This document discusses several cardioprotective reflexes that help regulate cardiac function and maintain homeostasis. It describes the baroreceptor reflex, which monitors changes in blood pressure via receptors in the carotid sinus and aortic arch. It maintains blood pressure through feedback loops involving the vasomotor center in the medulla. Other reflexes discussed are the chemoreceptor reflex, Bainbridge reflex, Cushing's reflex, Bezold-Jarisch reflex, Valsalva maneuver, and oculocardiac reflex. Prevention of adverse effects from these reflexes may involve atropine or lignocaine.
Cardiac reflexes involve afferent and efferent nerve pathways between the heart and central nervous system that help regulate cardiac function and homeostasis. Key reflexes discussed include the baroreceptor reflex, which helps maintain blood pressure, and the Bezold-Jarisch reflex, which causes hypotension, bradycardia, and coronary artery dilation in response to ventricular stimuli. Preventing or treating reflex cardiovascular changes during surgery may involve atropine, local anesthesia, lignocaine infusion, or adjusting anesthesia depth.
The document summarizes the cardiovascular system and regulation of blood pressure. It describes how the brain monitors and controls blood flow and pressure on a beat-to-beat basis to meet metabolic demands. Blood pressure is influenced by cardiac output, peripheral resistance, and blood volume. The document then discusses short term regulation of blood pressure by baroreceptor reflexes, chemoreceptor reflexes, and local mechanisms, as well as long term regulation by the renal-body fluid system including the renin-angiotensin-aldosterone mechanism.
Control of blood pressure involves both immediate and long-term mechanisms. Immediate control is mediated by autonomic reflexes like the baroreceptor reflex which senses changes in blood pressure and regulates sympathetic outflow. Intermediate control involves the renin-angiotensin-aldosterone system and arginine vasopressin. Long-term control is regulated by the kidneys which alter sodium and water balance. Most tissues also autoregulate blood flow by dilating or constricting arterioles in response to pressure and metabolic changes.
This document discusses cardiovascular physiology, including definitions of cardiac output and its determinants like heart rate, contractility, preload, and afterload. It describes the Frank-Starling relationship and how contractility, preload, and the anatomy and physiology of the coronary circulation impact cardiac output. Autoregulation and the control of arterial blood pressure through immediate, intermediate, and long-term mechanisms are examined. Various cardiac reflexes involving the baroreceptor, chemoreceptor, and other reflexes are also outlined.
This document discusses the concepts of blood pressure including systolic, diastolic, and mean arterial pressure. It defines normal blood pressure ranges and factors that can influence blood pressure such as age, sex, body size, emotions, exercise, meals, sleep, and gravity. The relationship between cardiac output, total peripheral resistance, and blood pressure is explained. Mechanisms for short-term blood pressure regulation including baroreceptor reflex, chemoreceptor reflex, and central nervous system ischemic response are outlined. Long-term regulation involves the kidneys, renin-angiotensin system, and pressure natriuresis.
Blood pressure is generated by ventricular contraction and measured in mmHg. It has two components: systolic (maximum pressure) and diastolic (minimum pressure). Blood pressure is regulated through both rapid nervous mechanisms like baroreceptor and chemoreceptor reflexes, and longer-term mechanisms involving blood volume control. Baroreceptors detect changes in blood pressure and stimulate the vasomotor center to increase or decrease sympathetic outflow and heart rate. Chemoreceptors detect chemical changes in blood and stimulate respiratory and cardiovascular responses during hypoxia or hemorrhage.
This document provides an overview of the regulation of circulation and blood pressure. It discusses how blood pressure is controlled through nervous mechanisms like the sympathetic and parasympathetic nervous systems as well as renal-body fluid mechanisms involving the renin-angiotensin system, aldosterone, and ADH. The autonomic nervous system regulates blood pressure through reflexes like the baroreceptor reflex which senses changes in blood pressure and activates sympathetic or parasympathetic responses as needed to maintain normal pressure.
Cardiac reflexes involve afferent and efferent nerve pathways between the heart and central nervous system that help regulate cardiac function and homeostasis. Key reflexes discussed include the baroreceptor reflex, which helps maintain blood pressure, and the Bezold-Jarisch reflex, which causes hypotension, bradycardia, and coronary artery dilation in response to ventricular stimuli. Preventing or treating reflex cardiovascular changes during surgery may involve atropine, local anesthesia, lignocaine infusion, or adjusting anesthesia depth.
The document summarizes the cardiovascular system and regulation of blood pressure. It describes how the brain monitors and controls blood flow and pressure on a beat-to-beat basis to meet metabolic demands. Blood pressure is influenced by cardiac output, peripheral resistance, and blood volume. The document then discusses short term regulation of blood pressure by baroreceptor reflexes, chemoreceptor reflexes, and local mechanisms, as well as long term regulation by the renal-body fluid system including the renin-angiotensin-aldosterone mechanism.
Control of blood pressure involves both immediate and long-term mechanisms. Immediate control is mediated by autonomic reflexes like the baroreceptor reflex which senses changes in blood pressure and regulates sympathetic outflow. Intermediate control involves the renin-angiotensin-aldosterone system and arginine vasopressin. Long-term control is regulated by the kidneys which alter sodium and water balance. Most tissues also autoregulate blood flow by dilating or constricting arterioles in response to pressure and metabolic changes.
This document discusses cardiovascular physiology, including definitions of cardiac output and its determinants like heart rate, contractility, preload, and afterload. It describes the Frank-Starling relationship and how contractility, preload, and the anatomy and physiology of the coronary circulation impact cardiac output. Autoregulation and the control of arterial blood pressure through immediate, intermediate, and long-term mechanisms are examined. Various cardiac reflexes involving the baroreceptor, chemoreceptor, and other reflexes are also outlined.
This document discusses the concepts of blood pressure including systolic, diastolic, and mean arterial pressure. It defines normal blood pressure ranges and factors that can influence blood pressure such as age, sex, body size, emotions, exercise, meals, sleep, and gravity. The relationship between cardiac output, total peripheral resistance, and blood pressure is explained. Mechanisms for short-term blood pressure regulation including baroreceptor reflex, chemoreceptor reflex, and central nervous system ischemic response are outlined. Long-term regulation involves the kidneys, renin-angiotensin system, and pressure natriuresis.
Blood pressure is generated by ventricular contraction and measured in mmHg. It has two components: systolic (maximum pressure) and diastolic (minimum pressure). Blood pressure is regulated through both rapid nervous mechanisms like baroreceptor and chemoreceptor reflexes, and longer-term mechanisms involving blood volume control. Baroreceptors detect changes in blood pressure and stimulate the vasomotor center to increase or decrease sympathetic outflow and heart rate. Chemoreceptors detect chemical changes in blood and stimulate respiratory and cardiovascular responses during hypoxia or hemorrhage.
This document provides an overview of the regulation of circulation and blood pressure. It discusses how blood pressure is controlled through nervous mechanisms like the sympathetic and parasympathetic nervous systems as well as renal-body fluid mechanisms involving the renin-angiotensin system, aldosterone, and ADH. The autonomic nervous system regulates blood pressure through reflexes like the baroreceptor reflex which senses changes in blood pressure and activates sympathetic or parasympathetic responses as needed to maintain normal pressure.
This document discusses cardiac output and the factors that affect it. It defines key terms like stroke volume, minute volume, cardiac index and cardiac reserve. It describes physiological factors like age, gender, exercise and posture as well as pathological factors like fever, anemia and heart failure that can impact cardiac output. The document also covers methods of measuring cardiac output like Fick's principle, dye dilution and thermodilution techniques.
Short-term regulation of blood pressure involves nervous and chemical mechanisms that act within seconds or minutes to control blood pressure. The nervous system regulates blood pressure by changing blood vessel diameter and heart rate through the sympathetic and parasympathetic nervous systems. Baroreceptors in the carotid sinus and aortic arch detect changes in blood pressure and stimulate reflex responses to return blood pressure to normal levels. Chemoreceptors sense oxygen and carbon dioxide levels and stimulate responses to maintain proper gas exchange in the lungs and tissues. If blood pressure drops severely, the brain triggers a central nervous system ischemic response to rapidly constrict blood vessels and raise blood pressure.
This document summarizes cardiovascular system regulation presented by Namungu Rickens. It introduces basic principles like blood flow regulation via pressure differences and vascular resistance. The Frank-Starling relationship and cardiovascular control loop are described. Local short-term regulation occurs via endothelial secretions and long-term via angiogenesis. Cardiac reflexes like the baroreceptor reflex and Bezold-Jarisch reflex maintain homeostasis through neural and humoral responses. The document provides an overview of cardiovascular system regulation at both the local and systemic levels.
This document discusses veins, venous pressure, microcirculation, lymphatics, local blood flow control, arterial blood pressure control, cardiac output regulation, and the coupling of cardiac and vascular function. Key points include that veins act as reservoirs and return 60% of blood to the heart, central venous pressure measures right atrial pressure, the Starling forces that govern capillary filtration, and mechanisms like autoregulation, reactive hyperemia, and baroreceptor reflexes that control local blood flow and arterial pressure.
This document discusses veins, central venous pressure (CVP), microcirculation, lymphatics, local control of blood flow, arterial blood pressure control, cardiac output, and the relationship between the cardiovascular and lymphatic systems. Key points include that 60% of blood is in veins, CVP is measured invasively or noninvasively, capillary filtration is determined by Starling forces, blood flow is regulated locally and through neural and hormonal mechanisms, and cardiac output is determined by stroke volume and heart rate.
1. Blood pressure is regulated through short, intermediate, and long-term control mechanisms. Short-term control is achieved through baroreceptor and chemoreceptor reflexes that sense changes in blood pressure and cardiac output.
2. Intermediate control is provided by the renin-angiotensin system, which causes vasoconstriction. Long-term control involves the renin-angiotensin-aldosterone system and hormones like vasopressin and atrial natriuretic peptide that regulate blood volume and vascular tone.
3. Local control of blood pressure is achieved through the actions of vasodilators like nitric oxide and vasoconstrictors like endothelin and angiotensin
There are three main mechanisms that control arterial blood pressure:
1. Rapid mechanisms act within seconds to minutes through baroreceptor and chemoreceptor reflexes in the medulla to increase or decrease heart rate, cardiac contractility, and peripheral resistance.
2. Intermediate mechanisms act over hours to days through stress relaxation of blood vessels and capillary fluid shifts to regulate blood volume and pressure.
3. Long-term mechanisms act over days to weeks through regulation of extracellular fluid volume by atrial natriuretic peptide, ADH, and the renin-angiotensin system to control blood pressure by altering sodium and water reabsorption in the kidneys.
This document discusses the regulation of blood pressure through short term, intermediate term, and long term mechanisms. Short term regulation occurs within seconds to minutes and involves the baroreceptor reflex, chemoreceptors, central nervous system ischemic response, and atrial stretch receptors. Intermediate term regulation occurs from 30 minutes to hours and involves the renin-angiotensin system, capillary shift mechanism, and stretch relaxation of blood vessels. Long term regulation acts over days to months and is controlled by the renal body fluid control mechanism and aldosterone.
The document discusses the neural regulation of circulation. It covers:
1. Neural control shifts blood flow between different parts of the body as needed, such as more to muscles during exercise.
2. The circulatory system has cardiac and vascular innervation from both the sympathetic and parasympathetic nervous systems which control heart rate, contraction force, and vessel diameter.
3. The brain monitors blood flow and pressure through signals and controls them by altering cardiac output, peripheral resistance, and blood volume through short, intermediate, and long-term mechanisms like baroreceptor reflexes, the renin-angiotensin system, and kidney functions.
1. The autonomic nervous system, specifically the sympathetic nervous system, plays a key role in rapidly controlling arterial pressure through three main mechanisms: constricting arterioles, constricting veins, and enhancing cardiac function.
2. Baroreceptors located in the carotid sinus and aortic arch detect changes in blood pressure and provide feedback signals to reduce pressure through vasodilation and reductions in heart rate and contractility.
3. Additional reflex mechanisms involving chemoreceptors, low pressure receptors, and atrial stretch receptors work to maintain normal arterial pressure and respond to changes in blood volume.
Maintaining homeostatic mean arterial blood pressuredwp_18
This document discusses mechanisms that regulate mean arterial blood pressure in the body. It describes that blood pressure needs to be regulated to maintain homeostasis. Short term mechanisms include baroreceptor and chemoreceptor reflexes which sense pressure changes and regulate heart rate and vessels. The renin-angiotensin-aldosterone system is a long term mechanism that helps regulate blood pressure and fluid balance. Hormones like atrial natriuretic peptide, epinephrine, norepinephrine, and vasopressin also affect blood pressure. The cardiovascular regulatory center integrates input from sensors and coordinates the autonomic nervous system response.
The document summarizes key concepts related to the cardiovascular system, blood pressure, blood flow, and resistance. It discusses how blood pressure is generated by the heart and maintained through a balance of cardiac output, peripheral resistance, and blood volume. The main short-term controls are neural and chemical mechanisms that regulate resistance to keep blood pressure stable. Long-term controls involve the kidneys regulating blood volume. Local blood flow is also autoregulated to meet tissue demands.
This document summarizes cardiac physiology and considerations for anesthesia in cardiovascular diseases. It discusses cardiac reflexes like the baroreceptor reflex and effects of anesthetic agents. It notes that volatile anesthetics decrease heart rate and contractility by reducing calcium entry. For diseases like coronary artery disease, the goal is maintaining a favorable supply-demand relationship. For mitral stenosis, sinus rhythm and avoiding tachycardia are important. Congenital heart diseases require exclusion of air from IV fluids to prevent paradoxical embolism.
Physiological Regulation of Arterial Blood Pressure.pptxKpgu
The document outlines the various mechanisms that regulate arterial blood pressure (ABP), including rapidly-acting nervous system reflexes, intermediate-acting hormone systems, and long-term renal control. It discusses the baroreceptor reflex, which senses changes in blood pressure and activates the sympathetic nervous system to rapidly constrict blood vessels and increase cardiac output. The renin-angiotensin system is an intermediate mechanism where low blood pressure triggers renin release to produce angiotensin II, a vasoconstrictor that also causes sodium retention. In the long-term, the kidneys regulate blood volume and pressure through pressure natriuresis, where higher pressure causes sodium excretion, and the renal control of fluid levels via
The document discusses regional circulations, focusing on coronary, cerebral, and cutaneous circulation. It provides details on the anatomy, blood supply, regulation, and clinical implications of each circulation. For coronary circulation, it describes the blood vessels that supply the heart muscle and how blood flow is regulated to meet myocardial oxygen demands. For cerebral circulation, it outlines the unique anatomical features of the brain's blood supply and factors that control blood flow. For cutaneous circulation, it explains the role of arteriovenous anastomoses and arterioles in regulating heat transfer and sympathetic nervous system control of cutaneous blood flow.
This document summarizes key concepts in cardiovascular physiology presented by Dr. Rashmit Shrestha. It discusses the circulatory system including the heart, blood vessels, and blood. It covers cardiac cycle, ventricular structure and function, factors affecting stroke volume, preload and afterload, contractility, and more. Key contributors to cardiovascular physiology like William Harvey are also acknowledged.
Regulation of blood pressure involves three main mechanisms - short term regulation via nervous mechanisms, intermediate acting physical mechanisms, and long term regulation by the kidneys. The baroreceptor reflex is the most important short term mechanism, maintaining minute to minute regulation. Baroreceptors in the carotid sinus and aorta detect changes in blood pressure and heart contractions. They signal the medulla to increase or decrease sympathetic outflow and heart rate, restoring blood pressure to normal levels. Over time, baroreceptors reset to the prevailing blood pressure. Together these mechanisms tightly control blood pressure within a normal range.
Baroreceptors And Negative Feedback MechanismSulav Shrestha
Baroreceptors are mechanoreceptors located in the carotid arteries and aorta that detect changes in blood pressure. As part of a negative feedback system called the baroreflex, baroreceptors send signals to the brain to increase or decrease heart rate and vascular resistance to maintain normal blood pressure. When blood pressure rises, baroreceptors inhibit the vasomotor center of the brain to decrease sympathetic nervous system activity and lower blood pressure. Conversely, lower blood pressure activates the vasomotor center to increase sympathetic activity and raise blood pressure. In addition to short term regulation, baroreceptors can reset over days to the new blood pressure level in cases of chronic high blood pressure.
Short-term control of blood pressure is mediated by the nervous system and chemicals that regulate peripheral resistance within seconds or minutes. The baroreceptor reflex detects changes in blood pressure and regulates heart rate, stroke volume, and vascular tone to maintain pressure. Chemoreceptors sense oxygen and carbon dioxide levels and stimulate the vasomotor center. If blood flow to the brain decreases severely, the CNS ischemic response triggers powerful vasoconstriction to increase pressure.
This document provides information on the regulation of circulation. It discusses three major types of regulation: neural, humoral, and local. For neural regulation, it describes the innervation of the heart and blood vessels by the sympathetic and parasympathetic nervous systems. It also discusses cardiovascular centers in the brainstem that control blood pressure. For humoral regulation, it outlines vasoconstrictors like epinephrine and angiotensin II, as well as the vasodilator nitric oxide. Finally, it briefly introduces local autoregulation mediated by myogenic activity and chemical factors.
This document discusses cardiac output and the factors that affect it. It defines key terms like stroke volume, minute volume, cardiac index and cardiac reserve. It describes physiological factors like age, gender, exercise and posture as well as pathological factors like fever, anemia and heart failure that can impact cardiac output. The document also covers methods of measuring cardiac output like Fick's principle, dye dilution and thermodilution techniques.
Short-term regulation of blood pressure involves nervous and chemical mechanisms that act within seconds or minutes to control blood pressure. The nervous system regulates blood pressure by changing blood vessel diameter and heart rate through the sympathetic and parasympathetic nervous systems. Baroreceptors in the carotid sinus and aortic arch detect changes in blood pressure and stimulate reflex responses to return blood pressure to normal levels. Chemoreceptors sense oxygen and carbon dioxide levels and stimulate responses to maintain proper gas exchange in the lungs and tissues. If blood pressure drops severely, the brain triggers a central nervous system ischemic response to rapidly constrict blood vessels and raise blood pressure.
This document summarizes cardiovascular system regulation presented by Namungu Rickens. It introduces basic principles like blood flow regulation via pressure differences and vascular resistance. The Frank-Starling relationship and cardiovascular control loop are described. Local short-term regulation occurs via endothelial secretions and long-term via angiogenesis. Cardiac reflexes like the baroreceptor reflex and Bezold-Jarisch reflex maintain homeostasis through neural and humoral responses. The document provides an overview of cardiovascular system regulation at both the local and systemic levels.
This document discusses veins, venous pressure, microcirculation, lymphatics, local blood flow control, arterial blood pressure control, cardiac output regulation, and the coupling of cardiac and vascular function. Key points include that veins act as reservoirs and return 60% of blood to the heart, central venous pressure measures right atrial pressure, the Starling forces that govern capillary filtration, and mechanisms like autoregulation, reactive hyperemia, and baroreceptor reflexes that control local blood flow and arterial pressure.
This document discusses veins, central venous pressure (CVP), microcirculation, lymphatics, local control of blood flow, arterial blood pressure control, cardiac output, and the relationship between the cardiovascular and lymphatic systems. Key points include that 60% of blood is in veins, CVP is measured invasively or noninvasively, capillary filtration is determined by Starling forces, blood flow is regulated locally and through neural and hormonal mechanisms, and cardiac output is determined by stroke volume and heart rate.
1. Blood pressure is regulated through short, intermediate, and long-term control mechanisms. Short-term control is achieved through baroreceptor and chemoreceptor reflexes that sense changes in blood pressure and cardiac output.
2. Intermediate control is provided by the renin-angiotensin system, which causes vasoconstriction. Long-term control involves the renin-angiotensin-aldosterone system and hormones like vasopressin and atrial natriuretic peptide that regulate blood volume and vascular tone.
3. Local control of blood pressure is achieved through the actions of vasodilators like nitric oxide and vasoconstrictors like endothelin and angiotensin
There are three main mechanisms that control arterial blood pressure:
1. Rapid mechanisms act within seconds to minutes through baroreceptor and chemoreceptor reflexes in the medulla to increase or decrease heart rate, cardiac contractility, and peripheral resistance.
2. Intermediate mechanisms act over hours to days through stress relaxation of blood vessels and capillary fluid shifts to regulate blood volume and pressure.
3. Long-term mechanisms act over days to weeks through regulation of extracellular fluid volume by atrial natriuretic peptide, ADH, and the renin-angiotensin system to control blood pressure by altering sodium and water reabsorption in the kidneys.
This document discusses the regulation of blood pressure through short term, intermediate term, and long term mechanisms. Short term regulation occurs within seconds to minutes and involves the baroreceptor reflex, chemoreceptors, central nervous system ischemic response, and atrial stretch receptors. Intermediate term regulation occurs from 30 minutes to hours and involves the renin-angiotensin system, capillary shift mechanism, and stretch relaxation of blood vessels. Long term regulation acts over days to months and is controlled by the renal body fluid control mechanism and aldosterone.
The document discusses the neural regulation of circulation. It covers:
1. Neural control shifts blood flow between different parts of the body as needed, such as more to muscles during exercise.
2. The circulatory system has cardiac and vascular innervation from both the sympathetic and parasympathetic nervous systems which control heart rate, contraction force, and vessel diameter.
3. The brain monitors blood flow and pressure through signals and controls them by altering cardiac output, peripheral resistance, and blood volume through short, intermediate, and long-term mechanisms like baroreceptor reflexes, the renin-angiotensin system, and kidney functions.
1. The autonomic nervous system, specifically the sympathetic nervous system, plays a key role in rapidly controlling arterial pressure through three main mechanisms: constricting arterioles, constricting veins, and enhancing cardiac function.
2. Baroreceptors located in the carotid sinus and aortic arch detect changes in blood pressure and provide feedback signals to reduce pressure through vasodilation and reductions in heart rate and contractility.
3. Additional reflex mechanisms involving chemoreceptors, low pressure receptors, and atrial stretch receptors work to maintain normal arterial pressure and respond to changes in blood volume.
Maintaining homeostatic mean arterial blood pressuredwp_18
This document discusses mechanisms that regulate mean arterial blood pressure in the body. It describes that blood pressure needs to be regulated to maintain homeostasis. Short term mechanisms include baroreceptor and chemoreceptor reflexes which sense pressure changes and regulate heart rate and vessels. The renin-angiotensin-aldosterone system is a long term mechanism that helps regulate blood pressure and fluid balance. Hormones like atrial natriuretic peptide, epinephrine, norepinephrine, and vasopressin also affect blood pressure. The cardiovascular regulatory center integrates input from sensors and coordinates the autonomic nervous system response.
The document summarizes key concepts related to the cardiovascular system, blood pressure, blood flow, and resistance. It discusses how blood pressure is generated by the heart and maintained through a balance of cardiac output, peripheral resistance, and blood volume. The main short-term controls are neural and chemical mechanisms that regulate resistance to keep blood pressure stable. Long-term controls involve the kidneys regulating blood volume. Local blood flow is also autoregulated to meet tissue demands.
This document summarizes cardiac physiology and considerations for anesthesia in cardiovascular diseases. It discusses cardiac reflexes like the baroreceptor reflex and effects of anesthetic agents. It notes that volatile anesthetics decrease heart rate and contractility by reducing calcium entry. For diseases like coronary artery disease, the goal is maintaining a favorable supply-demand relationship. For mitral stenosis, sinus rhythm and avoiding tachycardia are important. Congenital heart diseases require exclusion of air from IV fluids to prevent paradoxical embolism.
Physiological Regulation of Arterial Blood Pressure.pptxKpgu
The document outlines the various mechanisms that regulate arterial blood pressure (ABP), including rapidly-acting nervous system reflexes, intermediate-acting hormone systems, and long-term renal control. It discusses the baroreceptor reflex, which senses changes in blood pressure and activates the sympathetic nervous system to rapidly constrict blood vessels and increase cardiac output. The renin-angiotensin system is an intermediate mechanism where low blood pressure triggers renin release to produce angiotensin II, a vasoconstrictor that also causes sodium retention. In the long-term, the kidneys regulate blood volume and pressure through pressure natriuresis, where higher pressure causes sodium excretion, and the renal control of fluid levels via
The document discusses regional circulations, focusing on coronary, cerebral, and cutaneous circulation. It provides details on the anatomy, blood supply, regulation, and clinical implications of each circulation. For coronary circulation, it describes the blood vessels that supply the heart muscle and how blood flow is regulated to meet myocardial oxygen demands. For cerebral circulation, it outlines the unique anatomical features of the brain's blood supply and factors that control blood flow. For cutaneous circulation, it explains the role of arteriovenous anastomoses and arterioles in regulating heat transfer and sympathetic nervous system control of cutaneous blood flow.
This document summarizes key concepts in cardiovascular physiology presented by Dr. Rashmit Shrestha. It discusses the circulatory system including the heart, blood vessels, and blood. It covers cardiac cycle, ventricular structure and function, factors affecting stroke volume, preload and afterload, contractility, and more. Key contributors to cardiovascular physiology like William Harvey are also acknowledged.
Regulation of blood pressure involves three main mechanisms - short term regulation via nervous mechanisms, intermediate acting physical mechanisms, and long term regulation by the kidneys. The baroreceptor reflex is the most important short term mechanism, maintaining minute to minute regulation. Baroreceptors in the carotid sinus and aorta detect changes in blood pressure and heart contractions. They signal the medulla to increase or decrease sympathetic outflow and heart rate, restoring blood pressure to normal levels. Over time, baroreceptors reset to the prevailing blood pressure. Together these mechanisms tightly control blood pressure within a normal range.
Baroreceptors And Negative Feedback MechanismSulav Shrestha
Baroreceptors are mechanoreceptors located in the carotid arteries and aorta that detect changes in blood pressure. As part of a negative feedback system called the baroreflex, baroreceptors send signals to the brain to increase or decrease heart rate and vascular resistance to maintain normal blood pressure. When blood pressure rises, baroreceptors inhibit the vasomotor center of the brain to decrease sympathetic nervous system activity and lower blood pressure. Conversely, lower blood pressure activates the vasomotor center to increase sympathetic activity and raise blood pressure. In addition to short term regulation, baroreceptors can reset over days to the new blood pressure level in cases of chronic high blood pressure.
Short-term control of blood pressure is mediated by the nervous system and chemicals that regulate peripheral resistance within seconds or minutes. The baroreceptor reflex detects changes in blood pressure and regulates heart rate, stroke volume, and vascular tone to maintain pressure. Chemoreceptors sense oxygen and carbon dioxide levels and stimulate the vasomotor center. If blood flow to the brain decreases severely, the CNS ischemic response triggers powerful vasoconstriction to increase pressure.
This document provides information on the regulation of circulation. It discusses three major types of regulation: neural, humoral, and local. For neural regulation, it describes the innervation of the heart and blood vessels by the sympathetic and parasympathetic nervous systems. It also discusses cardiovascular centers in the brainstem that control blood pressure. For humoral regulation, it outlines vasoconstrictors like epinephrine and angiotensin II, as well as the vasodilator nitric oxide. Finally, it briefly introduces local autoregulation mediated by myogenic activity and chemical factors.
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
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5-hydroxytryptamine or 5-HT or Serotonin is a neurotransmitter that serves a range of roles in the human body. It is sometimes referred to as the happy chemical since it promotes overall well-being and happiness.
It is mostly found in the brain, intestines, and blood platelets.
5-HT is utilised to transport messages between nerve cells, is known to be involved in smooth muscle contraction, and adds to overall well-being and pleasure, among other benefits. 5-HT regulates the body's sleep-wake cycles and internal clock by acting as a precursor to melatonin.
It is hypothesised to regulate hunger, emotions, motor, cognitive, and autonomic processes.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
Mercurius is named after the roman god mercurius, the god of trade and science. The planet mercurius is named after the same god. Mercurius is sometimes called hydrargyrum, means ‘watery silver’. Its shine and colour are very similar to silver, but mercury is a fluid at room temperatures. The name quick silver is a translation of hydrargyrum, where the word quick describes its tendency to scatter away in all directions.
The droplets have a tendency to conglomerate to one big mass, but on being shaken they fall apart into countless little droplets again. It is used to ignite explosives, like mercury fulminate, the explosive character is one of its general themes.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
10 Benefits an EPCR Software should Bring to EMS Organizations Traumasoft LLC
The benefits of an ePCR solution should extend to the whole EMS organization, not just certain groups of people or certain departments. It should provide more than just a form for entering and a database for storing information. It should also include a workflow of how information is communicated, used and stored across the entire organization.
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3. CARDIAC REFLEXES
Cardiac reflexes are fast-acting reflex loops
between the Heart and CNS
Contribute to
- regulation of Cardiac function
- maintenance of Physiologic Homeostasis
Cardiac receptors are linked to the CNS by
myelinated or unmyelinated afferent fibres that
travel along the vagus nerve.
7. Changes in BP are monitored by Circumferential
and Longitudinal stretch receptors located in the
carotid sinus and aortic arch
Respond rapidly to changes in BP , maintain
powerful moment-to-moment control of arterial
pressure
Capable of regulating arterial BP around a preset
value through a Negative-feedback loop
8. BARORECEPTOR REFLEX CONT.
Respond much more to a rapidly changing
pressure than to a stationary pressure
Maintain relatively constant arterial pressure in the
upper body during Changes in Body Posture
Reduce the minute by minute variation in arterial
pressure
Pressure buffer system, Buffer nerves
12. Vasoconstrictor
area
Vasodilator
area
Sensory area
Tractus solitarius
Location Bilaterally
Anterolaterally
Upper medulla
Bilaterally
anterolateral
Lower medulla
Bilaterally
posterolateral
medulla ,lower pons
Neurons
Function
All levels of the
spinal cord,
Excite
sympathetic
nervous system.
Inc. BP
Project upwards
Inhibit
vasoconstrictor
area
Vasodilation
Dec. BP
Receive sensory
signals through the
Vagus and
Glossopharyngeal
nerves
Controls both
vasoconstrictor and
vasodilator areas
13.
14. Increase in MAP
↓
Stretch of BR
↓
Impulses to NTS
↓
Secondarysignals- Inhibit- Vasoconstrictor area
Excite - Vasodilator area
↓
Dec. Symp outflow
Inc. Parasymp outflow
↓
Vasodilatation,Dec HR,Contractility
↓
BP back to normal
15. BARORECEPTOR REFLEX CONT.
Important role during - Acute blood loss
Shock.
volatile anesthetics ( Halothane) inhibit the HR
component of this reflex
Concomitant use of CCB’s, ACE inhibitors, or
PDE inhibitors will lessen the CV response of
raising BP through the baroreceptor reflex
- direct effects on the peripheral vasculature
- interference with CNS signaling pathways
(calcium, angiotensin)
16. BARORECEPTOR RESETTING
Baroreceptor will adapt to the long term change of
blood pressure in 1-3 days
Adaptation makes the baroreceptor system
unimportant for long-term regulation of arterial
pressure
Patients with chronic hypertension often exhibit
perioperative circulatory instability as a result of a
decrease in their baroreceptor reflex response
17. CHEMORECEPTOR REFLEX
Chemosensitive cells located in the carotid bodies and
the aortic body.
Transduce chemical signals into nerve impulse
Each carotid or aortic body is supplied with an abundant
blood flow through a small nutrient artery,so that the
chemoreceptors are always in close contact with arterial
blood
Respond to - changes in pH (H+ ions excess)
- blood oxygen tension lack.
- blood Co2 tension excess
20. CHEMORECEPTOR REFLEX CONT.
Do not respond strongly until BP < 80 mm of Hg.
In the case of Persistent Hypoxia, the CNS will be
directly stimulated, with a resultant increase in
sympathetic activity.
21. CHEMORECEPTOR REFLEX CONT.
Stimulates the respiratory centers and thereby
increasing ventilatory drive
Ventilatory Response to Arterial Hypoximea
- Stimulates breathing when Pao2 <60 mm of Hg
- Inhibited by - Volatile Anaesthetics (0.1 MAC)
- Barbiturates
- Opiods
22. BAINBRIDGE REFLEX
Both the atria and the pulmonary arteries have in
their walls stretch receptors called Low-
pressure receptors.
They are similar to the baroreceptor stretch
receptors of the large systemic arteries
Prevents damming of blood in the Veins, Atria, and
Pulmonary circulation
23. BAINBRIDGE REFLEX CONT.
Increase in right-sided filling pressure
↓
Stretch receptors in
RA wall,CavoAtrial junction SA node(15%)
↓
Vagal afferent signals
↓
Vasomotor center in the medulla
↓
Dec PS tone (40-60%) Inc HR
FOC
24. CNS ISCHEMIC RESPONSE
Arterial pressure elevation in response to cerebral
ischemia
CNS ischemic response is one of the most powerful
of all the activators of the sympathetic
vasoconstrictor system
The degree of sympathetic vasoconstriction caused
by intense cerebral ischemia is often so great that
some of the peripheral vessels become occluded
and kidney caese urine production
25. CNS ISCHEMIC RESPONSE CONT.
Does not become significant until the arterial
pressure < 60 mm Hg and reaching its greatest
degree of stimulation at a pressure of 15 to 20 mm
Hg
Emergency pressure control system that acts
rapidly and very powerfully to prevent further
decrease in arterial pressure whenever blood flow
to the brain decreases dangerously close to the
lethal level.
“Last ditch stand” pressure control mechanism
26. CUSHING REFLEX
Increased intracranial pressure(ICP = MAP)
↓
Cerebral ischemia at the Medullary VMC
↓
initial activation of the SNS
Inc HR, BP, and contractility Inc vascular tone
↓ ↓
improved cerebral perfusion BR reflex
( MAP > ICP)
↓
Reflex Brady
28. BEZOLD-JARISCH REFLEX
Noxious ventricular stimuli ( Dec ventricular filling )
↓
Chemo, Mechano receptors within the LV wall
↓
Unmyelinated vagal afferent type C fibers.
↓
Reflex Inc in PS tone
↓
Triad Hypotension,
Paradoxical Bradycardia (cardioprotective)
Coronary artery dilatation.
29. BEZOLD-JARISCH REFLEX CONT.
Cardioprotective in MI, Thrombolysis or
Revascularization and Syncope
Spinal , Epidural
Less pronounced in patients with Cardiac
hypertrophy or Atrial fibrillation
30. VALSALVA MANEUVER
Forced expiration against a closed glottis
↓
Increased intrathoracic pressure
↓
Venous return, CO and BP will be decreased
↓
BR reflex
↓
Inc HR , Contractility
32. ABDOMINAL COMPRESSION REflEX.
When a BR or CR reflex is elicited, nerve signals
are transmitted simultaneously through skeletal
nerves to skeletal muscles of the body, particularly
to the abdominal muscles.
This compresses all the venous reservoirs of the
abdomen, helping to translocate blood out of the
abdominal vascular reservoirs toward the heart.
As a result , increased quantities of blood are made
available for the heart to pump
33. OCULOCARDIAC REFLEX
Pressure applied to the globe of the eye
Traction on the surrounding structures.
↓
Strech receptors on EOM
↓
Short ,Long ciliary N. ( Ophthalmic – Trigeminal )
↓
Gasserian ganglion
↓
Inc PS tone
↓
Bradycardia.
34. Incidence during opthalmic surgery - 30% to 90%.
Glycopyrrolate or Atropine reduce incidence
35. PREVENTION AND RX
Atropine - most widely used and effective agent
in prevention and Rx of parasympathomimetic
reflex responses.
Topical anaesthesia - can eliminate the reflex at
the afferent component.
I.V Lignocaine is more effective than topical and
attenuates the cardiovascular responses to
noxious stimuli.
Initial loading dose - 100 mg IV
Continous infusion of lignocaine - 2mg / min
36. DURING SX…..
Cessation of the applied stimulus
Increase the depth of anaesthesia.
IV Atropine - 5 – 10 μg/kg
Vasopressors- Persistent hypotension
37. REFERENCES
Guyton and Hall, Textbook of medical
physiology,11th Edition
Miller’s Anaesthesia 8th Edition
Stoelting’s Pharmacolgy nad Physiology in
Anaesthesia Practice 5th Edition
Barash Clinical anaesthesia 7th Edition