chapter 10, muscle Flashcards
What type of muscle is voluntary and striated, attached to bones?
Skeletal muscle
Skeletal muscle is responsible for body movements.
What type of muscle is involuntary and striated, found in the heart?
Cardiac muscle
Cardiac muscle is responsible for pumping blood.
What type of muscle is involuntary and non-striated, found in walls of hollow organs?
Smooth muscle
Examples include intestines and blood vessels.
What is one of the main functions of muscular tissue?
Movement
Skeletal muscles move the body; smooth muscles move substances.
What is the function of muscles in maintaining posture?
Stability
Muscles stabilize joints and maintain body posture.
How do muscles contribute to heat production?
Muscles generate heat through contraction
Example: shivering increases body temperature.
What is the ability of muscle tissue to respond to stimuli called?
Excitability
This characteristic allows muscles to react to signals.
What is the ability of muscle tissue to shorten and generate force?
Contractility
This property is essential for muscle function.
What is the connective tissue surrounding each muscle fiber called?
Endomysium
Endomysium provides support to individual muscle fibers.
What connective tissue surrounds muscle fascicles?
Perimysium
Perimysium binds groups of muscle fibers together.
What is the connective tissue surrounding the entire muscle?
Epimysium
Epimysium encases the muscle as a whole.
What is the structure of a single muscle cell called?
Muscle fiber
Muscle fibers are the basic units of muscle tissue.
What is the cell membrane of a muscle fiber known as?
Sarcolemma
Sarcolemma plays a key role in muscle contraction.
What are the long protein structures inside muscle fibers responsible for contraction?
Myofibrils
Myofibrils contain the contractile proteins actin and myosin.
What is the functional unit of muscle contraction?
Sarcomere
Sarcomeres are the repeating units in myofibrils.
What is the role of the sarcoplasmic reticulum (SR) in muscle fibers?
Stores calcium for muscle contraction
Calcium release from SR triggers muscle contraction.
What are the extensions of the sarcolemma that carry electrical impulses into the muscle?
T-tubules (Transverse tubules)
T-tubules help synchronize muscle contraction.
What is the thin filament in muscle fibers called?
Actin
Actin interacts with myosin during muscle contraction.
What is the thick filament in muscle fibers called?
Myosin
Myosin heads bind to actin to facilitate contraction.
What is the regulatory protein that binds calcium and controls muscle contraction?
Troponin
Troponin’s binding to calcium initiates contraction.
What blocks myosin binding sites on actin when the muscle is relaxed?
Tropomyosin
Tropomyosin prevents contraction in the relaxed state.
What model explains how muscles contract by filaments sliding past each other?
Sliding filament theory
This theory is fundamental to understanding muscle contraction.
What is a motor unit?
A motor neuron and all the muscle fibers it controls
Motor units vary in size depending on muscle function.
What neurotransmitter triggers muscle contraction?
Acetylcholine (ACh)
ACh is released at the neuromuscular junction.
What is the space between the neuron and muscle fiber called?
Synaptic cleft
The synaptic cleft is where neurotransmission occurs.
What enzyme breaks down acetylcholine, stopping contraction?
Acetylcholinesterase (AChE)
AChE regulates muscle contraction duration.
What molecule stores energy for quick ATP regeneration?
Creatine phosphate
Creatine phosphate serves as an energy reserve in muscle cells.
What type of respiration produces ATP without oxygen?
Anaerobic respiration
This process can lead to lactic acid buildup.
What type of respiration uses oxygen to produce ATP and is more efficient?
Aerobic respiration
Aerobic respiration is the preferred method for ATP production.
What is muscle fatigue?
Inability to maintain contraction due to lack of ATP or lactic acid accumulation
Muscle fatigue can affect performance.
What are slow oxidative (SO) fibers known for?
Fatigue-resistant, high endurance, aerobic metabolism
SO fibers are typically found in postural muscles.
What are fast glycolytic (FG) fibers known for?
Fatigue quickly, powerful, anaerobic metabolism
FG fibers are used in short bursts of intense activity.
What type of muscle contraction occurs when the muscle changes length while maintaining constant tension?
Isotonic contraction
Isotonic contractions include both concentric and eccentric types.
What is a concentric contraction?
Muscle shortens
Example: lifting a weight.
What is an eccentric contraction?
Muscle lengthens while maintaining tension
Example: lowering a weight.
What is an isometric contraction?
Muscle does not change length but maintains tension
Example: holding a plank.
What is muscular dystrophy?
Genetic disorder causing muscle degeneration
This condition leads to progressive weakness.
What is myasthenia gravis?
Autoimmune disorder affecting ACh receptors, leading to muscle weakness
Myasthenia gravis can significantly impact daily activities.
What is rhabdomyolysis?
Breakdown of muscle tissue releasing harmful proteins into the bloodstream
Rhabdomyolysis can occur from severe muscle damage.
What is fibromyalgia?
Chronic muscle pain with unknown cause
Fibromyalgia can be challenging to diagnose and treat.
