Ch.49 - Muscle SystemsSee all chapters
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Ch.1 - Introduction to Biology
Ch.2 - Chemistry
Ch.3 - Water
Ch.4 - Carbon
Ch.5 - Biological Molecules
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Ch.7 - The Membrane
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Ch.9 - Respiration
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Ch.43 - Immune System
Ch.44 - Osmoregulation and Excretion
Ch.45 - Endocrine System
Ch.46 - Animal Reproduction
Ch.47 - Nervous System
Ch.48 - Sensory Systems
Ch.49 - Muscle Systems
Ch.50 - Ecology
Ch.51 - Animal Behavior
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Ch.54 - Ecosystems
Ch.55 - Conservation Biology

Musculoskeletal System

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Musculoskeletal System
Additional Problems
The sarcoplasmic reticulum is a specialized form of ER that surrounds each myofibril. The sarcoplasmic reticulum functions to control cytosolic Ca2+ levels in the muscle cell. Changes in cytosolic Ca2+ concentrations couple action potentials to muscle contraction. The concentration of Ca2+ ions in the sarcoplasmic reticulum is typically much higher than the Ca2+ concentration in the cytosol. This concentration gradient is key to the movement of Ca2+ in the muscle cell in response to an action potential. The cycle diagram below shows the sequence of events that affect Ca2+ levels in a muscle cell, beginning with the propagation of an action potential down a T tubule (top of the diagram). Drag the labels to their appropriate locations on the cycle diagram below. Note that SR stands for sarcoplasmic reticulum.
The interaction between which protein and ion initiates contraction of skeletal muscle?a. troponin; sodium ionsb. myosin; sodium ionsc. tropomyosin; calcium ionsd. troponin; calcium ions
What is the primary function of wave summation?a. prevent muscle fatigueb. increase muscle tensionc. prevent muscle relaxationd. produce smooth, continuous muscle contraction
Drag the labels onto the diagram to label the steps of smooth muscle activation and deactivation.
The cross-bridge cycle starts when _________. select onea. ATP binds to troponin and is hydrolyzed to ADP and Pib. acetylcholine diffuses away from the synaptic cleftc. Ca2+ is actively transported into the sarcoplasmic reticulumd. Ca2+ from the sarcoplasmic reticulum binds to tropomyosine. Ca2+ from the sarcoplasmic reticulum binds to troponin
Cartilage is found ____a. surrounding organs such as the kidneysb. in the heartc. at the ends of bones such as the femurd. covering the surface of your bodye. connecting one bone to another
A skeletal muscle deprived of adequate ATP supplies will ________.a. immediately relaxb. enter a state where actin and myosin are unable to separatec. fire many more action potentials than usual and enter a state of "rigor"d. sequester all free calcium ions into the sarcoplasmic reticulum
Most of the ATP supplies for a skeletal muscle undergoing one hour of sustained exercise come from ________. a. creatine phosphate b. glycolysis c. substrate phosphorylation d. oxidative phosphorylation
The motor unit in vertebrate skeletal muscle refers to ________. a. one actin binding site and its myosin partner b. one sarcomere and all of its actin and myosin filaments c. one myofibril and all of its sarcomeres d. one motor neuron and all of the muscle fibers on which it has synapses
Action potentials in the heart move from one contractile cell to the next via ________.a. chemical synapses using acetylcholineb. chemical synapses using norepinephrinec. intercalated disksd. non-myelinated motor neurons
Connective tissues typically have ________.a. little space between the membranes of adjacent cellsb. the ability to transmit electrochemical impulsesc. the ability to shorten upon stimulationd. relatively few cells and a large amount of extracellular matrix
The venom of cobras contains a mixture of substances that have a variety of physiological effects. One substance in the venom works by preventing acetylcholine from binding to muscle receptors. How does the venom affect the prey of the cobra?a. Action potentials would be continuously generated, causing convulsive muscle contractions.b. Muscle contractions would be prevented, causing paralysis.c. Muscle contractions could still occur, but relaxation of the muscle would be impaired.d. Action potentials would be continuously generated, causing convulsive muscle contractions; muscle contractions would then be prevented, causing paralysis.
An endoskeleton is the primary body support for the ________. a. annelids, including earthworms b. insects, including beetles c. cartilaginous fishes, including sharks d. bivalves, including clams
A ball-and-socket joint connects ________. a. the radius to the ulna b. the radius to the humerus c. the ulna to the humerus d. the humerus to the scapula
Skeletal muscle is capable of which of the following?a. wave summationb. fused tetanusc. autorhythmicityd. wave summation and fused tetanuse. wave summation, fused tetanus and autorhythmicity
Blood is best classified as connective tissue because ________.a. its cells are separated from each other by an extracellular matrixb. it contains more than one type of cellc. its cells can move from place to placed. it is found within all the organs of the body
All types of muscle tissue have ________.a. striated banding patterns seen under the microscopeb. cells that lengthen when appropriately stimulatedc. a response that can be consciously controlledd. interactions between actin and myosin
If cartilage is avascular, how do chondrocytes get nutrients and eliminate waste?
Explain why, during exercise, muscle cells need liver cells for regeneration of glucose from lactate.
Which of the following statements accurately defines sarcoplasmic reticulum?A. a modified smooth endoplasmic reticulum that wraps around the myofibrils and stores calcium ions.B. Dome-shaped muscle located between the thoracic and abdominopelvic cavities.C. Flat muscle over the anterior, superficial abdomen.D. An extension of the sarcolemma that dives into the muscle fiber and surrounds myofibrils.
Define the following terms: (a) absolute refractory period, (b) relative refractory period, (c) compound nerve-action potential, (d) synapse, (e) neuro- myo junction, (f) motor unit, (g) reflex arc.