p.16
Muscle Cell Structure
What produces the banded or striated appearance of a muscle fiber?
The arrangement of thick and thin filaments.
p.21
Neuromuscular Junction
What is the neuromuscular junction?
A specialized intercellular connection between a motor neuron and a skeletal muscle fiber.
p.3
Functions of Muscle Tissue
What does muscle excitability refer to?
The ability of muscle tissue to respond to stimuli.
p.17
Muscle Cell Structure
Where is the M line located in a sarcomere?
In the center of each sarcomere.
p.40
Muscle Cell Structure
What is myography?
Myography is the study or recording of muscle activity.
p.7
Neuromuscular Junction
What system is required to stimulate skeletal muscles?
The central nervous system.
p.38
Muscle Fatigue and Recovery
How can anaerobic endurance be increased?
By brief, intense workouts.
p.63
Types of Muscle Tissue
What are the two types of smooth muscle?
Single-unit (visceral) smooth muscle and multiunit smooth muscle.
p.5
Skeletal Muscle Organization
Approximately how many skeletal muscles are included in the muscular system?
About 700 skeletal muscles.
p.20
Mechanism of Muscle Contraction
What role do T tubules play in muscle contraction?
T tubules trigger the release of calcium ions.
p.50
Mechanism of Muscle Contraction
What is the relationship between the strength of contraction and the strength of stimulus?
The strength of contraction is directly related to the strength of the stimulus.
p.59
Cardiac and Smooth Muscle Characteristics
What is the primary structural characteristic of cardiac muscle?
Cardiac muscle is striated and has intercalated discs.
p.5
Skeletal Muscle Organization
How are skeletal muscles attached to bones?
They are directly or indirectly attached to bones.
p.47
Mechanism of Muscle Contraction
What are the different types of muscle tone?
Normal, flaccid, spastic.
p.54
Mechanism of Muscle Contraction
What is isometric contraction?
Isometric contraction is a type of muscle contraction where the muscle length remains the same while the tension increases.
p.44
Mechanism of Muscle Contraction
What is the result of high calcium ion concentration in the cytosol?
It leads to complete tetanus, producing maximum tension.
p.38
Muscle Fatigue and Recovery
How can aerobic endurance be increased?
By sustained, low levels of activity.
p.39
Muscle Cell Structure
Do motor units come in varied sizes?
Yes, motor units come in varied sizes.
p.46
Mechanism of Muscle Contraction
What is a muscle twitch?
A muscle twitch is a single, rapid contraction and relaxation of muscle fibers following a single stimulus.
p.40
Mechanism of Muscle Contraction
What is a threshold stimulus?
A threshold stimulus is the minimum level of stimulation required to cause a muscle fiber to contract.
p.42
Mechanism of Muscle Contraction
What occurs during the latent phase of a twitch contraction?
The period after the stimulus before contraction begins.
p.1
Types of Muscle Tissue
What are the three types of muscle tissue?
Skeletal muscle, cardiac muscle, and smooth muscle.
p.1
Functions of Muscle Tissue
What is the primary function of muscle cells?
Specialized for contraction.
What is skeletal muscle tissue composed of?
Skeletal muscle tissue, connective tissue, nerves, and blood vessels.
p.54
Mechanism of Muscle Contraction
What is isotonic contraction?
Isotonic contraction is a type of muscle contraction where the muscle changes length while the tension remains constant.
p.64
Functions of Muscle Tissue
How does muscle tissue contribute to the maintenance of posture?
Muscle contractions help maintain body posture by stabilizing joints and supporting the skeleton.
p.64
Functions of Muscle Tissue
Which body systems are supported by muscle tissue?
Nervous, endocrine, cardiovascular, respiratory, digestive, urinary, and immune systems.
p.48
Muscle Disorders and Diseases
Are dying muscle fibers replaced during atrophy?
No, dying muscle fibers are not replaced.
p.55
Mechanism of Muscle Contraction
What role does gravity play in muscle elongation?
Gravity assists in the passive process of returning a muscle to its elongated state after contraction.
p.25
Mechanism of Muscle Contraction
What is the role of calcium in muscle contraction?
Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from actin's binding sites, allowing myosin to bind to actin and initiate muscle contraction.
p.59
Cardiac and Smooth Muscle Characteristics
How does the structure of cardiac muscle differ from skeletal muscle?
Cardiac muscle has intercalated discs and is branched, while skeletal muscle does not have intercalated discs and is not branched.
p.63
Types of Muscle Tissue
What is a key feature of multiunit smooth muscle?
It consists of many independent single-cell units.
p.44
Mechanism of Muscle Contraction
What is multiple wave summation?
It is the process of producing almost peak tension during rapid cycles of contraction and relaxation.
p.16
Muscle Cell Structure
How many sarcomeres does each myofibril have?
About 10,000 sarcomeres end to end.
p.24
Mechanism of Muscle Contraction
What role does ATP play in muscle contraction?
ATP provides the energy required for the myosin heads to detach from actin filaments and re-cock for another cycle of contraction.
What is the function of T tubules in muscle cells?
T tubules allow electrical impulses from the sarcoplasm to reach the cell’s interior.
p.6
Skeletal Muscle Organization
What is the epimysium?
A connective tissue that covers the entire muscle.
p.53
Mechanism of Muscle Contraction
What happens to muscle length and tension during isotonic contraction?
Tone or tension remains the same, but the length changes.
p.6
Skeletal Muscle Organization
How are tendons formed?
Collagen fibers from all three layers of connective tissue come together at the end of the muscle to form a tendon.
p.31
Energy Sources for Muscle Contraction
Why do muscle contractions require large amounts of energy?
Because muscle contraction requires large amounts of ATP.
p.20
Mechanism of Muscle Contraction
What happens when calcium binds to troponin?
It causes a shift in tropomyosin, exposing binding sites on actin filaments.
p.11
Skeletal Muscle Organization
What is the primary topic discussed in the provided text?
Structure of the skeletal muscle.
p.33
Energy Sources for Muscle Contraction
What are the two main types of metabolic pathways for energy production?
Aerobic and anaerobic pathways.
p.13
Muscle Cell Structure
What are sarcomeres made of?
Hundreds of thick and thin myofilaments.
p.34
Muscle Fatigue and Recovery
What is muscle fatigue?
Muscle fatigue is when a muscle will no longer perform at the required level, even if stimulated.
p.42
Mechanism of Muscle Contraction
What are the three phases of a twitch contraction?
Latent phase, contraction phase, and relaxation phase.
p.35
Muscle Fatigue and Recovery
What is muscle recovery?
The process of returning muscle to normal pre-exertion conditions.
p.48
Muscle Disorders and Diseases
Is muscle atrophy reversible?
Yes, if it is caused by a temporary reduction in use.
p.35
Muscle Fatigue and Recovery
What happens to lactate during muscle recovery?
Lactate is converted back to pyruvate.
p.12
Functions of Muscle Tissue
What is the primary function of skeletal muscle cells?
To facilitate movement by contracting and generating force.
p.9
Mechanism of Muscle Contraction
What causes muscle fiber contraction?
The shortening of myofibrils.
p.21
Neuromuscular Junction
What are the main components of the neuromuscular junction?
An axon terminal and a motor end plate.
p.58
Cardiac and Smooth Muscle Characteristics
What is automaticity in cardiac muscle?
The ability of cardiac muscle tissue to contract without neural stimulation.
p.51
Mechanism of Muscle Contraction
How does muscle fiber length affect tension production?
Optimal tension is produced when muscle fibers are at an intermediate length; too short or too long lengths result in decreased tension.
p.51
Mechanism of Muscle Contraction
Why does a muscle fiber produce less tension when it is too short?
Because the actin and myosin filaments overlap too much, reducing the number of cross-bridges that can form.
p.60
Cardiac and Smooth Muscle Characteristics
What advantage does the arrangement of myofilaments in smooth muscle provide?
More freedom of movement in contraction.
p.32
Energy Sources for Muscle Contraction
What are the two main pathways for energy sources in muscle contraction?
Aerobic pathway and anaerobic pathway.
p.41
Mechanism of Muscle Contraction
What does the amount of tension produced in an individual muscle fiber depend on?
The number of cross-bridges in the muscle fiber.
p.38
Energy Sources for Muscle Contraction
What is aerobic endurance?
The length of time muscle contractions are supported by mitochondrial activity.
p.14
Mechanism of Muscle Contraction
What are cross bridges in the context of muscle cell structure?
Cross bridges are connections formed between myosin heads and actin filaments during muscle contraction.
p.46
Mechanism of Muscle Contraction
How does a muscle twitch differ from tetanus?
A muscle twitch is a single contraction and relaxation cycle, while tetanus is a continuous, sustained contraction due to high-frequency stimulation.
p.20
Neuromuscular Junction
What initiates the excitation of the sarcolemma?
The excitation of the sarcolemma is initiated at the neuromuscular junction (NMJ).
p.6
Skeletal Muscle Organization
What does the perimysium do?
It divides the muscle into fascicles or bundles of muscle fibers and contains blood vessels and nerves supplying the fascicles.
p.20
Mechanism of Muscle Contraction
To which protein does calcium bind during muscle contraction?
Calcium binds to troponin.
p.51
Mechanism of Muscle Contraction
What is the length-tension relationship in muscle physiology?
It describes the relationship between the length of a muscle fiber and the tension it produces.
p.20
Mechanism of Muscle Contraction
What happens during muscle relaxation?
The sarcoplasmic reticulum (SR) actively pumps calcium back into its sacs.
p.26
Mechanism of Muscle Contraction
What is the result of myosin heads bending?
They pull thin filaments past them.
p.60
Cardiac and Smooth Muscle Characteristics
Where are smooth muscle cells commonly found?
In the walls of most organs, in the form of sheets, bundles, or sheaths.
p.62
Cardiac and Smooth Muscle Characteristics
What structural components does smooth muscle lack?
Smooth muscle lacks myofibrils, sarcomeres, and striations.
p.37
Muscle Fatigue and Recovery
Why do fast muscle fibers fatigue rapidly?
Because they have relatively few mitochondria and rely on glycolysis for energy.
p.37
Types of Muscle Tissue
What are the characteristics of slow muscle fibers?
Slow muscle fibers are about half the diameter of fast fibers, take three times as long to reach peak tension, are specialized to contract for extended periods, and are fatigue resistant.
p.7
Skeletal Muscle Organization
Why is an extensive network of blood vessels necessary in skeletal muscle?
To supply high energy use.
p.13
Mechanism of Muscle Contraction
Why are myofilaments crucial?
They are crucial to muscle contraction.
p.18
Muscle Cell Structure
What is the thin filament composed of?
A thin twisted strand of actin molecules.
p.34
Muscle Fatigue and Recovery
How does muscle fatigue affect endurance athletes?
It affects them after they use up their stores of glycogen and lipids.
p.54
Mechanism of Muscle Contraction
How does muscle tension change during isometric contraction?
The muscle tension increases while the muscle length remains the same during isometric contraction.
p.8
Mechanism of Muscle Contraction
How do T tubules contribute to muscle contraction?
T tubules allow for the unified contraction of the entire muscle fiber.
p.55
Mechanism of Muscle Contraction
What are the passive processes involved in muscle elongation following contraction?
Elastic forces, movements of opposing muscles, and gravity.
p.55
Mechanism of Muscle Contraction
What role do elastic forces play in muscle elongation?
Elastic forces contribute to the passive process of returning a muscle to its elongated state after contraction.
p.3
Functions of Muscle Tissue
What is muscle contractility?
The ability of muscle tissue to contract and generate force.
p.6
Skeletal Muscle Organization
What is a tendon?
A bundle of fibers that attaches muscle to bone.
p.58
Cardiac and Smooth Muscle Characteristics
What type of metabolism do cardiac muscle cells rely on?
Cardiac muscle cells rely on aerobic metabolism.
p.49
Mechanism of Muscle Contraction
How does muscle length affect muscle contraction?
The optimal muscle length allows for maximum force generation.
p.27
Mechanism of Muscle Contraction
What is the sliding-filament model?
The sliding-filament model is a theory that explains how muscles contract by the sliding of actin and myosin filaments over each other.
p.34
Muscle Fatigue and Recovery
What are the primary causes of muscle fatigue?
Depletion of energy reserves or a decline in pH from lactic acid production.
p.47
Mechanism of Muscle Contraction
What mechanisms are involved in regulating muscle tone?
Negative feedback mechanisms.
p.54
Mechanism of Muscle Contraction
How does muscle length change during isotonic contraction?
The muscle changes length during isotonic contraction.
p.64
Functions of Muscle Tissue
What are the main contributions of muscle tissue to homeostasis?
Movement, maintenance of internal temperature, maintenance of posture, and supporting various body systems.
p.48
Muscle Disorders and Diseases
What is muscle atrophy?
It occurs in a muscle that is not regularly stimulated by a motor neuron.
p.42
Mechanism of Muscle Contraction
How does the nervous system contribute to muscle movement?
The nervous system 'smooths out' movement.
p.35
Muscle Fatigue and Recovery
What are the key processes involved in muscle recovery?
Restoring oxygen levels, removing lactic acid, replacing intracellular energy reserves, losing heat produced during contraction.
p.35
Muscle Fatigue and Recovery
Why do breathing rate and depth remain increased after exercise?
To repay oxygen debt and restore resting conditions.
p.24
Mechanism of Muscle Contraction
What is the sliding filament theory?
The theory that muscle contraction occurs when actin filaments slide over myosin filaments, shortening the sarcomere.
p.36
Muscle Cell Structure
What are the two types of muscle fibers that affect muscle performance?
Fast-twitch and slow-twitch fibers.
p.2
Functions of Muscle Tissue
How do skeletal muscles help maintain body temperature?
Muscle contractions generate heat.
p.58
Cardiac and Smooth Muscle Characteristics
Can cardiac muscle cells undergo tetanus (sustained contraction)?
No, cardiac muscle cells cannot undergo tetanus.
p.26
Mechanism of Muscle Contraction
What binds to the exposed active sites on actin?
Myosin heads bind to them.
p.26
Mechanism of Muscle Contraction
What do myosin heads do after releasing from the active sites?
They bind to the next active site.
p.15
Muscle Cell Structure
What is the primary topic discussed in the provided text?
Structure of myofilaments.
p.39
Muscle Cell Structure
What constitutes a motor unit?
A motor neuron plus muscle fibers.
p.14
Muscle Cell Structure
What are the four different kinds of protein molecules found in myofilaments?
Myosin, Actin, Tropomyosin, Troponin.
p.46
Mechanism of Muscle Contraction
What is tetanus in muscle physiology?
Tetanus is a sustained muscle contraction that occurs when the muscle is stimulated at a high frequency, preventing relaxation between stimuli.
What components are found in skeletal muscles?
Skeletal muscle tissue, connective tissues, blood vessels, and nerves.
p.64
Functions of Muscle Tissue
In what way does muscle tissue help maintain internal temperature?
Muscle contractions generate heat, which helps maintain body temperature.
p.48
Muscle Disorders and Diseases
When can muscle atrophy be observed?
After a cast comes off a fracture.
p.10
Muscle Cell Structure
What is a triad in muscle cell structure?
A combination of two terminal cisternae and one T tubule.
p.55
Mechanism of Muscle Contraction
Is there an active mechanism for returning a muscle to a pre-contracted, elongated state?
No, there is no active mechanism for returning a muscle to a pre-contracted, elongated state.
p.21
Neuromuscular Junction
What does the axon terminal of the neuron contain?
Vesicles filled with acetylcholine (ACh), a neurotransmitter.
p.36
Functions of Muscle Tissue
How does physical conditioning or training affect muscle performance?
It is one of the factors that determine muscle performance.
p.21
Neuromuscular Junction
What happens to acetylcholine (ACh) after it is released from the axon terminal?
It diffuses across the synaptic cleft and binds to the receptor on the motor end plate.
p.21
Neuromuscular Junction
What enzyme is found in the synaptic cleft and the motor end plate, and what is its function?
Acetylcholinesterase (AChE), which breaks down acetylcholine (ACh).
p.51
Mechanism of Muscle Contraction
Why does a muscle fiber produce less tension when it is too long?
Because the actin and myosin filaments do not overlap enough, reducing the number of cross-bridges that can form.
p.60
Cardiac and Smooth Muscle Characteristics
How do smooth muscle cells compare in size to cardiac muscle cells?
They are similar in size.
p.65
Muscle Disorders and Diseases
What is myositis?
Myositis is the inflammation of muscle tissue.
p.41
Mechanism of Muscle Contraction
Can muscle cells generate compression?
No, muscle cells can only contract and produce tension.
p.32
Energy Sources for Muscle Contraction
How does the speed of the aerobic pathway compare to the anaerobic pathway?
The aerobic pathway is slower than the anaerobic pathway.
p.56
Cardiac and Smooth Muscle Characteristics
What makes cardiac muscle self-exciting?
It can generate its own electrical impulses without external stimuli.
p.62
Cardiac and Smooth Muscle Characteristics
How are adjacent smooth muscle cells connected?
Adjacent cells are bound together.
p.52
Mechanism of Muscle Contraction
What is the primary topic discussed in the text?
Strength of muscle contraction.
p.63
Types of Muscle Tissue
What characteristic is associated with single-unit (visceral) smooth muscle?
Autorhythmicity and peristalsis.
p.44
Mechanism of Muscle Contraction
What is incomplete tetanus?
It is a state where the muscle produces almost peak tension during rapid cycles of contraction and relaxation.
What is the sarcolemma?
The sarcolemma is a muscle cell’s plasma membrane.
p.16
Muscle Cell Structure
Where are thin filaments located in a sarcomere?
At either end of a sarcomere.
p.2
Functions of Muscle Tissue
What role do skeletal muscles play in maintaining posture?
They maintain posture and body position.
p.36
Functions of Muscle Tissue
What are the two factors that determine muscle performance?
Types of fibers in muscle (fast-twitch and slow-twitch) and physical conditioning or training.
p.58
Cardiac and Smooth Muscle Characteristics
What determines the timing of contraction in cardiac muscle?
Pacemaker cells, which are specialized cardiac muscle cells.
p.65
Muscle Disorders and Diseases
What are muscle strains and sprains?
Muscle strains are injuries to muscle fibers or tendons, while sprains are injuries to ligaments.
p.56
Cardiac and Smooth Muscle Characteristics
What is another name for cardiac muscle?
Striated involuntary muscle.
p.65
Muscle Disorders and Diseases
What is a muscle contusion?
A muscle contusion is a bruise caused by a direct blow or impact to the muscle.
p.56
Cardiac and Smooth Muscle Characteristics
How do cardiac muscle cells differ from skeletal muscle cells in terms of structure?
Cardiac muscle cells are striated and branched, and they have diads rather than triads.
p.49
Mechanism of Muscle Contraction
What is the stretch reflex and how does it relate to muscle contraction?
The stretch reflex is a muscle contraction in response to stretching within the muscle, helping to maintain muscle tone and posture.
p.37
Types of Muscle Tissue
How does the diameter of slow muscle fibers compare to fast muscle fibers?
Slow muscle fibers are about half the diameter of fast muscle fibers.
What is a sarcomere?
The segment of a myofibril between two Z disks.
p.38
Muscle Fatigue and Recovery
How can physical conditioning and training affect muscle performance?
It can increase power and endurance.
p.33
Energy Sources for Muscle Contraction
What is the primary difference between aerobic and anaerobic pathways?
Aerobic pathways require oxygen, while anaerobic pathways do not.
p.13
Muscle Cell Structure
What is a muscle fiber made of?
1000 or more parallel myofibrils.
p.14
Muscle Cell Structure
Which protein molecules make up the thin filaments in muscle cells?
Actin, Tropomyosin, Troponin.
p.40
Muscle Cell Structure
What does muscle graphing refer to?
Muscle graphing refers to the visual representation of muscle activity, often recorded during myography.
p.40
Mechanism of Muscle Contraction
What is a twitch contraction?
A twitch contraction is a single, rapid contraction of a muscle followed by relaxation.
p.44
Mechanism of Muscle Contraction
What occurs during complete tetanus?
The rate of stimulation is increased until the relaxation phase is eliminated, producing maximum tension.
p.16
Muscle Cell Structure
What are sarcomeres?
Repeating functional units of myofilaments.
What does the sarcolemma surround?
The sarcolemma surrounds the sarcoplasm or cytoplasm.
p.24
Mechanism of Muscle Contraction
How does calcium influence muscle contraction?
Calcium binds to troponin, causing a conformational change that moves tropomyosin away from actin's binding sites, allowing myosin to bind to actin.
p.55
Mechanism of Muscle Contraction
How do opposing muscles contribute to muscle elongation?
Movements of opposing muscles help in the passive process of returning a muscle to its elongated state after contraction.
p.53
Mechanism of Muscle Contraction
What happens to muscle length and tension during isometric contraction?
Length remains the same, but tension increases.
p.12
Energy Sources for Muscle Contraction
What is the function of mitochondria in skeletal muscle cells?
To produce ATP, the energy source for muscle contractions.
p.26
Mechanism of Muscle Contraction
What model explains the mechanism of muscle contraction?
The sliding-filament model.
p.12
Neuromuscular Junction
What is the role of the neuromuscular junction in skeletal muscle cells?
To transmit nerve impulses to muscle fibers, triggering contraction.
p.41
Mechanism of Muscle Contraction
What happens when a muscle fiber contracts?
It pulls on the collagen fibers of tendons, creating tension.
p.19
Mechanism of Muscle Contraction
What is required to uncover the active sites on actin for myosin interaction?
Movement of troponin and tropomyosin.
p.60
Cardiac and Smooth Muscle Characteristics
What is the shape and nuclear characteristic of smooth muscle cells?
Spindle-shaped and have a single nucleus.
p.32
Energy Sources for Muscle Contraction
What happens to pyruvate in the anaerobic pathway when oxygen levels are low?
It is converted to lactate.
What is a triad in muscle cells?
A structure formed by a T tubule and two SR sacs.
p.38
Energy Sources for Muscle Contraction
What is anaerobic endurance?
The length of time muscle contractions can be supported by glycolysis and existing ATP reserves.
p.47
Mechanism of Muscle Contraction
What characterizes muscle tone?
A low level of continuous muscle contraction while awake.
p.3
Functions of Muscle Tissue
What are the four functional characteristics of muscle?
Excitability, Contractility, Extensibility, Elasticity.
p.6
Skeletal Muscle Organization
What is the function of the endomysium?
It covers each muscle fiber and ties fibers together, containing capillaries and nerve fibers.
p.31
Mechanism of Muscle Contraction
What occurs during muscle contraction at the molecular level?
Each cross-bridge breaks down ATP into ADP and a phosphate group.
p.31
Energy Sources for Muscle Contraction
How is ADP recharged back to ATP during muscle contraction?
Energy stored in creatine phosphate (CP) is used to recharge ADP back to ATP.
p.58
Cardiac and Smooth Muscle Characteristics
Why is the entry of additional calcium important for cardiac muscle cells?
It is important because it allows for the proper contraction of cardiac muscle cells.
p.65
Muscle Disorders and Diseases
What is fibromyositis?
Fibromyositis is a condition characterized by inflammation of muscle and connective tissue.
p.56
Cardiac and Smooth Muscle Characteristics
What is the function of intercalated discs in cardiac muscle?
They connect cells to other cells and contain gap junctions that allow rapid communication between all cells.
What are satellite cells in muscle tissue?
Cells that assist in muscle repair and regeneration.
p.32
Energy Sources for Muscle Contraction
What does EPOC stand for?
Excess Postexercise Oxygen Consumption.
p.37
Types of Muscle Tissue
How much slower are slow muscle fibers compared to fast muscle fibers in reaching peak tension?
Slow muscle fibers take three times as long to reach peak tension compared to fast muscle fibers.
p.62
Cardiac and Smooth Muscle Characteristics
How are actin and myosin organized in smooth muscle?
Actin and myosin are not rigidly organized.
p.42
Mechanism of Muscle Contraction
What happens during the contraction phase of a twitch contraction?
Muscle fibers shorten and generate force.
What are myofibrils?
Cylinder-shaped structures running the length of a muscle fiber.
p.48
Muscle Disorders and Diseases
What happens to muscle fibers during atrophy?
Muscle fibers become smaller and weaker.
What are the openings in the sarcolemma connected to?
The openings in the sarcolemma lead into a network of tubules called transverse tubules, or T tubules.
p.35
Muscle Fatigue and Recovery
How does the body increase the rate of heat loss during muscle recovery?
By increasing sweat gland secretions and blood flow to the skin.
p.2
Functions of Muscle Tissue
How do skeletal muscles guard entrances and exits of the body?
They encircle openings of the digestive and urinary tracts.
p.3
Functions of Muscle Tissue
What is muscle elasticity?
The ability of muscle tissue to return to its original length after being stretched or contracted.
p.6
Skeletal Muscle Organization
What is an aponeurosis?
A broad sheet of fibers that connects muscles to each other.
p.26
Mechanism of Muscle Contraction
What happens to the active sites on actin during muscle contraction?
Active sites on actin are exposed.
p.31
Energy Sources for Muscle Contraction
Which enzyme regulates the reaction that recharges ADP to ATP?
Creatine phosphokinase (CPK or CK).
p.17
Muscle Cell Structure
What does the I band contain?
The lighter region containing the thin filaments and includes the Z line.
p.49
Mechanism of Muscle Contraction
How does the metabolic condition of individual fibers affect muscle contraction?
It influences the muscle's ability to generate force.
p.56
Cardiac and Smooth Muscle Characteristics
What is a syncytium in the context of cardiac muscle?
A network of cells that function as a unit.
p.65
Muscle Disorders and Diseases
What is muscular dystrophy?
Muscular dystrophy is a group of genetic disorders characterized by progressive muscle weakness and degeneration.
p.62
Cardiac and Smooth Muscle Characteristics
How are thick filaments arranged in smooth muscle?
Thick filaments are scattered throughout the sarcoplasm.
p.62
Cardiac and Smooth Muscle Characteristics
How are the anchoring sites of thin filaments arranged in smooth muscle?
The anchoring sites are not in a straight line.
p.62
Cardiac and Smooth Muscle Characteristics
Over what range of lengths can smooth muscle contract?
Smooth muscle can contract over a greater range of lengths.
p.34
Muscle Fatigue and Recovery
Why do sprinters experience muscle fatigue more quickly?
Because they rapidly build up lactic acid.
p.10
Muscle Cell Structure
What is the sarcoplasmic reticulum?
A specialized smooth endoplasmic reticulum.
p.64
Functions of Muscle Tissue
How does muscle tissue contribute to movement?
Muscle contractions enable movement of the body and its parts.
p.16
Muscle Cell Structure
Where do thick filaments lie in a sarcomere?
In the center of the sarcomere.
p.2
Functions of Muscle Tissue
How do skeletal muscles support soft tissues?
The abdominal wall and pelvic cavity floor are composed of skeletal muscle.
p.3
Functions of Muscle Tissue
What does muscle extensibility mean?
The ability of muscle tissue to be stretched without being damaged.
p.19
Muscle Cell Structure
What are the two main parts of each myosin molecule?
A tail and a globular head.
p.60
Cardiac and Smooth Muscle Characteristics
How are the myofilaments arranged in smooth muscle compared to skeletal muscle?
They have a different arrangement.
p.17
Muscle Cell Structure
What is the A band in a sarcomere?
The darker region running the length of the thick filaments, including the zone of overlap containing both thick and thin filaments.
p.41
Mechanism of Muscle Contraction
What is compression?
A push applied to an object.
p.49
Mechanism of Muscle Contraction
How do intensity and frequency of stimulation affect muscle contraction?
They influence the strength and duration of the muscle contraction.
p.65
Muscle Disorders and Diseases
What is a hernia?
A hernia occurs when an organ or tissue protrudes through a weak spot in the muscle or connective tissue.
What are A bands and I bands in muscle cells?
A bands are dark bands, and I bands are light bands in striated muscle.
p.42
Mechanism of Muscle Contraction
What occurs during the relaxation phase of a twitch contraction?
Muscle tension decreases and the muscle returns to its resting state.
p.24
Mechanism of Muscle Contraction
What is the molecular basis of muscle contraction?
The interaction between actin and myosin filaments within muscle cells.
What are myofibrils composed of?
Bundles of thick and thin myofilaments.
p.36
Functions of Muscle Tissue
What does endurance measure in terms of muscle performance?
The amount of time a particular activity can be performed.
p.12
Muscle Cell Structure
What is the role of the sarcoplasmic reticulum in skeletal muscle cells?
To store and release calcium ions during muscle contraction.
p.21
Neuromuscular Junction
What is the motor end plate?
The portion of the muscle sarcolemma.
p.43
Mechanism of Muscle Contraction
What does the Treppe phenomenon describe?
A gradual, steplike increase in contraction strength.
p.21
Neuromuscular Junction
What do neurons stimulate in the sarcolemma?
The production of an action potential (electrical impulse).
p.41
Mechanism of Muscle Contraction
When will movement occur in relation to tension and resistance?
Movement will occur only if the tension is greater than the object's resistance.
p.49
Mechanism of Muscle Contraction
What role does the recruitment of motor units play in muscle contraction?
It determines the number of muscle fibers activated to produce force.
p.41
Mechanism of Muscle Contraction
Are all sarcomeres in a muscle fiber involved in contraction?
Yes, all sarcomeres in a muscle fiber are involved in contraction.
What cellular components are abundant in muscle cells?
Multiple nuclei and many mitochondria.
p.49
Mechanism of Muscle Contraction
How does load affect muscle contraction?
The load determines the amount of force the muscle needs to generate to move or support it.
What role do T tubules play in muscle cells?
They help in impulse transmission.
p.62
Cardiac and Smooth Muscle Characteristics
How does smooth muscle function?
Smooth muscle functions involuntarily.
p.53
Mechanism of Muscle Contraction
Why does isometric contraction not produce movement?
Because the tension does not exceed the load.
p.43
Mechanism of Muscle Contraction
What is the Treppe phenomenon also known as?
The staircase phenomenon.
p.58
Cardiac and Smooth Muscle Characteristics
How do the contraction durations of cardiac muscle cells compare to skeletal muscle cells?
Cardiac muscle cells have contractions that are about 10 times longer than those of skeletal muscle cells.
p.58
Cardiac and Smooth Muscle Characteristics
How does the action potential affect the permeability of cardiac muscle cell plasma membranes?
The action potential increases the permeability of the cardiac muscle cell plasma membrane to calcium.
p.41
Mechanism of Muscle Contraction
What does tension tend to do?
Pull an object towards the source of tension.
p.17
Muscle Cell Structure
What is the H band and when is it visible?
The H band contains only thick filaments and is visible when the fiber is relaxed. It includes the M line and light regions on either side.
p.49
Mechanism of Muscle Contraction
What is the length-tension relationship in muscle contraction?
It describes how the force a muscle generates varies with its length.
p.37
Types of Muscle Tissue
What are the characteristics of fast muscle fibers?
Fast muscle fibers reach peak tension very quickly, are large in diameter, have large glycogen reserves, relatively few mitochondria, fatigue rapidly, and produce very powerful contractions.
p.62
Cardiac and Smooth Muscle Characteristics
Where are thin filaments anchored in smooth muscle?
Thin filaments are anchored to the sarcolemma.
p.62
Cardiac and Smooth Muscle Characteristics
How are contractions triggered in smooth muscle?
Contractions are triggered differently, with most of the calcium for the trigger entering from extracellular fluid.
p.31
Energy Sources for Muscle Contraction
What happens to excess ATP in resting muscle fibers?
It transfers energy to creatine, forming creatine phosphate (CP).
p.20
Mechanism of Muscle Contraction
What model explains the process of muscle contraction?
The sliding filament model.
p.17
Muscle Cell Structure
What is the M line made of?
Proteins that connect central portions of the thick filaments.
p.49
Mechanism of Muscle Contraction
What is the graded strength principle?
The ability to match the force of movement to the demands of the task.
p.31
Energy Sources for Muscle Contraction
What must happen after creatine phosphate energy reserves are exhausted?
ATP must be generated by different means, such as anaerobic glycolysis and aerobic metabolism.
p.32
Energy Sources for Muscle Contraction
What are the end products of the aerobic pathway?
ATP, water, and carbon dioxide.
p.65
Muscle Disorders and Diseases
What are some examples of muscle infections?
Examples of muscle infections include tetanus and poliomyelitis.
p.30
Energy Sources for Muscle Contraction
How is oxygen stored in muscle cells?
By attraction to myoglobin
p.37
Muscle Fatigue and Recovery
Why are slow muscle fibers fatigue resistant?
Because they have a greater oxygen supply due to an extensive capillary network, high levels of oxygen storage by myoglobin, and efficient oxygen use due to large numbers of mitochondria.
What are the two types of myofilaments?
Thick and thin filaments.
p.49
Mechanism of Muscle Contraction
What factors contribute to the graded strength principle?
Metabolic condition of individual fibers, recruitment of motor units, intensity and frequency of stimulation, muscle length, length-tension relationship, load, and stretch reflex.
p.56
Cardiac and Smooth Muscle Characteristics
What is a key characteristic of cardiac muscle cells?
They are relatively small with usually only one central nucleus.
p.65
Muscle Disorders and Diseases
What is myasthenia gravis?
Myasthenia gravis is an autoimmune disorder that causes weakness in the skeletal muscles.
p.62
Cardiac and Smooth Muscle Characteristics
What is the unique characteristic of smooth muscle contraction?
Contraction causes twisting like a corkscrew.
p.41
Mechanism of Muscle Contraction
Can tension be varied by changing the number of contracting sarcomeres in a muscle fiber?
No, tension cannot be varied by changing the number of contracting sarcomeres.
What are the sarcolemma and sarcoplasm?
The sarcolemma is the muscle cell membrane, and the sarcoplasm is the cytoplasm of a muscle cell.
p.41
Mechanism of Muscle Contraction
How do individual muscle fibers operate in terms of contraction?
Individual muscle fibers are either fully contracted ('on') or relaxed ('off').
p.56
Cardiac and Smooth Muscle Characteristics
Why are gap junctions important in cardiac muscle?
They allow rapid communication between cells, resulting in simultaneous contraction.
p.62
Cardiac and Smooth Muscle Characteristics
How is contractile force transmitted in smooth muscle?
Contractile force is transmitted throughout the tissue.
p.56
Cardiac and Smooth Muscle Characteristics
How do the impulses in cardiac muscle compare to those in skeletal muscle?
Cardiac muscle has more prolonged impulses.
p.37
Mechanism of Muscle Contraction
What contributes to the powerful contractions produced by fast muscle fibers?
The densely packed myofibrils in fast muscle fibers contribute to their powerful contractions.
p.37
Muscle Cell Structure
What role does myoglobin play in slow muscle fibers?
Myoglobin stores high levels of oxygen, contributing to the fatigue resistance of slow muscle fibers.
p.62
Cardiac and Smooth Muscle Characteristics
What stimuli can smooth muscle respond to?
Smooth muscle can respond to hormones, pacemaker cells, and motor neurons.
p.2
Functions of Muscle Tissue
What is one of the general functions of skeletal muscles?
<p>Move the skeleton - they do this by pulling on tendons which then moves bones.</p>
