chapter 9 - muscular system

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Question

Answer

During which phase are calcium ions actively transported into the sarcoplasmic reticulum?

relaxation

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What is the role of creatine phosphate during skeletal muscle contraction?

It is used to quickly regenerate ATP from ADP.

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T or F: Not all motor units of one entire skeletal muscle contract at once.

True

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True or false: Myofilaments shorten during contraction.

false

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Muscle fatigue is a condition described by ______ and is usually caused by prolonged use of a muscle.

the loss of a muscle's ability to contract

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A muscle that functions to cause action is referred to as the ______.

agonist

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The end of a muscle that is fixed (relatively immovable) is called its ______.

Origin

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Neurons have extensions (processes) called _______ that carry electrical impulses toward the cell they are innervating

axons

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The type of muscle that constitutes about 40% of the body's weight, is responsible for locomotion, facial expressions, posture, respiratory functions, and many other body movements is...

skeletal muscle

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The muscle shortens and generates force during the ___ phase of a muscle twitch.

contraction

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The first stage of anaerobic and aerobic respiration is ___.

glycolysis

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Tube-like invaginations of the sarcolemma that conduct action potentials toward the center of the muscle fiber are called ___.

transverse tubules.

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supplies energy for the synthesis of ATP

creatine phosphate

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Name the cordlike structures that connect muscles to bone

tendons

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The functional connection between a neuron and a skeletal muscle fiber is a

synapse

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Binding sites on the surface of actin allow the formation of cross-bridges with molecules of

myosin

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Within a skeletal muscle, fascicles are separated from each other by connective tissue called the _____, and muscle fibers are separated from each other by connective tissue called the _____

perimysium and endomysium

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Site for storage of calcium

sarcoplasmic reticulum

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Threadlike bundles of thick and thin filaments

myofibril

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Site of ATP production

mitochondria

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The first event in muscle fiber contraction is that

acetylcholine is released from the end of the motor neuron

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The enzyme acetylcholinesterase causes acetylcholine to

decompose

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A runner collapses during a race and is examined by a doctor. They have lost the ability to plantar flex at the ankle. Which of the following is probably the injured muscle?

Gastrocnemius

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Rigor mortis affects skeletal muscles a few hours after death, due to

a decrease in ATP and increased permeability to calcium.

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Muscle fatigue is due in part to decreased ATP levels in muscle cells.

TRUE

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Transverse (T) tubules are invaginations of the sarcolemma of a muscle cell.

TRUE

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Calcium ions bind to __________ in order to initiate a muscle contraction.

Troponin

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In order for muscle contraction to occur, cross-bridges form between __________.

Myosin and actin

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The muscle that opposes a particular action is called

antagonist

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In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the

Latent period

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The amount of oxygen needed to repay the oxygen debt includes the amount of oxygen that muscle cells need to resynthesize ATP.

True

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Tawanda finishes a sprint and suffers great pain in her calf muscles. Her muscle cramps are most likely due to a temporary deficit of

ATP

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bundles of fibers are called ___________ and is covered by the perimysium

fascicles

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Which of the following are types of muscles and are involuntary?

Cardiac

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In excitation-contraction coupling, the protein called ______ moves to expose binding sites on the actin filaments that can form cross-bridges.

tropomyosin

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A skeletal muscle fiber is ______.

a single muscle cell

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During muscle contraction, the sarcomeres shorten because ______.

thick and thin filament slide past one another, increasing their overlap

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The process of glycolysis is ______.

anaerobic

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When is lactic acid produced?

During anaerobic metabolism

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True or false: Muscles generate heat when they contract.

True

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When a single muscle fiber contracts when stimulated by a single impulse, the contractile response is called a(n) ______.

twitch

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The cells of ______ muscle are tapered, lack striations, and have a sarcoplasmic reticulum that is not very extensive.

smooth

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During a(n) ______ muscle contraction, the muscle either lengthens or shortens, while the tension stays constant.

isotonic

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during high-intensity exercise, anaerobic metabolism results in the production of pyruvic acid, which is then converted to ? acid

lactic

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the layer of connective tissue that most closely surrounds an entire skeletal muscle is called the

epimysium

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During muscle contraction, calcium ions combine with tropomyosin, and this exposes active sites for cross-bridge formation

false

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anaerobic respiration occurs primarily in mitochondria

false

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Liver cells convert lactic acid to ATP

false

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the minimal strength of stimulation needed to elicit a muscle contraction is called the threshold stimulus

True

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if a muscle contracts and its fibers shorten, the contraction is isometric

false

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white muscles have an increased capacity to carry on aerobic respiration

false

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Metabolic processes can use only about 25% of the energy released by cellular respiration

true

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the two major types of smooth muscles are intercalated muscle and cardiac muscle

false

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cardiac muscle is voluntary

false

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muscles and bones function as levers

true

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the masseter muscle functions in mastication

true

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exercise can lead to new muscle filament formation---even in old people

true

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Created by: yanise2006