{"id":219863,"date":"2025-05-27T05:57:52","date_gmt":"2025-05-27T05:57:52","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=219863"},"modified":"2025-05-27T05:57:55","modified_gmt":"2025-05-27T05:57:55","slug":"excretion-of-dilute-urine-requires","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/27\/excretion-of-dilute-urine-requires\/","title":{"rendered":"Excretion of dilute urine requires"},"content":{"rendered":"\n<p>Excretion of dilute urine requires:<\/p>\n\n\n\n<p>A.<\/p>\n\n\n\n<p>impermeability of the collecting duct to water.<\/p>\n\n\n\n<p>B.<\/p>\n\n\n\n<p>transport of sodium and chloride ions out of the descending loop of Henle.<\/p>\n\n\n\n<p>C.<\/p>\n\n\n\n<p>relative permeability of the distal tubule to water.<\/p>\n\n\n\n<p>D.<\/p>\n\n\n\n<p>the presence of ADH.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Correct Answer: A. Impermeability of the collecting duct to water.<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation <\/h3>\n\n\n\n<p>The ability of the kidneys to produce <strong>dilute urine<\/strong> is essential for maintaining the body\u2019s fluid and electrolyte balance. This process is regulated by the nephron, the functional unit of the kidney, which filters blood and selectively reabsorbs or secretes various substances to concentrate or dilute urine as needed.<\/p>\n\n\n\n<p>To excrete <strong>dilute urine<\/strong>, the kidneys must reabsorb <strong>solutes<\/strong> (such as sodium and chloride ions) while <strong>retaining water in the tubule<\/strong>, ultimately leading to the elimination of a fluid that has <strong>low osmolarity<\/strong> (i.e., is more dilute than plasma).<\/p>\n\n\n\n<p>The <strong>collecting duct<\/strong> plays a crucial role in this process. When the body needs to conserve water, <strong>antidiuretic hormone (ADH)<\/strong> is released, increasing the water permeability of the collecting duct, allowing water to be reabsorbed back into the bloodstream. However, when the body needs to eliminate excess water (i.e., produce dilute urine), <strong>ADH secretion is suppressed<\/strong>. As a result, the <strong>collecting duct becomes impermeable to water<\/strong>, and water remains in the tubular fluid, leading to <strong>dilute urine<\/strong>.<\/p>\n\n\n\n<p>Let\u2019s examine the other options:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>B.<\/strong> Transport of sodium and chloride out of the <em>descending<\/em> loop of Henle is incorrect. The descending limb is permeable to water, not solutes. Solute reabsorption occurs mainly in the <em>ascending<\/em> limb.<\/li>\n\n\n\n<li><strong>C.<\/strong> Permeability of the distal tubule to water would result in water reabsorption, concentrating the urine\u2014opposite of what is required for dilute urine.<\/li>\n\n\n\n<li><strong>D.<\/strong> The <em>presence<\/em> of ADH increases water reabsorption and leads to <strong>concentrated<\/strong> urine, not dilute. For dilute urine, <strong>absence<\/strong> of ADH is needed.<\/li>\n<\/ul>\n\n\n\n<p>Thus, the correct answer is <strong>A<\/strong>, because the <strong>impermeability of the collecting duct to water<\/strong>, due to <strong>lack of ADH<\/strong>, is necessary to retain water in the filtrate and excrete it as <strong>dilute urine<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/05\/learnexams-banner5-41.jpeg\" alt=\"\" class=\"wp-image-219864\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Excretion of dilute urine requires: A. impermeability of the collecting duct to water. B. transport of sodium and chloride ions out of the descending loop of Henle. C. relative permeability of the distal tubule to water. D. the presence of ADH. The Correct Answer and Explanation is: Correct Answer: A. Impermeability of the collecting duct [&hellip;]<\/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-219863","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219863","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=219863"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219863\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=219863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=219863"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=219863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}