If the vagal nerves to the heart were cut, the result would be that <\/p>\n\n\n\n
parasympathetic stimulation would increase, causing a decrease in heart rate<\/p>\n\n\n\n
the atrioventricular (AV) ?node would become the pacemaker of the heart<\/p>\n\n\n\n
the heart would stop, since-the vagal nerves trigger the heart to contract<\/p>\n\n\n\n
the heart rate would increase by about 25 ?beats per minute<\/p>\n\n\n\n
The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n The correct answer is: The vagus nerve (cranial nerve X) is a major component of the parasympathetic nervous system and plays a crucial role in regulating heart rate. It primarily innervates the sinoatrial (SA) node<\/strong>, which is the natural pacemaker of the heart. The vagus nerve releases acetylcholine (ACh)<\/strong>, which binds to muscarinic receptors in the heart, leading to a decrease in heart rate<\/strong> (a process known as vagal tone<\/strong>).<\/p>\n\n\n\n If the vagal nerves to the heart were severed, parasympathetic input to the SA node would be lost<\/strong>, and the heart would be left under the influence of the sympathetic nervous system<\/strong>. Since the vagus nerve normally slows down the heart, its removal would increase the resting heart rate<\/strong>.<\/p>\n\n\n\n In a healthy adult, the intrinsic firing rate of the SA node<\/strong> (without parasympathetic control) is about 100 beats per minute (bpm)<\/strong>. However, due to normal vagal tone, the resting heart rate is usually around 75 bpm<\/strong>. When the vagal nerve is cut, the heart rate increases by approximately 25 bpm<\/strong>, bringing it closer to the intrinsic rate of the SA node.<\/p>\n\n\n\n Thus, cutting the vagus nerve results in an increase in heart rate<\/strong> by about 25 bpm<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" If the vagal nerves to the heart were cut, the result would be that parasympathetic stimulation would increase, causing a decrease in heart rate the atrioventricular (AV) ?node would become the pacemaker of the heart the heart would stop, since-the vagal nerves trigger the heart to contract the heart rate would increase by about 25 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-204461","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/204461","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=204461"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/204461\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=204461"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=204461"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=204461"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
“The heart rate would increase by about 25 beats per minute.”<\/strong><\/p>\n\n\n\nExplanation:<\/h3>\n\n\n\n
Effects of Cutting the Vagal Nerve<\/strong><\/h4>\n\n\n\n
Why the Other Options Are Incorrect:<\/strong><\/h4>\n\n\n\n
\n