Physiology Template Past Paper PDF 2024

19, 18 Physiology team Tasneem Jarwan Faisal Mohammad  Blood Pressure Regulation 1 ☆sphygmomanometer : ‫ هو أداة‬،"‫ أو زي ما بنسميه "جهاز الضغط‬،‫جهاز قياس الضغط‬ ‫ الجهاز فيه كُ ّم بنلفّه‬.‫بسيطة بنستخدمها عشان نقيس ضغط الدم‬ ‫ وصمام لتفريغ الهواء‬،‫ ومنفاخ صغي...

19, 18 Physiology team Tasneem Jarwan Faisal Mohammad  Blood Pressure Regulation 1 ☆sphygmomanometer : ‫ هو أداة‬،"‫ أو زي ما بنسميه "جهاز الضغط‬،‫جهاز قياس الضغط‬ ‫ الجهاز فيه كُ ّم بنلفّه‬.‫بسيطة بنستخدمها عشان نقيس ضغط الدم‬ ‫ وصمام لتفريغ الهواء‬،‫ ومنفاخ صغير بننفخ منه الكُ ّم‬،‫على الذراع‬ ‫ بوقف الدم‬،‫ لما ننفخ الكُ ّم‬.‫ ومقياس بيبين لنا القراءة‬،‫شوي شوي‬ ‫ إذا كان الجهاز‬.‫ وبعدين بنبلّش نفتح الصمام ببطء‬،‫بالشريان‬ ‫ بنستخدم السماعة الطبية عشان نسمع صوت الدم وهو‬،‫يدوي‬ ‫ أول صوت بنسمعه هو الضغط‬.‫بيرجع يمر بالشريان‬ ‫ هاد‬،‫ ولما يوقف الصوت‬،) ‫االنقباضي(لما القلب بيضخ الدم‬ ‫ أما األجهزة الرقمية‬.)‫الضغط االنبساطي (لما القلب بيرتاح‬ ‫ فبتعمل كل إشي لحالها وبتعطيك القراءة مباشرة‬، ‫االلكترونية‬ ‫ ملم‬80/120 ‫ الضغط الطبيعي بيكون حوالي‬،‫ عادة‬.‫على الشاشة‬.‫زئبقي‬ Auscultatory method is the most commonly used method for measuring systolic and diastolic pressures.(hearing the sound) When cuff pressure reaches systolic pressure, one begins to hear tapping sounds in the antecubital artery; as the cuff pressure reaches diastolic pressure, one hears muffled sounds and then Korotkoff sounds disappear. Mean arterial pressure can be estimated by adding 40% of systolic pressure to 60% of diastolic pressure. Only the systolic pressure can be measured by sensing the pulsation by hand because when the cuff pressure is above the systolic pressure we can’t hear any pulse, but once it gets under it we will hear the pulse regardless of the pressure, so we can’t know when we’ve reached the diastolic pressure In this figure, the mean pressure is closer to the diastolic pressure MAP = 2/3 DP + 1/3 SP Another equation is: MAP = DP +1/3 PP PP=pulse pressure PP = SP - DP Also wa have : MAP = CO × TPR Arterial Pressure (MAP)can be increased by: Constricting almost all arterioles of the body which increases total peripheral resistance. Constricting large vessels of the circulation thereby increasing venous return and cardiac output. Directly increasing cardiac output by increasing heart rate and contractility. Autonomic Nervous System : How is it important in control of circulation? Sympathetic nervous system is important in control of circulation. Parasympathetic nervous system is important in regulating heart function ▪︎ Sympathetic nerve fibers innervate all vessels except capillaries and precapillary sphincters and some metarterioles. ▪︎ Innervation of small arteries and arterioles allow Parasympathetic nervous sympathetic nerves to increase vascular resistance. system is mainly important in control of heart rate via ▪︎ Large veins and the heart are also sympathetically the vagus nerve innervated. Short term regulation of BP: For any feedback we 3 components. The first component are receptors, the second component is a Control center , the third component is response. For our system to know If the pressure increases or decreases, we need a receptor. 1. Baroreceptors or pressoreceptos (High pressure) 2. Carotid and Aortic Baroreceptors Short-term blood pressure regulation Is controlled by the nervous system, whichh acts quickly. Receptor detect changes in pressure and send signals to adjust heart rate, vessel constriction, and blood flow,.providing a fast response to maintain stability. Baroreceptors (Pressoreceptors) – High Pressure Sensors: Baroreceptors, also known as pressoreceptors, detect changes in blood pressure. They are referred to as high-pressure baroreceptors because they are located in areas of the circulatory system where blood pressure is naturally high. Here’s a clearer explanation of their role and function: Detection of Blood Pressure Changes: Baroreceptors do not directly feel the absolute level of blood pressure. Instead, they sense changes in the stretch of blood vessel walls caused by fluctuations in blood pressure. Locations: 1. Carotid Sinus: Baroreceptors are found in the internal carotid artery, just after it branches from the common carotid artery. These receptors send signals to the cardiovascular center in the brain via Hering’s nerve, a branch of the glossopharyngeal nerve (Cranial Nerve IX). 2. Aortic Arch: Other baroreceptors are located in the arch of the aorta. They transmit information to the cardiovascular center via the vagus nerve (Cranial Nerve X). Central Processing: The signals from these baroreceptors are processed in the cardiovascular center, located in the medulla oblongata of the brainstem. Function: Baroreceptors sense changes in blood pressure and help the cardiovascular center adjust the activity of the autonomic nervous system to maintain stable blood pressure. For example: When blood pressure rises→ baroreceptors increase their signaling. When blood pressure drops→baroreceptor activity decreases. The Vasomotor Center (VMC): The VMC transmits impulses downward through the cord to almost all blood vessels. VMC is located bilaterally in the reticular substance of the medulla and the lower third of the pons. The VMC is composed of a vasoconstrictor area, vasodilator area, and sensory area. Arterial Baroreceptor Reflex: Important in short term regulation of arterial pressure. Reflex is initiated by stretch receptors called baroreceptors or pressoreceptorslocated in the walls of the large systemic arteries. A rise in pressure stretches baroreceptors and causes them to transmit signals to the VMC and feedback signals are sent via the automonic nervous system to the circulation to reduce AP back to normal. ‫ هي زي حساسات صغيرة موجودة بجدران‬،baroreceptors ‫مستقبالت الضغط‬ ‫ والشريان اللي قريب من القلب‬carotid ‫ زي الشريان اللي بالرقبة‬،‫الشرايين الكبيرة‬ ،‫ الشريان بيتمدد‬،‫ لما يرتفع ضغط الدم‬.‫ شغلها إنها تحس بتغيرات ضغط الدم‬.aorta ‫ لمركز‬،‫ وبتبعت إشارات للدماغ‬stretch receptors ‫وهون بتشعر هالحساسات النها‬ ‫ الدماغ على طول بيرد وبيعطي أوامر للقلب إنه‬. vmc ‫اسمه مركز األوعية الدموية‬.‫ وبيخلي الشرايين ترتخي عشان ينخفض الضغط ويرجع للوضع الطبيعي‬،‫يبطئ شوي‬ ‫ ولو ما اشتغلت ممكن‬،‫وجود هالمستشعرات مهم عشان يحافظ على ضغط الدم متوازن‬.‫يصير انخفاض أو ارتفاع مفاجئ يسبب مشاكل زي الدوخة أو حتى خطر على الصحة‬ Response of the Baroreceptors to Arterial Pressure is same to the response of a buffer , so it works best around the MAP (100) , if it increases or decreases around 100 , the impulse rate increases and decreases accordingly. □Carotid sinus baroreceptors respond to pressures between 60 and 180 mmHg. □ Baroreceptors respond to changes in arterial pressure. □ Baroreceptors reflex is most sensitive at a pressure of 100mmHg. □ As pressure increases the number of impulses from carotid sinus increaseswhich results in:1) inhibition of the vasoconstrictor 2) activation of the vagal center Baroreceptor mechanism. ‫زيادة الضغط و نقصان الضغط ف احفظوهم ك خطوات‬: ‫الدكتور مشى عالكالم اللي فالصورة في الحالتين‬  ‫‪Functions of the Baroreceptors‬‬ ‫‪ Maintains relatively constant pressure despite changes in body posture.‬‬ ‫لما الواحد يكون مستلقي وبعدين يوقف فجأة‪ ،‬الدم بينزل لألطراف السفلية بسبب الجاذبية‪ ،‬وهاد الشيء بخلي كمية الدم الراجعة‬ ‫للقلب تقل‪ ،‬فبنخفض ال‪ CO‬وضغط الدم‪.‬هون بيجي دور ال ‪ baroreceptors‬اللي بتحس بانخفاض الضغط وبتبعت إشارات‬ ‫للدماغ‪ ،‬تحديدًا لمركز األوعية الدموية‪. vmc‬الدماغ بسرعة بيشغل الجهاز العصبي ‪ SNS‬اللي بيساعد الجسم يعوض االنخفاض‬ ‫عن طريق تسريع ضربات القلب وتضييق األوعية الدموية باألطراف عشان يرجع الدم لألعضاء الحيوية‪.‬بهالطريقة الجسم بمنع‬ ‫الشعور بالدوخة أو اإلغماء لما نوقف فجأة‬ ‫عند كبار السن‪ ،‬االستجابة بتكون أضعف ألن مستقبالت ال ‪ baroreceptors‬بتقل حساسيتها مع العمر‪ ،‬والجهاز العصبي ما‬ ‫بيشتغل بكفاءة زي قبل‪.‬كمان األوعية الدموية بتصير أقل مرونة بسبب التصلب‪ ،‬وأحيانًا األمراض المزمنة زي السكري والضغط أو‬ ‫األدوية اللي بياخدوها بتزيد الوضع سوء‪.‬فوق هيك‪ ،‬ممكن يعانوا من نقص السوائل أو الجفاف‪ ،‬وهاد كله بخليهم معرضين أكتر‬ ‫للدوخة أو اإلغماء لما يوقفوا فجأة‪ ،‬وهاد بنسميه هبوط الضغط ‪.‬‬ ‫‪Opposes either increases or decreases in arterial pressure thereby reducing daily‬‬ ‫‪variations in arterial pressure.‬‬ ‫‪ They are unimportant in long term control of arterial pressure because the‬‬ ‫‪baroreceptors adapt.‬‬ Effect of Parasympathetic and Sympathetic Nervous Systems on Factors that Influence the Mean Arterial Pressure:. ‫هدول برضة الدكتور شرحهم مباشرة من هون و احفظوهم‬ IMP Note: When the number of impulses from these baroreceptors to the cardiovascular centers, such as the cardiac or vasomotor centers, increases, they inhibit the sympathetic nervous system and stimulate the parasympathetic nervous system. The number of impulses decreases when blood pressure drops because these baroreceptors are stretch receptors that respond to changes in the stretch of blood vessel walls. _____________________________________________________________________ Short-term regulators: (cont’d) ❖ Baroreceptors (low pressure) located at Rt. Atrium, Rt. Ventricle & Pulmonary artery (low pressure areas). They are sensitive to changes in Volume. An increase in volume → increase in venous return → increase in cardiac output → increase in MAP and vice versa. This work through atrial-hypothalamic reflex through stimulating Anti Diuretic Hormone (ADH) (Vasopressin) in case of low BP or inhibiting ADH in case of high BP, this will affect volume and BP through its effect on urine output and on TPR since ADH (Vasopressin) is strong vasoconstrictor.  low-pressure areas in the circulation are located in the right atrium, right ventricle, and pulmonary artery. These areas respond to changes in blood volume, which affect the stretch of their walls. An increase in blood volume stretches these areas and increases venous return. Higher venous return leads to an increase in cardiac output, which raises mean arterial pressure (MAP). To prevent excessive increases in MAP, stretch receptors in the right atrium and right ventricle are activated. When the right atrium stretches, it triggers the right atrial- hypothalamic reflex. This reflex signals the hypothalamus to reduce the secretion of antidiuretic hormone (ADH). ADH normally helps reabsorb water in the kidneys and return it to the extracellular fluid, increasing blood volume. By decreasing ADH secretion, less water is reabsorbed, which reduces blood volume, venous return, cardiac output, and ultimately lowers arterial pressure. When ADH secretion is reduced, water is not reabsorbed from the kidney and instead is excreted in the urine, increasing urine output. ADH, also known as vasopressin, has another function: it causes vasoconstriction, which increases vascular resistance. Therefore, when ADH (vasopressin) levels decrease, vasodilation occurs, leading to a reduction in vascular resistance.” Short term regulators cont: Low pressure baroreceptors work also through affecting the Glomerular Filtration Rate (GFR) in kidney by causing Afferent arteriolar dilation in case of high BP due to high volume or Vasoconstriction in case of low BP due to low volume. Affecting the GFR means affecting the urine volume. This type of low-pressure baroreceptor reflex is called atrio-renal reflex. The atriovenous reflex, triggered by increased stretch in the low-pressure baroreceptors in the right atrium or right ventricle, sends signals to the kidney. This causes vasodilation of the afferent arteriole, the blood vessel supplying the nephron. Vasodilation increases blood flow to the kidney, which raises the glomerular filtration rate (GFR). As a result, more fluid is filtered and excreted in the urine, reducing blood volume and decreasing venous return.  Negative Feedback Regulation of Baroreceptor Reflex A decrease in baroreceptor impulse rate activates the sympathetic nervous system and reduces parasympathetic activity. This leads to an increase in blood pressure. Sympathetic activation causes vasoconstriction, which increases arterial resistance, heart rate, and cardiac contractility, ultimately raising blood pressure. This is the feedback mechanism by which baroreceptors help regulate blood pressure. ____________________________________________________________________ ❖ chemoreceptors: Another short-term regulator of blood pressure Is the chemoreceptors. These are located in the same areas as the high-pressure baroreceptors. Peripheral chemoreceptors are found In the carotid bodies near the carotid bifurcation and In the arch of the aorta Carotid and Aortic Chemoreceptors : Highly Vascular: Chemoreceptors are highly vascularized to ensure they sense chemical concentrations that match arterial.blood :Sensitivity: They are sensitive to.Lack of oxygen (hypoxia).Excess carbon dioxide (hypercapnia).High hydrogen ion concentration (low pH) Activation EffectsActivation of chemosensitive receptors excites the vasomotor center, leading to sympathetic nervous system activation.They do not activate the parasympathetic nervous system Threshold for Activation: Chemoreceptors are not stimulated until blood pressure falls.below 80 mmHg Chemoreceptors are influenced by the partial pressures of oxygen (O₂) and carbon dioxide (CO₂) in the blood, as well as hydrogen ion (H⁺) concentration, which affects pH. These chemicals in the blood are the same as in the interstitial fluid around the chemoreceptors due to their high blood flow. Chemoreceptors in the carotid bodies are supplied by the same nerves as baroreceptors, specifically the 9th cranial nerve (glossopharyngeal), which is assisted by the.vagus nerve. Signals from these receptors are sent to the vasomotor center (VMC) :When blood pressure decreases, blood flow to these areas also decreases, leading to:.Increased CO₂.Decreased O₂.Increased H⁺ concentration, which lowers pH When oxygen levels are high, CO₂ and H⁺ levels decrease, inhibiting chemoreceptor activity. Unlike baroreceptors, which are buffers and respond at a mean arterial pressure (MAP) of about.100 mmHg, chemoreceptors are mainly activated when MAP drops below normal levels A buffer Is a system that maintains stability by responding to changes in its environment. It works best around Its Km (the point at whichh it operates most efficiently). Chemoreceptors function around a pressure of 80 mmHg and are stimulated when the pressure drops slightly below the mean arterial pressure (MAP).  Blood Pressure Regulation 2 Factors affecting Total Peripheral Resistance Total peripheral resistance Is mainly affected by radius and, to a l’sser extent, blood viscosity. Radius: Resistance is Inversely proportional to the radius of the blood vessel raised to the power of 4 (Poiseuille's law). Eve” small changes in radius.significantly affect resistance Viscosity: Blood viscosity is primarily influenced by red blood cells and plasma.proteins Additionally, angiotensin II Is a key vasoconstrictor that Increases resistance.by narrowing blood vessels  ‫الدماغ‪ ،‬وتحديدًا مركز القلب واألوعية‪ ،‬براقب حركة الجسم وضغط الدم عن طريق حساسات معينة بالجسم‪.‬هاي الحساسات بتشمل‬ ‫حساسات الحركة اللي بتحس إذا كنت عم تتحرك أو تبذل جهد‪ ،‬وحساسات الدم اللي بتحس إذا األكسجين قليل أو ثاني أكسيد الكربون زايد‪،‬‬ ‫يسرع ضرباته ويقويها عن طريق‬ ‫وحساسات الضغط اللي بتحس إذا ضغط الدم عالي أو واطي‪.‬الدماغ بعدها بيبعت أوامر للقلب‪ ،‬يا إما ّ‬ ‫األعصاب السمبثاوية إذا كنت بحاجة لطاقة أكتر‪ ،‬أو يخفف ضرباته عن طريق العصب الحائر إذا كنت مرتاح‪.‬هيك الجسم بيحافظ على‬ ‫توازنه حسب اللي بيحتاجه‪.‬‬ ‫‪Least changing‬‬ ‫‪factor in our‬‬ ‫‪body.‬‬  ‫‪Intermediate / Long term Regulation of BP‬‬ ‫لما يصير حادث والمصاب يفقد دم‪ ،‬هذا يعني إنه فقد كمية من الدم اللي بيعمل على تقليل العودة الوريدية (‪ ،)VR‬وبالتالي بينخفض النتاج‬ ‫القلبي (‪ )CO‬والضغط الشرياني المتوسط (‪.)MAP‬هون بيبدأ الجسم يتدخل بسرعة لتنظيم الوضع‪ ،‬وهاي هي اآلليات اللي بتشتغل بالتدريج‪:‬‬ ‫تدخل الباروريسبتور (‪ :)Baroreceptors‬وهي األسرع استجابة‪ ،‬بتحس بانخفاض الضغط وبترسل إشارات للدماغ لتفعيل الجهاز‬ ‫‪.1‬‬ ‫العصبي ال‪.sns‬هذا يؤدي إلى زيادة ضربات القلب وتضييق األوعية الدموية (‪ )vasoconstriction‬لتعويض االنخفاض في‬ ‫الضغط‪.‬إذا نجح هذا النظام خالل أول ‪ 10‬دقائق‪ ،‬بيكون الوضع مستقر‪.‬‬ ‫تدخل الغدة الكظرية ( ‪ :)Adrenal Medulla‬إذا استمر انخفاض الضغط ألكثر من ‪ 10‬دقائق‪ ،‬الغدة الكظرية بتبدأ تفرز اإلبينفرين‬ ‫‪.2‬‬ ‫(‪.)Epinephrine‬اللي بيحتاج شوي زيادة وقت ألنه يتكون من (‪ ،)Tyrosine‬بيعمل على تضييق األوعية الدموية وتقليل النزيف‬ ‫وتحفيز القلب‪.‬‬ ‫ُفرز الـ‪( ADH‬المعروف كـ ‪ )Vasopressin‬من تحت‬ ‫تدخل الهرمون المضاد إلدرار البول (‪ :)ADH‬بعد حوالي ‪ 15‬دقيقة‪ ،‬ي َ‬ ‫‪.3‬‬ ‫المهاد‪.‬وظيفته تقليل فقدان السوائل من الكلى‪ ،‬وزيادة إعادة امتصاص الماء للحفاظ على حجم الدم‪.‬‬ ‫نظام الرينين‪-‬أنجيوتنسين‪-‬ألدوستيرون (‪ :)Renin-Angiotensin-Aldosterone System‬إذا استمر االنخفاض في الضغط‬ ‫‪.4‬‬ ‫يحول بروتين األنجيوتنسينوجين‬‫لفترة أطول (حوالي ساعة)‪ ،‬ينخفض تدفق الدم إلى الكلى‪.‬الكلى تفرز إنزيم الرينين (‪ ،)Renin‬اللي ّ‬ ‫(‪ 14‬حمض أميني)‪ ،‬الذي يُفرز من الكبد‪ ،‬إلى أنجيوتنسين‪ 10( 1-‬أحماض أمينية)‪.‬إذا كان الكبد متضرر‪ ،‬فهذا النظام بيصير غير‬ ‫فعال ألن األنجيوتنسينوجين يتم إنتاجه هناك‪.‬‬ ‫األنجيوتنسين والضغط‪ :‬األنجيوتنسين يُحول الحقًا إلى أنجيوتنسين‪ ،2-‬وهو مركب قوي جدًا يسبب تضييق األوعية الدموية ويحفز‬ ‫‪.5‬‬ ‫إفراز األلدوستيرون‪ ،‬مما يساعد على االحتفاظ بالصوديوم والماء لتعويض نقص الدم‪.‬‬ ‫الزبدة ‪ :‬الجسم بيمتلك أنظمة متتالية ومتكاملة للتعامل مع فقدان الدم‪ ،‬تبدأ بسرعة مع الباروريسبتور‪ ،‬بعدين الغدة الكظرية‪ ،‬وبعدها تدخل أنظمة‬ ‫الهرمونات للحفاظ على ضغط الدم وحجم السوائل‪.‬إذا كان أي جزء من هذه األنظمة معطل (مثل الكبد)‪ ،‬ممكن يفشل الجسم في استعادة‬ ‫التوازن بشكل كامل‪.‬‬ ‫‪In case of continuous blood loss, three systems start working:‬‬ ‫)‪(if baroreceptors didn’t work effectively‬‬ ‫‪1. Epinephrine – Adrenal medulla system, it works as intermediate term and needs‬‬ ‫‪about 10 min to work, causes vasoconstriction. Epinephrine is better than sympathetic‬‬ ‫‪NS because it can reach any vessel unlike the SNS.‬‬ ‫‪2. ADH (vasopressin) system, its needs about 30 min to work, causes‬‬ ‫‪vasoconstriction, also it increases water reabsorption in the kidneys to increase the‬‬ ‫‪blood volume and BP.‬‬ ‫‪3. Renin-Angiotensin-Aldosterone system takes 1 hour to be effective‬‬ ‫‪Angiotensinogen (14 amino acid peptide) is converted into Angiotensin I (10 amino‬‬ ‫‪acid peptide) by Renin that comes from afferent arteriolar cell that supplies the kidney,‬‬ ‫‪the angiotensin I is converted into angiotensin II (8 amino acid peptide) by Angiotensin-‬‬ ‫‪converting enzyme (ACE) that is mainly in the lungs.‬‬ ‫‪Angiotensin II (A II) is the most important vasoconstrictor. A II also stimulates‬‬ ‫)‪,aldosterone synthesis and secretion from the adrenal cortex (Zona glomerulosa‬‬ ‫‪aldosterone goes to the kidney and increases Na+ reabsorption from the renal‬‬ ‫‪nephron and so water. A II is also a positive inotropic agent.‬‬ If the pressure Is not adjusted, the person could go into what Is called decompensatory shock. If this progresses, it can lead to irreversible shock. Shock refers to a significant decrease In blood pressure, resulting In inadequate blood flow to tissues. In the case of Irreversible shock, no matter what interventions are made, the person will not survive. The fourth system here works opposite to the other system. The three systems work in concert together. 4. Atrial Natriuretic peptide (ANP) : ANP is a 28 amino acid peptide released mainly from the Right Atrium in response to stretch. It causes an increase in GFR (Glomerular filtration rate) so it increases Na+ (Natrium) and water excretion to the urine, which decreases blood volume. Its concentration decreases when BP is low and its concentration increases if BP is high, mainly due to blood volume overload. In cases like shock, where blood pressure Is low, ANP secretion decreases becausee the atrium is not stretched. ANP Is only released when the atrium experiences stretch from high blood volume or pressure. 5. CNS Ischemic Response (last chance to survive) ☆ CNS Ischemic response is activated in response to cerebral ischemia. ☆ Reduced cerebral blood flow causes CO2 buildup which stimulates vasomotor center there by increasing arterial pressure. ☆ CNS Ischemic response is one of the most powerful activators of the sympathetic vasoconstrictor system. ☆ CNS Ischemic response is not activated until pressure falls below 60mmHg greatest activation occurs at pressures of 15-20mmHg. ☆ Cushing reaction is a special type of CNS ischemic response. ☆ Prolonged CNS ischemia has a depressant effect on the vasomotor center. ‫ يعني الدم ما عم يوصل للدماغ بشكل كافي بسبب انخفاض تدفق‬،)Brain Ischemia( ‫لما يصير عند الشخص نقص بالتروية الدماغية‬ ‫ كيف؟ بيعمل‬.‫ عشان يحاول يرفع ضغط الدم‬sns ‫ الدماغ بيدخل حالة طوارئ وبيرسل إشارات قوية للجهاز العصبي‬،‫ بهالحالة‬.‫الدم‬ ‫ ألنها‬،)Last Ditch( "‫ هاي االستجابة بنسميها "الفرصة األخيرة‬.‫) بكل مكان بالجسم‬Vasoconstriction( ‫تضييق باألوعية الدموية‬ ‫ ألنها استجابة‬،‫ ملم زئبقي‬60 ‫ بس هاي اآللية ما بتشتغل إال إذا الضغط نزل أقل من‬.‫آخر محاولة ينقذ فيها الجسم الدماغ من التلف‬.‫للطوارئ القصوى‬. Atrial and Pulmonary Artery Reflexes: ◇ Low pressure receptors in atria and pulmonary arteries minimize arterial pressure changes in response to changes in blood volume ◇ Increases in blood volume activates low pressure receptors which in turn lower arterial pressure. ◇ Activation of low-pressure receptors enhances Na+ and water by: 1- Decreasing rate of antidiuretic hormones. 2- Increasing glomerular filtration rate. 3- Decreasing Na+ reabsorption Bainbridge Reflex: ¤ Prevents damming of blood in veins and atria and pulmonary circulation. ¤ Increase in atrial pressure increases heart rate. ¤ Stretch of atria sends signals to VMC via vagal afferents to increase heart rate and contractility. Blood Pressure Regulation Mean Arterial Pressure (MAP) = 1/3 systolic pressure + 2/3 diastolic pressure CO = MAP \TPR. MAP= CO * TPR Renal Body Fluid System for Long Term Arterial Pressure Control: Plays a dominant role in long term pressure control As extracellular fluid volume increases arterial pressure increases The increase in arterial pressure causes the kidneys to lose Na and water which returns extracellular fluid volume to normal Preassure Natriuresis and Diuresis The effect of pressure to increase water excretion is called pressure diuresis The effect of pressure to increase Na excretion is called pressure natriuresis ‫) بتتأقلم‬Baroreceptors( ‫ ألنه‬،‫ لضغط الدم‬long-term regulation ‫ ما إلهم أهمية كبيرة في‬Vasoconstrictors ‫ والـ‬Vasodilators ‫الـ‬ ‫ الجسم بيعتبره الوضع الطبيعي وما بيعمل عليه‬،‫ ملم زئبقي ألكثر من يوم‬150 ‫ لو ظل ضغط الدم‬،ً‫ مثال‬.‫) مع الوضع الجديد وبتعتبره طبيعي‬Adapt(.‫ (حجم السوائل خارج الخلية) ووظيفة الكلى‬ECF volume ‫ الزم نركز على أشياء ثانية زي‬،‫ عشان هيك‬.‫تعديل‬ ‫؟‬Long-Term ‫كيف بتشتغل الكلى في الـ‬.Urine Output ‫ بزيد‬.Blood Pressure ‫ بزيد‬.Cardiac Output (CO) ‫ بزيد‬:‫ لتر من السوائل للجسم‬1 ‫ لو أضفنا‬،ً‫مثال‬ :Short-Term ‫ مقابل‬Long-Term ‫ في‬Gain :‫ وهو عبارة عن‬،‫ هو مقياس لمدى فعالية الجسم في تصحيح الخطأ‬Gain ‫الـ‬.Correction / Error :‫ يعني‬،105 ‫ الباروريسبتورز ممكن ينزلوه لـ‬،120 ‫ وارتفع لـ‬MAP = 100 ‫ إذا كان‬:Baroreceptors ‫بالنسبة للـ‬ Correction = 15.Error = 5.‫ يعني تصحيحهم محدود وضعيف‬،Gain = 15 / 5 = 3 ‫فالـ‬ :ً‫ تقريبا‬100.001 ‫أنظمة الكلى والهرمونات بتقدر تنزل الضغط لـ‬:Chemical and Fluid Regulation ‫بالنسبة للـ‬.Correction = 20.0 ً ‫ = تقريبا‬Error.‫ وهذا يعني إنه تصحيحهم طويل المدى فعال جداً مقارنة بالباروريسبتورز‬،‫ = ال نهائي‬Gain = 20 / 0 ‫فالـ‬ ‫) أكتر من االعتماد‬ECF volume ‫ الجسم بيعتمد على توازن السوائل والكيميائيات (مثل الكلى والـ‬،‫ لتنظيم ضغط الدم على المدى الطويل‬:‫النتيجة‬.‫توسيع األوعية‬/‫على الباروريسبتورز أو تضييق‬ Graphical Analysis of Renal Body Fluid Mechanism: The major determinants of long-term arterial pressure control: 1- Based on renal function curve 2- Salt and water intake line Equilibrium point is where intake and output curves intersect Renal body fluid feedback system has an infinite gain Failure of Total Peripheral Resistance to Elevate Long-term Arterial Pressure: * Changes in TPR does not affect long-term arterial pressure level. * One must alter the renal function curve in order to have long-term changes in arterial pressure. * Changing renal vascular resistance does lead to long-term changes in arterial pressure. ‫ و العكس صحيح بس ال‬CO ‫قلت المقاومه زاد ال‬ ‫اما بال‬، long term ‫ بتضل زي ما هي بال‬MAP ‫ في حاله صار توسع للوعاء بتقل المقاومة‬short Sodium is a Major Determinant of ECFV: ○ As Na+ intake is increased; Na+ stimulates drinking, because increased Na+ concentration stimulates thirst and ADH secretion. ○ Changes in Na+ intake leads to changes in extracellular fluid volume (ECFV). ○ ECFV is determined by the balance of Na+ intake and output. Renin-Angiotensin System □ Renin is synthesized and stored in modified smooth muscle cells in afferent arterioles of the kidney. □ Renin is released in response to a fall in pressure □ Renin acts on a substance called angiotensinogen to form a peptide called angiotensin 1 □ AI is converted to AII by a converting enzyme located in the endothelial cells in the pulmonary circulation.Actions of the Renin Angiotensin System: Causes vasoconstriction Causes Na+retention by direct and Indirect acts on the kidney Causes shift in renal function curve to right Renin Angiotensin System: Effect of Na+ intake: RAS is Important in maintaining a normal AP during changes in Na+intake. As Na+intake is increased renin levels fall to near 0. As Na+intake is decreased renin levels increase significantly. RAS causes the Na+loading renal function curve.to be steep Adrenal Gland as the source of Aldosterone (cortex) and Epinephrine (medulla): Zona ( ‫الطبقة الخارجية من القشرة‬ ‫ هذه الطبقة‬،‫ في الصورة‬:)Glomerulosa ‫موضحة كجزء من القشرة وهي مسؤولة عن إفراز‬ ‫ وهو هرمون يساعد على تنظيم توازن‬،‫األلدوستيرون‬.‫األمالح والماء في الجسم‬ ‫ موضح في الجزء‬:)Medulla( ‫النخاع الكظري‬ ‫ وهو مسؤول عن إفراز‬،‫الداخلي من الغدة بالصورة‬ ‫) والنورإبينفرين‬Epinephrine( ‫اإلبينفرين‬ ‫ وهما هرمونات تساعد الجسم‬،)Norepinephrine(.‫على االستجابة لحاالت الطوارئ والتوتر‬ Juxtaglomerular Apparatus: This is a kidney, vasoconstriction and vasodilation primarily occur in the afferent and efferent arterioles, affecting blood flow.into and out of the glomerulus Juxtaglomerular cells, located In the afferent arterioles of the kidney, release renin when they sense decreased blood pressure Angiotensin primarily influences the.arteriole to control glomerular filtration rate (GFR) ‫تمت كتابة هذا الشيت صدقة جارية عن روح والدة زميلنا عمرو رائد من دفعة تيجان‬ ‫دعواتكم لها بالرحمة والمغفرة‬ ‫‪Thank you‬‬