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Stack #3789810
chapter 9 - muscular system
Question | Answer |
---|---|
During which phase are calcium ions actively transported into the sarcoplasmic reticulum? | relaxation |
What is the role of creatine phosphate during skeletal muscle contraction? | It is used to quickly regenerate ATP from ADP. |
T or F: Not all motor units of one entire skeletal muscle contract at once. | True |
True or false: Myofilaments shorten during contraction. | false |
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 |
A muscle that functions to cause action is referred to as the ______. | agonist |
The end of a muscle that is fixed (relatively immovable) is called its ______. | Origin |
Neurons have extensions (processes) called _______ that carry electrical impulses toward the cell they are innervating | axons |
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 |
The muscle shortens and generates force during the ___ phase of a muscle twitch. | contraction |
The first stage of anaerobic and aerobic respiration is ___. | glycolysis |
Tube-like invaginations of the sarcolemma that conduct action potentials toward the center of the muscle fiber are called ___. | transverse tubules. |
supplies energy for the synthesis of ATP | creatine phosphate |
Name the cordlike structures that connect muscles to bone | tendons |
The functional connection between a neuron and a skeletal muscle fiber is a | synapse |
Binding sites on the surface of actin allow the formation of cross-bridges with molecules of | myosin |
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 |
Site for storage of calcium | sarcoplasmic reticulum |
Threadlike bundles of thick and thin filaments | myofibril |
Site of ATP production | mitochondria |
The first event in muscle fiber contraction is that | acetylcholine is released from the end of the motor neuron |
The enzyme acetylcholinesterase causes acetylcholine to | decompose |
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 |
Rigor mortis affects skeletal muscles a few hours after death, due to | a decrease in ATP and increased permeability to calcium. |
Muscle fatigue is due in part to decreased ATP levels in muscle cells. | TRUE |
Transverse (T) tubules are invaginations of the sarcolemma of a muscle cell. | TRUE |
Calcium ions bind to __________ in order to initiate a muscle contraction. | Troponin |
In order for muscle contraction to occur, cross-bridges form between __________. | Myosin and actin |
The muscle that opposes a particular action is called | antagonist |
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 |
The amount of oxygen needed to repay the oxygen debt includes the amount of oxygen that muscle cells need to resynthesize ATP. | True |
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 |
bundles of fibers are called ___________ and is covered by the perimysium | fascicles |
Which of the following are types of muscles and are involuntary? | Cardiac |
In excitation-contraction coupling, the protein called ______ moves to expose binding sites on the actin filaments that can form cross-bridges. | tropomyosin |
A skeletal muscle fiber is ______. | a single muscle cell |
During muscle contraction, the sarcomeres shorten because ______. | thick and thin filament slide past one another, increasing their overlap |
The process of glycolysis is ______. | anaerobic |
When is lactic acid produced? | During anaerobic metabolism |
True or false: Muscles generate heat when they contract. | True |
When a single muscle fiber contracts when stimulated by a single impulse, the contractile response is called a(n) ______. | twitch |
The cells of ______ muscle are tapered, lack striations, and have a sarcoplasmic reticulum that is not very extensive. | smooth |
During a(n) ______ muscle contraction, the muscle either lengthens or shortens, while the tension stays constant. | isotonic |
during high-intensity exercise, anaerobic metabolism results in the production of pyruvic acid, which is then converted to ? acid | lactic |
the layer of connective tissue that most closely surrounds an entire skeletal muscle is called the | epimysium |
During muscle contraction, calcium ions combine with tropomyosin, and this exposes active sites for cross-bridge formation | false |
anaerobic respiration occurs primarily in mitochondria | false |
Liver cells convert lactic acid to ATP | false |
the minimal strength of stimulation needed to elicit a muscle contraction is called the threshold stimulus | True |
if a muscle contracts and its fibers shorten, the contraction is isometric | false |
white muscles have an increased capacity to carry on aerobic respiration | false |
Metabolic processes can use only about 25% of the energy released by cellular respiration | true |
the two major types of smooth muscles are intercalated muscle and cardiac muscle | false |
cardiac muscle is voluntary | false |
muscles and bones function as levers | true |
the masseter muscle functions in mastication | true |
exercise can lead to new muscle filament formation---even in old people | true |