1.0All About Cardiovascular System and Disordershttps://johnsonfrancis.org/professionalJohnson Francishttps://johnsonfrancis.org/professional/author/jf/rich600338<blockquote class="wp-embedded-content" data-secret="X2dBWSkkJS"><a href="https://johnsonfrancis.org/professional/sinus-node-mcq/">Sinus node – MCQ</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://johnsonfrancis.org/professional/sinus-node-mcq/embed/#?secret=X2dBWSkkJS" width="600" height="338" title="“Sinus node – MCQ” — All About Cardiovascular System and Disorders" data-secret="X2dBWSkkJS" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://johnsonfrancis.org/professional/wp-includes/js/wp-embed.min.js </script> Sinus node – MCQ Sinus node is situated at: a) Junction of the superior vena cava and right atrium b) Junction of right atrium and left atrium c) Junction of inferior vena cava and right atrium d) Junction of coronary sinus and right atrium Click here for the correct answer