the sarcomere overlap
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Storehouse of the cell
Mitochondria
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sliding of myofilaments and shortening of sarcomeres causes the shortening of the muscle fibers
Sliding filament theory
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states that msucles either contract with all force possible under existing conditions or do not contract at all
All or None principle
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neuron that stimulates muscle contraction deliver stimulus to muscle tissue.
Motor neuron
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refers to the axon terminal of a motor neuron together with the motor end plate
Neuromuscular junction
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The region of the sarcolemma adjacent to the axon terminal
Motor end plate
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expanded bulblike structures of the distal ends of the axon terminals.
Synaptic end bulbs
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membrane enclosed sacs contained in synaptic end bulbs store chemicals called neurotransmitters including acetylcholine.
Synaptic vesicles
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neurotransmitter released at neuromuscular junction in skeletal muscles
Acetylcholine
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invaginate area of the sarcolemma under the axon terminal.
Synaptic gutter
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space between the sarcolemma under the axon terminal.
Synaptic cleft
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numerous folds of the sarcolemma along the synaptic gutter
Subneural clefts
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composed of motor neuron together with all the muscle fibers it stimulates.
Motor unit
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What are the contraction cycle
ATP hydrolysis.
Attachment of myosin to actin to form cross-bridges.
Power stroke.
Detachment of myosin from actin.
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What are the two specific changes during contraction
Structural change and electrical change
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Refractory period: the period of lost excitability
Absolute refractory period
Relative refractory period
Supranormal
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period when muscle cannot be stimulated
Absolute refractory period
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period when a stronger stimulus cause excitation
Relative refractory period
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a time when the cell is highly excitable that stimulus of minimal threshold can cause excitation
Supra-normal
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Phases of Contraction
Lag phase
Contraction phase
Relaxation phase
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brief period between the application of stimulus to the beginning of contraction
Lag phase
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- upward tracing
- caused by cross bridge activity
Contraction phase
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- indicated by downward tracing
- caused by the active transport of calcium ions back into the sarcoplasmic reticulum
Relaxation phase
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- indicated by downward tracing
- caused by the active transport of calcium ions back into the sarcoplasmic reticulum
Relaxation phase
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Types pf stimuli that muscle receives
Liminal (threshold) stimulus
Sub-liminal stimulus
Maximal
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the stimulus is lesser in intensity that does not reach the patient’s consciousness; cannot initiate contraction
Sub-liminal stimulus
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all motor units are excited with only single stimulus.
Maximal
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TYPES OF HEAT PRODUCTION DURING CONTRACTION
Initial heat and recovery heat
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heat release during actual contraction process and combination of 3 events of the contraction
Initial heat
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What are the 3 events of contraction
1. Heat of activation
- heat is produced from the breakdown of ATP to ADP and AMP
2. Heat of shortening
- heat is deliberated when there is a change in the length of muscle
3. Heat of relaxation
- heat is produced when contracted muscle relaxes
92
- occur after contraction and when recovery is over
- produced when there is restoration of lost energy in prepartion of the muscle for
the next contraction
Recovery Heat
93
FACTORS THAT AFFECT THE STRENGTH/HEIGHT OF CONTRACTION
Strength of stimulus
Speed of stimulus
Weight of load
Duration
Summation/summatotal
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composed of phosphocreatine and ATP
Phosphagen system
95
short-lived molecule which rapidly degenerates to a more stable ADP, used to provide energy for muscle contraction.
Atp
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a product of CHON metabolism
- maintains adequate amounts of ATP
Phosphocreatine
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Metabolic process by which glycogen or glucose from the blood is broken down to pyruvic acid – the process results in the synthesis of ATP.
Glycolysis
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- occurs in the absence of oxygen
- oocurs in the breakdown of glucose to yield ATP and lactic acid
Anaerobic process
99
- requires oxygen and breaks down glucose by glycolysis
- produces ATP, CO2 and H2O.
Aerobic system
100
does not produce movement but increases firmness of muscle that maintains posture
Tonic
101
responsible for movements of arms and legs
Isotonic
102
length of muscle does not change but the amount of tension increases during the contraction process.
Isometric
103
- contraction of an entire muscle in response to a stimulus that causes an action potential in one or more muscle fibers.
Twitch
104
smooth, sustained contraction produced by a series of very rapid stimuli to a muscle
Tetanic
105
a rapid stimulation occurs in which tension produced will rise to a peak and a period of relaxation will be very short to brief
Incomplete
106
the frequency of stimulation is so high that the relaxation phase has been completely eliminated.
Complete
107
- a staircase effect or phenomenon
Treppe
108
- cardiac arrhythmia in which muscles of the heart function irregularly
- involuntary brief twitch of a muscle that is not visible under the skin and is not associated with the movement of the affected muscle
Fribrillation
109
a violent, involuntary contraction of the entire muscle group
Convulsion
110
TYPES OF MUSCLE ACTIONS
1. Agonist
- prime mover
- plays the major role in accomplishing a particular movement
2. Antagonist
- acts against the prime movers
3. Synergists
- muscles that work together to cause a movement
- enables the prime movers to perise smoothy and efficiently
4. Fixator
- muscle which steadies the bone which gives the action of the prime movers so that insertion will move
- stabilizes the origin of the prime movers
111
an abnormal congenital condition characterized by progressive symmetric wasting of the leg and pelvic muscles
Duchenne’s Muscular Dystrophy
112
decrease in muscle size as a result of disuse/immobility
Muscular atrophy
113
chronic, progressive degenerative disease resulting from the destruction of acetylcholine receptors in the neuromuscular junction
Myasthenia Gravis
114
painful spastic muscle contraction resulting from irritation within the muscle
Cramps
115
sudden involuntary contraction of skeletal muscle/ brief period complete tetannus
Spasm
116
Convulsion
strong involuntary contraction of the entire muscle group
117
shortening of muscle cells or muscle fibers
Contracture
118
loss of muscle tone wherein the muscle appears soft and flabby
Flaccidity
119
an increase in size of individual muscle cells due to chronic stimulation and use
Hypertrophy
120
increase in number of muscle cells
Hyperplasia
121
inflammation of muscle tissue
Myositis
122
muscle pain
Myalgia
123
inflammation of the surrounding connective tissues of the muscle
Fibrositis
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tear or break in the ligaments in tendons
Sprain
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tear or break in the muscles
Strain
