Cardiac Physiology
The subvalvular apparatus consists of chordae tendineae and the papillary muscles. The chordae tendineae attach to the edges of mitral leaflets or to its ventricular surface. The left ventricle has…
Gas Exchange
Larynx The larynx is a complex structure that lies anterior to the 4th to the 6th cervical vertebra and consists of several muscles, their ligaments, and associated cartilaginous structures (Fig….
Neurophysiology
The impulse travels along the nerve membrane as an action potential. This is entirely mediated by the receptors within the membrane. Indeed, removal of the axoplasm from the nerve fiber…
Circulatory Physiology
Endothelial Function and Regulation of Vascular Tone Endothelial synthesis and release of vasoactive mediators are important elements in the regulation of vascular tone. Substances are released by the endothelium in…
Intravenous Sedatives and Hypnotics
The fact that total body clearance of propofol exceeds hepatic blood flow is consistent with extrahepatic clearance (pulmonary uptake and first-pass elimination, renal excretion) of propofol.14,16 Pulmonary uptake of propofol…
Opioid Agonists and Antagonists
Chemical Structure of Opium Alkaloids The active components of opium can be divided into two distinct chemical classes: phenanthrenes and benzylisoquinolines. The principal phenanthrene alkaloids present in opium are morphine,…
Local Anesthetics
Local anesthetics are poorly soluble in water and therefore are marketed most often as water-soluble hydrochloride salts. These hydrochloride salt solutions are acidic (pH 6), contributing to the stability of…
Sympatholytics
Clinical Uses The principal use of phentolamine is the treatment of acute hypertensive emergencies, as may accompany intraoperative manipulation of a pheochromocytoma or autonomic nervous system hyperreflexia. Administration of phentolamine,…
Metabolism
For adults, total energy expenditure averages 39 kcal/kg in males and 34 kcal/kg in females. Approximately 20 kcal/kg is expended as basal metabolism necessary to maintain integrity of the cell…
Normal Endocrine Function
The pituitary gland lies in the sella turcica at the base of the brain and is connected to the hypothalamus by the pituitary stalk. Physiologically, the gland is outside the…
