Heart location

Histamine in the Cardiovascular System. It has been known for many years that histamine is present in sympathetic nerves and has a distribution within the heart that parallels that of norepinephrine (see Epinephrine and norepinephrine). A physiological role for cardiac histamine as a modulator of sympathetic responses is highly plausible (15). A pool of histamine in rat heart located neither in mast cells nor in sympathetic nerves has been demonstrated. The turnover of this metaboHcaHy active pool of histamine appears to be maintained by normal sympathetic activity. 

Connective tissue— A biochemically distinct group of the body s tissues, which provide structural support for other body tissues. Examples of connective tissue include bone and cartilage. Mitral valve—A one way gateway for blood leaving the heart, located at the aorta. 

FIGURE 17.31 Electron micrograph of a dog heart muscle. The terminal cisterna of the SR (TC-SR) is associated with the t-tnbnle (TT) by means of foot strnctnres (FS), forming a dyad junction. ME indicates the location of myofilaments. LT-SR signifies the longitudinal tubule of the SR. (From Fteischer,. S ., and Inni, M., 1989. Amiual Review of Biophysics and. Biophysical Chemisti y 18 333-364.)... 

GLUT4 is a glucose transporter exclusively expressed in tissues with insulin-sensitive glucose uptake (heart, muscle, fat). Under basal conditions, GLUT4 is predominantly located in intracellular vesicles, and is... 

In striated muscles, SR is well developed to surround the myofibrils and is divided into two parts, the terminal cisternae (TC) and longitudinal tubules (LT). TC forms triad (skeletal muscle) or dyad (heart) structure with transverse tubules. The ryanodine receptor is located only in the TC, whereas the Ca2+ pump/SERCA is densely packed in both TC and LT. 

Ritodrine has an effect on beta (p)2-adrenergic receptors, principally those that innervate the uterus. Stimulation of these p2-adrenergic receptors inhibits uterine smooth muscle contractions. The pradrenergic receptors are located in the heart and are not stimulated by ritodrine when administered as prescribed. Ritodrine is used to... 

Many serious health problems result from abnormally located blood clots heart attacks (clots in coronary arteries), pulmonary embolism (clots in the lungs), and peripheral arterial occlusion and deep vein thrombosis (clots in the limbs). Each year heart attacks alone afflict over a million people in the United States, and almost half of them die as a result. 

Cardiovascular Effects. No studies were located regarding cardiovascular effects in humans after inhalation exposure to endosulfan. Routine gross and histopathologic examination of the heart and aorta of rats exposed (nose-only) to concentrations of endosulfan of up to 2 mg/m for 6 hours/day,... 

With regard to epinephrines potential adverse cardiac effects, it is important to remember that in anaphylaxis, the heart is a target organ. Mast cells located between myocardial fibers, in perivascular tissue, and in the arterial intima are activated through IgE and other mechanisms to release chemical mediators of inflammation, including histamine, leukotriene C4, and prostaglandin D2. Coronary artery spasm, myocardial injury, and cardiac dysrhythmias have been documented in some patients before epinephrine has been injected for treatment of anaphylaxis, as well as in patients with anaphylaxis who have not been treated with epinephrine [11, 12]. 

Intravenous or oral doses of a P-blocker should be administered early in the care of a patient with STE ACS, and then oral agents should be continued indefinitely. Early administration of a P-blocker to patients lacking a contraindication within the first 24 hours of hospitalization is a quality care indicator.2,3 In ACS the benefit of P-blockers mainly results from the competitive blockade of P,-adrenergic receptors located on the myocardium. Pi-Blockade produces a reduction in heart rate, myocardial contractility, and blood pressure, decreasing myocardial oxygen demand. As a result of these effects, P-blockers reduce the risk for recurrent ischemia, increase in infarct size and risk of reinfarction, and occurrence of ventricular arrhythmias in the hours and days following MI.39... 

The prostate is a heart-shaped, chestnut-sized organ that encircles the portion of the proximal urethra that is located at the base of the urinary bladder. The prostate produces secretions which are part of the ejaculate. 

The heart is located underneath the sternum and between the lungs. In most adults, it weighs between 250 and 350 grams (0.55-0.77 lb). Its major role is to provide oxygen-rich blood to all organs and areas of the body. As a secondary function, the heart secretes atrial natriuretic factor (ANF), a hormone that regulates blood pressure and volume status. The inability of the heart to pump enough blood to maintain normal body requirements is known as heart failure. Refer to Chapter 3 for more information on heart failure. 

Mineral Oil Hydraulic Fluids. No studies were located regarding cardiovascular effects in humans after inhalation, oral, or dermal exposure to mineral oil hydraulic fluids. In the only animal study available, histopathological examination of the hearts from rats exposed to <1.0 mg/m3 of the water-in-oil emulsion hydraulic fluid Houghto-Safe 5047F for 90 days, 23 hours/day, showed no treatment-related lesions (Kinkead et al. 1991). 

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