Vasoconstriction

Participation in disease progression A variety of diseases including stroke, atherosclerosis, diabetes, ischemic heart diseases and neurodegenerative diseases are caused from the disturbances in mitochondrial functions. The production of peroxynitrite occurs either within mitochondria or may achieved from extra mitochondrial compartments. Peroxynitrite inhibits Mn-SOD by nitration (MacMillan-Crow LA and Thompson, 1999) and thus checking the breaking of nearby formed superoxide that further promotes its formation. Peroxynitrite causes toxicity in mitochondria through two mechanisms- either by oxidative reactions directly or by free radical-induced damage involving CO2 that forms CO3− • and NO2• radicals (Radi et al., 2002a, b). This latter reaction is highly feasible in mitochondria due to the CO2 production during decarboxylation reactions in main organelles (Radi et al., 2002a, b). The peroxynitrite also affects tricarboxylic acid cycle by inhibiting aconitase (mitochondrial matrix enzyme) via oxidatively disrupting 4Fe-4S center of the enzyme (Castro et al., 1994; Han et al., 2005) and mitochondrial creatine kinase (mitochondrial intermembrane space enzyme) (Stachowiak et al., 1998). Circulatory shock Circulatory shock is a syndrome of widespread cellular hypoxia, triggered by a systemic alteration of perfusion and delivery and/or utilization of tissue oxygen, eventually causing end-organ dysfunction and death (Kumar et al., 2001). It can be subdivided into 4 distinct…

Reduced heart rate leads to decreased cardiac output so the cardiovascular centre slows the rate of sympathetic impulses which causes vasoconstriction due to decreased sympathetic resistance which causes a decrease of arterial blood pressure. Baroreceptors are quick to counteract the drop in pressure but are slow in the elderly due to slower neural responses. Chemoreceptors monitor changes in chemical composition of blood and are located by the baroreceptors of the carotid sinus and aortic arch.…

Introduction Haemostasis is the ability to stop the flow of blood in an event of external injury or a breach in a reasonably sized vessel within minutes without affecting the rest of blood flow in the body. The haemostasis consists of four main processes vascular response, platelet response, Coagulation and Fibrinolysis. But when haemostasis is not stopped and goes overactive or get activated inappropriately activated can cause thrombosis and few other complications. The first three step in…

a mammal’s face (specifically marine), there is a reduction in heart rate. This correlates to peripheral vasoconstriction, which is a reduced blood flow in the extremities of the mammal. This is known as a splenic blood redistribution, where the blood redistributes to certain essential organs in the body, in this case mainly the heart and the brain. Another effect that is similar to peripheral vasoconstriction is bradycardia. This reflex is characterized by the abnormally slow heart rate, which…

At the SA node of my heart the epinephrine was increasing the autorhythmicity of my pacemaker therefore causing an increase in my heart rate (Genetic Science Learning Center, 2016). The AV node which is located in between the tissues of the heart was making sure that there were normal electrical impulses traveling throughout my heart (McKinley, 2016). On the other hand, this vasodilation was decreasing the general systemic resistance to blood flow. My internal organs were experiencing…

Humans and other mammals have a Diving Response, which can be also known as ‘The Mammalian Dive Response/Reflex. The Diving reflex consists of set of reflexes that are activated when our face is cooled or if we hold our breath. This is a clever psychological mechanism because it enables our bodies to manage and to tolerate a lower level of oxygen in an environment that we do not normally face every day. There are three main changes that occur in our body when our Dive reflex triggers;…

Sleep apnea disrupts specific homeostatic processes of blood pressure, which could eventually lead to heart disease or failure. Hypertension (high blood pressure) represents a failure in homeostasis. Blood pressure acts as a regulated variable for the heart rate. Sleep apnea can cause an imbalance in this variable. The pauses in normal breathing triggers an alarm to initiate vasoconstriction to pump blood to vital organs quickly. Changes to this variable results in the body initiating a…

High blood pressure increases mean arterial pressure, which could damage arteries and lead to further complications to organs if left untreated. The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure and is stimulated in response to hypotension. The kidneys release renin into the bloodstream that combines with angiotensinogen, which is released from the liver. This process produces angiotensin I. Angiotensin I combines with Angiotensin-converting enzyme (ACE) to produce…

myocardium, valves, and pericardium (including tamponade); pulmonary hypertension or massive pulmonary embolism leading to right and left heart failure; impaired venous return (e.g., abdominal compartment syndrome or positive pressure ventilation) B. Systemic vasodilation: sepsis, antihypertensives, afterload reducers, anaphylaxis C. Renal vasoconstriction: hypercalcemia, catecholamines, calcineurin inhibitors, amphotericin B D. Impairment of renal autoregulatory responses: cyclooxygenase…

disease on cardiac mechanics Chronic chest disease may affect right and left ventricular function by changing intrathoracic pressure. Lung hyperinflation may increase RA pressure and subsequent reduction in venous return and RV pre-load (Fessler, 1997). In COPD patients, hyperinflation has been directly correlated with reduced atrial chamber size, global right ventricular dysfunction, and reduced left ventricular filling (Watz et al., 2010). Alveolar hypoxia is a strong…