Chap 7-Physiology of Muscle

Created by Ghina

p.1

What is the primary function of muscle cells?

A. To produce hormones

B. To store energy

C. To transmit nerve impulses

D. To generate force and movements

E. To absorb nutrients

Select an answer

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Explanation

Muscle cells are specifically designed to generate force and movements, which are essential for regulating both the internal environment of the body and producing movements in the external environment.

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Muscle Cell Structure and Function

What is the primary function of muscle cells?

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Types of Muscle Tissues

Which of the following is NOT a type of muscle mentioned?

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Types of Muscle Tissues

What is the primary function of skeletal muscles?

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Types of Muscle Tissues

How is the contraction of skeletal muscle initiated?

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Types of Muscle Tissues

What type of control is skeletal muscle contraction usually under?

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Types of Muscle Tissues

What type of muscles surround hollow organs and tubes such as the stomach and blood vessels?

p.3

Types of Muscle Tissues

Which system primarily controls the contraction of smooth muscles?

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Types of Muscle Tissues

Are smooth muscles normally under voluntary control?

p.3

Types of Muscle Tissues

What is a characteristic feature of smooth muscle cells?

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Types of Muscle Tissues

What can cause smooth muscles to contract autonomously?

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Types of Muscle Tissues

What type of muscle tissue is responsible for pumping blood through the circulatory system?

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Types of Muscle Tissues

What is a key characteristic of striated (cardiac) muscle tissue?

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Types of Muscle Tissues

Which of the following best describes the function of cardiac muscle?

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Skeletal Muscle Characteristics

What is another name for a skeletal muscle fiber?

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Skeletal Muscle Characteristics

What is a key characteristic of skeletal muscle cells?

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Skeletal Muscle Characteristics

How are skeletal muscle fibers formed?

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Skeletal Muscle Characteristics

What visual feature is characteristic of skeletal muscle fibers?

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Skeletal Muscle Characteristics

What type of muscle is skeletal muscle classified as?

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Skeletal Muscle Characteristics

When is skeletal muscle differentiation completed?

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Skeletal Muscle Characteristics

What happens to skeletal muscle fibers after birth?

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Muscle Fiber Types and Properties

What are satellite cells?

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Muscle Fiber Types and Properties

What is a limitation of satellite cells in muscle repair?

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Skeletal Muscle Characteristics

What is located immediately beneath the outer cell membrane of skeletal muscle fibers?

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Skeletal Muscle Characteristics

What fills the clefts and spaces between the myofibrils in skeletal muscle fibers?

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Skeletal Muscle Characteristics

What are the tubular invaginations of the sarcolemma in skeletal muscle fibers called?

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Skeletal Muscle Characteristics

What structural feature reflects the fusion of primitive muscle cells in skeletal muscle fibers?

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Skeletal Muscle Characteristics

What is the primary function of the sarcoplasmic reticulum in skeletal muscle fibers?

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Muscle Fiber Types and Properties

What distinguishes type I muscle fibers from type II muscle fibers in terms of contraction speed?

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Contraction Mechanism in Skeletal Muscle

What is the primary enzyme involved in muscle contraction that is stained to differentiate muscle fiber types?

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Muscle Fiber Types and Properties

Which type of muscle fiber is more susceptible to fatigue?

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Muscle Fiber Types and Properties

What physiological property is related to the endurance of muscle fibers?

p.8

Contraction Mechanism in Skeletal Muscle

What is the relationship between the speed of contraction and myosin ATPase activity?

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Muscle Fiber Types and Properties

What is a characteristic of Type 1 skeletal muscle fibers?

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Muscle Fiber Types and Properties

Which type of skeletal muscle fiber is known as 'white muscle'?

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Muscle Fiber Types and Properties

What is a key feature of Type 2A skeletal muscle fibers?

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Muscle Fiber Types and Properties

Which skeletal muscle fiber type is characterized by high glycogen content?

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Muscle Fiber Types and Properties

What is the primary energy source for Type 1 skeletal muscle fibers?

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Muscle Fiber Types and Properties

What determines the functional characteristics of a whole muscle?

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Muscle Fiber Types and Properties

Which type of muscle fibers are typically found in muscles that require sustained contraction?

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Muscle Fiber Types and Properties

How can muscle fiber composition vary among different breeds of horses?

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Muscle Fiber Types and Properties

What type of muscles contract briefly but quickly and with great force?

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Muscle Fiber Types and Properties

What is the primary characteristic of slow twitch endurance fibers?

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Skeletal Muscle Characteristics

What is the appearance of striations in skeletal muscle cells?

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Skeletal Muscle Characteristics

What do the alternating light and dark bands in myofibrils correspond to?

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Skeletal Muscle Characteristics

What are the light zones in skeletal muscle called?

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Skeletal Muscle Characteristics

What is the fundamental unit of contraction in striated muscle?

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Skeletal Muscle Characteristics

What bisects each I band in skeletal muscle?

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Skeletal Muscle Characteristics

What do A bands in skeletal muscle consist of?

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Skeletal Muscle Characteristics

What is the segment of myofibril between adjacent Z lines called?

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Skeletal Muscle Characteristics

What is the primary component of a thick filament in skeletal muscle?

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Muscle Cell Structure and Function

How many myofibrils can each striated muscle fiber contain?

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Muscle Fiber Types and Properties

What is the composition of a thin filament in skeletal muscle?

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Contraction Mechanism in Skeletal Muscle

How many thick and thin myofilaments are approximately found in each myofibril?

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Skeletal Muscle Characteristics

What defines the boundaries of a sarcomere in skeletal muscle?

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Muscle Cell Structure and Function

What is the basic contractile unit of muscle tissue called?

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Muscle Cell Structure and Function

Which protein is primarily associated with thick filaments in the sarcomere?

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Muscle Cell Structure and Function

What is the function of the Z disk in a sarcomere?

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Muscle Cell Structure and Function

What is the region called where thick and thin filaments overlap in a sarcomere?

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Muscle Cell Structure and Function

Which protein is represented by red lines in the sarcomere diagram?

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Contraction Mechanism in Skeletal Muscle

What is the primary function of the sarcoplasmic reticulum in muscle fibers?

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Contraction Mechanism in Skeletal Muscle

What role do transverse tubules (T systems) play in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

How do transverse tubules relate to the sarcoplasmic reticulum?

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Skeletal Muscle Characteristics

What is the typical diameter range of skeletal muscle fibers?

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Muscle Fiber Types and Properties

Which factor is associated with larger skeletal muscle fibers in animals?

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Muscle Fiber Types and Properties

In general, which gender is reported to have larger muscle fibers?

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Skeletal Muscle Characteristics

What is the relationship between muscle fiber size and muscle size?

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Contraction Mechanism in Skeletal Muscle

What initiates skeletal muscle contraction?

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Contraction Mechanism in Skeletal Muscle

Where does the action potential that triggers skeletal muscle contraction originate?

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Contraction Mechanism in Skeletal Muscle

What type of synapse is the neuromuscular junction classified as?

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Contraction Mechanism in Skeletal Muscle

What neurotransmitter is released at the neuromuscular junction to trigger muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is the role of nicotinic acetylcholine receptors at the neuromuscular junction?

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Contraction Mechanism in Skeletal Muscle

What is the local depolarization of the sarcolemma at the neuromuscular junction called?

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Contraction Mechanism in Skeletal Muscle

What happens after the end-plate potential occurs in the sarcolemma?

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Contraction Mechanism in Skeletal Muscle

What triggers the opening of electrically gated channels in the sarcolemma?

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Contraction Mechanism in Skeletal Muscle

What ion diffuses inward when the electrically gated channels open?

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Contraction Mechanism in Skeletal Muscle

What is the result of the inward diffusion of sodium ions in muscle cells?

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Calcium Role in Muscle Contraction

What happens when an action potential occurs at the dihydropyridine receptor?

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Contraction Mechanism in Skeletal Muscle

What is the dihydropyridine receptor's function in muscle contraction?

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Calcium Role in Muscle Contraction

What is the significance of the link between the dihydropyridine receptor and the sarcoplasmic reticulum?

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Calcium Role in Muscle Contraction

What is the primary ion involved in the contraction process of muscle fibers?

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Calcium Role in Muscle Contraction

What role do calcium ions (Ca2+) play in muscle contraction?

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Calcium Role in Muscle Contraction

What happens to Ca2+ concentration before muscle stimulation?

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Calcium Role in Muscle Contraction

What occurs when the Ca2+ channels in the sarcoplasmic reticulum open?

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Calcium Role in Muscle Contraction

What is the role of calcium ions in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is the result of muscle contraction as described in the text?

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Contraction Mechanism in Skeletal Muscle

What initiates the process of muscle contraction according to the sequence described?

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Contraction Mechanism in Skeletal Muscle

What initiates the interaction of thick and thin filaments during muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is the result of the sliding movement of thin filaments during contraction?

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Contraction Mechanism in Skeletal Muscle

What is the role of acetylcholine (ACh) in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What happens to the muscle fiber as a result of the contraction process?

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Calcium Role in Muscle Contraction

Which ion is primarily involved in the contraction of muscle fibers?

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Muscle Cell Structure and Function

What are the two main parts of a myosin molecule in a thick filament?

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Contraction Mechanism in Skeletal Muscle

What is the function of the myosin head in a thick filament?

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Muscle Cell Structure and Function

How do myosin heads attach to the thick filament?

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Muscle Cell Structure and Function

Where are myosin heads located in relation to the thick filament?

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Contraction Mechanism in Skeletal Muscle

What is the role of the flexible arm of the myosin molecule?

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Muscle Fiber Types and Properties

What are the main components of thick filaments in muscle tissue?

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Contraction Mechanism in Skeletal Muscle

What role do cross-bridges play in muscle contraction?

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Calcium Role in Muscle Contraction

Which component is responsible for regulating muscle contraction by blocking the binding sites on actin?

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Calcium Role in Muscle Contraction

What is the function of troponin in muscle fibers?

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Contraction Mechanism in Skeletal Muscle

Which of the following correctly describes the relationship between actin and myosin in muscle contraction?

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Muscle Cell Structure and Function

What are the main components of a thin filament in muscle tissue?

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Muscle Cell Structure and Function

How are actin molecules arranged in thin filaments?

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Muscle Cell Structure and Function

What role does tropomyosin play in the thin filament structure?

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Muscle Cell Structure and Function

What is the function of troponin in the thin filament?

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Muscle Cell Structure and Function

Which of the following best describes the structure of the troponin-tropomyosin complex?

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Contraction Mechanism in Skeletal Muscle

What role do calcium ions play in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is the function of tropomyosin in muscle fibers?

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Contraction Mechanism in Skeletal Muscle

What happens to tropomyosin when calcium ions bind to troponin?

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Contraction Mechanism in Skeletal Muscle

What is the result of the binding of myosin heads to actin during muscle contraction?

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Contraction Mechanism in Skeletal Muscle

In the relaxed state of a muscle fiber, what is the position of the cross-bridge binding sites on actin?

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Contraction Mechanism in Skeletal Muscle

What occurs when the myosin head binds to actin during muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is the result of the myosin head rotating toward the center of the sarcomere?

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Contraction Mechanism in Skeletal Muscle

What must be available for the contraction cycle to continue?

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Contraction Mechanism in Skeletal Muscle

What happens during the power stroke phase of the cross-bridge cycle?

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Contraction Mechanism in Skeletal Muscle

What is the role of ATP in the cross-bridge cycle?

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Contraction Mechanism in Skeletal Muscle

What happens to the sarcomere during muscle contraction?

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Skeletal Muscle Characteristics

Which band remains the same length during muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What occurs to the thin filaments during muscle contraction?

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Muscle Fiber Types and Properties

What is the role of the Z lines during muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is true about the filaments themselves during contraction?

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Calcium Role in Muscle Contraction

What happens to Ca2+ in the muscle after the action potentials end?

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Calcium Role in Muscle Contraction

What role do ion pumps in the sarcoplasmic reticulum play during muscle relaxation?

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Calcium Role in Muscle Contraction

What is the consequence of a lack of ATP in muscle relaxation?

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Contraction Mechanism in Skeletal Muscle

What happens to the thin and thick filaments during muscle relaxation?

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Calcium Role in Muscle Contraction

What is left in the sarcoplasm of relaxed resting muscle?

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Calcium Role in Muscle Contraction

What role does calcium play in muscle contraction according to the illustrations?

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Contraction Mechanism in Skeletal Muscle

In the relaxed state of muscle fibers, what is the status of the myosin binding sites?

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Contraction Mechanism in Skeletal Muscle

What happens to the myosin binding sites when the muscle fiber is excited?

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Contraction Mechanism in Skeletal Muscle

Which components are involved in the cross-bridge binding process in muscle contraction?

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Calcium Role in Muscle Contraction

What is the effect of the troponin complex in muscle fibers?

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Strength of Muscle Contraction

What does the all-or-none law of muscle contraction state?

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Strength of Muscle Contraction

To which structures does the all-or-none law apply?

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Strength of Muscle Contraction

What factors can affect the force of contraction in a muscle fiber?

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Strength of Muscle Contraction

Does the all-or-none law apply to the entire muscle, such as the biceps brachii?

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Strength of Muscle Contraction

What happens when a muscle fiber receives a nervous impulse?

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Strength of Muscle Contraction

What is motor unit summation (recruitment)?

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Strength of Muscle Contraction

What is the result of activating more motor units in a muscle?

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Strength of Muscle Contraction

Which of the following best describes the relationship between motor units and muscle strength?

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Strength of Muscle Contraction

What happens to the force output when multiple motor units are recruited?

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Strength of Muscle Contraction

What is the primary factor that allows for greater strength in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What is temporal summation in muscle contraction?

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Contraction Mechanism in Skeletal Muscle

What happens during temporal summation when a second stimulus is applied?

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Contraction Mechanism in Skeletal Muscle

In normal muscle function, what types of summation occur?

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Contraction Mechanism in Skeletal Muscle

What is illustrated by the third twitch in the provided graph?

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Contraction Mechanism in Skeletal Muscle

What does the y-axis represent in the graph of muscle twitches?

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Strength of Muscle Contraction

What is tetany in muscle contraction?

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Strength of Muscle Contraction

What happens when the frequency of stimulation becomes very rapid in muscle contraction?

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Strength of Muscle Contraction

What occurs as the frequency of stimulation increases in muscle contraction?

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Strength of Muscle Contraction

What is indicated by the term 'summation' in muscle contraction?

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Strength of Muscle Contraction

What is the result of reaching a very high frequency of stimulation in muscle contraction?

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Types of Muscle Contraction

What is the primary function of muscle contraction?

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Types of Muscle Contraction

What type of muscle contraction occurs when the muscle shortens?

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Types of Muscle Contraction

Which type of contraction occurs when a muscle lengthens?

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Types of Muscle Contraction

In which scenario would you observe eccentric contraction?

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Types of Muscle Contraction

What is an example of concentric contraction?

p.36

Types of Muscle Tissues

What type of muscle contraction occurs when a limb is held stationary against equal resistance?

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Types of Muscle Tissues

During which type of contraction does the muscle length change while the tension remains constant?

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Types of Muscle Tissues

In an isometric contraction, what happens to the muscle length?

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Types of Muscle Tissues

What is the primary characteristic of isotonic contraction?

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Types of Muscle Tissues

Which of the following best describes isometric contraction?

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Rigor Mortis and Muscle Relaxation

What happens to myosin heads when ATP is depleted in a muscle?

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Rigor Mortis and Muscle Relaxation

What is rigor mortis?

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Rigor Mortis and Muscle Relaxation

What causes the rigidity in rigor mortis?

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Rigor Mortis and Muscle Relaxation

What happens to the muscles during rigor mortis?

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Rigor Mortis and Muscle Relaxation

What eventually happens to the muscles after rigor mortis?

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Smooth Muscle Characteristics

What is a key difference between skeletal muscle and smooth muscle contraction?

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Smooth Muscle Characteristics

What allows smooth muscle to maintain a constant pressure with little energy?

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Smooth Muscle Characteristics

How does the functional diversity of smooth muscle compare to skeletal muscle?

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Smooth Muscle Characteristics

What is a characteristic of smooth muscle contraction compared to skeletal muscle?

p.38

Smooth Muscle Characteristics

In which organs is smooth muscle particularly important for maintaining tone?

p.39

Calcium Role in Muscle Contraction

What is the primary role of Ca2+ in smooth muscle contraction?

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Calcium Role in Muscle Contraction

Where is calcium stored in smooth muscle cells?

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Calcium Role in Muscle Contraction

How does calcium enter smooth muscle cells during contraction?

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Contraction Mechanism in Skeletal Muscle

What happens to myosin during smooth muscle contraction?

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Calcium Role in Muscle Contraction

What promotes relaxation in smooth muscle after contraction?

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Smooth Muscle Characteristics

What characterizes smooth muscle cells that do not have action potentials (APs) during contraction?

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Smooth Muscle Characteristics

What happens to the membrane potential of smooth muscle cells that do not generate action potentials?

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Smooth Muscle Characteristics

Which type of channels are present in smooth muscle cells that do have action potentials during contraction?

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Cardiac Muscle Characteristics

What is a key characteristic of cardiac muscle compared to skeletal muscle?

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Contraction Mechanism in Skeletal Muscle

How do cardiac muscle cells contract without nerve stimulation?

p.41

Cardiac Muscle Characteristics

What role do autonomic nerves play in cardiac muscle function?

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Contraction Mechanism in Skeletal Muscle

What is the function of gap junctions in cardiac muscle?

p.41

Cardiac Muscle Characteristics

What is the primary function of myocardial pacemaker cells?

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Cardiac Muscle Characteristics

How does the duration of the cardiac action potential compare to that of skeletal muscle?

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Cardiac Muscle Characteristics

What is a unique feature of the cardiac action potential compared to skeletal muscle?

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Calcium Role in Muscle Contraction

What role does intracellular Ca2+ play in cardiac muscle contraction?

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Contraction Mechanism in Skeletal Muscle

How does cardiac muscle contraction compare to that of skeletal muscle?

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Cardiac Muscle Characteristics

What is the contraction time in cardiac muscle related to?

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