{"id":778,"date":"2019-02-24T17:52:58","date_gmt":"2019-02-25T00:52:58","guid":{"rendered":"https:\/\/blogs.ubc.ca\/mrpletsch\/?p=778"},"modified":"2019-02-24T17:53:47","modified_gmt":"2019-02-25T00:53:47","slug":"circulatory-system-part-3-blood-pressure","status":"publish","type":"post","link":"https:\/\/blogs.ubc.ca\/mrpletsch\/2019\/02\/24\/circulatory-system-part-3-blood-pressure\/","title":{"rendered":"Circulatory System Part 3: Blood Pressure"},"content":{"rendered":"<p>Blood pressure <b>is defined as the force of the blood on the walls of the arteries.<\/b><\/p>\n<ul>\n<li>The ventricles can hold ~70ml of blood, therefore during <b>contraction<\/b> that volume is displaced and pushed out to the aorta and further arteries.<\/li>\n<li><b>Due to this, arteries must be<\/b><b> elastic<\/b><b> and have expandable walls<\/b> (more on structure later)<\/li>\n<\/ul>\n<p><iframe loading=\"lazy\" width=\"700\" height=\"394\" src=\"https:\/\/www.youtube.com\/embed\/Ab9OZsDECZw?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>Blood Pressure depends on:<\/p>\n<ol>\n<li><b>Cardiac output<\/b><b> = the amount of blood pumped from the heart each minute.<\/b> \u00a0Cardiac output is determined by multiplying the heart rate by the stroke volume.<\/li>\n<li><b>Stroke volume = the quantity of blood pumped with each heartbeat.<\/b><\/li>\n<\/ol>\n<p>Since the heart is constantly contracting and relaxing (remember our ECG &#8211; T-wave = relaxation of ventricle) the blood pressure is not constant.<\/p>\n<h3><b>Think: When would blood pressure be higher in the arteries?<\/b><\/h3>\n<figure id=\"attachment_779\" aria-describedby=\"caption-attachment-779\" style=\"width: 200px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-779\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/200w.gif\" alt=\"\" width=\"200\" height=\"309\" \/><figcaption id=\"caption-attachment-779\" class=\"wp-caption-text\">Figure 1: Blood pressure changes on arterial walls<\/figcaption><\/figure>\n<p>Blood pressure changes:<\/p>\n<ol>\n<li><b>When the <\/b><b>ventricles contract<\/b><b>, e<\/b><b>lastic connective tissue and smooth muscle in the <\/b><b>walls of the arteries stretch<\/b><b> to accommodate the increase in fluid pressure. <\/b>\u00a0(QRS Complex)\n<ol>\n<li>Higher blood pressure<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<ol start=\"2\">\n<li><b> After, the <\/b><b>arterial walls <\/b><b>recoil<\/b><b> like an elastic band as the heart begins the <\/b><b>relaxation phase<\/b><b>.<\/b> (T-wave)\n<ol>\n<li>The recoil forces help push blood through arterioles toward the tissues.<\/li>\n<li>Lower Blood Pressure<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p>That is why we get <b>two blood pressure readings<\/b> when we use a <b>sphygmomanometer:<\/b><\/p>\n<figure id=\"attachment_780\" aria-describedby=\"caption-attachment-780\" style=\"width: 360px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-780\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.39.46-PM.png\" alt=\"\" width=\"360\" height=\"242\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.39.46-PM.png 360w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.39.46-PM-300x202.png 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><figcaption id=\"caption-attachment-780\" class=\"wp-caption-text\">Figure 2: Blood Pressure Reading<\/figcaption><\/figure>\n<ol>\n<li><b>Systolic Pressure<\/b> (Systole) &#8211; Pressure during ventricular contraction.<\/li>\n<li><b>Diastolic Pressure<\/b> (Diastole) &#8211; Pressure when ventricles are <b>not<\/b> contracting.(Atrial contraction\/ventricle recovery)<\/li>\n<\/ol>\n<figure id=\"attachment_781\" aria-describedby=\"caption-attachment-781\" style=\"width: 640px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-781\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Heart_3_animated.gif\" alt=\"\" width=\"640\" height=\"527\" \/><figcaption id=\"caption-attachment-781\" class=\"wp-caption-text\">Figure 3: Differences between systolic\/diastolic<\/figcaption><\/figure>\n<p><b>Sphygmomanometer &#8211; <\/b><b>An instrument for measuring blood pressure<\/b> (or that thing at safeway). Typically consists of a rubber cuff and mercury on a graduated scale.<\/p>\n<figure id=\"attachment_782\" aria-describedby=\"caption-attachment-782\" style=\"width: 863px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-782\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.41.21-PM.png\" alt=\"\" width=\"863\" height=\"234\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.41.21-PM.png 863w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.41.21-PM-300x81.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.41.21-PM-768x208.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.41.21-PM-552x150.png 552w\" sizes=\"auto, (max-width: 863px) 100vw, 863px\" \/><figcaption id=\"caption-attachment-782\" class=\"wp-caption-text\">Figure 4: Example sphygmomanometer<\/figcaption><\/figure>\n<p>Measuring Blood Pressure with a <b>sphygmomanometer<\/b> :<\/p>\n<ol>\n<li><b>Typically a cuff is placed around the arm to measure pressure on the brachial artery (off of subclavian artery)<\/b><\/li>\n<li>The cuff is pumped to cut off blood flow.<\/li>\n<li>Air is slowed released, allowing blood to move into the artery again. This will measure the <b>systolic pressure<\/b><b>.<\/b><\/li>\n<li>When the cuff relaxes, blood can move into the arteries freely. This allows for the <b>diastolic pressure<\/b> or relaxation period pressure to be measured.<\/li>\n<\/ol>\n<p><em>For more detailed instructions and theory please refer to your &#8220;Blood Pressure and Cardiac Output Lab&#8221;<\/em><\/p>\n<figure id=\"attachment_783\" aria-describedby=\"caption-attachment-783\" style=\"width: 789px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-783\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.07-PM.png\" alt=\"\" width=\"789\" height=\"437\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.07-PM.png 789w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.07-PM-300x166.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.07-PM-768x425.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.07-PM-552x306.png 552w\" sizes=\"auto, (max-width: 789px) 100vw, 789px\" \/><figcaption id=\"caption-attachment-783\" class=\"wp-caption-text\">Figure 5: Breaking down the reading<\/figcaption><\/figure>\n<figure id=\"attachment_784\" aria-describedby=\"caption-attachment-784\" style=\"width: 804px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-784\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.38-PM.png\" alt=\"\" width=\"804\" height=\"465\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.38-PM.png 804w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.38-PM-300x174.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.38-PM-768x444.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.43.38-PM-552x319.png 552w\" sizes=\"auto, (max-width: 804px) 100vw, 804px\" \/><figcaption id=\"caption-attachment-784\" class=\"wp-caption-text\">Figure 6: The Blood Pressure Stages<\/figcaption><\/figure>\n<h3>Blood Pressure: Some Related Health Issues<\/h3>\n<p><b>High Blood Pressure (Hypertension)<\/b> &#8211; Often caused by diet and lifestyle. Stress\/drugs can also lead to period of hypertension (Blood pressure &gt; 140\/90)<\/p>\n<ul>\n<li>Ex.<b> Atherosclerosis <\/b>&#8211; Hardening of arteries due to loss of elasticity. Caused by <b>plaques<\/b> (fatty deposits from digested food).<\/li>\n<\/ul>\n<figure id=\"attachment_785\" aria-describedby=\"caption-attachment-785\" style=\"width: 1000px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-785\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/atherosclerosis.jpg\" alt=\"\" width=\"1000\" height=\"773\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/atherosclerosis.jpg 1000w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/atherosclerosis-300x232.jpg 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/atherosclerosis-768x594.jpg 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/atherosclerosis-552x427.jpg 552w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><figcaption id=\"caption-attachment-785\" class=\"wp-caption-text\">Figure 7: Atherosclerosis<\/figcaption><\/figure>\n<figure id=\"attachment_786\" aria-describedby=\"caption-attachment-786\" style=\"width: 774px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-786\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.46.05-PM.png\" alt=\"\" width=\"774\" height=\"394\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.46.05-PM.png 774w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.46.05-PM-300x153.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.46.05-PM-768x391.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.46.05-PM-552x281.png 552w\" sizes=\"auto, (max-width: 774px) 100vw, 774px\" \/><figcaption id=\"caption-attachment-786\" class=\"wp-caption-text\">Figure 8: Dangerous effects of hypertension<\/figcaption><\/figure>\n<p><b>Low Blood Pressure (Hypotension)<\/b><b> &#8211; Can be negative as well. (Blood Pressure lower than 90\/60)<\/b><\/p>\n<ul>\n<li>Ex. Kidney cannot function without sufficient pressure for filtration.<\/li>\n<\/ul>\n<figure id=\"attachment_787\" aria-describedby=\"caption-attachment-787\" style=\"width: 783px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-787\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.47.22-PM.png\" alt=\"\" width=\"783\" height=\"389\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.47.22-PM.png 783w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.47.22-PM-300x149.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.47.22-PM-768x382.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.47.22-PM-552x274.png 552w\" sizes=\"auto, (max-width: 783px) 100vw, 783px\" \/><figcaption id=\"caption-attachment-787\" class=\"wp-caption-text\">Figure 9: Dangerous effects of hypotension<\/figcaption><\/figure>\n<h3>Blood Pressure Control and Homeostasis<\/h3>\n<p><span style=\"text-decoration: underline;\"><strong>Homeostasis<\/strong> <\/span>&#8211; The movement towards stable conditions\/equilibrium through physiological processes.<\/p>\n<p>(i.e. release of hormones to dilate\/constrict vessels, or to increase\/lower heart rate).<\/p>\n<p>Blood pressure is monitored by the <b>medulla oblongata<\/b><b> in the brainstem<\/b>. (Monitors autonomic or involuntary functions).<\/p>\n<ul>\n<li>Body can <b>dilate (widen) <\/b>arterioles to lower blood pressure (<i>Vasodilation)<\/i><\/li>\n<li>Body can <b>constrict<\/b> (narrow) to raise blood pressure. (<i>Vasoconstriction)<\/i><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_788\" aria-describedby=\"caption-attachment-788\" style=\"width: 207px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-788\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.48.45-PM.png\" alt=\"\" width=\"207\" height=\"269\" \/><figcaption id=\"caption-attachment-788\" class=\"wp-caption-text\">Figure 10: Brain Anatomy<\/figcaption><\/figure>\n<h5>Medulla oblongata control and the <b>autonomic nervous system:<\/b><\/h5>\n<p>Activation of <b>sympathetic nervous system<\/b><b> (<\/b>fight or flight) increased heart rate therefore increase cardiac output and therefore increases blood pressure.<\/p>\n<p>Activation of <b>parasympathetic nervous system <\/b><b>(<\/b>feed and breed) lowers heart rate therefore lowers cardiac output and therefore lowers blood pressure.<\/p>\n<figure id=\"attachment_789\" aria-describedby=\"caption-attachment-789\" style=\"width: 784px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-789\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.50.52-PM.png\" alt=\"\" width=\"784\" height=\"466\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.50.52-PM.png 784w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.50.52-PM-300x178.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.50.52-PM-768x456.png 768w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.50.52-PM-552x328.png 552w\" sizes=\"auto, (max-width: 784px) 100vw, 784px\" \/><figcaption id=\"caption-attachment-789\" class=\"wp-caption-text\">Figure 11: Homeostatic control &#8211; returning raised blood pressure to normal<\/figcaption><\/figure>\n<figure id=\"attachment_790\" aria-describedby=\"caption-attachment-790\" style=\"width: 766px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-790\" src=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.51.15-PM.png\" alt=\"\" width=\"766\" height=\"480\" srcset=\"https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.51.15-PM.png 766w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.51.15-PM-300x188.png 300w, https:\/\/blogs.ubc.ca\/mrpletsch\/files\/2019\/02\/Screen-Shot-2019-02-24-at-4.51.15-PM-552x346.png 552w\" sizes=\"auto, (max-width: 766px) 100vw, 766px\" \/><figcaption id=\"caption-attachment-790\" class=\"wp-caption-text\">Figure 12: Homeostatic control &#8211; returning lowered blood pressure to normal<\/figcaption><\/figure>\n<h3>A Quick Review:<\/h3>\n<ul>\n<li>Blood pressure = force on <b>arterial walls<\/b>. Arterials walls are <b>elastic<\/b> which allow for stretching and contracting during heart contractions.<\/li>\n<li>Systolic Pressure &#8211; Pressure during ventricular contraction (higher!)<\/li>\n<li>Diastolic Pressure &#8211; Pressure during ventricular relaxation (lower!)<\/li>\n<li>Measured with a \u00a0<b>sphygmomanometer &#8211; 120 systolic\/80 diastolic = normal\/ideal.<\/b><\/li>\n<li><b>Blood pressure is regulated by the medulla oblongata. Body tries to keep blood pressure stable and normal. Drugs\/diet\/lifestyle can lead to hypertension (high blood pressure). Hypotension (Low blood pressure) can cause kidney problems among others)<\/b><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p class=\"post-excerpt\">Blood pressure is defined as the force of the blood on the walls of the arteries. The ventricles can hold&#8230;<\/p>\n","protected":false},"author":48401,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1199859],"tags":[],"class_list":["post-778","post","type-post","status-publish","format-standard","hentry","category-biology-12"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/posts\/778","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/users\/48401"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/comments?post=778"}],"version-history":[{"count":2,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/posts\/778\/revisions"}],"predecessor-version":[{"id":792,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/posts\/778\/revisions\/792"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/media?parent=778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/categories?post=778"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/mrpletsch\/wp-json\/wp\/v2\/tags?post=778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}