Archive For The “CCTV” Category

Adaptation to Nephron Loss

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Adaptation to Nephron Loss

To ensure adequate solute, water, and acid-base balance, the surviving nephrons in the diseased kidney must adjust by increasing their filtration and excretion rates. Without such adjustments, patients with chronic renal failure are vulnerable to edema formation and severe volume overload, hyperkalemia, hyponatremia, and azotemia. Thus, during progressive renal disease, sodium balance is maintained by…

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NORMAL VOLUME HOMEOSTASIS

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NORMAL VOLUME HOMEOSTASIS

Protection of extracellular fluid volume is a fundamental characteristic of fluid and electrolyte homeostasis. The homeostatic mechanisms sense changes in the effective circulating volume(ECV). ECV is difficult to define because it is not a measurable and distinct body fluid compartment. ECV relates to the”fullness” and pressure within the arterial tree. Because only 15% of total…

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THE DISTAL NEPHRON

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THE DISTAL NEPHRON

The distal convoluted tubule is a water-impermeable segment of the nephron that continues the dilution of luminal fluid through active sodium chloride absorption. Sodium absorption in the distal nephron occurs primarily by a thiazide diuretic-sensitive, chloride-coupled transport process. The cortical collecting duct reabsorbs sodium by a mineralocorticoid-sensitive process. In states of volume depletion and maximal…

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Common Presenting Complaints

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Common Presenting Complaints

Dyspnea(shortness of breath) is a common complaint of patients with pulmonary disease. Timing and acuity of onset, exacerbating and alleviating factors, and degree of functional impairment are key elements of the history Associated symptoms such as cough, hemoptysis, chest pain, wheezing, orthopnea, and paroxysmal nocturnal dyspnea, as well as environmental triggers, should be elicited and…

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PHYSIOLOGY OF PULMONARY HYPERTENSION

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PHYSIOLOGY OF PULMONARY HYPERTENSION

The pulmonary vasculature is a high-capacity, low-resis-tance system, and it functions under relatively low pressure. The normal pulmonary arterial systolic and mean pressures are less than 30 mm Hg and less than 20 mm Hg, respectively. Diseases of this sys-tem impair gas exchange across the pulmonary alveoli and result in an increase in pulmonary arterial…

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AORTIC DISSECTION

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AORTIC DISSECTION

An aortic dissection is a tear in the aortic intima through which blood enters and subsequently dissects distally along the plane between the intima and media of the vessel, creating a true and false lumen in the aorta. Hypertension and Marian’s syndrome are the most common predisposing factors. Type A disections originate in the ascending…

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ATRIOVENTRICULAR RECIPROCATING ARRHYTHMIAS

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ATRIOVENTRICULAR RECIPROCATING ARRHYTHMIAS

Normally, the AV node is the only pathway that allows the wave of depolarization to conduct from the atria to the ventricles. However, anomalous bands of tissue( accessory pathways or bypass tracts) may exist and form an additional conduction pathway. The conductive properties of these bypass tracts differ from those Av of the node in…

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Nonatherosclerotic Causes of Cardiac Ischemia

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Nonatherosclerotic Causes of Cardiac Ischemia

Although atherosclerosis is by far the most common disease affecting the coronary arteries, it is by no means the only one. Several nonatherosclerotic processes may affect the coronary arteries and produce acute coronary insufficiency. Acute embolization down a coronary artery mia and infarction. The most common sources of such emboli include infectious endocarditis, mural thrombi…

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The death of Ivan Ilych !

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The death of Ivan Ilych !

So Ivan Ilych seventeen years after his marriage. He was al ready a Public Prosecutor of long standing, and had declined several proposed transfers while awaiting a more desirable post, when an unanticipated unpleasant occurrence quite upset the peaceful course of life. He was expecting to be offered the post of presiding judge in a…

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Histories !

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Histories !

The corpus of scholarship on Iranian history and culture is at best uneven, and the field lies open for the enterprising researcher. Many of the historical sources are still unpublished or remain to be located and studied by historians .There are few adequate general works on tranian history, The most recent one is Donald Wilber’s…

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