{"id":90226,"date":"2025-06-01T10:23:27","date_gmt":"2025-06-01T10:23:27","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=90226"},"modified":"2025-06-01T10:23:27","modified_gmt":"2025-06-01T10:23:27","slug":"which-one-of-the-following-statements-regarding-muscle-contraction-and","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/","title":{"rendered":"Which one of the following statements regarding muscle contraction and"},"content":{"rendered":"

Which one of the following statements regarding muscle contraction and relaxation is correct?<\/p>\n

[amp_mcq option1=”It involves movement of Zn++ ion.” option2=”It involves Ca++ ion of blood.” option3=”It involves release of Ca++ from sarcoplasmic reticulum (SR) and pumping Ca++ back in SR.” option4=”It involves exchange of Na and K.” correct=”option3″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC CAPF – 2018<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nMuscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation.
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\nMuscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.
\n<\/section>\n
\nWhile other ions like Na+ and K+ are crucial for the electrical signaling (action potential) that triggers muscle contraction, and Zn++ is involved in various metabolic processes, the direct mechanism governing the binding and unbinding of myosin to actin, which constitutes the contraction\/relaxation cycle, is primarily regulated by the availability of intracellular Ca++.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following statements regarding muscle contraction and relaxation is correct? [amp_mcq option1=”It involves movement of Zn++ ion.” option2=”It involves Ca++ ion of blood.” option3=”It involves release of Ca++ from sarcoplasmic reticulum (SR) and pumping Ca++ back in SR.” option4=”It involves exchange of Na and K.” correct=”option3″] This question was previously asked in … <\/p>\n

Detailed SolutionWhich one of the following statements regarding muscle contraction and<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1085],"tags":[1114,1117,1328],"class_list":["post-90226","post","type-post","status-publish","format-standard","hentry","category-upsc-capf","tag-1114","tag-biology","tag-skeletal-and-muscle-system","no-featured-image-padding"],"yoast_head":"\nWhich one of the following statements regarding muscle contraction and<\/title>\n<meta name=\"description\" content=\"Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation. Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following statements regarding muscle contraction and\" \/>\n<meta property=\"og:description\" content=\"Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation. Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T10:23:27+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Which one of the following statements regarding muscle contraction and","description":"Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation. Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following statements regarding muscle contraction and","og_description":"Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation. Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T10:23:27+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-regarding-muscle-contraction-and\/","name":"Which one of the following statements regarding muscle contraction and","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T10:23:27+00:00","dateModified":"2025-06-01T10:23:27+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. 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