... I. Factors Involved in Blood Circulation A. Blood Flow - the actual VOLUME of blood moving through a particular site (vessel or organ) over a certain TIME period (liter/hour, ml/min) B. Blood Pressure - the FORCE exerted on the wall of a blood vessel by the blood contained within (millimeters of Mercury; mm Hg) blood pressure = the systemic arterial pressure of large vessels of the body (mm Hg) C. Resistance to Flow (Peripheral Resistance) - the FORCE resisting the flow of blood through a vessel (usually from friction) 1. viscosity - a measure of the "thickness" or "stickiness" of a fluid flowing through a pipe a. V water < V blood < V toothpaste b. water flows easier than blood 2. tube length - the longer the vessel, the greater the drop in pressure due to friction 3. tube diameter - smaller diameter = greater friction D. Relation Between Blood Flow, Pressure, Resistance difference in blood pressure ( P) Blood Flow (F) = peripheral resistance (R) a. increased P -> increased flow b. decreased P -> decreased flow c. increased R (vasoconstriction) -> DECREASED flow d. decreased R (vasodilation) -> INCREASED flow II. Systemic Blood Pressure A. Blood Pressure Near the Heart ...
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...Cardiovascular Responses to Posture and Hydrostatic Pressure Answer to Question# 1: The systolic blood pressure measurement using the auscultation method would be closer to the true value than palpation method. It is due to the use of stethoscope to measure blood pressure in the auscultation method, which is far sensitive than using fingers in the palpation method (i.e. due to her chances of human error during sensing the beats). With it, the auscultation method has the apparatus set parallel to the heart; hence pressure measurements taken are expected to similar to that of the heart and more accurate. Answer to Question# 2: Systolic Pressure – the physiological determinant is the ‘cardiac output’. According to following equation: Cardiac...
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...Renin-Angiotensin-Aldosterone System The renin-angiotensin-aldosterone system, otherwise known as RAAS is a complex hormone system that regulates blood pressure and fluid balance in the human body. When blood volume is low, juxtaglomerular cells in the kidneys activate prorenin, which secretes renin directly into the blood stream circulation. Subsequently, a drop in blood volume additionally releases angiotensinogen from liver, in which renin converts into angiotensin I. Angiotensin I is then converted to angiotensin II through the enzyme angiotensin converting enzyme (ACE) found in the lung. Angiotensin II is a potent biological compound that causes blood vessels to constrict, resulting in an increase in blood pressure. Additionally, angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Furthermore, thirst or antidiuretic hormone can effectively stimulates the pituitary gland, which could release corticotropin-releasing hormone stimulating the adrenal cortex and thereby releasing aldosterone. Aldosterone contributes to the RAAS system by causing the tubules of the kidneys to increase the reabsorption of sodium and water back into the blood stream. Thus, an increase in the reabsorption of water, increases the volume of fluid in the body, which increases the blood pressure. Once the blood volume and blood pressure stabilizes, these collective effects triggers a negative feedback which essentially shutdown the production of renin, effectively decreasing...
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...will increase heart rate, systolic pressure, pulse pressure, but decreases diastolic pressure due to vasodilation of the aorta, and the mean arterial will remain the same. The figures illustrate the effect of exercise for instance figure 1, 3 ,4, and 5 shows an increase in systolic pressure, pulse pressure, heart rate and mean arterial pressure compared to at rest, whereas figure 2 shows a decrease in diastolic pressure due to peripheral vasodilation, which facilitates blood flow to the working muscles. Secondly, during dynamic exercise, the sympathetic branch of the autonomic nervous system start activation. The sympathetic nervous system is responsible for the "fight-or-flight"...
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... Pathophysiology Initiation | * Decreased tissue oxygenation * Decreased intravascular volume * Decreased Myocardial contractility (cardiogenic ) * Obstruction of blood flow (obstructive) * Decreased vascular tone (distributive) * Septic (mediator release) * Neurogenic (suppression of SNS) | No observable clinical indications Decreased CO may be noted with hemodynamic monitoring | Compensatory | * Neural compensation by SNS * Increased HR and Contractiliy * Vasoconstriction * Redistribution of blood flow from nonessential to essential organs * Bronchodilation * Endocrine Compensation (RAAS, ADH, glucocorticoid release) * Renal reabsorption of sodium, chloride, and water * Vasoconstriction * Glycogenolysis | * Increased HR (EXCEPT NEUROGENIC) * Narrowed pulse pressure * Rapid, deep respirations causing respiratory alkalosis * Thirst * Cool,moist skin * Oliguria * Diminished bowel sounds * Restlessness progressing to confsion * Hyperglycemia * Increased specific gravity and decreased creatinine clearance. | Progressive | * Progressive tissue hypoperfusion * Anaerobic metabolism wih lactic acidosis * Failure of sodium potassium pump * Cellular edema | * Dysrhythmias * Decreased BP with narrowed pulse pressure * Tachypnea * Cold, clammy skin * Anuria * Absent bowel sounds * Lethargy progressing to coma * Hyperglycemia * Increase BUN, CREATININE, AND POTASSIUM * Respiratory...
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...balance. The system also helps maintain a close to normal blood volume and blood pressure. “The enzyme renin will be secreted when afferent arteriole’s sense a drop in blood pressure, in response to sympathetic stimulation, and when the macula densa senses decreased numbers of chloride, potassium, and sodium ions” (Shier, Butler, & Lewis, 2012 pg.476). The juxtaglomerular cells will secrete renin (enzyme) in response to the stimuli. Once the renin is secreted and in the bloodstream it acts with the plasma protein angiotensinogen to form angiotensin I. Angiotensin I will act to a second enzyme angiotensin-converting enzyme ACE (in lungs and plasma) will quickly convert to angiotensin II and angiotensin II will stimulate aldosterone from the adrenal glands (Shier, et. al 2012). Why will the body activate the RAAS system? For example when there is a drop in blood pressure in the body the RAAS system will sense the change and secrete renin once activated by the stimuli (drop in blood pressure). Renin binds or acts on angiotensinogen to form angiotensin I and converts to angiotensin II. Angiotensin II will cause vasoconstriction on the efferent arterioles, thus in simple terms will help raise blood pressure. Another aspect is that angiotensin II will act on the kidneys and stimulate the adrenal gland to secret the hormone aldosterone. Aldosterone can reabsorb sodium and water, which can help raise blood pressure. (Shier, et. al, 2012) The three classes of drugs that will...
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...heart failure, the increase in the resistance against which the heart pumps (afterload) further depresses cardiac output. A reduced renal blood flow induces renin secretion and increased plasma aldosterone and angiotensin concentrations. Water and sodium retention increases blood volume causing central venous pressure to increase. These changes overall first help to maintain cardiac output however in the long term they eventually cause morbidity and mortality (BOOK). Treatment of heart failure begins with angiotensin converting enzyme (ACE) inhibitor and as severity increases a diuretic is added which supports the excretion of sodium and water (book). In very severe heart failure, the addition of β-blocker further decreases mortality in patients on ACE inhibitors and diuretics. Valsartan/ Sacubitril is a combination drug approved for use in heart failure. It has a brand name of Entresto and is also previously known as LCZ696....
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...constant conditions within the internal environment of the body in order to sustain health and functioning, despite changes in the external environment. The kidney, a principal regulator of the internal environment of the body, establishes homeostasis by regulating the concentration of ions, water and blood volume, pH balance of plasma, and through the elimination of the waste products of metabolism (Tilley, 2003). The functional unit of the kidney, the nephron, is composed of two key structures: the glomerulus and the renal tubule. The afferent and efferent arterioles supply blood to the glomerulus. As a network of capillaries, the glomerulus acts as a filtering unit by keeping normal proteins and cells in the blood while allowing the filtrate, which contains particles such as ions, sugars, and ammonia, to pass through to the glomerular capsule and exits into the renal tubule (Tilley, 2003). Glomerular filtration is regulated by blood pressure and osmosis. A decrease in blood pressure results in the release of renin by renal juxtaglomerular cells, which is transformed into angiotensin, ultimately causing vasoconstriction. Vasoconstriction results in the increase of blood pressure, thus powering filtration (Ira, 2009). There are four distinct regions of the renal tubule through which the filtrate is modified prior to becoming urine: the proximal convoluted tubule, the loop of Henle, the distal convoluted tubule, and the collecting duct (Crowder, 2010). The proximal convoluted...
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...system. The disease progresses rapidly. It is defined hemodynamically as a mean arterial pressure (mPAP) > 25 mmHg and pulmonary capillary wedge pressure (PCWP) of < 15 mm Hg. PAH is characterized by destructive vascular changes that include: inflammation, vasoconstriction, cell proliferation, hypertrophy and (in severely symptomatic patients) formation of plexiform lesions (Archer, Weir & Wilkins, 2010). Progression of these structural changes eventually leads to right ventricular strain and dysfunction. Within the pulmonary vasculature, three pathways that are known to be involved in pulmonary arterial hypertension include: endothelin, nitric oxide and prostacyclin. These pathways...
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...Isha Kaba Isha Kaba Homestatics Homestatics Contents Introduction 2 Homeostasis 3 Body Temperature 3 Blood Sugar level 3 Water Content 3 Negative Feedback 4 Figure1: flow chart Negative feed back 4 How the body regulates its temperature 4 Conditions: 5 Hot Temperature 5 Cold Temperature 5 The Skin and its function in temperature regulation 5 Figure 2: Downward position of hair. Figure 3: upright position of hair 6 The Brain as a Device for temperature control 6 Figure 4: Hypothalamus 6 Heart rate increase during exercise 7 Temperature 7 Cold 7 Hot 7 Process 7 Vasoconstriction 7 Vasodilation 7 Arterioles 7 Narrows 7 widens 7 Blood flow in skin capillaries 7 Dissipation of heat from the body 7 Reduction 7 Increases 7 Table 1 7 How blood glucose is regulated 8 Table 2 9 Figure 7 9 Reference 9 Introduction Maintaining the body temperature and other related mechanisms sustaining life is essential because the body needs to be in perfect equilibrium. The term equilibrium can be simplified as the stated in which all forces are kept in a balanced state and tis can also be related to the human body. This report is based on the study of the human body and its control system in keeping it at perfect equilibrium hence scientifically termed Homeostasis. Homeostasis Homeostasis can be defined as the body’s ability to maintain a constant internal environment. The internal environment...
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...located? cardiac muscle What does a vegetative state refer to? depression of the RAS and inability to initiate action Which is NOT part of the criteria for a declaration of "brain death"? presence of any head injury What is the best definition of aphasia? inability to comprehend or express language appropriately What is an early indicator of increased intracranial pressure? decreasing responsiveness What is the rationale for vomiting with increased intracranial pressure? pressure on the emetic center in the medulla What is the typical change in blood pressure with increased intracranial pressure? increasing pulse pressure A brain tumor causes a headache because the tumor stretches the meninges and blood vessels wall Which of the following causes papilledema? increased pressure of CSF at the optic disc What is the effect of an enlarging brain abscess on cardiovascular activity? systemic vasoconstriction and slower heart rate As intracranial pressure rises, the pupil of the eye, ipsilateral to the lesion, becomes dilated and unresponsive to light because of the pressure on the: PNS fiber in cranial nerve III Which indicates that CSF is normal? clear and colorless fluid Which is TRUE about malignant brain tumors? primary brain tumors metastasize outside the CNS Which would be the...
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...known as cold-water immersion into their exercise routine (7). Much of the research regarding cold-water immersion is controversial and unclear among researchers. Cold-water immersion protocols remain imprecise with regards to the: duration, timing, temperature, and activity level required. However, much of the physiological response to water immersion is well documented. When immersed inside a tub of water, the force at which water acts upon the immersed body is known as hydrostatic pressure (5). The pressure of the water causes a displacement of fluids in the extremities to the central cavity resulting in an extensive list of physiological benefits. One of the physiological benefits is the displacement of gas, fluid substances, and substrates. Since the human body is comprised of approximately 60% water and water is non-compressible, meaning it occupies the same volume regardless of pressure, (Chaplin, 2005) Gas and fluid substances will naturally move from areas of high pressure to low pressures. Therefore if an athlete is immersed in waist high water, the compressive forces from the water will squeeze the fluids of the lower extremities to the thoracic region like a tube of toothpaste from the bottom up. Thereby removing metabolic waste and substrates from the fatigued muscles in the lower limbs leading to enhanced recovery (5). Although water alone has many therapeutic properties, many of the recovery responses observed from cold-water immersion are temperature dependent...
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...Musculoskeletal response: The short term effects on your muscles include an increase in temperature and metabolic activity. This is the speed at which chemical reactions take place in the body. As a result of this, there is a much greater demand for oxygen because there is an increase of blood supply through the capillary dilation. Once you start to exercise your muscle begin to demand for more oxygen there is also a higher demand of other nutrient like carbohydrates and fats which are need to make adenosine triphosphate (ATP). Your body uses red blood cells to transport oxygen around your body; your blood vessels expand to allow more blood into your muscles more efficiently and quicker. When there is an increase in blood supply blood is being pumped to the working muscle therefore less oxygen is delivered to the organs that do not require it as much. Heat is produced when doing exercise this comes from friction from muscles contractions, when this happens your body carries the heat in the blood to the surface of your skin which is then removed through sweat. The reason why this occurs is because when your body start to heat up enzymes stop working and cells start to cook this can have a massive affecting the body, so heat is then removed using vasodilation. Another musculoskeletal response is an increase in muscle pliability this means your muscles adjusts and are more flexible. The reason why your muscle adjust whilst doing exercise is because your muscles contain lactic...
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...1risk of high blood pressure increases as you age. High blood pressure is more common in males at his 2age. High blood pressure is particularly common among African-Americans, so the fact that K.H. is African American poses a higher risk. His heart rate is normal and the description does not indicate family history of hypertension, but it is noted that K.H is 30 pounds over his ideal weight. Persons who are overweight have a higher risk of developing hypertension. Due to the fact that K.H. has been placed on a salt restricted diet, it is safe to assume that he was consuming high amounts of sodium in his diet prior, which is a primary risk factor of hypertension. K.H.âs has a systolic pressure is 135 and the diastolic pressure is 96. This is stage 1 hypertension. The rationale for treating the patient with an ACE inhibitor is that Angiotensin II needs to be controlled because that is what ultimately is narrowing the blood vessels and causing the blood pressure to increase. An ACE inhibitor slows the production of Angiotensin II. The mechanism of action includes the modification of the production of Angiotensin II. This is a vasoconstrictor. Vasoconstriction is what leads to the elevation of B/P. Angiotensin II is made from angiotensin I through the means of the angiotensin converting enzyme. ACE inhibitors impede the activity of the enzyme ACE and this leads to the decrease in production of angiotensin II. Consequently, you have vasodilation and blood pressure is...
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...Hypertension Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure. Hypertension is the consistent elevation of systemic arterial blood pressure. It is also the most common primary diagnosis in the United States (Brashers, 2010). It is one of the most common worldwide diseases afflicting humans. Because of the associated morbidity and mortality and the cost to society, hypertension is an important public health challenge. Over the past several decades, extensive research, widespread patient education, and a concerted effort on the part of health care professionals have led to decreased mortality and morbidity rates from the multiple organ damage arising from years of untreated hypertension. I. Prevalence of disease (in US) and risk factors Hypertension is a major U.S. health problem affecting some 50 million individuals. Approximately 65% of Americans older than age 60 have hypertension. Of those diagnosed with hypertension, over 30% do not have their hypertension adequately treated and controlled. Ninety to ninety-five percent of hypertension is idiopathic and called primary hypertension. Five to ten percent of hypertension is the result of an identifiable etiologic cause and is called secondary hypertension. According to Center of Disease Control (CDC) the prevalence of hypertension, 45.3% had been treated...
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