While the sarcoplasmic reticulum of muscle was first described by nineteenth-century microscopists, its true significance was not ap-preciated until its intricate structure was revealed much later by the electron microscope. What could you tell a nineteenth-century microscopist to enlighten him or her about the structure of the sarcoplasmic reticulum and its role in the coupling of excitation and contraction?

While the sarcoplasmic reticulum of muscle was first described by nineteenth-century microscopists, its true significance was not ap-preciated until its intricate structure was revealed much later by the electron microscope. What could you tell a nineteenth-century microscopist to enlighten him or her about the structure of the sarcoplasmic reticulum and its role in the coupling of excitation and contraction?

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter8: Muscle Physiology

Section: Chapter Questions

Problem 2TAHL

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If you were to watch muscle tissue contract: Under a light microscope, would you see the muscle fibers get narrower, or the striations get thinner? Explain. At the EM level, focusing on one sarcomere, you would be able to see a region of thick filaments overlapping two regions of thin filaments. Use the structure of the thick filaments to explain how ONE region of thick filaments is able to pull in microfilament in two opposite directions (both toward the center of the sarcomere).
Skeletal muscle has several distinct fiber types. Type I is used primarily for aerobic activity, whereas type IIb is specialized for short, intense bursts of activity. How could you distinguish between these types of muscle fiber if you viewed them with an electron microscope?
Skeletal muscle fibres are very metabolically active and are adapted to create a lot of ATP from aerobic cellular respiration. Additionally, cells require other things to stay alive. Explain how the following three organ systems contribute to allowing a muscle cell to carry out its roles: a) Respiratory system b) Cardiovascular system c) Gastrointestinal system asap please.
One of the primary characteristics of all muscle tissue is contractility, the ability to shorten (contract) and lengthen (relax). You've identified the various components of a myofibril above. Now, use the table below to indicate what occurs to each band, line, or zone when the muscle contracts vs. relaxes. What occurs to this region / structure during contraction/relaxation? Region / Structure A-Band H-Band I-Band M-Line Z-Line Zone of Overlap Sarcomere No change Shortens Lengthens Muscle Contraction Muscle Relaxation
The ability of myosin to walk along an actin filament may be observed with the aid of an appropriately equipped microscope. Describe how such assays are typically performed. Why is ATP required in these assays? How can such assays be used to determine the direction of myosin movement or the force produced by myosin?
Can you match the sacromere anatomy with the proper answer from the list below the table graph? Sarcomere Anatomy Description/Reaction Thin Filaments ? Thick Filaments ? A Band ? I Band ? M Line ? H Zone ? Z Disc ? A) G-Actin, F-Actin, Troponin, Tropomyosin B) Myosin C) Bisected by the M Line, this area shows only the thick filaments without any thin filamentous overlap D) The point of origin for myosin filaments found in the center of the sarcomere E) An area in the center of the sarcomere marked by the entire length of the thick filaments F) A space between sarcomeres with the z-disc in the center; this region shows Actin's anchorage points and extension without myosin overlap G) Anchoring point for the thin filaments
Which of the following regions of a sarcomere at rest is characterized by the presence of myosin only? a) A band b) H zone c) I band d) Z line
Contractile bundles occur in nonmuscle cells; these structures are less organized than the sarcomeres of muscle cells. What is the purpose of nonmuscle contractile bundles?
Compare the rate of Ca2+ release from the sarcoplasmic reticulum to the rate of Ca2+ return back to the sarcoplasmic reticulum. Which of the following is true? The rate of ca2+ returns is faster than the rate of ca2+ release The rate of ca2+ release is faster than the rate of ca2+ return Rates of Ca2+ release from and return to the sarcoplasmic reticulum are the same.
Why do skeletal muscle fibers appear striated when viewed through a light microscope?
Fast twitch muscle fibers are characterized by all of the following EXCEPT: a) fatigue resistant O b) direct relationship to the anaerobic energy system O c) rapid contraction O d) used in sprinting
Cardiac and skeletal muscle are both “striated” types of muscle and yet they have very distinct functional characteristics. a) Skeletal muscle functions as discrete motor units and the cardiac muscle works as a functional syncytium. Define the italicized terms in the previous sentence, explain their importance, and describe the cellular features that underlie these functional differences. b) Cardiac muscle exhibits automaticity, while excitation of skeletal muscle is neurogenic. Define the italicized terms and provide a brief explanation of mechanisms underlying each.